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Just learned something there...

Great job on this. I learned quite a bit. Another keeper for the archive.

Good info, Dave,

Are those studs in some of the mold corners to help the eventual two-part mold fit more precisely?

Dan

When doing a 2 part mold, I do pull my masters out before I paint the mold release. I've found the silicone can run into the smallest opening and it won't come out if there is no mold release. I paint the first part, then put my pieces back in their positions before pouring the second part.

Looks like the silicone is the Alumilite from Hobby Lobby. I find that stuff so soft and flexible that I can glue a driver torso to the bottom of a small plastic cup and cover it with alumilite. After curing, I can remove the cup and push the driver out of the mold. I then cast a one piece driver in that mold and the rubber stretches so much that the driver will come right out.

Another trick I have used for two part molds is to glue a piece of sprue or something similiar to your master so the air can be released when you push both halves together. Otherwise most of your parts will have air trapped in the mold cavity and it won't fill up with plastic.

The alumilite is so soft and flexible that I have been able to mold a Cox Chaparral driver in one piece.

You guys doing bodies will find that Shotguns process is especially great if you apply it to a body. You will make a thin body in one cast and the inside will have the nice finish the outside does.

The casting thread is really good and all of us learn a bit from each other and make what we need. It was much like this back in the 80's when we had to make our tires and plastic bits. We didn't have this great communication back then.

Another excellent Shotgun production! Great info on the use of sprue as vents when making two-part molds. I always wondered how to do that . . . and now I know!

Thanks,
Rick V.

I sent in my pre-pre order :)

Great post!! Do you need to do anything to keep the silicon from seeping through the Lego bricks?

Fascinating and awesome Tut SD!!!

I have never been using channels but air is no problem nevertheless.
What I do to remove the clay more easily is to brush a very thin layer of Vaseline onto the clay before I press the parts in, but avoid Vaseline on the parts.

Roland

Great work!

VERY cool tutorial Dave! I added risers to the '48 Chevy body using clay - never thought about using model car sprues! That is a slick idea and definitely nicer to keep in place than my "rolled into thin ribbons" clay! :D

Great job! A lot of my drivers are missing their noses! I keep a little Tamiya putty around and use it on my finger to fill any problems like that. First body mold I made using that soft rubber the outer mold spread 3/8 inch or so and I cut some wood and with rubber bands kept the sides in the proper place.

That pink rubber is good stuff and easy to work with. With 40% coupons it is a good deal at Hobby Lobby.

I started buying wax paper to cover my work bench top when I mold. The plastic does stick to it, but it makes a neat clean work surface and I just roll it up and throw it away after doing 2-3 pours.

Lots of great information here! Question: After you've injected the resin with the syringe, can you clean the syringe for reuse, or do you have to discard it and ask the pharmacist for a replacement? ("Hey, my kid has a really bad cold . . . ")

Thanks!
Rick V.