Bottom Stripping

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Triton106
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Joined: Fri Apr 18, 2003 4:51 pm
Location: San Francisco Bay Area

Bottom Stripping

Post by Triton106 »

Spring is here again in the SF Bay Area. Rain has stopped, sky is blue, flowers is in blossom, boat bottoms are waiting to stripped ;-)

This year I vowed to strip the bottom paint accumulated over the last who knows how many years completely, down to the gelcoat. There have been several discussions already on this forum and I have read many if not all of them. As recommended by Tim and others I plan to use carbide scraper for that purpose. My question is that although I have been using ablative bottom paint which seem to come off with relative ease some of the older paint the PO used seem to be rock hard and refuse to yield to scarping no matter how hard I try. I cannot afford soda blast. So I am thinking of using chemical stripper but that is toxic and expensive. Sanding does not seem intuitively would be easier. What are your suggestions as how to deal with hard bottom paint?
Ray D. Chang
Triton 106 in Berkeley, CA
bcooke
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Re: Bottom Stripping

Post by bcooke »

If the scraper won't touch it:

PC7335 and 36 grit sandpaper. Change the paper often. 3m 6800 series full faced respirator. Wear a hat, gloves and long sleaves. Some people use the vacuum attachment. It does reduce the dust but it won't eliminate it. You will need a couple of filters for the vacuum if you go that route.

It won't be painless...
-Britton
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Rachel
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Re: Bottom Stripping

Post by Rachel »

Although I have not used it myself, I have read good things about Franmar Soy-strip, which is one of the "less toxic" strippers. I'm pretty sure there is a post in the archives here of a fellow who stripped the whole bottom of his Shields class boat with it in Chicago. There were photos.

At one point in time I was thinking about stripping the VC-17 off of the boat I had at the time, and I considered Soy-strip, but when I called them to ask if it was safe to use with barrier coat underneath (that boat was barrier coated when I got it and I didn't have any reason to want to strip that off), they said no. So I did not ever try the product.

Peel Away is another product people use, but after reading about it compared to Soy-strip I would have tried Soy-strip first, myself. It may be worth experimenting with a bit of each to see what works best on your particular coating (I wonder what it is?).

By the way, If you do sand it off, I'm pretty sure Sven's will require you to use vacuum sanders (they may have one you can rent).

Rachel

Edited to add: Here are two threads you might find of interest. The first one is the one I mentioned about Franmar/Shields; the second one talks about Peel Away.

http://plasticclassicforum.com/viewtopi ... it=franmar

http://plasticclassicforum.com/viewtopi ... it=franmar
Triton106
Candidate for Boat-Obsession Medal
Posts: 392
Joined: Fri Apr 18, 2003 4:51 pm
Location: San Francisco Bay Area

Re: Bottom Stripping

Post by Triton106 »

Thanks Britton, Rachel!

I spoke with the folks at Svendsens. I cannot seem to avoid using chemical stripper if I don't want to soda blast it. Since Blossom has accumulated multiple layers of various bottom paint I opted for the Jasco Premium Paint and Varnish Remover. I know this stuff will eat through gelcoat so I applied it very cautiously and avoided thinnest areas. This chemical works very quickly. In 15 mims you can see paint start to bubble. I only apply a small area at a time and kept it thin. Although it is difficult to control how much old paint it will eat through I erred on the side of too little vs. too much. After the first application of the stripper and scraping it with carbide scraper the progress is noticable. I have not been able to get to the gelcoat yet but the remaining paint is thin enough that I can smooth out with a pnuematic sander.

I have only stripped the portside today. I plan to finish off scrapping the starboard side tomorrow and sand the bottom smooth on Wednesday. Then repair some areas where gelcoat is visibally damaged with epoxy coat on Thursday and Friday. I will then repaint on Saturday and Sunday. I hope ot splash on Monday.

Everytime I haul the boat out it's like a battle with the time. Not only I can find just one week vacation at a time Svendsens lay day charge doubles after 10 days. Good thing my friend Rob is helping me with other projects like replacing ball valves with seacocks.
Ray D. Chang
Triton 106 in Berkeley, CA
Triton106
Candidate for Boat-Obsession Medal
Posts: 392
Joined: Fri Apr 18, 2003 4:51 pm
Location: San Francisco Bay Area

Re: Bottom Stripping

Post by Triton106 »

I finally found something I hate to do more than my tax...

Day 4 and I am still sanding the bottom. Of course, I did not spend all four days sending. At least 1/3 of the time was spent on finding parts and tools and helping Rob removing old ball valves and installing new seacocks. It looks like I will need to sand one more day tomorrow to just get the bottom to an acceptable condition before repainting. I am disappointed that I did not get to the gelcoat completely. The more I sanded the more I discover that the original gelcoat has cosmetic blisters in a number of places. Various patches have been made in the past with different material and colors. I can count at least five different colors, the original light blue gelcoat, white material patching over some blisters, gray patches, black patches, red bottom paint. I am running out of time to completely stripped it down to the gelcoat. I will have to spending one more day tomorrow to smooth out the bottom in its current condition and wait for the next haul out to do it properly. Next time I will opt for soda blasting instead of endless scraping and sanding. Sometimes, I have to admit my own limitations.

I will report back with some pictures when the bottom is repainted. Thanks!
Ray D. Chang
Triton 106 in Berkeley, CA
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