Bottom Stripping

Plymouth Sailor

Plymouth Sailor

.
Dec 11, 2015
291
Hunter 25 Plymouth
Looking for a relatively inexpensive way of stripping my anti-fouling paint (multiple layers/years). Not interested in sand blasting however I am interested in some sort of paint stripping solution. My boat is fiberglass so don't want any harmful chemicals. Your wisdom appreciated!
 
D

dlochner

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Jan 11, 2014
11,467
Sabre 362 113 Fair Haven, NY
The cheapest way is to go at it with a paint scraper. Get as much of the old stuff off by scrapping as is reasonably possible and then attack with paint stripper or 40 grit sandpaper.
 
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Justin_NSA

Justin_NSA

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Jul 7, 2004
8,403
Hunter 30T Cheney, KS
I wet-sanded mine but you'll feel it for a long time. I've seen demos of random orbital sanders with vacuum containment that would be easier and smarter.
 
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rgranger

rgranger

.
Jan 19, 2010
12,389
Hobie 16 & Rhodes 22 Skeeter Charleston
Several years ago, I posted a recipe for homemade peel away. I found the link in an old thread but it seems to be dead now.

If you get a 5lb bag of garden lime (lowes) and about 5 or 6 cups of potassium hydroxide (sodium hydroxide is also okay) and mix that in a 5 gal PVC bucket. Add just enough water to give it a pancake batter consistency. Take a paint roller and roll it onto the bottom paint and let it dry. Blast it off with a pressure washer and the ablative paint will come right off. There will be a few tough spots so just repeat a few times on those spots.

ENVIRONMENTAL! Bottom paint is toxic. You don't want to let it simply run off or get in your lawn. Lay some old bed sheets or some other type of cloth under your boat. When you blast off the paint with the pressure washer, the water will filter through the sheet but the paint chips will be caught on top.

SAFETY! This paste is very basic (caustic) and will chap your skin in a most unpleasant way if you get it on your skin. It will basically (pun intended) turn the oils and wax in your skin into soap and leave your skin like raw hide. Wear long sleeves. DO NOT let it get in your eyes and last DO NOT LET IT GET IN YOUR EYES!

One more thing ....DO NOT LET IT GET IN YOUR EYES.

If you don't know a chemist who can get you the hydroxide salts, drain-o and many other drain cleaners are mostly potassium hydroxide. Also canning lye is a mixture of metal hydroxide salts so that will also work.
 
D

dlochner

.
Jan 11, 2014
11,467
Sabre 362 113 Fair Haven, NY
rgranger said:
Several years ago, I posted a recipe for homemade peel away. I found the link in an old thread but it seems to be dead now.

If you get a 5lb bag of garden lime (lowes) and about 5 or 6 cups of potassium hydroxide (sodium hydroxide is also okay) and mix that in a 5 gal PVC bucket. Add just enough water to give it a pancake batter consistency. Take a paint roller and roll it onto the bottom paint and let it dry. Blast it off with a pressure washer and the ablative paint will come right off. There will be a few tough spots so just repeat a few times on those spots.

ENVIRONMENTAL! Bottom paint is toxic. You don't want to let it simply run off or get in your lawn. Lay some old bed sheets or some other type of cloth under your boat. When you blast off the paint with the pressure washer, the water will filter through the sheet but the paint chips will be caught on top.

SAFETY! This paste is very basic (caustic) and will chap your skin in a most unpleasant way if you get it on your skin. It will basically (pun intended) turn the oils and wax in your skin into soap and leave your skin like raw hide. Wear long sleeves. DO NOT let it get in your eyes and last DO NOT LET IT GET IN YOUR EYES!

One more thing ....DO NOT LET IT GET IN YOUR EYES.

If you don't know a chemist who can get you the hydroxide salts, drain-o and many other drain cleaners are mostly potassium hydroxide. Also canning lye is a mixture of metal hydroxide salts so that will also work.
Click to expand
Ah, better living through chemistry! :cool:

Now what were saying about the eyes?
 
shemandr

shemandr

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Jan 1, 2006
7,084
Slickcraft 26 Sailfish
Listen to the Chemistry Professor. Protect your eyes! Likely a very good formula for at home. Boatyards probably won't go for this unless you convince them you'll manage the waste. Some around here are pretty un-convincable.
Having done one bottom I have to say there won't be a #2. Try to buy a boat with a good bottom and apply bottom paint miserly.
 
Gene Neill

Gene Neill

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Sep 30, 2013
3,546
1988 Catalina 22 North Florida
I scraped every inch off the bottom of the Albin Vega this summer, using a 1 1/4" wood chisel. It went pretty easily over 90% of the surface. A few stubborn spots required mechanized sanding and/or some real elbow grease on the chisel. Also, a residue was left behind that required light sanding, and some chisel marks in the gel coat as well.

I tried to "eat the elephant one bite at a time" by committing myself to scraping one hour a day, every day. It worked out well, but I'd hate to do a bigger boat that way.
 
Head Sail

Head Sail

.
Nov 13, 2013
723
Catalina 34 Tacoma
Plymouth Sailor said:
Looking for a relatively inexpensive way of stripping my anti-fouling paint (multiple layers/years). Not interested in sand blasting however I am interested in some sort of paint stripping solution. My boat is fiberglass so don't want any harmful chemicals. Your wisdom appreciated!
Click to expand
Why do you want to remove it? Just paint the areas that need painting and let the thick areas wear off. I like easy.
 
victorhoisington

victorhoisington

.
Jan 22, 2008
296
Islander Freeport, 41 Ketch Longmont, CO
Having done this on 2 boats (Hunter 25 and Hunter 28), its more tedious than difficult and does take time. I sanded both boats, and the random orbit sander driven by an air compressor worked best. It takes a while to get the technique down so that you are removing paint and not gelcoat but once you are there its pretty straight forward. I wore a full face mask/respirator to avoid the dust and you either need a dust collector or lay down tarps to collect the dust. 80 grit sandpaper worked well and laid a nice base for the 4 coats of interlux 2000 as the new base coat.

You'll have to find places today that will let you do this work since many yards won't or can't allow it anymore. If you do it at home lay tarps regardless since the residue will kill the grass or pollute your concrete. You don't want the old stuff running into the storm sewer.

good luck.
 
sailme88

sailme88

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Jan 19, 2010
1,172
Catalina 34 Casco Bay
I know you're not interested in sand blasting, but I had very good results with glass bead blasting. Outstanding results..
 
rgranger

rgranger

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Jan 19, 2010
12,389
Hobie 16 & Rhodes 22 Skeeter Charleston
I sand blasted a cast iron keel with amazing results. It is kind of fun too
 
C

Crazy Dave Condon

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Jun 8, 2004
10,067
-na -NA Anywhere USA
There are a couple warnings that you all need to know. First I would never sand a hulll with 40 grit as it is too course. 80 grit is industry standard as anything courser can do damage.
As for sanding I highly suggest using a vacuum system because many of you do not realize how far dust flies thru the air and when I allowed individuals who simply sanded in my yard, dust flew over onto other boats as far as 200 feet away. It created a mess particularly on the older boats. I stopped that quickly. Dust on the older boats got into the pores of gel coat which took compounding and waxing to restore those boats. I ate the cost. So use vacuum sytems and wash your boat off entirely far away from the house with the wind blowing in the opposite direction
 
D

dlochner

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Jan 11, 2014
11,467
Sabre 362 113 Fair Haven, NY
The cratered bottom from years of accumulated bottom paint probably has a greater effect on the boat's performance than the weight of the paint. An ugly bottom is a slow bottom.
 
P

Pirate Dave

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Dec 23, 2016
191
Catalina 27 Clinton CT
Boatyards probably won't go for this unless you convince them you'll manage the waste. Some around here are pretty un-convincible

In CT ALL boatyards are required by law to capture the waste water runoff from powerwashing and all sanders have to collect the dust in bags. They also require you to put down a tarp prior to scraping. The fine for a violation is $100k if caught
 
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