Bondo Hair

[WesGrimes]

Has anyone used Bondo Hair, or a similar fiberglass strand reinforced body filler on their builds?

I need to do some contour molding on my body (The teardop trailer body that is ) and I do not want to end up with a 1/2" thick wall of bondo that is going to crack when I hit a pot hole.

My thought was to use the Bondo Hair for the major contouring and final coat it with regular Bondo.

I might add that I have no idea what I am doing here

Any of our resident glass experts have any advice?

Thanks,
Wes

[Ageless]

Get some fiberglass window screen. Apply a very thin coat of bondo; bed the screen, apply enough bondo to fill

Never, never go beyond 1/8" thick with bondo!!

[caseydog]

Never, never go beyond 1/8" thick with bondo!!

Earl Scheib and the folks at Maaco might beg to differ.

But, I agree, Bondo is best used in extreme moderation.

CD

[WesGrimes]

But what if I do need to fill more than 1/8"?

The idea behind the Bondo Hair is that it is a bunch of fiberglass strands mixed with Bondo. If I understand the product correctly, you can apply it much thicker, and the embedded strands of fiberglass will keep it from breaking.

Ageless, Is the window screen reinforcement still needed at just 1/8" thick?

Thanks for the guidance.

Wes

[Ageless]

If you need to go thicker than 1/8", get some mill fiber. This is very short pieces of glass cloth; almost a powder. Mix with regular resin to make a filler putty.

Bondo in any form; is only used for minor surface leveling.

[afreegreek]

better than bondo is a little bit of epoxy thickened to the max with colloidal silica, low density fairing filler or microlite. you only need enough epoxy to get it to stick together and a thin coat where you're going to apply it. btw, bondo applied to raw wood won't stick worth a $hit no matter how thick or thin it is.

http://www.westsystem.com/ss/fillers

[afreegreek]

if you want a bondo type filler, this is much better. it's lighter, sands better, is waterproof, has a longer working time, and you can build it up much thicker than bondo. it's an epoxy base product.

http://www.awlgrip.com/products/search/ ... ir_LW.aspx

[doug hodder]

Like previously mentioned....thickening agents in an epoxy work much better than a "bondo" polyester type filler....There are fillet and fairing additives that do the job great and won't want to pop off like bondo. I don't do the wood powder from a sanding cup...some do, I just get the correct additive and not worry about it working out. Just my experience with it all. Doug

[WesGrimes]

Thank you all!

I could smell that I was about to do something really stupid! It is kind of like the sweet smell of rain in the air before a summer storm...

[AZSpyder]

Recently I have been trying foam in a spray can for building up shapes. I used one that goes by the name "Great Stuff". It is intended for filling gaps around the house. Polyester resin does not melt it. I built up some areas and carved and sanded to shape before adding a layer of fiberglass cloth. Just don't go too thick or it will not expand in the center of the glob until you carve into it, then it starts expanding and squirting out making a wonderful mess. I had to build a dam to make it so thick that it did that. Don't expect it to set up right if you try more then 1 1/2 to 2 inches at a time.
Jerry

[WesGrimes]

Recently I have been trying foam in a spray can for building up shapes. I used one that goes by the name "Great Stuff". It is intended for filling gaps around the house. Polyester resin does not melt it. I built up some areas and carved and sanded to shape before adding a layer of fiberglass cloth. Just don't go too thick or it will not expand in the center of the glob until you carve into it, then it starts expanding and squirting out making a wonderful mess. I had to build a dam to make it so thick that it did that. Don't expect it to set up right if you try more then 1 1/2 to 2 inches at a time.
Jerry

Jerry,
I have been using both 2 part PU foam and the Great Stuff canned PU foam to make my shape that I am now covering in glass.


The thing is, I have gotten a little carried away here and there with sanding the foam down. Adding additional foam to the existing foam would be possible, but a royal pain in da rear. I have chosen to cover it in one layer of fiberglass, and then fill it up to shape with *something* and cover it with a couple of more layers of glass before fairing and painting.

P.S. I have used both the pour and mix and canned foam and I can tell you with out a doubt that the pour and mix is WAY BETTER! I ordered mine from Jamestown distributors.

Thanks,
Wes

[starleen2]

Wes - a different approach - I used bondo as a filler before applying fiberglass - I used it to fill some wide gaps and to shape some contours on the Ladybug - THEN covered it over with glass to secure it in place. After the resin cured, I applied a skim coat OVER the glass for final sanding.

[parnold]

For information on the "hair" bondo check out this pdf. I have used duraglass many times.

http://uschem.com/products/docs/TDS_Duraglas1.pdf

max recommended thickness is only 1/4 inch. I won't tell you about the car I drove for years with over an inch thick of this stuff on it. Car was totalled by some kid that was high as a kite. Paid someone to replace the rear axle, but I pounded out the dent my self. I drove the car for another 70,000 miles after the repair, which was literally 4 years.

afreegeek said:

bondo applied to raw wood won't stick worth a $hit no matter how thick or thin it is.

What kind of bondo are you using, I've never had any adhesion problems? I've built several speaker cabinets, and the tear.

[dh]

Reminds me of the guy in 11th grade who fixed up a 62 Chevy truck. Hit a speed bump and half the fender fell off.

[eamarquardt]

Never, never go beyond 1/8" thick with bondo!!

Earl Scheib and the folks at Maaco might beg to differ. :lol:

But, I agree, Bondo is best used in extreme moderation.

CD

I've never heard of Maaco! Was concerned that my only choice for "superior autobody work" was Earl Schieb" here in So. Cal.! Googled Maaco and was relieved to learn that there are THREE of them within 50 miles. My lucky day!!

Cheers,

Gus