Topics

Sand Blasting vs. Soda


Patrick McAneny
 

My boat's topsides are about to be painted with awlcraft ,and I would like to remove a couple of layers of old bottom paint prior to that being done. The marina only does sand blasting. I have gotten the impression that soda is preferable to sand ,but not sure if this is true. The marina manager assured me that they can sand blast without damaging the gelcoat. He also recommended three coats of barrier coating prior to bottom paint.
Is there any good reason not to have a boat sand blasted ? 
Thanks,
Pat
SM Shenanigans 


Mark McGovern
 

Pat,

Soda Blasting is significantly less aggressive then Sand Blasting and is much less likely to cause damage to your gelcoat.  Personally, I would not have my boat bottom Sand Blasted.

When I was considering what to do with Cara's bottom to remove all the layers of old anti-fouling, I contacted Olivier Beaute.  Olivier had done our pre-purchase survey and as part of the survey report he had recommended that we do something to remove the large accumulation of old antifouling at our next haul out.  When I asked him about Soda Blasting, he wrote:

"This is a good way to remove the old anti-fouling coats, as long as the operator is careful and does not insist too much on a specific area. In fact, as soon as the white gel-coat can be seen, the operator must move its tool. With 22 years of practice, these people surely know what they're doing.  What would be bad is to remove the gel-coat and get to the GRP, which would mean the glass scales coat is affected. This sometimes happens with dry sand-blasting, more rarely with wet-sand blasting."

I also asked about adding a barrier coat after Soda Blasting, and he replied:

 "AMEL spreads polyester resin with glass scales, in the mold, after the gel coat is sprayed and before the first glass cloth. No epoxy as polyester and epoxy are not compatible when wet.  This is supposed to fight water penetration and it works rather good.  The epoxy coat as a « barrier » is not necessary because you already have one. Moreover, before you could apply epoxy, you would need to wait for the hull to be very dry.  All you need before the anti fouling is a coat of the primer recommended by the anti fouling manufacturer."

We decided to do two coats of Interprotect 2000e before applying out bottom coat anyway since we had her down to gelcoat for what we hope is the only time in our ownership.  

--
Mark McGovern
SM #440 Cara
Deale, MD USA


eric freedman
 

I preferred to do it the old fashioned way. I brought Kimberlite down to gel coat using 13 gallons of chemical stripper. It is tedious and 100% safe. You just don't know how good the operator of the soda blaster is. He might have 20 years of experience-- doing it the way. All the operator of the blaster has to do is lose concentration and blast right through the gelcoat and into Amels unique interior barrier coating.
Just a suspenders and belt solution. after washing the remnants of the stripper off , i had the boat sanded and applied 4 coats of Interprotect.
Kimberlite should now be good for another 18 years. Fair Winds
Eric

On July 16, 2020 at 2:33 PM Mark McGovern <mfmcgovern@...> wrote:

Pat,

Soda Blasting is significantly less aggressive then Sand Blasting and is much less likely to cause damage to your gelcoat.  Personally, I would not have my boat bottom Sand Blasted.

When I was considering what to do with Cara's bottom to remove all the layers of old anti-fouling, I contacted Olivier Beaute.  Olivier had done our pre-purchase survey and as part of the survey report he had recommended that we do something to remove the large accumulation of old antifouling at our next haul out.  When I asked him about Soda Blasting, he wrote:

"This is a good way to remove the old anti-fouling coats, as long as the operator is careful and does not insist too much on a specific area. In fact, as soon as the white gel-coat can be seen, the operator must move its tool. With 22 years of practice, these people surely know what they're doing.  What would be bad is to remove the gel-coat and get to the GRP, which would mean the glass scales coat is affected. This sometimes happens with dry sand- blasting, more rarely with wet-sand  blasting."

I also asked about adding a barrier coat after Soda Blasting, and he replied:

 "AMEL spreads polyester resin with glass scales, in the mold, after the gel coat is sprayed and before the first glass cloth. No epoxy as polyester and epoxy are not compatible when wet.  This is supposed to fight water penetration and it works rather good.  The epoxy coat as a « barrier » is not necessary because you already have one. Moreover, before you could apply epoxy, you would need to wait for the hull to be very dry.  All you need before the anti fouling is a coat of the primer recommended by the anti fouling manufacturer."

We decided to do two coats of Interprotect 2000e before applying out bottom coat anyway since we had her down to gelcoat for what we hope is the only time in our ownership.  

--
Mark McGovern
SM #440 Cara
Deale, MD USA

 


Patrick McAneny
 

Eric, I would think with 13 gallons you would be able to coat the boat 4 times. Did it take multiple coats to get it down to the gel coat,was it the kind of stripper you place plastic over ? It seems like so much work,that I would like to have it sand blasted and be done with it,but on the other hand I don't want to damage the gel coat. There is always pros &cons ,decisions are never easy and obvious,at least not for me.
Thanks,
Pat
SM Shenanigans


-----Original Message-----
From: eric freedman <kimberlite@...>
To: main@AmelYachtOwners.groups.io; Mark McGovern <mfmcgovern@...>
Sent: Thu, Jul 16, 2020 2:43 pm
Subject: Re: [AmelYachtOwners] Sand Blasting vs. Soda

I preferred to do it the old fashioned way. I brought Kimberlite down to gel coat using 13 gallons of chemical stripper. It is tedious and 100% safe. You just don't know how good the operator of the soda blaster is. He might have 20 years of experience-- doing it the way. All the operator of the blaster has to do is lose concentration and blast right through the gelcoat and into Amels unique interior barrier coating.
Just a suspenders and belt solution. after washing the remnants of the stripper off , i had the boat sanded and applied 4 coats of Interprotect.
Kimberlite should now be good for another 18 years. Fair Winds
Eric

On July 16, 2020 at 2:33 PM Mark McGovern <mfmcgovern@...> wrote:

Pat,

Soda Blasting is significantly less aggressive then Sand Blasting and is much less likely to cause damage to your gelcoat.  Personally, I would not have my boat bottom Sand Blasted.

When I was considering what to do with Cara's bottom to remove all the layers of old anti-fouling, I contacted Olivier Beaute.  Olivier had done our pre-purchase survey and as part of the survey report he had recommended that we do something to remove the large accumulation of old antifouling at our next haul out.  When I asked him about Soda Blasting, he wrote:

"This is a good way to remove the old anti-fouling coats, as long as the operator is careful and does not insist too much on a specific area. In fact, as soon as the white gel-coat can be seen, the operator must move its tool. With 22 years of practice, these people surely know what they're doing.  What would be bad is to remove the gel-coat and get to the GRP, which would mean the glass scales coat is affected. This sometimes happens with dry sand- blasting, more rarely with wet-sand  blasting."

I also asked about adding a barrier coat after Soda Blasting, and he replied:

 "AMEL spreads polyester resin with glass scales, in the mold, after the gel coat is sprayed and before the first glass cloth. No epoxy as polyester and epoxy are not compatible when wet.  This is supposed to fight water penetration and it works rather good.  The epoxy coat as a « barrier » is not necessary because you already have one. Moreover, before you could apply epoxy, you would need to wait for the hull to be very dry.  All you need before the anti fouling is a coat of the primer recommended by the anti fouling manufacturer."

We decided to do two coats of Interprotect 2000e before applying out bottom coat anyway since we had her down to gelcoat for what we hope is the only time in our ownership.  

--
Mark McGovern
SM #440 Cara
Deale, MD USA

 


 

Well, in this case, I am more old-fashion than Eric! Scrape, then sand.
image.png
CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar


On Thu, Jul 16, 2020 at 2:38 PM Patrick McAneny via groups.io <sailw32=aol.com@groups.io> wrote:
Eric, I would think with 13 gallons you would be able to coat the boat 4 times. Did it take multiple coats to get it down to the gel coat,was it the kind of stripper you place plastic over ? It seems like so much work,that I would like to have it sand blasted and be done with it,but on the other hand I don't want to damage the gel coat. There is always pros &cons ,decisions are never easy and obvious,at least not for me.
Thanks,
Pat
SM Shenanigans


-----Original Message-----
From: eric freedman <kimberlite@...>
To: main@AmelYachtOwners.groups.io; Mark McGovern <mfmcgovern@...>
Sent: Thu, Jul 16, 2020 2:43 pm
Subject: Re: [AmelYachtOwners] Sand Blasting vs. Soda

I preferred to do it the old fashioned way. I brought Kimberlite down to gel coat using 13 gallons of chemical stripper. It is tedious and 100% safe. You just don't know how good the operator of the soda blaster is. He might have 20 years of experience-- doing it the way. All the operator of the blaster has to do is lose concentration and blast right through the gelcoat and into Amels unique interior barrier coating.
Just a suspenders and belt solution. after washing the remnants of the stripper off , i had the boat sanded and applied 4 coats of Interprotect.
Kimberlite should now be good for another 18 years. Fair Winds
Eric

On July 16, 2020 at 2:33 PM Mark McGovern <mfmcgovern@...> wrote:

Pat,

Soda Blasting is significantly less aggressive then Sand Blasting and is much less likely to cause damage to your gelcoat.  Personally, I would not have my boat bottom Sand Blasted.

When I was considering what to do with Cara's bottom to remove all the layers of old anti-fouling, I contacted Olivier Beaute.  Olivier had done our pre-purchase survey and as part of the survey report he had recommended that we do something to remove the large accumulation of old antifouling at our next haul out.  When I asked him about Soda Blasting, he wrote:

"This is a good way to remove the old anti-fouling coats, as long as the operator is careful and does not insist too much on a specific area. In fact, as soon as the white gel-coat can be seen, the operator must move its tool. With 22 years of practice, these people surely know what they're doing.  What would be bad is to remove the gel-coat and get to the GRP, which would mean the glass scales coat is affected. This sometimes happens with dry sand- blasting, more rarely with wet-sand  blasting."

I also asked about adding a barrier coat after Soda Blasting, and he replied:

 "AMEL spreads polyester resin with glass scales, in the mold, after the gel coat is sprayed and before the first glass cloth. No epoxy as polyester and epoxy are not compatible when wet.  This is supposed to fight water penetration and it works rather good.  The epoxy coat as a « barrier » is not necessary because you already have one. Moreover, before you could apply epoxy, you would need to wait for the hull to be very dry.  All you need before the anti fouling is a coat of the primer recommended by the anti fouling manufacturer."

We decided to do two coats of Interprotect 2000e before applying out bottom coat anyway since we had her down to gelcoat for what we hope is the only time in our ownership.  

--
Mark McGovern
SM #440 Cara
Deale, MD USA

 


Patrick McAneny
 

Bill, Come on,you are too young to be in that old school. I stood back today and looked at that big hull and thought about how long it would take me to scrape and sand it down to the gel coat ,probably 200 hrs.,then walked right over to the office to inquire about sand blasting. Eric has me rethinking using a stripper,like Peel Away,but my negative side figures it probably doesn't work as advertised,nothing does. 
Stay Safe Down There,
Pat
SM Shenanigans


-----Original Message-----
From: CW Bill Rouse <brouse@...>
To: main@AmelYachtOwners.groups.io Notification <main@amelyachtowners.groups.io>
Sent: Thu, Jul 16, 2020 4:20 pm
Subject: Re: [AmelYachtOwners] Sand Blasting vs. Soda

Well, in this case, I am more old-fashion than Eric! Scrape, then sand.
image.png
CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar


On Thu, Jul 16, 2020 at 2:38 PM Patrick McAneny via groups.io <sailw32=aol.com@groups.io> wrote:
Eric, I would think with 13 gallons you would be able to coat the boat 4 times. Did it take multiple coats to get it down to the gel coat,was it the kind of stripper you place plastic over ? It seems like so much work,that I would like to have it sand blasted and be done with it,but on the other hand I don't want to damage the gel coat. There is always pros &cons ,decisions are never easy and obvious,at least not for me.
Thanks,
Pat
SM Shenanigans


-----Original Message-----
From: eric freedman <kimberlite@...>
To: main@AmelYachtOwners.groups.io; Mark McGovern <mfmcgovern@...>
Sent: Thu, Jul 16, 2020 2:43 pm
Subject: Re: [AmelYachtOwners] Sand Blasting vs. Soda

I preferred to do it the old fashioned way. I brought Kimberlite down to gel coat using 13 gallons of chemical stripper. It is tedious and 100% safe. You just don't know how good the operator of the soda blaster is. He might have 20 years of experience-- doing it the way. All the operator of the blaster has to do is lose concentration and blast right through the gelcoat and into Amels unique interior barrier coating.
Just a suspenders and belt solution. after washing the remnants of the stripper off , i had the boat sanded and applied 4 coats of Interprotect.
Kimberlite should now be good for another 18 years. Fair Winds
Eric

On July 16, 2020 at 2:33 PM Mark McGovern <mfmcgovern@...> wrote:

Pat,

Soda Blasting is significantly less aggressive then Sand Blasting and is much less likely to cause damage to your gelcoat.  Personally, I would not have my boat bottom Sand Blasted.

When I was considering what to do with Cara's bottom to remove all the layers of old anti-fouling, I contacted Olivier Beaute.  Olivier had done our pre-purchase survey and as part of the survey report he had recommended that we do something to remove the large accumulation of old antifouling at our next haul out.  When I asked him about Soda Blasting, he wrote:

"This is a good way to remove the old anti-fouling coats, as long as the operator is careful and does not insist too much on a specific area. In fact, as soon as the white gel-coat can be seen, the operator must move its tool. With 22 years of practice, these people surely know what they're doing.  What would be bad is to remove the gel-coat and get to the GRP, which would mean the glass scales coat is affected. This sometimes happens with dry sand- blasting, more rarely with wet-sand  blasting."

I also asked about adding a barrier coat after Soda Blasting, and he replied:

 "AMEL spreads polyester resin with glass scales, in the mold, after the gel coat is sprayed and before the first glass cloth. No epoxy as polyester and epoxy are not compatible when wet.  This is supposed to fight water penetration and it works rather good.  The epoxy coat as a « barrier » is not necessary because you already have one. Moreover, before you could apply epoxy, you would need to wait for the hull to be very dry.  All you need before the anti fouling is a coat of the primer recommended by the anti fouling manufacturer."

We decided to do two coats of Interprotect 2000e before applying out bottom coat anyway since we had her down to gelcoat for what we hope is the only time in our ownership.  

--
Mark McGovern
SM #440 Cara
Deale, MD USA

 


 

I hired 2 guys in Turkey...2 days at about 6 hours a day and one of them worked twice as hard/fast as the other.

CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar


On Thu, Jul 16, 2020 at 4:09 PM Patrick McAneny via groups.io <sailw32=aol.com@groups.io> wrote:
Bill, Come on,you are too young to be in that old school. I stood back today and looked at that big hull and thought about how long it would take me to scrape and sand it down to the gel coat ,probably 200 hrs.,then walked right over to the office to inquire about sand blasting. Eric has me rethinking using a stripper,like Peel Away,but my negative side figures it probably doesn't work as advertised,nothing does. 
Stay Safe Down There,
Pat
SM Shenanigans


-----Original Message-----
From: CW Bill Rouse <brouse@...>
To: main@AmelYachtOwners.groups.io Notification <main@amelyachtowners.groups.io>
Sent: Thu, Jul 16, 2020 4:20 pm
Subject: Re: [AmelYachtOwners] Sand Blasting vs. Soda

Well, in this case, I am more old-fashion than Eric! Scrape, then sand.
image.png
CW Bill Rouse Amel Owners Yacht School
Address: 720 Winnie, Galveston Island, Texas 77550 
View My Training Calendar


On Thu, Jul 16, 2020 at 2:38 PM Patrick McAneny via groups.io <sailw32=aol.com@groups.io> wrote:
Eric, I would think with 13 gallons you would be able to coat the boat 4 times. Did it take multiple coats to get it down to the gel coat,was it the kind of stripper you place plastic over ? It seems like so much work,that I would like to have it sand blasted and be done with it,but on the other hand I don't want to damage the gel coat. There is always pros &cons ,decisions are never easy and obvious,at least not for me.
Thanks,
Pat
SM Shenanigans


-----Original Message-----
From: eric freedman <kimberlite@...>
To: main@AmelYachtOwners.groups.io; Mark McGovern <mfmcgovern@...>
Sent: Thu, Jul 16, 2020 2:43 pm
Subject: Re: [AmelYachtOwners] Sand Blasting vs. Soda

I preferred to do it the old fashioned way. I brought Kimberlite down to gel coat using 13 gallons of chemical stripper. It is tedious and 100% safe. You just don't know how good the operator of the soda blaster is. He might have 20 years of experience-- doing it the way. All the operator of the blaster has to do is lose concentration and blast right through the gelcoat and into Amels unique interior barrier coating.
Just a suspenders and belt solution. after washing the remnants of the stripper off , i had the boat sanded and applied 4 coats of Interprotect.
Kimberlite should now be good for another 18 years. Fair Winds
Eric

On July 16, 2020 at 2:33 PM Mark McGovern <mfmcgovern@...> wrote:

Pat,

Soda Blasting is significantly less aggressive then Sand Blasting and is much less likely to cause damage to your gelcoat.  Personally, I would not have my boat bottom Sand Blasted.

When I was considering what to do with Cara's bottom to remove all the layers of old anti-fouling, I contacted Olivier Beaute.  Olivier had done our pre-purchase survey and as part of the survey report he had recommended that we do something to remove the large accumulation of old antifouling at our next haul out.  When I asked him about Soda Blasting, he wrote:

"This is a good way to remove the old anti-fouling coats, as long as the operator is careful and does not insist too much on a specific area. In fact, as soon as the white gel-coat can be seen, the operator must move its tool. With 22 years of practice, these people surely know what they're doing.  What would be bad is to remove the gel-coat and get to the GRP, which would mean the glass scales coat is affected. This sometimes happens with dry sand- blasting, more rarely with wet-sand  blasting."

I also asked about adding a barrier coat after Soda Blasting, and he replied:

 "AMEL spreads polyester resin with glass scales, in the mold, after the gel coat is sprayed and before the first glass cloth. No epoxy as polyester and epoxy are not compatible when wet.  This is supposed to fight water penetration and it works rather good.  The epoxy coat as a « barrier » is not necessary because you already have one. Moreover, before you could apply epoxy, you would need to wait for the hull to be very dry.  All you need before the anti fouling is a coat of the primer recommended by the anti fouling manufacturer."

We decided to do two coats of Interprotect 2000e before applying out bottom coat anyway since we had her down to gelcoat for what we hope is the only time in our ownership.  

--
Mark McGovern
SM #440 Cara
Deale, MD USA

 


Ralf Schroeder
 

Hello,
My boys used sand blasting for my baghira.
But they blasted sand in three or more steps. So it's not that difficult for the ship.

After that, the Baghira has some very small holes. But this holes also has a different owner when he removed the old layers of paint with a random orbital sander.
This is not from blasting, but from air or water inclusions in the old painting and the beginning of osmosis.
So he and my boys smooth the ships with an epoxy spatula. Then 7 layers of an epoxy paint and then the antifouling.

Now, it looks very good.

Ralf
SV Baghira, Sharki #42


eric freedman
 

The pink holes in the hull were made by the factory to blow fresh air into the hull to ventilate it for the workers.

I used 4 coats of Interprotect . then 2 coats of hard epoxy and then 2 coats of ablative paint.

Last photo is of the chemical we used.

Fair Winds

Eric

Amel Super Maramu #376

 

 

From: main@AmelYachtOwners.groups.io [mailto:main@AmelYachtOwners.groups.io] On Behalf Of CW Bill Rouse
Sent: Thursday, July 16, 2020 4:20 PM
To: main@AmelYachtOwners.groups.io Notification
Subject: Re: [AmelYachtOwners] Sand Blasting vs. Soda

 

Well, in this case, I am more old-fashion than Eric! Scrape, then sand.

image.png

Image removed by sender.

CW Bill Rouse Amel Owners Yacht School

Address: 720 Winnie, Galveston Island, Texas 77550 

Image removed by sender.Image removed by sender.Image removed by sender.

 

View My Training Calendar

Image removed by sender.

 

 

On Thu, Jul 16, 2020 at 2:38 PM Patrick McAneny via groups.io <sailw32=aol.com@groups.io> wrote:

Eric, I would think with 13 gallons you would be able to coat the boat 4 times. Did it take multiple coats to get it down to the gel coat,was it the kind of stripper you place plastic over ? It seems like so much work,that I would like to have it sand blasted and be done with it,but on the other hand I don't want to damage the gel coat. There is always pros &cons ,decisions are never easy and obvious,at least not for me.

Thanks,

Pat

SM Shenanigans

-----Original Message-----
From: eric freedman <kimberlite@...>
To: main@AmelYachtOwners.groups.io; Mark McGovern <mfmcgovern@...>
Sent: Thu, Jul 16, 2020 2:43 pm
Subject: Re: [AmelYachtOwners] Sand Blasting vs. Soda

I preferred to do it the old fashioned way. I brought Kimberlite down to gel coat using 13 gallons of chemical stripper. It is tedious and 100% safe. You just don't know how good the operator of the soda blaster is. He might have 20 years of experience-- doing it the way. All the operator of the blaster has to do is lose concentration and blast right through the gelcoat and into Amels unique interior barrier coating.
Just a suspenders and belt solution. after washing the remnants of the stripper off , i had the boat sanded and applied 4 coats of Interprotect.
Kimberlite should now be good for another 18 years. Fair Winds
Eric


On July 16, 2020 at 2:33 PM Mark McGovern <mfmcgovern@...> wrote:

Pat,

Soda Blasting is significantly less aggressive then Sand Blasting and is much less likely to cause damage to your gelcoat.  Personally, I would not have my boat bottom Sand Blasted.

When I was considering what to do with Cara's bottom to remove all the layers of old anti-fouling, I contacted Olivier Beaute.  Olivier had done our pre-purchase survey and as part of the survey report he had recommended that we do something to remove the large accumulation of old antifouling at our next haul out.  When I asked him about Soda Blasting, he wrote:

"This is a good way to remove the old anti-fouling coats, as long as the operator is careful and does not insist too much on a specific area. In fact, as soon as the white gel-coat can be seen, the operator must move its tool. With 22 years of practice, these people surely know what they're doing.  What would be bad is to remove the gel-coat and get to the GRP, which would mean the glass scales coat is affected. This sometimes happens with dry sand- blasting, more rarely with wet-sand  blasting."

I also asked about adding a barrier coat after Soda Blasting, and he replied:

 "AMEL spreads polyester resin with glass scales, in the mold, after the gel coat is sprayed and before the first glass cloth. No epoxy as polyester and epoxy are not compatible when wet.  This is supposed to fight water penetration and it works rather good.  The epoxy coat as a « barrier » is not necessary because you already have one. Moreover, before you could apply epoxy, you would need to wait for the hull to be very dry.  All you need before the anti fouling is a coat of the primer recommended by the anti fouling manufacturer."

We decided to do two coats of Interprotect 2000e before applying out bottom coat anyway since we had her down to gelcoat for what we hope is the only time in our ownership.  


--
Mark McGovern
SM #440 Cara
Deale, MD USA


 


Craig Briggs
 

Hi Eric,
The picture of the stipper you used doesn't show the full label but does show rockmiracle.com. I recall Rock Miracle is the brand I used years ago. It had methylene chloride which is the toxic stuff that made it work. Their website is under construction so I couldn't see if the product still has methylene chloride - there seems to be an "original" version and perhaps a newer "safe-but-doesn't-work-very-well" version. Did yours have methylene chloride and if so, do you know where to tget it?
Thanks,
Craig 


eric freedman
 

Hi Craig,

Sorry, I don't recall.

If you speak with the vendor the product was used 3 years ago.

Best,

Eric

On July 18, 2020 at 11:24 AM "Craig & Katherine Briggs SN 68 Sangaris Tropic Isle Harbor, FL via groups.io" <sangaris@...> wrote:

Hi Eric,
The picture of the stipper you used doesn't show the full label but does show rockmiracle.com. I recall Rock Miracle is the brand I used years ago. It had methylene chloride which is the toxic stuff that made it work. Their website is under construction so I couldn't see if the product still has methylene chloride - there seems to be an "original" version and perhaps a newer "safe-but-doesn't-work-very-well" version. Did yours have methylene chloride and if so, do you know where to tget it?
Thanks,
Craig