Make a fiberglass fan shroud
(→General Comments on Fiberglassing) |
(→General Comments on Fiberglassing) |
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'''Gel coat''' - this is resin filled with a high solids usually colored pigment. It can either serve as a primered surface to be sanded and painted or as in the case of boats, can be the final colored finish. It is sprayed in a polished female mold without reinforcement, then 'glas is laminated on it. It is much softer than plain resin and works like a sanding primer. Good stuff. | '''Gel coat''' - this is resin filled with a high solids usually colored pigment. It can either serve as a primered surface to be sanded and painted or as in the case of boats, can be the final colored finish. It is sprayed in a polished female mold without reinforcement, then 'glas is laminated on it. It is much softer than plain resin and works like a sanding primer. Good stuff. | ||
| − | '''Epoxy''' - much stronger than polyester but more persnikety (I think that's a word!) and expensive. Also check with the supplier for compatibility 'cause some cloths won't work with some resins. I would only use this for looks if making a carbon fiber part. | + | '''Epoxy''' - much stronger than polyester but more persnikety (I think that's a word!) and expensive. Also check with the supplier for compatibility 'cause some cloths won't work with some resins. I would only use this for looks if making a carbon fiber part. Epoxy resin is also tough on skin and your respiratory tract, and is much harder to work with, vacuum bagging the parts when laminating is commonly used with epoxy, because it is so much harder to remove air pockets with rollers or squeegees. |
| − | '''Vinyl Ester''' - this is a stronger version of polyester resin and somewhere between polyester and epoxy in strength. | + | '''Vinyl Ester''' - this is a stronger version of polyester resin and somewhere between polyester and epoxy in strength. It has the ease of workability of polyester and compliments the strength of fiberglass much better than polyester. Not usually needed in what we do. Vinyl ester is much more heat resistant than either of the polyester resins, and also chemical resistant. It also shrinks alot less, so print-through is less of a problem. If you want to easily make some very strong, rigid and lightweight parts, use vinyl ester resin, along with either fiberglass mat or cloth, and add a layer of 6 oz carbon fiber in the middle of the laminate. |
| − | As far as how much to use depends on the part you are making. If I were making that fan shroud I would lay up two layers of mat over most of it and reinforce all the edges with a third layer. All 2 oz mat. This would give a very light weight body, a little less than 1/8" thick and stronger edges a little more than 1/8" thick. | + | As far as how much to use depends on the part you are making. If I were making that fan shroud I would lay up two layers of mat over most of it and reinforce all the edges with a third layer. All 2 oz mat. This would give a very light weight body, a little less than 1/8" thick and stronger edges a little more than 1/8" thick. |
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| + | There are also many cores available for use in FRP laminates, use of a core can increase the rigidity of a part without increasing the weight or tendancy of thick parts to get mottled after time and exposure to heat. Some of the cores you can use are: | ||
| + | Balsa wood, this is used in large flat areas and needs to be bedded in...not really a good choice but it is one of the oldest cores. Boatbuilders used it extensively for reinforcing large flat areas such as decks, hull bottoms and cabin roofs. | ||
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| + | Coremat is a material that looks similar to the absorbent paper shop rags that come in a roll, it's made with fiberglass and microballoons, along with a binder. It's mich more flexible than balsa, and it comes in several thicknesses, 3mm, 5mm, and 8mm..This you lay up into your part, just like another layer of matt or cloth, then put another layer of mat over the top. | ||
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| + | Urethane foam..this comes in varying thicknesses, and is used much like balsawood. | ||
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| + | Use a core anywhere you have a large flat or gently curved area, roofs, hood tops, floorpans, bellypans. The underside of fenders above the tires is a good place to use coremat, as it will provide a cushion against stars from rocks being thrown up by the tires. | ||
A body part would need a couple layers of 2oz mat, a layer of 1.5oz plain weave cloth and possibly a third layer of mat, depending on size. Again reinforce edges as required with a strip of mat. You can also reinforce edges with woven tape, this puts many continuous unbroken filaments parallel with the edge of a part, and will make it much more resistant to cracking from the edge in. | A body part would need a couple layers of 2oz mat, a layer of 1.5oz plain weave cloth and possibly a third layer of mat, depending on size. Again reinforce edges as required with a strip of mat. You can also reinforce edges with woven tape, this puts many continuous unbroken filaments parallel with the edge of a part, and will make it much more resistant to cracking from the edge in. | ||
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