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Thursday, 20 September 2012 22:33

Building Body Molds from Plugs is No Easy Task

Written by Rich Evans
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This month’s column is Part 2 of my June column about building a junior motor sport body for a motor sport vehicle for an 11-year-old driver. 

In the last column, I talked about building the plug to make a mold. As we left it, I was creating the plug form. I was working to get the plug completed so it was totally true to where I was satisfied enough to make a mold. Doing body work is one thing, but making a plug and going to a mold is just repeating steps and you can’t even see the light at the end of the tunnel. I am totally exhausted from it. The hundreds, almost thousands, of hours I’ve put into it just to get a part. After you get a mold made, it’s amazing how you can put out a part every 30–35 hours, after the hundreds of hours I spent making the mold. So, there are rewards at the end of it—to make that part in that short amount of time and get exactly all the details you wanted.

Getting back to the plug, I left it at 400 grit. I did a wet sand after primering: 80 grit, 150 grit, with 400 grit, then I’m ready for sealer. Next, I wipe it down with carbon wax twice, then come back with a release agent that I spray on. Then, I mask all the areas off, to break this down into a form of how everything comes apart to get the body out. We mark off a section of the car—the roof, hood and trunk is one section. I make a flange using a fiberglass 1/8 inch sheet, two inches wide. This flange is where we are going to bolt this mold together. Then we’re going to use locating buttons along the top to keep everything together. We use clay, hot glue, and wood to give it structure. Then I come back with FBS brown tape that allows me to draw out my lines, tape two inches, then come back and glue blocks of wood all the way down where I put the tape. Then I cut and make a flange that goes all the way around that perimeter. After I do that, then I wax everything once again, use release agent, then put tooling gel coat down. Any cracks or imperfections are filled with clay, like sculpturing. Then, we’re gonna lay mat down and use cloth and a Squeegee to get all the air bubbles out, then pull off the cloth and let that cure. We also use a paste, too, to get down in the corners where the cloth might not sink down and pull up.

We do that once, then we come back the next day and grind everything, put another mat down, another cloth, and do it again for a total of five times. That way, you have a total of almost a half inch of thickness.

After we finish that, we tear off the flange, we go to the left and right side of the car and make another part and do the same thing: the wax, the tooling gel coat, the mat, the cloth, the same process.

Then we go to the rear of the car and do the same thing, plus the wheel wells, the rocker, the rear part of the bumper. There are 14 pieces to the mold by the time I am done. That’s hundreds of hours just to make this one mold.

Then I have to build a frame because the mold is so heavy. I have to build the frame while the mold is connected to the plug to make it even. I build the frame out of thick gauge 2x4 square tubing, then we mount casters on it, connect supporting bars, and then take it off, finish welding it, and turn it upside down. Next we take the mold off the plug, clean it up with water, then bolt it together. After that, we repeat the process of cleaning the mold, putting it all together, sanding down the imperfections on the mold with 400 grit to make sure its all smooth, then we go back and wax everything, put release agent, gel coat (not tooling gel coat), then repeat the same process on all the pieces. I’m using mat and cloth to get air bubbles out and make it stronger. Then I come back with some reinforcing 5mm Cormat which will fill up with resin to add density to flat areas. The next day, I come back and put everything together, using paste, cut out strips of mat, connect everything together, bolt the mold together. Three or four hours after that, we’re ready to pull it apart. Then I spend five hours cleaning everything. Finally I’m done with the first Rich Evans-designed motor sports  body. This doesn’t count all the accessories … the wings, scoops, side scoops, front bumper, etc.

Seems like now I am getting away from parts and add-ons. Now I’m making complete bodies. Who would have figured?

I have major respect for  guys who are building molds out there. It’s a whole different task. Props to the guys who are making molds day in and out, because as a car builder, you can see daylight at the end of the tunnel. But in this field, you don’t even know how many sand strokes you need to get to the end.

I’m excited about the project and to see it on the track in full motion. Then I can sit back and enjoy.

The body is ready to sand  down, seal and paint, and it’s ready to go. I’ve got scribe marks to cut the doors out, and scribe marks for the hood and the deck lid. The whole idea is for this to look like a real car featured in the motor sport world. Stay tuned to see where this car will be seen and what it’s going to be doing on the track.

Follow me on Rich Evans Designs on Facebook, RichEvansDesigns.com, BuilditwithRichEvans.com, and HuntingBeachBodyWorks.com.

Thanks to all my sponsors, with a shout-out to FBS, a title sponsor of World Wide Car Building, and my other sponsors listed on my website.

See ya at SEMA. It’s a great month to be around automobiles.

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