Who can tell me about "Kitty Hair" for fiberglass work.

I've only used kitty hair once that I can remember and that was as a filler / build up between layers of woven mat. From what I have been able to read, its primary use is as a filler, NOT for structural strength over a large area.

Here is why I ask, my car is still in the shop (week 6) and when I spoke to the guys in the body shop I was told they repaired the composite hood with kitty hair. To give you an idea, the composite the hood is made of is about 3/16" thick. (give or take, I haven't measured it other than by eyeball.) The deer I hit struck the hood hard enough it was cracked all the way through, cracks visible on the bottom side in a spider web pattern probably about 8" in diameter, about 12" on the top.

The "repair" performed was to sand away the paint and primer, slap kitty hair on it, sand smooth and repaint. My gut feeling is this sort of repair has no real structural strength compared to laying down a woven mat and glassing it. I envision hitting a bad bump when it?s cold (or hot) or someone leans on it, etc. and the filler simply pops out.

Need onions on this repair. Will Kitty hair bond well enough? Is there any structural strength with this sort of fix? At 100+ MPH am I going to watch it crumble before my eyes?


As to why the hood is being repaired instead of replaced, it's no longer available from GM. (Did find one in a warehouse but the guy wanted almost a grand for it and the insurance balked.)

Re: Who can tell me about "Kitty Hair" for fiberglass work.

Kitty Hair is a fine product for this application. It's been used as a body filler for some time now. I believe Evercoat makes it. Has fiberglass strands in it, making it durable.

Re: Who can tell me about "Kitty Hair" for fiberglass work.

Hey bubba,

When you say structural, I began wandering what stresses are placed upon hood? I guess my comment is that structural on the hull of a boat doesn't correlate to structural on the hood of a car.

I haven't used Kitty Hair, but have used other fillers with FG strands. It seems pretty strong to me. Good luck with the repair.

Re: Who can tell me about "Kitty Hair" for fiberglass work.

Bubba1235 said:

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Not arguing the point, just concerned.

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Your concen is justified, Bubba, and curiosity got the best of me.

I contacted an old friend who repairs surfboards. He started using Kitty Hair several years ago. At the time he started using it, he thought it was the best thing on the market. He stated in over 7 years he has never had one returned due to a faulty repair. I would assume a surfbord sees more force than a car hood.

We haven't been in touch in a couple years....a good thing came out of my call....we are going fishing together this evening and he is buying dinner at our once favorite waterfront dining hole.

I forgot about Kitty Hair over time. I will be following this thread with interest on other's opinions.

Re: Who can tell me about "Kitty Hair" for fiberglass work.

sasto said:

I would assume a surfbord sees more force than a car hood.

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I wouldn't assume that at all, and I would think that it would be a potentially catastrophic assumption to make.
Given the widely different characteristics of the two, I am not sure the relevance, either.

A surfboard has inherently more rigidity (sandwich construction....double layer around a core) and strength.
I still suggest that an auto forum that "specialises" in F/G vehicles would be a better source of info than this one....

Tim Frank said:

Not sure that I have any suggestions on cleaning, actually, I am sure I don't....:facepalm: but maybe I can offer a helpful idea.

Check out a forum for Corvettes or other mostly F/G autos and post your question there. I would think that this has happened before, and there would be a greater likelihood of someone having had the same problem in that sample group; you may get some hands-on advice from the BTDT gang as to exactly what the scope of the cleaning would have to entail for an acceptable result, what to watch out for, and other info.

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Re: Who can tell me about "Kitty Hair" for fiberglass work.

Bubba1235 said:

I would feel a 100 times better if the repair had a layer or two of woven mat in it. Keep in mind, the cracks go all the way through to the underside of the hood.

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I don't blame ya'.....Bubba!

Re: Who can tell me about "Kitty Hair" for fiberglass work.

Bubba1235 said:

Tim,

I talked with a several guys on the Camaro / Vette forum. All of them said replace the hood. General concensus is that because the hood is so thin and light weight it can't really be repaired without more work than a new hood would cost. On the positive side, I found one for about $700 and am going to talk to the insurance company and see if they will go for it or maybe eat half the cost if I pick up the other half.

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They are the guys who should know....so you are likely on the right track with a NOS (if that is what you found) or a good used.

Re: Who can tell me about "Kitty Hair" for fiberglass work.

That's great!
By the sounds of it then, both you and the dealer will be getting "new ones".

Re: Who can tell me about "Kitty Hair" for fiberglass work.

I once worked in a body shop that repaired the front end fiberglass hoods on school buses. We were one of the first DOT body shops to start using the stuff and it made the work go faster with good results.You could fill in large areas that would take forever using just layers of mat.

Re: Who can tell me about "Kitty Hair" for fiberglass work.

little technical information here.

kitty hair is nothing more than long strand fibreglass in a pre mixed hi grade resin solution. the long strands give good structural properties.
imho......a thin woven product over the whole thing would be far superior.
it would however be best used to form an area or fill and shape an area like a fender. on a hood.....the fairing time would not be cost effective.

the bond is only as good as the prep work . it would be fine as a repair, however, it is cheaper to replace as suggested above.

6 weeks is an insanely long time for a repair bud.....even for a busy shop.

Re: Who can tell me about "Kitty Hair" for fiberglass work.

It works good for standard repairs. In the case of a high speed race car Im sure your insurance agent knowing all this figured a new solid race ready hood is safer......Maybe these would help out . They are made just for such things