Fiberglassing
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==General information== | ==General information== | ||
| + | Fiberglass, fiberglas, 'glass are all terms used to describe a composite building material that contains a fibrous material that is saturated with an eventually hardened resin of some sort. The fiber component (usually finely stranded common glass, others discussed below) give the composite amazing tensile strength but, being a cloth, has no ability to hold a form. Thus the need for the resin which when saturated into the cloth is hardened with a chemical reaction giving the system strength against bending and shear forces. Not only does the resin give the composite form, it also is used to provide a surface for the desired finish of the product. Each component contributes a unique quality to the final composite and the whole is better than the parts. | ||
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| + | The following sections discuss some items that should be helpful to getting started in using fiberglass on your projects. Once you start using it and get comfortable with it, you will wonder how you ever lived without it. It is FUN!!!! | ||
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| + | ===How much mat (or cloth) to use=== | ||
You may wonder how many layers of mat to use; what kind of mat or cloth to use, etc. There isn't a single answer for all parts. The shroud shown in [[Make a fiberglass fan shroud]] is mainly for form and has little strength requirements, so it can be laid up with just the chopped strand mat. However, if it were a body part or some other part that would see some stress, the design should include one or more layers of woven cloth which is many times stronger than the mat. | You may wonder how many layers of mat to use; what kind of mat or cloth to use, etc. There isn't a single answer for all parts. The shroud shown in [[Make a fiberglass fan shroud]] is mainly for form and has little strength requirements, so it can be laid up with just the chopped strand mat. However, if it were a body part or some other part that would see some stress, the design should include one or more layers of woven cloth which is many times stronger than the mat. | ||
==Types of fiberglass== | ==Types of fiberglass== | ||
===Chopped strand mat=== | ===Chopped strand mat=== | ||
| − | '''Chopped strand mat''' is rated in ounces/sq ft. It commonly comes in 3/4, 1.5 and 2 oz/ | + | '''Chopped strand mat''' is rated in ounces/sq ft. It commonly comes in 3/4, 1.5 and 2 oz/sq-ft thicknesses. The 2 oz is probably most popular because it builds thickness quickly. The lighter thicknesses are obviously for smaller, more delicate applications. For most car parts, use the 2 oz. This material should always be used as a first layer in a finely finished mold such as a boat hull where there is a gel coat layer (final finish colored resin layer) then the 'glass. If you lay a layer of woven cloth directly under the gel coat it will 'print' through the gel coat and you will always see the pattern of the cloth no matter how much you sand and polish. The random pattern of the chopped mat strands isolates the cloth pattern from the final surface. Again, in a "male" mold, this isn't a consideration. |
===Surface veil=== | ===Surface veil=== | ||
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====Graphite==== | ====Graphite==== | ||
| − | Also called "carbon fiber". Really exotic, looks purty and necessary for the 350mph crowd, not so much for shade tree guys. To be purty, must be laid up in vinyl ester or epoxy resin in shiny female molds. Is fairly brittle so commonly has a layer of aramid cloth or fiberglass for toughness. | + | Also called "carbon fiber". Really exotic, looks purty and necessary for the 350mph crowd, not so much for shade tree guys. To be purty, must be laid up in vinyl ester or epoxy resin in shiny female molds. Is fairly brittle so commonly has a layer of aramid cloth or fiberglass for toughness. This stuff is sized in thousands of filaments, i.e. 1K, 5K, 12K, etc. |
====S-glass or E-glass==== | ====S-glass or E-glass==== | ||
These are high quality woven glass that is measurably stronger than regular woven fiberglass. More expensive and not necessary in most of hotrodding. | These are high quality woven glass that is measurably stronger than regular woven fiberglass. More expensive and not necessary in most of hotrodding. | ||
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| + | E-glass is actually the commonly found fiberglass that you would pick up at a boat supply or hardware store. | ||
| + | S-glass is the higher quality fiberglass mentioned above. Typically, E-glass is not labeled as such, it is the S-glass that is always prominently labeled. | ||
====Aramid==== | ====Aramid==== | ||
| − | Also called '''Kevlar''', this stuff is amazingly strong and tough. It is so tough, it is almost impossible to cut! It is used as strength enhancer in very light weight applications that need extraordinary | + | Also called '''Kevlar''', this stuff is amazingly strong and tough. It is so tough, it is almost impossible to cut! It is used as strength enhancer in very light weight applications that need extraordinary strength. Again, it is overkill for just about anything in hotrodding. |
====Unidirectional==== | ====Unidirectional==== | ||
| − | Like | + | Like it sounds, this is a specialty cloth that has most of its strands in one direction. It is sewn together and for special applications. Can be made of any of the above threads. Not necessary in hotrodding. |
==Types of resins== | ==Types of resins== | ||
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=====Ortho===== | =====Ortho===== | ||
| − | Made with | + | Made with orthophthalic acid, ortho is what you get if you don't specify anything else. Fine for most everything in hotrodding. |
=====Iso===== | =====Iso===== | ||
| − | Made with | + | Made with isophthalic acid, it bonds a little better than ortho but costs more. Again ortho is fine for most hotrodding work. An added benefit to using "iso" resin is that it is more heat resistant than ortho resin, it will withstand 210°F as opposed to 170°F for most ortho resins. Iso resin is also called "tooling" resin, because it is designed for moldmaking, and can withstand many heat/cool cycles and remain dimensionally stable. |
=====Waxed resin===== | =====Waxed resin===== | ||
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===Vinyl ester=== | ===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 hotrodding. Vinyl ester is much more heat resistant than either of the polyester resins, and also chemical resistant. It also shrinks | + | 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 hotrodding. Vinyl ester is much more heat resistant than either of the polyester resins, and also chemical resistant. It also shrinks a lot 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. |
==Cores== | ==Cores== | ||
| − | 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 | + | 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 tendency of thick parts to get mottled after time and exposure to heat. 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 a core, as it will provide a cushion against stars from rocks being thrown up by the tires. |
Some of the cores you can use are: | Some of the cores you can use are: | ||
===Balsa wood=== | ===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. | + | 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. Boat builders used it extensively for reinforcing large flat areas such as decks, hull bottoms and cabin roofs. It's even used in the floorpans of Corvettes, for stiffening the floor ([http://www.corvettecenter.com/_junkfiles/techhistory.htm], [http://en.wikipedia.org/wiki/Ochroma_pyramidale], [http://books.google.com/books?id=WrWydEwsc_4C&pg=PA10&lpg=PA10&dq=balsa+wood+corvettes&source=bl&ots=LnYxhxTRmR&sig=1FR2Yef1j7CmevLxt6PYj0PG6Vw&hl=en&ei=ySmpSseTIIbSsQPf6PyOBQ&sa=X&oi=book_result&ct=result&resnum=9#v=onepage&q=balsa%20wood%20corvettes&f=false]). |
===Coremat=== | ===Coremat=== | ||
| − | This 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 much 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 mat or cloth, then put another layer of mat over the top. | + | This is a material that looks similar to the absorbent paper shop rags that come in a roll. It's made with fiberglass and microballoons (more on 3-M microbaloons, aka microspheres [http://multimedia.3m.com/mws/mediawebserver?mwsId=66666UuZjcFSLXTtm8TXlxTtEVuQEcuZgVs6EVs6E666666--&fn=MicrospApGuide_DMR.pdf HERE], along with a binder. It's much 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 mat or cloth, then put another layer of mat over the top. |
===Urethane foam=== | ===Urethane foam=== | ||
| − | This comes in varying thicknesses, and is used much like | + | This comes in varying thicknesses, and is used much like balsa wood. Not only is it good for filler material in a fiberglass layup, it is great for carving molds for parts. Folks have even carved entire car bodies from urethane foam blocks then used that for making a female fiberglass mold which in turn is used to make production car bodies. |
==Fiberglassing procedure== | ==Fiberglassing procedure== | ||
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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. | 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. | ||
| − | For one example, see [http://www.hotrodders.com/forum/journal.php?action=view&journalid=2439&page=25&perpage=5&reverse= this journal entry from Willys36]. It's a shell for the headliner of a '53 Chevy pickup, and used only 2 layers of mat (about 3/32" thick) for light weight and flexibility. It is more than strong enough. This is also an example of a part made from a female mold, but without the gel coat since it is covered with upholstery and doesn't need a paintable finish. | + | For one example, see [http://www.hotrodders.com/forum/journal.php?action=view&journalid=2439&page=25&perpage=5&reverse= this journal entry from Willys36]. It's a shell for the headliner of a '53 Chevy pickup, and used only 2 layers of mat (about 3/32" thick) for light weight and flexibility. It is more than strong enough. This is also an example of a part made from a sort of female mold (the roof of the truck), but without the gel coat since it is covered with upholstery and doesn't need a paintable finish. |
===Reinforcing edges=== | ===Reinforcing edges=== | ||
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