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I've got a Catalina 27 with several years worth of bottom paint on her. I plan to strip her down to the gelcoat and do a complete bottom job. I've read mixed reviews of various chemical peelers. I'm wondering if there's a consensus on one product that seems to work the best. If so, what is it? If not, and good ole fashioned scraping is the way to go, what's the proper procedure?

Thanks in advance for the advice!
 

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Chemical worked well on my topsides issue it did not really work on the bottom in my case

The chemical on the bottom was costly and slower than hand scraping FOR the type of paint buildup i HAD
 

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I scraped, then used a razor blade, after that an orbital sander with 50 grit paper connected to a shop vac. It's slow going but leaves you with a clean surface to work with.
It was a 3 weekend job.
 

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Owned by Velcro
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Get one of those scrapers with a tungsten carbide blade in them and have at it with some elbow grease. Faster and less messy then using chemicals and a lot cheaper as well. Then sand for a good finish and use a small roller to build your bottom paint system back up to what you want. A small roller, its faster then using those big things, less tiring ans saves on paint with a better finish.


ATB

Michael
 

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Neither. Soda blasting with an experienced operator will do the job in less than 2 hours.

Otherwise a manual scraper and lots of elbow grease followed sanding with 60/80 grit W/D used wet. But it is HARD GRAFT.
 

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Soda Blasting is very expensive IF your working on a budget , in my case if would have been in the 1500 dollar range :)

And it will take more than two hours to even tape off the boat from the mess
 

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Barquito
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To add to SeaChanger's question: If using a tungsten/carbide scraper, is it a good idea to dress the edges a bit so they don't leave gouges? I think scraping is the way to go, too. However, on my boat the shape of the bottom makes it difficult to avoid the gouges.
 

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Freedom isn't free
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Scrape, Scrape, Scrape, and 80grit, to 250 grit... WEAR A MASK, WEAR GOGGLES, WEAR A chem suit!

It's messy as all heck, sanding is brutal.







By the way, NEVER again. Worst work I've ever done.
 

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If you are at a yard you may want to check with them, they may have strict requirements as to who and how it is done. The advantage of soda blasting is it will likely give you the best finish (assuming a good operator) and they will clean up afterwards. Clean up can be a tough one, and many yards are no longer allow DIY bottom paint removal.
 

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Neither. Soda blasting with an experienced operator will do the job in less than 2 hours.
+ 1

Soda blasting prices varies with the area. Also not every marina will allow it. Where I am there is a new dust-less process that will do the same thing, will not harm the gel coat and no need to tent the boat. In my case, to do it the long and hard way would cost at least $400 - $200 for the full face mask alone.

Another 500 will cover soda blasting. It will be healthier and money well spent because...

Scrape, Scrape, Scrape, and 80grit, to 250 grit... WEAR A MASK, WEAR GOGGLES, WEAR A chem suit!

It's messy as all heck, sanding is brutal.
By the way, NEVER again. Worst work I've ever done.
because of that!
 

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I'm thinking of soda blasting on my next winter haul out. Would there be any caveats to soda blasting in the Fall and then painting in the Spring?
 

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I used a combination of carbide scraper and ¾" wood chisel as detailed here:

http://mysite.verizon.net/resocsxq/maioccowoodworking/Bottom_Stripping.html#0

If I was to do it again, I'd just go with the carbide scraper. As to whether to dress the points of the scraper, it's a good idea. I didn't do it but should have. On the other hand, I did not gouge the hull, possibly because a) I was careful and b) the hull's curvature was enough that the full width of the blade was never in contact.

I would have like to soda b;last the hull, but the cost was too much to consider seriously. My brother-in-law and I got a good upper body workout.
 

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In our area it seems the soda blasting process stops several inches from the waterline (so as not to damage the gelcoat on the topsides?) So you will still have to do some manual work where it will show.

I am in the carbide scraper camp. Over the years, I've used carbide scrapers to strip the bottom paint from an 18' catboat and a 23' powerboat with excellent results. It wasn't necessary--even with the hard chine and strakes on the powerboat--to round the ends of the scraper. The trick is to apply pressure to fracture the brittle bottom paint, which comes off in chunks, leaving much less dust than brute force sanding. This is where the sharp, long-life edge of a two handled carbide scraper comes into play. What you don't want to do is shave or plane the bottom paint. Recycled, discarded shrink-wrap served as a drop cloth.

I then used 80 grit paper with a palm sander before applying Interlux 2000 barrier coats. Applying bottom paint over the barrier coat was a cinch.

A bit of advice: tape your waterline beforehand. If you are concerned about airborne debris, consider tenting your boat--perhaps from your rub rail to the ground with polyethylene--to keep peace with your neighbors and the yard manager. As it turned out, I didn't need to tent the boat, as the dust from scraping and sanding was minimal, but I did use a vacuum cleaner attachment to the sander.
 
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