( Made easy- Ya Right)
Hi Kats, I've been getting a lot of E-mails lately about how to make a fiberglass mold, mostly people looking to make a "one of" Custom piece for there car,( bumper, hood, skirt etc.) which ever it may be. I know there are many ways to make molds, as many as there are Custom car builders, and I don't know everything (not even close) but the method I will show you worked for me and it could work for you. What I have learned over the years has been self taught and I made many mistakes along the way, so hopefully this new section will help someone get a better idea of what it takes to make a mold and maybe make those IMSA style flares they always wanted for there V W or a Daytona wing for there Opel G T, ( way to many fumes inhaled) I'm also going to add at the end of this section Fiberglass supplies that can be ordered threw this web site, so hang on your going to have a itchy ride ahead of you.
Here are a few of the fiberglass products I have made
Before we start take CAUTION in using these materials they are DANGEROUS CHEMICALS use gloves at all times, eye protection, respirator or particle mask, long sleeve shirts and adequate ventilation. Read and follow all manufactures instructions and take all precautions, take it from me inhaling the fumes can give you DRAIN BAMAGE and the itching isn't fun either.
Well here we go, first things first grab yourself some paper and a pencil sit down and start drawing out some ideas of what your looking to make, take a bunch of your favorite car magazines open up to a picture of something similar to what your looking for, take a part from here and a part from there and draw out your ideas, ( of coarse in this day and age you can just use your PC to do the same thing, but I'm from the old school , PC in my time meant Pencil and Crayons ) this saves a lot of time later in the building stage.
OK now that you have all your ideas what to do with them?, here's something else to think about, are you going to make a "one of" part?, make just one piece to install on your car?, or would you like to make many and try and sell them?. If your going to try and sell the parts the mold will have to be thicker and stronger to withstand the abuse.
Now that that's over we can start building your Kustom part, you can use just about anything you have around to build your part clay, Styrofoam, cardboard and tape, Bondo, and what ever else you can think of using, I have used both methods, clay I use for making smaller pieces like my shifter knobs. Which ever way you choose to do expect A LOT of sanding to get the shape you want.
I have taken Styrofoam and carved it close to the shape I was looking for, then covered it with Bondo and sanded it to the exact shape I was looking for. The same with cardboard and 2 inch tape, got the piece close to what I was looking for then covered it with Bondo and sand to shape, like I said there are many ways of making your part this is just a few and I'm a firm believer in using what you have handy.
This original piece you are making is called a "Plug" it is the piece you are going to use to make your mold from or when the piece is finished you can mount it on your car. Here is a picture of the first large piece I ever made it is a front bumper cover for my 82 Chevy Suburban, I made this piece because after looking threw all the parts catalogs I could not find anything close to what I wanted, so what to do? Hay make me own and here's how it was done.
First I started with my original bumper, I placed card board over the bumper and used 2 inch tape to join all the pieces together and smooth out the bumper, then I laid fiberglass mat and resin on it to firm it up this way when it was hardened I would have a good strong base to lay a coat of Bondo on. I extended the bottom of the bumper to make a spoiler and added cut outs for 6 inch lights and a sunken plate, this all took a lot of time and like I said A LOT of sanding.
Once the bumper took shape and I sanded it down to a 180/220 grit finish I sprayed on a Polyester primer that is mixed with a hardener this primer is specially made for making molds, this primer is very thick it's almost like spraying on a coat of Bondo, this primer can be sanded with 180 grit paper and worked all the way down to 1000 wet, then this is polished to a high gloss finish. What ever your plug looks like your mold is going to mirror it, that is how nice a finish your plug has is as nice a finish your mold will have.
Now next step after my bumper has sat for couple of days I wax it about 3 to 4 times giving enough time in between to dry to a haze then remove with a clean dry cotton cloth, (just like you would wax your car), this is a special wax used for mold making. When the bumper is ready I spray on 3 coats of Tooling Gel coat, this is a gel coat that is a little thicker then regular gel coat, (gel coat is a resin with pigment in it) once that tacks up ( almost dried) I start brushing on my resin with a brush then lay on my glass.
Here's what your going to need to get yourself started in the wonderful world of glassing, polyester resin and hardener, some plastic mixing cups, gloves, different size brushes and a fiberglass roller.
The fiberglass I use is 1 1/2 once mat, before I go any further let me tell you the difference between mat and cloth fiberglass, cloth are strands of glass weaved together in a pattern like a basket forming a cloth (sounds good), mat is strands of glass in a random pattern, cloth is stronger then mat but the cloth will always leave a print or pattern when cured and you don't want this pattern to show up on your mold, see pics for better understanding.
OK I hope that helps you a little more with the difference in glass, now after brushing on the resin I lay out my glass into the mold it saves time if you cut your glass pieces into smaller pieces ahead of time and I rip the glass in half ( look at picture again) .
It works the glass into the mold a lot faster then trying to use large pieces, glass will form and take the shape of anything you put it on but don't use a large or stiff piece or it will work against you, use the brush to work out any air bubbles that might get trapped under the mat you can also use a fiberglass roller ( a very handy tool no glass man should be with out one) soak the glass with the resin don't leave any dry spots, then lay another layer of glass on top, I usually use about three layers of glass ( six if ripped apart) then let it cure for a while, I would normally trim any glass excess off the mold with a razor blade just as it is hardening it makes clean up a lot easier later on. Once the glass has cured you can gently pry it out using a wooden mixing stick and you could also blow air in between the mold and your glass piece to remove it faster.
Here are more pictures of molds and the parts made from them: click to enlarge
The 1st and 2nd pictures are Tear Drop skirts and the mold (gray skirt is mold) 3rd, 4th and 5th picture are Tear Drop tail light housings, the gray piece is the mold, the glass piece made with no gel coat just the mat laid over the mold.
This piece is called a "pie plate" is is used on Big Tank mid 60's Corvettes, the black piece is the mold, you can see that the finished piece is an exact mirror image of the mold. I know I must have missed a lot along the way of explaining the procedures of making a mold and I will be going back and adding a lot more info. and pictures but Hopefully this will hold you over and get you started, I will also be adding a page with all the supplies you will need to make a fiberglass mold or just do fiberglass repairs LOOK for that soon, if you have any other questions just E-mail at email@example.com I will do my best to answer them, Later Kats