[KRD]

I making a fiberglass console. Do you think that paper mache' is a good idea for making the mold. Will fiberglass or Duraglass eat through the paper mache'?

[powerrodsmike]

Paper mache is not the best material to put fiberglass over unless you brace it up really good from underneath. It tends to break when you do your laminating. You shouldn't have a problem with the resin eating the paper mache unless you use a glue that dissolves under resin. try a little test sample. Or you could make your paper mache buck and then coat it with several layers of resin to make it stiff. then wax it several times or use some Vaseline or poly vinyl alcohol (PVA) to seal it off from the final laminate. I have found a better material to use is the thick poster board like they use for matte picture framing. It is about 1/16 thick. Build a wood frame then staple the posterboard to it. Use that for the flat areas and sections with straight, (not compound), curves. You can then use modeling clay to fill in any areas that need complex shapes. I like using this method when I have a customer's car to do and I don't want to spend eternity protecting the interior of the car from what I'll describe next. Method B: you can do what we do at the fiberglass shop and use polyurethane foam. (don't use Styrofoam, It melts when polyester resin touches it).It comes in sheets from about 1" to about 8" thick or more. With that stuff you can make your shape as intricate as you'd like. It is light and shapes really easily with sure-form files , sand paper, knives, sticks, fingernails. You can glue it together with a hot-melt glue gun. It does make a mess with dust though. Chicken wire is another old timey way guys used to make a buck. You can use most any material for a buck, as long as it meets these standards: stiff and strong enough to be dimensionally stable throughout the process of shaping and laminating, be unaffected by the solvents in the resin that you are using, You can tape off the entire buck and wax it to seal it off from the resin, in fact this makes it much easier to remove the buck after you are done with making the part. You can leave the buck under the part if you want to, just skip the waxing part. We always removed the buck and sanded the inside of the part after we were done and it really made a clean, professional looking part. I'm sure that there are other ways to build a frp console, these are ways that have worked for me. hope this helps.

[KRD]

1 more question

rather than spending all the time to build the mold, could I just use my stock console and add what I want with the clay, then glass it?

[powerrodsmike]

Are you trying to build a "mold" that you can build a part in and then reuse, or are you going to use your old console as a "buck" to build a shape over . the difference is a mold can be used many times over to make many parts. Making a proper mold is time consuming but worth the effort if you want a part that is almost completely finished upon removal from the mold. Most all production fiberglass parts are built in molds. When you build a part using the buck method, you build a shape, glass over it, Remove the buck from underneath, (or not, depends on your needs) then do your bodywork or in the case of an interior part, cover it in fabric of some type. This is the method for one-off custom stuff. I will assume that this is what you want to do. Yes you can use clay. If your stock console is covered in fabric or a plastic that can be dissolved by the resin you can modify the shape however you would like. Use clay or cardboard or wood, then tape the whole thing off with 2" masking tape. Use some kind of mold release like wax or Pam nonstick spray. Do your layup. Then you can peel the stock console out from the new laminated part you made. Hopefully your stock console is shaped so that it won't lock up in the new part. The sides have to be angled so that the widest part is on the open end. Look at an ice cube tray and you will see what I mean. If it looks like you can't get the old console that you are using for your buck out then there are ways to deal with that. You can cut the buck out from inside, which will destroy your original. (if it isn't toast already) Or you can make the new part thin enough to flex away from the buck where it locks up, then reinforce it with some more layers after it is pulled (kind of tricky if you aren't a seasoned "glues on me" guy). Or you can cut the new part enough to get it off and patch it back together. I like the first way best. Sometimes I'll cut the buck in enough pieces to get it out before I start building the new part over it. Just tape it back together so you can layup over it. All of this assumes that you want to have a lightweight part with no trace of the original part stuck to it and you are making this one part . There is a really good book about this stuff. It is called "How to Build Fiberglass Hot Rods, Customs, Kit Cars: By: Tex Smith.
Sorry to be so verbose, I hope this helps you

[KRD]

Yep, that help a lot. Thanks a million.