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Repairing a busted up Cowl

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Repairing a busted up Cowl

Old 05-25-2005, 10:24 AM
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dasintex
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Default Repairing a busted up Cowl

Had a rough landing and busted up the cowl; replacement is no longer available; cowl is repairable all pieces fit together; my plan is, unless someone has some better advice, is to use lightweight Fiberglass cloth on the inside to hold the fractured portions together then mix up some epoxy and micro balloons as filler and apply on the outside surface to the cracks/fractured areas, sand and paint; am I on track; One question: I was told that I could use epoxy with the fiberglass cloth instead of Fiberglass resin/hardener: good idea or bad; if it is good idea to use epoxy; do I thin it out and with what? Thanks.
Old 05-25-2005, 12:10 PM
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Default RE: Repairing a busted up Cowl

Good plan except I would use this CA (IN A WELL VENTILATED AREA) to apply 1 or 2 oz fiberglass on the inside. After you've made the initial repair, add a couple of more layers of lightweight fiberglass on inside to strengthen the cowl.
Old 05-25-2005, 12:37 PM
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Default RE: Repairing a busted up Cowl

What material is the cowling made from?
Old 05-25-2005, 12:46 PM
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dasintex
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Default RE: Repairing a busted up Cowl

Luvbipes: Are you suggesting thin CA because it sets quicker and will hold the fractured parts together in less time decreasing the need to hold them in place for a long time?

Lightfoot: It's a cowl from Kyosho and I believe its thin Fiberglass; when I used the Dremel to make engine cutouts the dust gave me the impression it was fiberglass; just not too thick; not very stout, pretty certain its not plastic.
Old 05-26-2005, 04:30 AM
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shogunmst
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Default RE: Repairing a busted up Cowl

This is what i did.....I CAed the cowl back together then luck for me, I knew someone who was able to vacume me another to remake with thin layers of fibergalss.
Old 05-26-2005, 02:12 PM
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JohnW
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Default RE: Repairing a busted up Cowl

If you have dust, sound like glass to me.

The CA method posted above works, but the down side is that it is brittle and may crack. For small repairs, I'll use CA becasue it is quick. But for larger repairs, I prefer to use epoxy to fix glass parts.

Yes, the best method is to lay new glass behind and fill in outside consmetic cracks with a filler. Expoxy/balloons work as well as many autobody catalized fillers such as Evercoat.

For best success, sand the back surface with coarse paper. You're not looking for smooth, but a good surface for the expoxy to bond to so it can look a bit rough. Clean well with alcohol, MEK or similar. Let dry. Precut cloth to cover the area to be repaired.

For best results, you need a thin (like warm syrup) epoxy. If you have laminating epoxy, which I doubt becuase of the question, use it, otherwise normal building epoxy will flow well if warm. Thinners (such as MEK) will help flow some, but I'd avoid them because they can get trapped in the expoy. I's suggest warming the expoy to about 100F before mixing in a warm water bath. Be aware that it will kick a whole lot faster when pre-warmed, so use 30 minute or higher.

Mix epoxy and lay the cloth over the spot to be repaired. Using a small (1/2" - 1" wide or simialar) brush, "paint" the epoxy onto the glass, working the glass to the shape of the part. The glass will change color from white to clear when you have "wetted" the glass enough. It is easy to apply too much epoxy. If you have pools of epoxy floating on top of the glass, they only add weight and very little strenght. You can remove this excess epoxy by daubing with a paper towel. What you are looing for is clearly wet cloth, but no pools of epoxy. Once satisfied, let cure.

If the part is really fubar, you may wish to tape and brace (on the outside) the part to the proper shape before laying the glass.

I probably made it sound complicated with the detail, but it really is very simple and quick.

Forgot to mention this above. You will want to use glass of the same weight as the part for repair. Not knowing your part, If it is 40/60 sized model, I'd start with 2lb glass. You can always lay more layers if needed. As for the microballoon, that stuff won't sand well if you mix it to thin. You may be suprised to find you can mix a LOT of the beads in a small blob of epoxy. Shoot for a mix that is the consistency around that of mayo or peanut butter. It will sand a lot easier. Rememeber, the stuff on the outside is just cosmetic, the strenght comes from the glass behind.

Cheers.

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