Bill Burke
Plymouth, Mass
Boat Name: Irish Wake
Model/Year: Catalina 22, 1983
Hull No. 11499
Hailing Port: Plymouth, Mass |
 08/18/2008 7:58 PM Pacific Time
I'm in the process of bottom painting. I've sanded down the surface for bite, but in the process, I've found a couple of spots where the current coat chipped away down to the gel coat. Can you fill this gap with something, or do you just "build up" layers of the new paint to get a smoother surface? |
Aaron M Benham
33a Loomis Hights
Boat Name: Tidely-Idley: The never ending project
Model/Year: 1978 C22
Hull No. 8070
Hailing Port: |
08/19/2008 12:22 PM Pacific Time
If the damage only goes as deep as the gel coat than its just a simple matter of opening the damaged area slightly (you can use the edge of a screwdriver, a dremel tool or an angle grinder depending on the size of the area),cleaning thouroughly with acetone (or MEK) and filling with gel coat paste. The advantage of this method is that you can color match the gel coat which I suppose is not all that important below the water line or under your bottom paint.
You can also fill the areas with epoxy based puttys made for ther purpose or mix your own from laminating epoxy and colliodal silica. The advantage to epoxy is that it can help reduce water intrusion and is generally a stronger repair..
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Aaron M Benham
33a Loomis Hights
Boat Name: Tidely-Idley: The never ending project
Model/Year: 1978 C22
Hull No. 8070
Hailing Port: |
08/19/2008 12:24 PM Pacific Time
Sorry, misread your question. Just scrape away the loose stuff and paint over it. If you want, you can smooth the edges by sanding them but don't breath the dust. |
Bill Burke
Plymouth, Mass
Boat Name: Irish Wake
Model/Year: Catalina 22, 1983
Hull No. 11499
Hailing Port: Plymouth, Mass |
08/20/2008 10:13 AM Pacific Time
I can sand down the edges of where the antifouling paint stops (looks like small crater), but I think there will still be a noticable depression. Is there a filler or an epoxy (basically like a bondo) that I can fill in, sand down and make it even? |
Aaron M Benham
33a Loomis Hights
Boat Name: Tidely-Idley: The never ending project
Model/Year: 1978 C22
Hull No. 8070
Hailing Port: |
08/20/2008 12:18 PM Pacific Time
I don't know of any fillers for bottom paint other than bottom paint. The only alternative is to strip the bottom which is a messy and time consuming job to be avoided at all costs. Bottom paint is soft and designed to be removable at some point while fillers are designed to be permanent. The only advantage to stripping is that you don't have to worry about paint compatibility.
Just remember this point as you make your decision; its all underwater and nobody will see it. |
Steven Keplinger
Severna Park MD 21146
Boat Name: Nifty
Model/Year: 1978
Hull No. CTYH7999M78B
Hailing Port: Round Bay |
08/20/2008 2:29 PM Pacific Time
If you're actually into the gel coat, or below, Bondo (don't tell...) will work fine; especially the fiber reinforced kind. It will fair out plenty smooth for below the waterline. Practice a bit. I use a Fein Multi-Tool with a triangular diamond coated grout removal blade to undercut cracks in order to give the epoxy or Bondo a mechanical grip. Then (and this is almost an art) just before the stuff hardens up, I shave it flush to the gel coat with a very sharp knife. If there's a lot of excess to come off, a Stanley SureForm works a charm. I seem to get more mileage out of their small convex models than any thing else they make. If you use the SureForm, keep it clean with another scraping tool, right away. Otherwise, the hardened Bondo will be next to impossible to remove. I use my pocket knife to clean the Stanley.
You can come back after its dry with 100 sandpaper. I use a 6" random orbit sander for this (mine's a Porter-Cable), hooked by a 12' hose to a Fein vacume. I have a full face respirator with appropriate filters. Don't even think about messing with paint dust without a superior respirator! The stuff is poison, ask any barnacle! It's poison to people too. Be safe!
After you get all of your Bondo patching finished, give each one a thin coat of epoxy primer. Fair that.
Howmsoever, don't use it to fill in voids in the old bottom paint. Here, you can either fair it out gradually with (say) 80 grit paper to about the size of a dinner plate, or under (say) the size of a tennis ball, in which case you can putty knife in a slosh of Interlux 244, or whatever today's equivalent is (my can's 10 years old). This stuff is well nigh near permanent...but not quite: you will be able to remove it when you strip all the old bottom paint away. If you go the fairing putty way (like 244), keep a bit of your new bottom paint handy; it likes to be painted over as soon as it skims up.
Just remember, it's the bottom we're talking about. Unless you're into very serious racing, a fair smooth hull is perfectly sufficient.
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Ryan Graham
Douglasville, Ga.
Boat Name: Luana Cordelia
Model/Year: C22 1978
Hull No. 8587
Hailing Port: Douglasville, Ga (on the hard) |
09/15/2010 6:27 PM Pacific Time
Dont use bondo. Order a fiberglass boat repair kit at your local boat shop or order it off the net. You mix the epoxy very well then add in your microballoons or other easily sanded filler. Block sand the area with 220 using little pressure. This stuff will set fast and be sandable usually in a few hours. It will also not react with water once set as bondo will do. This is the correct fix for mild scratches that you will paint. If deeper you may need to grind into the fiberglass and wet lay some fabric. Easy to do but you will need to do some homework for the method. |
