Advice needed on thru hull fittings when painting f/glass boat

Hi Folks,

I am in the process of restoring a 20 foot F/glass boat. It is the first time I've tried something like this so please excuse me if I ask some dumb questions.

The boat's hull is in very solid but has been painted at some time and whoever did it just slapped the paint on without filling gouges, scratches etc. I intend to strip the old paint of and after preparing the surface properly I will use a two pack epoxy paint on the topside and deck.

The boat has several thru hull fittings on the stern, these being two Bilge pump outlets, one Exhaust outlet and two hinges for the stern mounted rudder. I would like to remove these to make it easier to repaint the hull. So my question is should I remove them? And if so is it ok to refit them onto a painted surface or do they have to be in contact with the F/glass to seal properly. Also what sort of sealant should I use to make them watertight again?

Thanks,
Bluey.

Re: Advice needed on thru hull fittings when painting f/glass boat

I would remove them. They most likely meed to be resealed. 3m 4200 if you ever want to get them off again. 3m 5200 if you want permanent. I use the 4200.

Re: Advice needed on thru hull fittings when painting f/glass boat

I agree with proshadetree, the paint between the hull and fittings won't be a problem. 3M 4200 is fine to reseal.

Re: Advice needed on thru hull fittings when painting f/glass boat

3m (makes 4200 and 5200) recommends that the sealing surface be prepped by scuffing. I recommend you sand off the paint in the area where the sealant needs to bond. If you are working with finish paint only remove the paint under the sealing flange of the thru-hull fittting. This way the sanded area will not show. Some paints contain silicone, if you do not remove it in the sealing surface, the caulk will not bond. Also clean the sealing surface of the sanded area with solvent and the flange of the fitting before putting it place.

Re: Advice needed on thru hull fittings when painting f/glass boat

When I do paint jobs I try to remove as much hardware as possible..so yes if you can remove the fittings please do.

The reason being is that when you tape them you will have an edge exposed to water .. ( could get under your paint and pop it around the fitting ).

Now..to reseal I would scuff the new paint around the hole with a scotch bright ( no need to remove the paint IMO ) and clean with windex before your install.

I also would use something like 3m 4000 ( Not the 4200 ). Yes you can remove the fitting if you need to using the 4200..but while doing so it might Peel up the surrounding paint EEK. You could scribe around the fitting first with a razor to score the new paint..but then your left back to water intrution..

I think being Above the waterline 4200 is not needed..

YD.

Re: Advice needed on thru hull fittings when painting f/glass boat

Wow I thought you needed to seal them all. I even sealed my bilge vents on my Bayliner. Learn something new everyday.

Re: Advice needed on thru hull fittings when painting f/glass boat

proshadetree said:

Wow I thought you needed to seal them all. I even sealed my bilge vents on my Bayliner. Learn something new everyday.

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No no proshade..I said 4200 is not needed..

Sorry if I sounded like you dont have to seal..just not with 4200.. use 4000 instead..

Yes Indead you Seal Everything lol...just in above waterline hull applications 4200 is too much..

Deck fittings yea..4200.. there are Few 5200 applications that I can think of ( bigger boats with loads of hardware etc..you know when you want to use 5200 ).

YD.

Re: Advice needed on thru hull fittings when painting f/glass boat

5200 below the water line? Like maybe ac intakes?

Re: Advice needed on thru hull fittings when painting f/glass boat

proshadetree said:

5200 below the water line? Like maybe ac intakes?

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5200 for Anything below waterline..

YD.

Re: Advice needed on thru hull fittings when painting f/glass boat

Hi everyone,
Many thanks to each of you for all the good advice, I do apologise for not responding to your posts sooner. There were some interesting points raised that I had not considered before, thanks for sharing your knowledge with me.

Cheers,
Bluey.