Re-painting bottom...how much prep?

[Buzz Killington]

I have been using stripper/scrapers and an electric sander to get the horrible mess of antifouling off my T-bird.

Here's how the best of it looks right now:

I am going to be painting the hull with Rustoleum Topside. Boat is trailered. My question is, do I need to worry about stripping EVERY bit of the old antifouling off, or is a good, clean, level surface (like shown in the pic, more or less, with some residue) OK?

EDIT: or can I prime over this goop?

Thanks!

Dave
getting there

 

[Greg Mrozinski]

Re: Re-painting bottom...how much prep?

Honestly, if it were me, I would strip down to gel coat before painting. If for no other reason than to prevent paint failure and then have to fix it. Painting prep is a PITA! So much so that I would only want to do it once!

 

[oops!]

Re: Re-painting bottom...how much prep?

in a paint job......the prep IS EVERYTHING.

when you think you MIGHT be done....do it again...then again till you know your done.

i prepped for gellcoating, thought i was done....and wasn't even close.

i would also remove any old bottom paint down to the gellcoat......its only another few hours work. but the results will speak for themselves.

good luck.
oops

 

[Buzz Killington]

Re: Re-painting bottom...how much prep?

My understanding (I don't have the label handy) was that the Rustoleum topside could be applied on good, existing paint that was well-scuffed. If I take this down all the way, I'd have to prime it, wouldn't I?

 

[tmcalavy]

Re: Re-painting bottom...how much prep?

Yes, but Rustoleum makes a good primer, too. Can't tell from your pix...is it a glass or aluminum hull? If aluminum and you strip down to bare surface, you need to prime with a self-etching primer...not hard to find and not that pricey. If it's glass, I have no idea.

 

[NateL]

Re: Re-painting bottom...how much prep?

After reading your post I looked up this "topside" stuff and I states on there site that it's for above the water line. As far as primer goes a self etch primer is used for metal. You'll probably wanna use two or three coats of a good "high build" primer. If you end up priming it (which I believe is always a good idea) spray a couple coats on let it dry to manufacture's directions sand it and if its where you want it the paint. A good coat of primer/sealer can save you some headache in the end. Not only will it help seal up some bad if ya missed anything, but it will also give you a look at what your end result will be as far as smoothness in your final finish. "Your finish is only as good as what's underneath"