While sanding my bottom paint I sanded some areas maybe a little too deep. I believe I took some gel coat off but didn't reach fiberglass. Am I able to just paint new bottom paint and it will be water tight. I dont want to run into any blistering because I didn't seal it. I will try and post a picture if I can. Thanks
Do i need to repair this? Bottom paint mistake
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Bottom paint is not waterproof. If your hull is porous for whatever reason, bottom paint will not stop moisture absorption. Unless you really sanded off all the gel coat you should be OK but if you are unsure if there is gel coat, sure there isn't or won't sleep at night, you need to apply a barrier coat. . Read and follow the directions precisely.
Surface prep, temperature and coating times are important to getting a good bond
FYI, moisture by itself in the hull skin does not mean you will develop blisters. The chemical process is more complicated. All fiberglass hulls will absorb some moisture if left in the water.
That said, your hull is 19 years old. If you were going to have a blister problem you would have had it by now.
Surface prep, temperature and coating times are important to getting a good bond
FYI, moisture by itself in the hull skin does not mean you will develop blisters. The chemical process is more complicated. All fiberglass hulls will absorb some moisture if left in the water.
That said, your hull is 19 years old. If you were going to have a blister problem you would have had it by now.
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Hey seasick does that look like gel coat to you? What layer would be under your gel coat? Fiberglass? It's not deep as u can tell. If you were in my position what would you do? Could you recommend a barrier coat? The white is not shiny it's more of a mat finish
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What grit was the sandpaper you used. If coarse, I can't tell if the gel coat is worn away. What you can do is hand sand it with finer grits until you get to 320 or so. At that point you should be able to better determine how the gel coats looks. If that area is the same color as the rest of the hull, you probably still have some gel coat .
SkunkBoat
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that looks like gelcoat You sanded thru the barrier coat. The barrier coat is usually grey or silver but could be white.
It would be best to touch it up with epoxy barrier paint. Its a two part paint that needs mixing and then has to go on before it hardens. Its expensive paint and smallest is probably a quart.
You have to mix a small amount in correct proportion. Don't mix what you can't use.
TotalBoat epoxy barrier is $46 qt
It would be best to touch it up with epoxy barrier paint. Its a two part paint that needs mixing and then has to go on before it hardens. Its expensive paint and smallest is probably a quart.
You have to mix a small amount in correct proportion. Don't mix what you can't use.
TotalBoat epoxy barrier is $46 qt
I used 60 grit sand paper on a an orbital sander. Picked up a 2 part epoxy resin today fearing I Messed up.. whats the best way to fix my issue with old bottom paint still on most of the boat. Skunkboat what's your favorite boat store? We are in the area?
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Its not "shiny" because you were sanding it.
You may or may not already have an epoxy barrier coat on there. Not all boats need it and not everyone applies it. However, if you currently don't have blisters, then you should be fine to just correct the area you sanded too far and lay down some eopxy resin "just to be safe". Then reapply your bottom paint.
You should be researching some of the various terms that have been mentioned so you better understand.
Why are you sanding in the first place? Unless it's very thick/heavy, it's not necessary. If you do need to get rid of a bunch of old layers, you would be best advised to hire a professional to soda blast the bottom.
You may or may not already have an epoxy barrier coat on there. Not all boats need it and not everyone applies it. However, if you currently don't have blisters, then you should be fine to just correct the area you sanded too far and lay down some eopxy resin "just to be safe". Then reapply your bottom paint.
You should be researching some of the various terms that have been mentioned so you better understand.
Why are you sanding in the first place? Unless it's very thick/heavy, it's not necessary. If you do need to get rid of a bunch of old layers, you would be best advised to hire a professional to soda blast the bottom.
You are using either the wrong equipment or the wrong technique, or both, to get all those circles imprinted on your hull. And where are you working, there are strict hazmat/environmental restrictions on removing bottom paint in most places.
Just paint the spot with your bottom paint and see how that spot holds up over the season. I would not apply plain epoxy because it doesn't stick well to polyester gel coat and most of us here agree you still have gel coat.
One piece of advice. It is important to know if possible what type of paint your old bottom paint is. You can not apply new ablative 'hard coat' over old ablative paint. You can apply either hard coat or ablative over old hard coat.
It may be a tad late but to test what type of old paint you have, use a wet rag ( wet with water) and wipe the old paint firmly. Look at the rag and if it is colored like your paint color, you have ablative paint.
Of course if you sanded everything and you wipe with a wet rag, you will see color on the rag regardless of the paint type.
To do a test in that case, you need to thoroughly wash a section, wipe with acetone, let dry and then do the wet rag test.
One piece of advice. It is important to know if possible what type of paint your old bottom paint is. You can not apply new ablative 'hard coat' over old ablative paint. You can apply either hard coat or ablative over old hard coat.
It may be a tad late but to test what type of old paint you have, use a wet rag ( wet with water) and wipe the old paint firmly. Look at the rag and if it is colored like your paint color, you have ablative paint.
Of course if you sanded everything and you wipe with a wet rag, you will see color on the rag regardless of the paint type.
To do a test in that case, you need to thoroughly wash a section, wipe with acetone, let dry and then do the wet rag test.
Actually... epoxy not sticking to polyester or vinylester is an old myth. It's been proven that it works just fine in recent years (and I've personally used it a number of times). I use to think that, too! But, you could always use polyester resin if you felt better about that.
Just apply the epoxy over the exposed area, hit it with a scrub pad and water, then do the bottom paint. It doesn't matter if some of the epoxy goes over old bottom paint.
As Seasick noted, though... you've been very rough with your sanding - which is another reason I mentioned having someone experienced remove the bottom paint for you.
Just apply the epoxy over the exposed area, hit it with a scrub pad and water, then do the bottom paint. It doesn't matter if some of the epoxy goes over old bottom paint.
As Seasick noted, though... you've been very rough with your sanding - which is another reason I mentioned having someone experienced remove the bottom paint for you.
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Dennis do you agree with seasick and I should just bottom paint and see how it hold up this season or should I touch it up with 2 part epoxy?
I don't "disagree" with that. However, if you do end up with bilsters, the time spent repairing those if greater than slapping a coat of resin on there which will guarantee you don't get blisters. Re-read my post #9 about this. The variable in play, though, is how much gel you removed due to being too aggressive and what impact that has on getting/not getting blisters.
Is it just me, or do others think there's no gelcoat outside of the sanded are?
Isn't that chopped strand?
Isn't that chopped strand?
Is that the same sanded area shown in the first photo, there is no gel coat for sure.. I can't tell if any fibers are exposed or if the section still has a resin 'skin'. Regardless, you need to seal that area with resin. I am of the old school and have been told not to apply polyester over epoxy but I have also watch a few videos of how that can work.
In either case, you still have to apply either gel coat , a barrier coat, or both
There are many videos on fiberglass techniques. Try looking at Boatworkstoday.com for video pertinent to your situation.
And Dennis, Boatworkstoday does have a video about polyester and epoxy bonding. I believe it proves your point
In either case, you still have to apply either gel coat , a barrier coat, or both
There are many videos on fiberglass techniques. Try looking at Boatworkstoday.com for video pertinent to your situation.
And Dennis, Boatworkstoday does have a video about polyester and epoxy bonding. I believe it proves your point
To me that doesn't look like what you would get if you were sanding a flat area and applied too much pressure on your sander, held it in place too long or turned it up on it's edge. I think that is a raised spot in the bottom (possibly a blister) that you uncovered by sanding. I would investigate further. Continue sanding and see if it occurs in other places.
Interesting observation although I didn't see that spot as a possible blister. I still don't know what it is for sure but if it were a blister and was 'raised' to start with, I would expect the sanding to expose fibers and I don't see any. All the fibers seem to be fully covered with resin.
This is just a guess, of course, but it may be a previous repair where they didn't worry too much about making it look nice since it was getting bottom paint, anyways. I'd be curious to see the interior side of that area, if it's accessible.
That occurred to me earlier but I would not have expected the repair to use chopped strand mat.
If the surface is smooth I suggest that the OP just paints it using a primer coat and bottom paint. I wouldn't do the barrier coat at this point. See how the paint wears and if any other weird spots develop. If there are more questional spots then a complete paint removal ( blasting or a lot of sanding), spot repair as needed, epoxy barrier coat and bottom paint.
Last time I priced that out it was $95 a foot at a boat yard and is probably more today based on the prices I see for good bottom paint