Need bottom paint removal help

[KCKracker]

I just bought a 21-ft trophy and it looks like they rolled on some black bottom paint and also it looks like there's some primer above that and around it wondering how to remove all of this garbage and get back down to the gel coat

 

[dingbat]

I just bought a 21-ft trophy and it looks like they rolled on some black bottom paint and also it looks like there's some primer above that and around it wondering how to remove all of this garbage and get back down to the gel coat

Looks like bottom paint.....
You can scrape or soda blast to remove but your bottom will never look good again.
Faced with the same problem, I scraped the best I could and repainted with2 coats of "hard" anti-fouling paint.
Was easier to keep looking good than stripping and dealing with the alternative.

 

[KCKracker]

Paint remover won't take it off?

 

[dingbat]

Paint remover won't take it off?

No problem if you don’t mind laying on your back for hours on end with a toxic mixture of bottom paint and paint stripper dripping all over you…

If you don’t like scrapping you could always sand. Break out the respirator and a couple large sheets of plastic to catch the (toxic) dust and spend a day or two sanding it off.

If the paint was applied correctly, the gel coat was first sanded and a barrier coat applied prior to applying who knows how many coats of bottom paint. I’ve seen bottom paint an 1/8” thick…

No matter what method you use to remove the old paint, your going to be left with a mess for a bottom that needs to be dealt with.

 

[Chris51280]

I did mine with 220 sandpaper. worked out good but it sure is a lot of work. need to go back to use finer sand paper and then polish. but it looks better now without the crusty red paint

 

[alldodge]

Pay to have it removed, I did
Paid to have mine removed down to the gel. Some spots it was removed to the glass. I then painted 4 coats of Interlux Performance VC which is epoxy.

You could use stripper but it will take a few coats and probably still need to sand

 

[Chris51280]

stripper made a bigger mess and gummed up my sand paper.

 

[Lectro88]

who knows how many coats of bottom paint. I’ve seen bottom paint an 1/8” thick…

True..


This was true in my case. And I have not finished this task... YET.
I started out with 120 grit on an electric orbital sander and after about 20 seconds with that I went to 36 grit and it still laughed at me.
I spent at least an hour with 36 and only got a section at the rib right at the waterline. I had Black and Blue in hidden layers. I wondered if each new owner applied a layer every year since 1969. @#!$%^&?!
I quickly figured that a new approach was in order.
I found some 24 and 16 grit roll stock it was 8' or 12" wide and several yards in length.
I glue this to new hook and loop discs and it really wakes things up.
Have not tried my altered discs on bottom paint yet, and I since acquired an air orb. sander.
This works great for shaping stringers.
My point is,.. after getting off topic.
It takes a pretty aggressive approach with bottom paint and its MESSY and time consuming no matter what method you choose.
My method is also with the mind set of re-gel-coating is near in the future.
So while others cringe keep that in mind. choose what works for you best.
This was just my encounter with bottom paint.

 

[Chris1956]

If you have it soda blasted, it will be a matte finish, but intact gelcoat. You may be able to shine it up.

A 36 grit grinder will strip it down to the gelcoat, but it will rough up and likely remove some of the surface of the gel coat. it will not take long as the antifouling paint is real soft.

If you go this route, you will want to paint the bottom for appearance. if trailering a 1 part polyurethane will work. Obviously you will want to sand it to 80 grit before painting. Roll and tip of the paint is pretty good.

 

[Lectro88]

If you have it soda blasted, it will be a matte finish, but intact gelcoat. You may be able to shine it up.

A 36 grit grinder will strip it down to the gelcoat, but it will rough up and likely remove some of the surface of the gel coat. it will not take long as the antifouling paint is real soft.

If you go this route, you will want to paint the bottom for appearance. if trailering a 1 part polyurethane will work. Obviously you will want to sand it to 80 grit before painting. Roll and tip of the paint is pretty good.

You are correct in all you stated.

Allow me to clarify a few things,. about my reply.
1st. I was using an orbital Sander, not a grinder. (big difference)
2nd. it was electric, so again maybe not as aggressive as a good air version.
3rd. my plan was to get through MOST of the minimum if not thicker than 1/8" layers.., then ease up with 80-120 grit. again it was thick as 2-4 layers of fiberglass.,.(part of this I didn't clarify)
4th. My particular situation was a pretty challenging, old and many layers.
and I made it clear a re-gel was to follow so not so much concern about a few scratches, as you have a whole different prep process for that. going through the gears.
I should have been more detailed, and yes 36 grit is aggressive, I took it for granted this was already understood.
Sometimes 1 forgets, not everyone has same exposure to smaller unexplained details,
And we are hammering this out from a keyboard. so a lot can be missed as we short hand explanations.

 

[tpenfield]

I've used 'Peel Away' to soften up bottom paint so it can be easily removed with putty knives. Then you could media blast to get any residual.

The challenge is always to remove the paint and leave the gelcoat.

 

[cptbill]

Put on your best tyvek get your sander and have at it. Of course put down a tarp or plastic so you can dispose of the sanding properly. Media blasting and soda blasting also will work as stated above, stripers also. It just depends on what your trying to pu back on