[Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)


James Alton
 

I have always avoided the chemical strippers myself due to concerns of short and long term damage to the gel coat.  The stuff goes into any cracks in the gel coat and can get into the laminate and or into any voids under the gel coat which is not a good thing.   The suggestion that was made to use a good sharp scrapper is IMO a good way to go,  just take your time.  As was also suggested, go with the carbide blades.  The Bahco 660 or 665 scrapper works well for me,  you can find these on Amazon.  You can also sand it off with a dustless system or use this as a follow up to the scrapping.  Definitely avoid using a heat gun as it is just too easy to craze the gel coat. 

Best of luck,

James Alton
SV Sueno,  Maramu #220
Sardinia,  Italy

On Jan 15, 2017, at 1:11 PM, santorinlo18@... [amelyachtowners] <amelyachtowners@...> wrote:


Hi Forum, Just about to scrap bottom - is sand blasting good method? seen the end result - looks neat but rough compare to manual. Not sure if good or bad, however, about 50% cost compare to manual + chemical. Any experiences or view




Patrick McAneny
 

I have been thinking I would like to get rid of all the layers of bottom paint. I was wondering about chemical stripers , if they work and how well. Seems like you may run the risk of scratching the gel coat scraping , is that a concern and how wide of a scraper would you use. I got a quote of almost $3000. to sandblast, more than I expected , being a one day job , but if it saves ten days of scraping ... Just wondering what others have done. Also wondering how one deals with the bottom of the keel only a couple of inches off the ground and resting on blocking.
Pat SM#123


-----Original Message-----
From: James Alton lokiyawl2@... [amelyachtowners] <amelyachtowners@...>
To: amelyachtowners
Sent: Sun, Jan 15, 2017 8:16 pm
Subject: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 
I have always avoided the chemical strippers myself due to concerns of short and long term damage to the gel coat.  The stuff goes into any cracks in the gel coat and can get into the laminate and or into any voids under the gel coat which is not a good thing.   The suggestion that was made to use a good sharp scrapper is IMO a good way to go,  just take your time.  As was also suggested, go with the carbide blades.  The Bahco 660 or 665 scrapper works well for me,  you can find these on Amazon.  You can also sand it off with a dustless system or use this as a follow up to the scrapping.  Definitely avoid using a heat gun as it is just too easy to craze the gel coat. 

Best of luck,

James Alton
SV Sueno,  Maramu #220
Sardinia,  Italy

On Jan 15, 2017, at 1:11 PM, santorinlo18@... [amelyachtowners] <amelyachtowners@...> wrote:


Hi Forum, Just about to scrap bottom - is sand blasting good method? seen the end result - looks neat but rough compare to manual. Not sure if good or bad, however, about 50% cost compare to manual + chemical. Any experiences or view



Ann-Sofie Svanberg <kanalmamman@...>
 

We used a paint remover in 2013, it didn’t save any time maybe some effort. But it was a really relly messy job that we don’t recomend anyone to do. You have to have wear a full Water proof protection to not be hurt, you have to use tons of Water to washit away with, not only from the hull but even from the ground as the solutions is high corrosive. It you don’t wash the ground properly dogs or cats or other animal can get their pawn really bad damaged. We didn’t have this full body waterproof coverage and got some nasty burns where the raincoat didn’t cover.
Also you have to have the right temperature. If it is to hot the solution dries out and do the work. We hade to cover with adhesive plastic film to keep the moisture. As I said really really messy.

 

We had the work re-done in Trinidad, scraped down to the gelcoat and then new paint. I belive that we paid about 2500 USD for it. And it was done manualy.

 

Regards

Ann-Sofie

 

Skickades från E-post för Windows 10

 

Från: Patrick Mcaneny sailw32@... [amelyachtowners]
Skickat: den 16 januari 2017 14:38
Till: amelyachtowners@...
Ämne: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 

 

I have been thinking I would like to get rid of all the layers of bottom paint. I was wondering about chemical stripers , if they work and how well. Seems like you may run the risk of scratching the gel coat scraping , is that a concern and how wide of a scraper would you use. I got a quote of almost $3000. to sandblast, more than I expected , being a one day job , but if it saves ten days of scraping ... Just wondering what others have done. Also wondering how one deals with the bottom of the keel only a couple of inches off the ground and resting on blocking.
Pat SM#123


-----Original Message-----
From: James Alton lokiyawl2@... [amelyachtowners]
To: amelyachtowners
Sent: Sun, Jan 15, 2017 8:16 pm
Subject: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 
I have always avoided the chemical strippers myself due to concerns of short and long term damage to the gel coat.  The stuff goes into any cracks in the gel coat and can get into the laminate and or into any voids under the gel coat which is not a good thing.   The suggestion that was made to use a good sharp scrapper is IMO a good way to go,  just take your time.  As was also suggested, go with the carbide blades.  The Bahco 660 or 665 scrapper works well for me,  you can find these on Amazon.  You can also sand it off with a dustless system or use this as a follow up to the scrapping.  Definitely avoid using a heat gun as it is just too easy to craze the gel coat. 

Best of luck,

James Alton
SV Sueno,  Maramu #220
Sardinia,  Italy

On Jan 15, 2017, at 1:11 PM, santorinlo18@... [amelyachtowners] <amelyachtowners@...> wrote:


Hi Forum, Just about to scrap bottom - is sand blasting good method? seen the end result - looks neat but rough compare to manual. Not sure if good or bad, however, about 50% cost compare to manual + chemical. Any experiences or view



Steve Lawson <lawson911@...>
 

I did my bottom a few years ago, and my current boat is a Dufour 39 ( working my way up to an Amel ). It's a dirty, rotten, time consuming job, that you may do once, but will never repeat. Sandblasting is old school, the latest and greatest is soda blasting, which does a great job, is environmentally friendly, and is easier on the hull than sandblasting.
Cheers

On Jan 16, 2017, at 9:31 AM, Patrick Mcaneny sailw32@... [amelyachtowners] <amelyachtowners@...> wrote:

 

I have been thinking I would like to get rid of all the layers of bottom paint. I was wondering about chemical stripers , if they work and how well. Seems like you may run the risk of scratching the gel coat scraping , is that a concern and how wide of a scraper would you use. I got a quote of almost $3000. to sandblast, more than I expected , being a one day job , but if it saves ten days of scraping ... Just wondering what others have done. Also wondering how one deals with the bottom of the keel only a couple of inches off the ground and resting on blocking.
Pat SM#123


-----Original Message-----
From: James Alton lokiyawl2@... [amelyachtowners] <amelyachtowners@...>
To: amelyachtowners <amelyachtowners@...>
Sent: Sun, Jan 15, 2017 8:16 pm
Subject: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 
I have always avoided the chemical strippers myself due to concerns of short and long term damage to the gel coat.  The stuff goes into any cracks in the gel coat and can get into the laminate and or into any voids under the gel coat which is not a good thing.   The suggestion that was made to use a good sharp scrapper is IMO a good way to go,  just take your time.  As was also suggested, go with the carbide blades.  The Bahco 660 or 665 scrapper works well for me,  you can find these on Amazon.  You can also sand it off with a dustless system or use this as a follow up to the scrapping.  Definitely avoid using a heat gun as it is just too easy to craze the gel coat. 

Best of luck,

James Alton
SV Sueno,  Maramu #220
Sardinia,  Italy

On Jan 15, 2017, at 1:11 PM, santorinlo18@... [amelyachtowners] <amelyachtowners@...> wrote:


Hi Forum, Just about to scrap bottom - is sand blasting good method? seen the end result - looks neat but rough compare to manual. Not sure if good or bad, however, about 50% cost compare to manual + chemical. Any experiences or view



christian alby <calbyy@...>
 

 we did clean the hull of our 1982 Maramu april 2016 using cryogenic blasting; quite common now in the industry in Europe.
- boat had been in water since april 2014, unused since april 2015, growing weeds by the bushel & great farm for oysters & mussels -

Cryogenic blasting uses CO2 gas to produce carbonic dry ice pellets blasted on the hull at low air pressure; no dirt or pollution and less agressive on gel coat resins.
cleaned all layers of antifouling paint which had been splattered on during ? ages (no record of maintenance when we boughht the boat 2016) ?
went down to gel coat layers & left them clean to survey the hull and dry out before laying on new protection (époxy coating) underwater.
reasonable price (Euros 2K Euros for a speedy process - took 4 hours (setting up, work & dismantling apparatus) to team of 2 to clean the bottom hull of the Maramu.

If available in your corner of the Oceans, I would recommend that you check industrial cleaning companies for the service - search companies or small operators working for metal, housing (front coatings), wood, stone cleaning using low pressure compressors.

Worth the cost when you gain another 10 to 15 years of trouble free hull & the extra speed from a clean & smooth hull.

fair winds & clean hulls

christian alby, Maramu Désirade VIII, Canet/roussillon





De : "Steve Lawson lawson911@... [amelyachtowners]" <amelyachtowners@...>
À : amelyachtowners@...
Envoyé le : Lundi 16 janvier 2017 16h34
Objet : Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 
I did my bottom a few years ago, and my current boat is a Dufour 39 ( working my way up to an Amel ). It's a dirty, rotten, time consuming job, that you may do once, but will never repeat. Sandblasting is old school, the latest and greatest is soda blasting, which does a great job, is environmentally friendly, and is easier on the hull than sandblasting.
Cheers

On Jan 16, 2017, at 9:31 AM, Patrick Mcaneny sailw32@... [amelyachtowners] <amelyachtowners@...> wrote:

 
I have been thinking I would like to get rid of all the layers of bottom paint. I was wondering about chemical stripers , if they work and how well. Seems like you may run the risk of scratching the gel coat scraping , is that a concern and how wide of a scraper would you use. I got a quote of almost $3000. to sandblast, more than I expected , being a one day job , but if it saves ten days of scraping ... Just wondering what others have done. Also wondering how one deals with the bottom of the keel only a couple of inches off the ground and resting on blocking.
Pat SM#123


-----Original Message-----
From: James Alton lokiyawl2@... [amelyachtowners] <amelyachtowners@...>
To: amelyachtowners <amelyachtowners@...>
Sent: Sun, Jan 15, 2017 8:16 pm
Subject: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 
I have always avoided the chemical strippers myself due to concerns of short and long term damage to the gel coat.  The stuff goes into any cracks in the gel coat and can get into the laminate and or into any voids under the gel coat which is not a good thing.   The suggestion that was made to use a good sharp scrapper is IMO a good way to go,  just take your time.  As was also suggested, go with the carbide blades.  The Bahco 660 or 665 scrapper works well for me,  you can find these on Amazon.  You can also sand it off with a dustless system or use this as a follow up to the scrapping.  Definitely avoid using a heat gun as it is just too easy to craze the gel coat. 

Best of luck,

James Alton
SV Sueno,  Maramu #220
Sardinia,  Italy

On Jan 15, 2017, at 1:11 PM, santorinlo18@... [amelyachtowners] <amelyachtowners@...> wrote:


Hi Forum, Just about to scrap bottom - is sand blasting good method? seen the end result - looks neat but rough compare to manual. Not sure if good or bad, however, about 50% cost compare to manual + chemical. Any experiences or view





amelforme
 

Misters Alby and Lawson give very good and correct advice on stripping the bottom of old paint buildup. While sand blasting is a fast and relatively cheap way to remove old paint, it more often than not has disastrous side effects.

 

Here is why. Sand is not only very hard, but the grains are not uniform in size. This is a bad combination. High pressure air accelerates the pieces of sand from the nozzle that the operator holds in his hands. The trouble is, the different sized grains also have different mass/weight and get accelerated to vastly different speeds because of this. The higher speed sand projectiles easily penetrate deeper into the laminate than you might ever imagine, especially in areas where the gel coat gets thin or removed by the process. Even the best anti-osmosis coatings that you might apply are not totally waterproof/vapor proof. This fact, in conjunction with the hundreds of thousands of tiny holes created by the larger sand particles, provides an easy pathway for moisture to migrate into the very resin rich layer of mat fiberglass that Amel and other better quality boat builders use as a “veil” to limit the amount of ‘print through’ that the structural woven layers of fiberglass would transfer to the gel coated exterior surfaces if this “veil” were not present. And remember, all Amel boats built from the advent of the Super Maramu onward have the proprietary Amel anti osmotic coatings applied AFTER the gel coat is shot into the mold. It is on the inside of the gel coat.

 

Water vapor combining with left over elements caused by cartelization of liquid resin into solid resin is the primary cause of osmotic blisters. There are other things that can cause blisters, but for this discussion about sand blasting, enough is enough. Some boat manufacturers that offer blister warranties on new product specifically prohibit employing sand blasting and sand sweeping (adds some water to the mix!! ) and doing so voids the warranty. Trust me. I could go on for pages about all of this but since I don’t want to put anyone to sleep I’ll stop now.

 

I have fully participated in the surveys of hundreds  of Super Maramus, some four and five times now, that I have been fortunate to have sold. In almost every case of boats having thousands and thousands of little blisters, it was caused by sandblasting the old bottom paint off. It used to shock owners when the boat came out of the water and billions of blisters were there where none were before and I would ask them, “ When did you sandblast the bottom?”

 

So please, Amel friends, don’t sand blast your boat’s bottom. Whatever method you employ, if you see fiberglass laminate of any description, properly reapply ( That means read the instructions. Twice ) a well-known and proven anti –osmotic coating. Keep moisture out of your laminate. If anyone wants more information or wants to discuss the blisters you may have on your boat, don’t hesitate to contact me by phone or email.

 

And always, above all, have fun with your Amel!

 

Joel

 

Joel F. Potter/Cruising Yacht Specialist LLC

THE EXPERIENCED AMEL GUY

954 462 5869 office

954 812 2485 cell

 

 

 

From: amelyachtowners@... [mailto:amelyachtowners@...]
 ESent: Monday, January 16, 2017 12:01 PM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 

 

 we did clean the hull of our 1982 Maramu april 2016 using cryogenic blasting; quite common now in the industry in Europe.

- boat had been in water since april 2014, unused since april 2015, growing weeds by the bushel & great farm for oysters & mussels -

 

Cryogenic blasting uses CO2 gas to produce carbonic dry ice pellets blasted on the hull at low air pressure; no dirt or pollution and less agressive on gel coat resins.

cleaned all layers of antifouling paint which had been splattered on during ? ages (no record of maintenance when we boughht the boat 2016) ?

went down to gel coat layers & left them clean to survey the hull and dry out before laying on new protection (époxy coating) underwater.

reasonable price (Euros 2K Euros for a speedy process - took 4 hours (setting up, work & dismantling apparatus) to team of 2 to clean the bottom hull of the Maramu.

 

If available in your corner of the Oceans, I would recommend that you check industrial cleaning companies for the service - search companies or small operators working for metal, housing (front coatings), wood, stone cleaning using low pressure compressors.

 

Worth the cost when you gain another 10 to 15 years of trouble free hull & the extra speed from a clean & smooth hull.

 

fair winds & clean hulls

 

christian alby, Maramu Désirade VIII, Canet/roussillon

 

 

 


De : "Steve Lawson lawson911@... [amelyachtowners]" <amelyachtowners@...>
À : amelyachtowners@...
Envoyé le : Lundi 16 janvier 2017 16h34
Objet : Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 

 

I did my bottom a few years ago, and my current boat is a Dufour 39 ( working my way up to an Amel ). It's a dirty, rotten, time consuming job, that you may do once, but will never repeat. Sandblasting is old school, the latest and greatest is soda blasting, which does a great job, is environmentally friendly, and is easier on the hull than sandblasting.
Cheers


On Jan 16, 2017, at 9:31 AM, Patrick Mcaneny sailw32@... [amelyachtowners] <amelyachtowners@...> wrote:

 

I have been thinking I would like to get rid of all the layers of bottom paint. I was wondering about chemical stripers , if they work and how well. Seems like you may run the risk of scratching the gel coat scraping , is that a concern and how wide of a scraper would you use. I got a quote of almost $3000. to sandblast, more than I expected , being a one day job , but if it saves ten days of scraping ... Just wondering what others have done. Also wondering how one deals with the bottom of the keel only a couple of inches off the ground and resting on blocking.

Pat SM#123

-----Original Message-----
From: James Alton lokiyawl2@... [amelyachtowners] <amelyachtowners@...>
To: amelyachtowners <amelyachtowners@...>
Sent: Sun, Jan 15, 2017 8:16 pm
Subject: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 

I have always avoided the chemical strippers myself due to concerns of short and long term damage to the gel coat.  The stuff goes into any cracks in the gel coat and can get into the laminate and or into any voids under the gel coat which is not a good thing.   The suggestion that was made to use a good sharp scrapper is IMO a good way to go,  just take your time.  As was also suggested, go with the carbide blades.  The Bahco 660 or 665 scrapper works well for me,  you can find these on Amazon.  You can also sand it off with a dustless system or use this as a follow up to the scrapping.  Definitely avoid using a heat gun as it is just too easy to craze the gel coat. 

 

Best of luck,

 

James Alton

SV Sueno,  Maramu #220

Sardinia,  Italy

 

On Jan 15, 2017, at 1:11 PM, santorinlo18@... [amelyachtowners] <amelyachtowners@...> wrote:

 

 

Hi Forum, Just about to scrap bottom - is sand blasting good method? seen the end result - looks neat but rough compare to manual. Not sure if good or bad, however, about 50% cost compare to manual + chemical. Any experiences or view

 

 

 


Danny and Yvonne SIMMS
 

Amen to that Joel,
we have lost Bebe Bill. What are we going to do if we lose you too.
Kind Regards
Danny
SM 299 Ocean pearl
Mangonui
New Zealand



From: "'Joel Potter' jfpottercys@... [amelyachtowners]"
To: amelyachtowners@...
Sent: Tuesday, 17 January 2017 10:07 AM
Subject: RE: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 
Misters Alby and Lawson give very good and correct advice on stripping the bottom of old paint buildup. While sand blasting is a fast and relatively cheap way to remove old paint, it more often than not has disastrous side effects.
 
Here is why. Sand is not only very hard, but the grains are not uniform in size. This is a bad combination. High pressure air accelerates the pieces of sand from the nozzle that the operator holds in his hands. The trouble is, the different sized grains also have different mass/weight and get accelerated to vastly different speeds because of this. The higher speed sand projectiles easily penetrate deeper into the laminate than you might ever imagine, especially in areas where the gel coat gets thin or removed by the process. Even the best anti-osmosis coatings that you might apply are not totally waterproof/vapor proof. This fact, in conjunction with the hundreds of thousands of tiny holes created by the larger sand particles, provides an easy pathway for moisture to migrate into the very resin rich layer of mat fiberglass that Amel and other better quality boat builders use as a “veil” to limit the amount of ‘print through’ that the structural woven layers of fiberglass would transfer to the gel coated exterior surfaces if this “veil” were not present. And remember, all Amel boats built from the advent of the Super Maramu onward have the proprietary Amel anti osmotic coatings applied AFTER the gel coat is shot into the mold. It is on the inside of the gel coat.
 
Water vapor combining with left over elements caused by cartelization of liquid resin into solid resin is the primary cause of osmotic blisters. There are other things that can cause blisters, but for this discussion about sand blasting, enough is enough. Some boat manufacturers that offer blister warranties on new product specifically prohibit employing sand blasting and sand sweeping (adds some water to the mix!! ) and doing so voids the warranty. Trust me. I could go on for pages about all of this but since I don’t want to put anyone to sleep I’ll stop now.
 
I have fully participated in the surveys of hundreds  of Super Maramus, some four and five times now, that I have been fortunate to have sold. In almost every case of boats having thousands and thousands of little blisters, it was caused by sandblasting the old bottom paint off. It used to shock owners when the boat came out of the water and billions of blisters were there where none were before and I would ask them, “ When did you sandblast the bottom?”
 
So please, Amel friends, don’t sand blast your boat’s bottom. Whatever method you employ, if you see fiberglass laminate of any description, properly reapply ( That means read the instructions. Twice ) a well-known and proven anti –osmotic coating. Keep moisture out of your laminate. If anyone wants more information or wants to discuss the blisters you may have on your boat, don’t hesitate to contact me by phone or email.
 
And always, above all, have fun with your Amel!
 
Joel
 
Joel F. Potter/Cruising Yacht Specialist LLC
THE EXPERIENCED AMEL GUY
954 462 5869 office
954 812 2485 cell
 
 
 
From: amelyachtowners@... [mailto:amelyachtowners@...]
 ESent: Monday, January 16, 2017 12:01 PM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)
 
 
 we did clean the hull of our 1982 Maramu april 2016 using cryogenic blasting; quite common now in the industry in Europe.
- boat had been in water since april 2014, unused since april 2015, growing weeds by the bushel & great farm for oysters & mussels -
 
Cryogenic blasting uses CO2 gas to produce carbonic dry ice pellets blasted on the hull at low air pressure; no dirt or pollution and less agressive on gel coat resins.
cleaned all layers of antifouling paint which had been splattered on during ? ages (no record of maintenance when we boughht the boat 2016) ?
went down to gel coat layers & left them clean to survey the hull and dry out before laying on new protection (époxy coating) underwater.
reasonable price (Euros 2K Euros for a speedy process - took 4 hours (setting up, work & dismantling apparatus) to team of 2 to clean the bottom hull of the Maramu.
 
If available in your corner of the Oceans, I would recommend that you check industrial cleaning companies for the service - search companies or small operators working for metal, housing (front coatings), wood, stone cleaning using low pressure compressors.
 
Worth the cost when you gain another 10 to 15 years of trouble free hull & the extra speed from a clean & smooth hull.
 
fair winds & clean hulls
 
christian alby, Maramu Désirade VIII, Canet/roussillon
 
 
 

De : "Steve Lawson lawson911@... [amelyachtowners]" <amelyachtowners@...>
À : amelyachtowners@...
Envoyé le : Lundi 16 janvier 2017 16h34
Objet : Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)
 
 
I did my bottom a few years ago, and my current boat is a Dufour 39 ( working my way up to an Amel ). It's a dirty, rotten, time consuming job, that you may do once, but will never repeat. Sandblasting is old school, the latest and greatest is soda blasting, which does a great job, is environmentally friendly, and is easier on the hull than sandblasting.
Cheers

On Jan 16, 2017, at 9:31 AM, Patrick Mcaneny sailw32@... [amelyachtowners] <amelyachtowners@...> wrote:
 
I have been thinking I would like to get rid of all the layers of bottom paint. I was wondering about chemical stripers , if they work and how well. Seems like you may run the risk of scratching the gel coat scraping , is that a concern and how wide of a scraper would you use. I got a quote of almost $3000. to sandblast, more than I expected , being a one day job , but if it saves ten days of scraping ... Just wondering what others have done. Also wondering how one deals with the bottom of the keel only a couple of inches off the ground and resting on blocking.
Pat SM#123

-----Original Message-----
From: James Alton lokiyawl2@... [amelyachtowners] <amelyachtowners@...>
To: amelyachtowners <amelyachtowners@...>
Sent: Sun, Jan 15, 2017 8:16 pm
Subject: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)
 
I have always avoided the chemical strippers myself due to concerns of short and long term damage to the gel coat.  The stuff goes into any cracks in the gel coat and can get into the laminate and or into any voids under the gel coat which is not a good thing.   The suggestion that was made to use a good sharp scrapper is IMO a good way to go,  just take your time.  As was also suggested, go with the carbide blades.  The Bahco 660 or 665 scrapper works well for me,  you can find these on Amazon.  You can also sand it off with a dustless system or use this as a follow up to the scrapping.  Definitely avoid using a heat gun as it is just too easy to craze the gel coat. 
 
Best of luck,
 
James Alton
SV Sueno,  Maramu #220
Sardinia,  Italy
 
On Jan 15, 2017, at 1:11 PM, santorinlo18@... [amelyachtowners] <amelyachtowners@...> wrote:
 
 
Hi Forum, Just about to scrap bottom - is sand blasting good method? seen the end result - looks neat but rough compare to manual. Not sure if good or bad, however, about 50% cost compare to manual + chemical. Any experiences or view
 
 
 



amelforme
 

Thanks Danny. I love Amel way too much to do anything else. I think we can get Bebe Bill to keep an eye on us and say 'whoa' when things that are not a good idea are shared. Bill never fails to impress me with the depth of his knowledge about all things Amel. We need to petition him, gently, to still hang out with us. Anyone else who agrees please post 'here here' under a new subject line. I suggest 'Admiral Bill'


Joel F. Potter
THE EXPERIENCED AMEL GUY
954-812-2485

On Jan 16, 2017, at 4:37 PM, Danny and Yvonne SIMMS simms@... [amelyachtowners] <amelyachtowners@...> wrote:

 

Amen to that Joel,
we have lost Bebe Bill. What are we going to do if we lose you too.
Kind Regards
Danny
SM 299 Ocean pearl
Mangonui
New Zealand



From: "'Joel Potter' jfpottercys@... [amelyachtowners]" <amelyachtowners@...>
To: amelyachtowners@...
Sent: Tuesday, 17 January 2017 10:07 AM
Subject: RE: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 
Misters Alby and Lawson give very good and correct advice on stripping the bottom of old paint buildup. While sand blasting is a fast and relatively cheap way to remove old paint, it more often than not has disastrous side effects.
 
Here is why. Sand is not only very hard, but the grains are not uniform in size. This is a bad combination. High pressure air accelerates the pieces of sand from the nozzle that the operator holds in his hands. The trouble is, the different sized grains also have different mass/weight and get accelerated to vastly different speeds because of this. The higher speed sand projectiles easily penetrate deeper into the laminate than you might ever imagine, especially in areas where the gel coat gets thin or removed by the process. Even the best anti-osmosis coatings that you might apply are not totally waterproof/vapor proof. This fact, in conjunction with the hundreds of thousands of tiny holes created by the larger sand particles, provides an easy pathway for moisture to migrate into the very resin rich layer of mat fiberglass that Amel and other better quality boat builders use as a “veil” to limit the amount of ‘print through’ that the structural woven layers of fiberglass would transfer to the gel coated exterior surfaces if this “veil” were not present. And remember, all Amel boats built from the advent of the Super Maramu onward have the proprietary Amel anti osmotic coatings applied AFTER the gel coat is shot into the mold. It is on the inside of the gel coat.
 
Water vapor combining with left over elements caused by cartelization of liquid resin into solid resin is the primary cause of osmotic blisters. There are other things that can cause blisters, but for this discussion about sand blasting, enough is enough. Some boat manufacturers that offer blister warranties on new product specifically prohibit employing sand blasting and sand sweeping (adds some water to the mix!! ) and doing so voids the warranty. Trust me. I could go on for pages about all of this but since I don’t want to put anyone to sleep I’ll stop now.
 
I have fully participated in the surveys of hundreds  of Super Maramus, some four and five times now, that I have been fortunate to have sold. In almost every case of boats having thousands and thousands of little blisters, it was caused by sandblasting the old bottom paint off. It used to shock owners when the boat came out of the water and billions of blisters were there where none were before and I would ask them, “ When did you sandblast the bottom?”
 
So please, Amel friends, don’t sand blast your boat’s bottom. Whatever method you employ, if you see fiberglass laminate of any description, properly reapply ( That means read the instructions. Twice ) a well-known and proven anti –osmotic coating. Keep moisture out of your laminate. If anyone wants more information or wants to discuss the blisters you may have on your boat, don’t hesitate to contact me by phone or email.
 
And always, above all, have fun with your Amel!
 
Joel
 
Joel F. Potter/Cruising Yacht Specialist LLC
THE EXPERIENCED AMEL GUY
954 462 5869 office
954 812 2485 cell
 
 
 
From: amelyachtowners@... [mailto:amelyachtowners@...]
 ESent: Monday, January 16, 2017 12:01 PM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)
 
 
 we did clean the hull of our 1982 Maramu april 2016 using cryogenic blasting; quite common now in the industry in Europe.
- boat had been in water since april 2014, unused since april 2015, growing weeds by the bushel & great farm for oysters & mussels -
 
Cryogenic blasting uses CO2 gas to produce carbonic dry ice pellets blasted on the hull at low air pressure; no dirt or pollution and less agressive on gel coat resins.
cleaned all layers of antifouling paint which had been splattered on during ? ages (no record of maintenance when we boughht the boat 2016) ?
went down to gel coat layers & left them clean to survey the hull and dry out before laying on new protection (époxy coating) underwater.
reasonable price (Euros 2K Euros for a speedy process - took 4 hours (setting up, work & dismantling apparatus) to team of 2 to clean the bottom hull of the Maramu.
 
If available in your corner of the Oceans, I would recommend that you check industrial cleaning companies for the service - search companies or small operators working for metal, housing (front coatings), wood, stone cleaning using low pressure compressors.
 
Worth the cost when you gain another 10 to 15 years of trouble free hull & the extra speed from a clean & smooth hull.
 
fair winds & clean hulls
 
christian alby, Maramu Désirade VIII, Canet/roussillon
 
 
 

De : "Steve Lawson lawson911@... [amelyachtowners]" <amelyachtowners@...>
À : amelyachtowners@...
Envoyé le : Lundi 16 janvier 2017 16h34
Objet : Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)
 
 
I did my bottom a few years ago, and my current boat is a Dufour 39 ( working my way up to an Amel ). It's a dirty, rotten, time consuming job, that you may do once, but will never repeat. Sandblasting is old school, the latest and greatest is soda blasting, which does a great job, is environmentally friendly, and is easier on the hull than sandblasting.
Cheers

On Jan 16, 2017, at 9:31 AM, Patrick Mcaneny sailw32@... [amelyachtowners] <amelyachtowners@...> wrote:
 
I have been thinking I would like to get rid of all the layers of bottom paint. I was wondering about chemical stripers , if they work and how well. Seems like you may run the risk of scratching the gel coat scraping , is that a concern and how wide of a scraper would you use. I got a quote of almost $3000. to sandblast, more than I expected , being a one day job , but if it saves ten days of scraping ... Just wondering what others have done. Also wondering how one deals with the bottom of the keel only a couple of inches off the ground and resting on blocking.
Pat SM#123

-----Original Message-----
From: James Alton lokiyawl2@... [amelyachtowners] <amelyachtowners@...>
To: amelyachtowners <amelyachtowners@...>
Sent: Sun, Jan 15, 2017 8:16 pm
Subject: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)
 
I have always avoided the chemical strippers myself due to concerns of short and long term damage to the gel coat.  The stuff goes into any cracks in the gel coat and can get into the laminate and or into any voids under the gel coat which is not a good thing.   The suggestion that was made to use a good sharp scrapper is IMO a good way to go,  just take your time.  As was also suggested, go with the carbide blades.  The Bahco 660 or 665 scrapper works well for me,  you can find these on Amazon.  You can also sand it off with a dustless system or use this as a follow up to the scrapping.  Definitely avoid using a heat gun as it is just too easy to craze the gel coat. 
 
Best of luck,
 
James Alton
SV Sueno,  Maramu #220
Sardinia,  Italy
 
On Jan 15, 2017, at 1:11 PM, santorinlo18@... [amelyachtowners] <amelyachtowners@...> wrote:
 
 
Hi Forum, Just about to scrap bottom - is sand blasting good method? seen the end result - looks neat but rough compare to manual. Not sure if good or bad, however, about 50% cost compare to manual + chemical. Any experiences or view
 
 
 



Patrick McAneny
 

Ann -Sofie , Thanks for the feedback , chemical stripping does not seem to be the way , too messy . Diane just told me that today is your birthday , and that she sent you wishes thru facebook , so let me add my wishes for a Happy Birthday ! We hope to see you guys again someday.
Pat & Diane,
SM Shenanigans


-----Original Message-----
From: Ann-Sofie Svanberg kanalmamman@... [amelyachtowners]
To: Patrick Mcaneny sailw32@... [amelyachtowners]
Sent: Mon, Jan 16, 2017 9:27 am
Subject: SV: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 
We used a paint remover in 2013, it didn’t save any time maybe some effort. But it was a really relly messy job that we don’t recomend anyone to do. You have to have wear a full Water proof protection to not be hurt, you have to use tons of Water to washit away with, not only from the hull but even from the ground as the solutions is high corrosive. It you don’t wash the ground properly dogs or cats or other animal can get their pawn really bad damaged. We didn’t have this full body waterproof coverage and got some nasty burns where the raincoat didn’t cover.
Also you have to have the right temperature. If it is to hot the solution dries out and do the work. We hade to cover with adhesive plastic film to keep the moisture. As I said really really messy.
 
We had the work re-done in Trinidad, scraped down to the gelcoat and then new paint. I belive that we paid about 2500 USD for it. And it was done manualy.
 
Regards
Ann-Sofie
 
Skickades från E-post för Windows 10
 
Från: Patrick Mcaneny sailw32@... [amelyachtowners]
Skickat: den 16 januari 2017 14:38
Till: amelyachtowners@...
Ämne: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)
 
 
I have been thinking I would like to get rid of all the layers of bottom paint. I was wondering about chemical stripers , if they work and how well. Seems like you may run the risk of scratching the gel coat scraping , is that a concern and how wide of a scraper would you use. I got a quote of almost $3000. to sandblast, more than I expected , being a one day job , but if it saves ten days of scraping ... Just wondering what others have done. Also wondering how one deals with the bottom of the keel only a couple of inches off the ground and resting on blocking.
Pat SM#123


-----Original Message-----
From: James Alton lokiyawl2@... [amelyachtowners] <amelyachtowners@...>
To: amelyachtowners <amelyachtowners@...>
Sent: Sun, Jan 15, 2017 8:16 pm
Subject: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 
I have always avoided the chemical strippers myself due to concerns of short and long term damage to the gel coat.  The stuff goes into any cracks in the gel coat and can get into the laminate and or into any voids under the gel coat which is not a good thing.   The suggestion that was made to use a good sharp scrapper is IMO a good way to go,  just take your time.  As was also suggested, go with the carbide blades.  The Bahco 660 or 665 scrapper works well for me,  you can find these on Amazon.  You can also sand it off with a dustless system or use this as a follow up to the scrapping.  Definitely avoid using a heat gun as it is just too easy to craze the gel coat. 

Best of luck,

James Alton
SV Sueno,  Maramu #220
Sardinia,  Italy

On Jan 15, 2017, at 1:11 PM, santorinlo18@... [amelyachtowners] <amelyachtowners@...> wrote:


Hi Forum, Just about to scrap bottom - is sand blasting good method? seen the end result - looks neat but rough compare to manual. Not sure if good or bad, however, about 50% cost compare to manual + chemical. Any experiences or view



greatketch@...
 

Joel,

Do you have an opinion on soda blasting?  Like sand blasting but uses sodium carbonate (baking soda) instead of sand, a much softer, more gentle, material.  It's not available everywhere, and requires some specialized equipment.

I had a few boats stripped like this in the past, and the gelcoat sure LOOKED good afterwards, but I did not have a long enough followup to see any long term effects.

Bill Kinney
SM#160,  Harmonie
Big Majors Spot, Bahamas


antonio scipioni
 

Hi guys 
Last year I remove The old antifouling and I prefer to do this job by my hand. It is very tiresome, you can use a gently water sandblaster. 
Consider that is very important don't damage the gelcoat cause you 'll have in future osmosis problem.
Fair Winds
Antonio
Vagabundo
SN108 
Now in Cannigione 

Inviato da iPhone

Il giorno 17/gen/2017, alle ore 02:58, greatketch@... [amelyachtowners] <amelyachtowners@...> ha scritto:

 

Joel,


Do you have an opinion on soda blasting?  Like sand blasting but uses sodium carbonate (baking soda) instead of sand, a much softer, more gentle, material.  It's not available everywhere, and requires some specialized equipment.

I had a few boats stripped like this in the past, and the gelcoat sure LOOKED good afterwards, but I did not have a long enough followup to see any long term effects.

Bill Kinney
SM#160,  Harmonie
Big Majors Spot, Bahamas


Santorin LO
 

Thank you all for the advice, Please allow me to summarise the views so far: Chemicals - messy and risky, Sandblast - risky. Based on the Joel's detailed explanation - Scraping is way. One more open question here (believe for you Joel) - Sodablasting?


Sv Garulfo
 

Hi Christian,

Do you have a contact for cryogenic blasting in west french med?

Thomas

Amel 54 #122
Cap d'Agde, France



On Mon, 16 Jan 2017 at 17:01, christian alby calbyy@... [amelyachtowners] <amelyachtowners@...> wrote:

 we did clean the hull of our 1982 Maramu april 2016 using cryogenic blasting; quite common now in the industry in Europe.
- boat had been in water since april 2014, unused since april 2015, growing weeds by the bushel & great farm for oysters & mussels -

Cryogenic blasting uses CO2 gas to produce carbonic dry ice pellets blasted on the hull at low air pressure; no dirt or pollution and less agressive on gel coat resins.
cleaned all layers of antifouling paint which had been splattered on during ? ages (no record of maintenance when we boughht the boat 2016) ?
went down to gel coat layers & left them clean to survey the hull and dry out before laying on new protection (époxy coating) underwater.
reasonable price (Euros 2K Euros for a speedy process - took 4 hours (setting up, work & dismantling apparatus) to team of 2 to clean the bottom hull of the Maramu.

If available in your corner of the Oceans, I would recommend that you check industrial cleaning companies for the service - search companies or small operators working for metal, housing (front coatings), wood, stone cleaning using low pressure compressors.

Worth the cost when you gain another 10 to 15 years of trouble free hull & the extra speed from a clean & smooth hull.

fair winds & clean hulls

christian alby, Maramu Désirade VIII, Canet/roussillon





De : "Steve Lawson lawson911@... [amelyachtowners]" <amelyachtowners@...>
À : amelyachtowners@...
Envoyé le : Lundi 16 janvier 2017 16h34
Objet : Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)


 
I did my bottom a few years ago, and my current boat is a Dufour 39 ( working my way up to an Amel ). It's a dirty, rotten, time consuming job, that you may do once, but will never repeat. Sandblasting is old school, the latest and greatest is soda blasting, which does a great job, is environmentally friendly, and is easier on the hull than sandblasting.
Cheers

On Jan 16, 2017, at 9:31 AM, Patrick Mcaneny sailw32@... [amelyachtowners] <amelyachtowners@...> wrote:

 
I have been thinking I would like to get rid of all the layers of bottom paint. I was wondering about chemical stripers , if they work and how well. Seems like you may run the risk of scratching the gel coat scraping , is that a concern and how wide of a scraper would you use. I got a quote of almost $3000. to sandblast, more than I expected , being a one day job , but if it saves ten days of scraping ... Just wondering what others have done. Also wondering how one deals with the bottom of the keel only a couple of inches off the ground and resting on blocking.
Pat SM#123


-----Original Message-----
From: James Alton lokiyawl2@... [amelyachtowners] <amelyachtowners@...>
To: amelyachtowners <amelyachtowners@...>
Sent: Sun, Jan 15, 2017 8:16 pm
Subject: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 
I have always avoided the chemical strippers myself due to concerns of short and long term damage to the gel coat.  The stuff goes into any cracks in the gel coat and can get into the laminate and or into any voids under the gel coat which is not a good thing.   The suggestion that was made to use a good sharp scrapper is IMO a good way to go,  just take your time.  As was also suggested, go with the carbide blades.  The Bahco 660 or 665 scrapper works well for me,  you can find these on Amazon.  You can also sand it off with a dustless system or use this as a follow up to the scrapping.  Definitely avoid using a heat gun as it is just too easy to craze the gel coat. 

Best of luck,

James Alton
SV Sueno,  Maramu #220
Sardinia,  Italy

On Jan 15, 2017, at 1:11 PM, santorinlo18@... [amelyachtowners] <amelyachtowners@...> wrote:


Hi Forum, Just about to scrap bottom - is sand blasting good method? seen the end result - looks neat but rough compare to manual. Not sure if good or bad, however, about 50% cost compare to manual + chemical. Any experiences or view





christian alby <calbyy@...>
 

Good morning
contacts are for our area Languedoc Rousssilon
a) BIOGOM - Franck Gautier +33(0)667609548 in Montpellier - web site Nettoyage par Hydrogommage, aérogommage, sablage | Biogom dans le 66, 11, 34, 30, 13, 83, 06 
b) AXIUM - Claire Berçot +33(0)627703499 in Canet Roussillon - Turnkey services from receiving & authorisations in Canet Technical zone, thru cleaning, blasting (subcontract Biogom) to painting ...
fair winds


Christian Alby - France home fixe +33 (0)5 34 39 06 02 home Internet +33 (0)9 60 37 22 72 mobile +33 (0)6 42 69 07 80



De : "Garulfo sv svgarulfo@... [amelyachtowners]"
À : amelyachtowners@...
Envoyé le : Mercredi 5 avril 2017 16h02
Objet : Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 
Hi Christian,

Do you have a contact for cryogenic blasting in west french med?

Thomas

Amel 54 #122
Cap d'Agde, France



On Mon, 16 Jan 2017 at 17:01, christian alby calbyy@... [amelyachtowners] <amelyachtowners@...> wrote:
 
 we did clean the hull of our 1982 Maramu april 2016 using cryogenic blasting; quite common now in the industry in Europe.
- boat had been in water since april 2014, unused since april 2015, growing weeds by the bushel & great farm for oysters & mussels -

Cryogenic blasting uses CO2 gas to produce carbonic dry ice pellets blasted on the hull at low air pressure; no dirt or pollution and less agressive on gel coat resins.
cleaned all layers of antifouling paint which had been splattered on during ? ages (no record of maintenance when we boughht the boat 2016) ?
went down to gel coat layers & left them clean to survey the hull and dry out before laying on new protection (époxy coating) underwater.
reasonable price (Euros 2K Euros for a speedy process - took 4 hours (setting up, work & dismantling apparatus) to team of 2 to clean the bottom hull of the Maramu.

If available in your corner of the Oceans, I would recommend that you check industrial cleaning companies for the service - search companies or small operators working for metal, housing (front coatings), wood, stone cleaning using low pressure compressors.

Worth the cost when you gain another 10 to 15 years of trouble free hull & the extra speed from a clean & smooth hull.

fair winds & clean hulls

christian alby, Maramu Désirade VIII, Canet/roussillon





De : "Steve Lawson lawson911@... [amelyachtowners]" <amelyachtowners@...>
À : amelyachtowners@...
Envoyé le : Lundi 16 janvier 2017 16h34
Objet : Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 
I did my bottom a few years ago, and my current boat is a Dufour 39 ( working my way up to an Amel ). It's a dirty, rotten, time consuming job, that you may do once, but will never repeat. Sandblasting is old school, the latest and greatest is soda blasting, which does a great job, is environmentally friendly, and is easier on the hull than sandblasting.
Cheers

On Jan 16, 2017, at 9:31 AM, Patrick Mcaneny sailw32@... [amelyachtowners] <amelyachtowners@...> wrote:

 
I have been thinking I would like to get rid of all the layers of bottom paint. I was wondering about chemical stripers , if they work and how well. Seems like you may run the risk of scratching the gel coat scraping , is that a concern and how wide of a scraper would you use. I got a quote of almost $3000. to sandblast, more than I expected , being a one day job , but if it saves ten days of scraping ... Just wondering what others have done. Also wondering how one deals with the bottom of the keel only a couple of inches off the ground and resting on blocking.
Pat SM#123


-----Original Message-----
From: James Alton lokiyawl2@... [amelyachtowners] <amelyachtowners@...>
To: amelyachtowners <amelyachtowners@...>
Sent: Sun, Jan 15, 2017 8:16 pm
Subject: Re: [Amel Yacht Owners] Sandblasting Good or Bad?(to remove Antifouling to Gellcoat)

 
I have always avoided the chemical strippers myself due to concerns of short and long term damage to the gel coat.  The stuff goes into any cracks in the gel coat and can get into the laminate and or into any voids under the gel coat which is not a good thing.   The suggestion that was made to use a good sharp scrapper is IMO a good way to go,  just take your time.  As was also suggested, go with the carbide blades.  The Bahco 660 or 665 scrapper works well for me,  you can find these on Amazon.  You can also sand it off with a dustless system or use this as a follow up to the scrapping.  Definitely avoid using a heat gun as it is just too easy to craze the gel coat. 

Best of luck,

James Alton
SV Sueno,  Maramu #220
Sardinia,  Italy

On Jan 15, 2017, at 1:11 PM, santorinlo18@... [amelyachtowners] <amelyachtowners@...> wrote:


Hi Forum, Just about to scrap bottom - is sand blasting good method? seen the end result - looks neat but rough compare to manual. Not sure if good or bad, however, about 50% cost compare to manual + chemical. Any experiences or view