Auto Body filler?

[BuzzStPoint]

After cutting apart the boat and now into the fiber glassing.
I'm having an issue trying to get everything smooth.
I either have the problem of grinding down past the cloth and re applying. Or 2 much resin and having to grind down again.

Since this in on the Topside of the boat and not below the waterline, Can I use autobody filler to smooth things about?

 

[Bob_VT]

Re: Auto Body filler?

Rumor has it that it absorbs water...... make some peanut butter and use it for fairing

 

[wicked]

Re: Auto Body filler?

dont worry about using bondo or plastic filler it will not absorb water if properly primed, i repainted my boat about five years ago and used autobody fill and it was under the water line and has held up excellent. i think that saying bondo absorbes water is an old wives tale!!

 

[Mark42]

Re: Auto Body filler?

After cutting apart the boat and now into the fiber glassing.
I'm having an issue trying to get everything smooth.
I either have the problem of grinding down past the cloth and re applying. Or 2 much resin and having to grind down again.

Since this in on the Topside of the boat and not below the waterline, Can I use autobody filler to smooth things about?

Yes, especially if its a polyester resin. Use a high quality body filler like Marsons Platinum Premium Gold filler. Its a high end body filler that is meant to be used in difficult adhesion situations. This stuff sticks like no body filler I've seen before. After curing, its hard to get off the applicators, your fingers and anything else it gets on.

I did a lot of research and talked to a few body shops about my project and what to use. The Marsons was recognized as a top shelf product. I think its a 3M product if I remember right.

I would not use it below the water line, but above it is no problem.

 

[Mark42]

Re: Auto Body filler?

dont worry about using bondo or plastic filler it will not absorb water if properly primed, i repainted my boat about five years ago and used autobody fill and it was under the water line and has held up excellent. i think that saying bondo absorbes water is an old wives tale!!

I think the problem lies where a boat is slipped or moored and water can penetrate the paint and attack the body filler. Because Bondo is about 40% Talc, it can absorb moisture readily. So that is the problem with using Bondo below the water line. Even polyester and vinylester gel coats are not impervious to water, as is testified by osmosis blisters on the hull of many moored boats.

Above the water line, its no problem, and even over epoxy, I don't think its a problem. Notice the lack of threads about failed bondo filler. Either no one uses it, or its used and works fine.

 

[wicked]

Re: Auto Body filler?

just came back from the garage and the stuff i used was called PARASOL and it will not absorb water , look it up if need be. most people use clear cloat over the paint to protect it just like the automotive industry

 

[BuzzStPoint]

Re: Auto Body filler?

yeah, it's the upper cap.

I'm using the Bondo Fiberglass resin. The website says that's a Poly resin.
Since I don't have any bondo now, I mixed up a small batch resin and applied a thick coat on 2 spots. This I should be able to sand down, But it the vertical sides that the resin doesn't want to stay put. This is why I thought the putty auto body filler would come in handy.

My local Menards has Interlux Marine paint and primer. So i'll be using that.

 

[ondarvr]

Re: Auto Body filler?

Parasol will absorb water, everything does, will the water have detrimental affects.....that's hard to say. It appears to be a better than normal product and at $50.00 per quart it better be. At that price you could use a marine grade product, I'm not saying Parasol isn't, just never used it. Cheap body filler sucks up water like a sponge, its not an old wives tale, so high humidity areas and under water use are out of the question, in some applications above the water line it may work, but isn't a great option,.

 

[jonesg]

Re: Auto Body filler?

yeah, it's the upper cap.

I'm using the Bondo Fiberglass resin. The website says that's a Poly resin.
Since I don't have any bondo now, I mixed up a small batch resin and applied a thick coat on 2 spots. This I should be able to sand down, But it the vertical sides that the resin doesn't want to stay put. This is why I thought the putty auto body filler would come in handy.

My local Menards has Interlux Marine paint and primer. So i'll be using that.

you need some cabosil powder, it makes the resin almost gel and prevents running in vertical applications. Just stir it into the resin until you say "yeh thats more like it" then add the mekp and use it fast as it will gel up a lot quicker, for higher strength areas just add some chopped fibre to the basic cabolsil putty and it will set hard as stone.

 

[erikgreen]

Re: Auto Body filler?

Hmm, the thing I find interesting about this is that you're wanting to use an automotive product to do a repair, yet you're planning on painting with a top quality expensive paint.

As has been mentioned, if you can afford the interlux then get a marine grade filler to work with. If you don't want to mix your own up, that is.

Same deal with the Bondo resin. Bondo is decent quality polyester, but it's far too thick to easily wet out fiberglass that's more than about 8 oz fabric or the same thickness of mat. You need to get a layup poly resin meant for boats, or a thin epoxy.

If you're able to use the good paint why not do the rest of the repair right?

Erik

 

[BuzzStPoint]

Re: Auto Body filler?

The only reason I mentioned the Interlux, it's because thats all I have seen around the stores.
Only other recommendation I had was to use Tractor Paint.
But the other day I seen the interlux while getting paint for my work.

If I can find carbisol then I'll use that.

 

[BuzzStPoint]

Re: Auto Body filler?

Stopped and picked up some fill. But I didn't pick up standard Bondo body filler.
I picked up..

Bondo? Bondo-Glass? Fiberglass Reinforced Filler
Bondo-Glass is a unique reinforced filler containing short, interlocking fiberglass strands and fibers that make it twice as strong as regular body filler. Repairs small (dime size or smaller) rusted-out metal holes and shattered fiberglass body parts.

Works great on boats! Eliminates the need for backing strips, fiberglass resin or cloth on small holes and rusted-out areas. Sandable in only 20 minutes and compatible with all paint systems. Waterproof. Includes Red Cream Hardener

I was able to take care of the trouble spots that would have taken me a few days worth of Resin work.

 

[wca_tim]

Re: Auto Body filler?

depending on how large the "imprefections" you're trying to fill are, you can use a high build epoxy-based marine primer... it's water-imprevious and can be used to fill and smooth pretty substantial surface stuff.

if you use resin thickened with carbosil (love that stuff) add baloons to make it easy to sand and then recoat the whole thing with a good marine epoxy primer... just my two cents.,,

 

[BuzzStPoint]

Re: Auto Body filler?

The normal hardware stores here didn't have any, nor did they know what I was talking about.
I didn't try any paint stores or marine stores. Probably could get it at carquest but dont want to pay their prices.

 

[NSBCraig]

Re: Auto Body filler?

Body filler does NOT absorb water. That's just not true, I've soaked chunks in water for weeks, when I took them out I dried the surface and the sanded into them- zero moisture. I cut them up and still nothing.

Don't just put think coats of resin anywhere it will fail when stressed. Poly needs reinforcing.

Bondo resin is waxed so that's kind of a pain since you need to sand between coats.

 

[RogersJetboat454]

Re: Auto Body filler?

2.5 year old thread people...