Making Resin Parts From My Scratch Build

[trooper96[501st]]

 

On an impulse (and maybe a fit of bad judgment), I broke apart my beautiful scratch built E-11 blaster (pictured above) with the bright idea that I would make molds from the parts to make resin copies to share with some friends. Here is a picture of the carnage below:

 

 

The blaster was constructed with plastic sheet, wood, hardware, and whatever else I could find, from templates found on the Blaster Builders Club forum and from this site. It’s not a perfect clone of a screen used blaster like some of the commercially available resin kits, but I tried to pay close attention to all the details, and I am rather proud of the result. Here are a few progress pics of my build:

 

 

 

 

 

 

 

OK, this is where your expertise will really help me:

 

1. Making the molds... This is what I can get locally http://shop.hobbylobby.com/products/high-strength-3-mold-making-rubber-181719/ for about $20 a pound with a coupon. Is there a less expensive option for molding rubber?

 

2. Prepping the parts... I know I will have some spaces to fill. I don’t want to permanently fill them, as I would like to reassemble the blaster when this project is done. What would you recommend?

Edited May 22, 2015 by trooper96

[gazmosis[501st]]

WOW. Getting into the world of molding and casting is not as easy as one would like to think it is. for the ultimate in accurate detail capturing, silicone is the way to go. However, there are as many silicones as there are stars in the sky and none of them are cheap. http://www.reynoldsam.com/   Click on that link and play around on that site sight for a while. If you are serious about producing repeatable casts, that is where you need to start

[trooper96[501st]]

Which is a good shore hardness to use?

[Sonnenschein]

 

 

 

1. Making the molds... This is what I can get locally http://shop.hobbylobby.com/products/high-strength-3-mold-making-rubber-181719/ for about $20 a pound with a coupon. Is there a less expensive option for molding rubber?

 

2. Prepping the parts... I know I will have some spaces to fill. I don’t want to permanently fill them, as I would like to reassemble the blaster when this project is done. What would you recommend?

 

 

1.Don't save on rubber. Cheap silicone breaks down after a few casts

 

2. Clay. 

 

 

Which is a good shore hardness to use?

 

 

That depends. Soft silicone if you have undercuts

Edited May 22, 2015 by Sonnenschein

[gazmosis[501st]]

One of THE most important things to remember is that if you are going the silicone route to make molds and you are going to fill your minute holes and tiny areas with clay, THE CLAY MUST BE SULPHUR FREE CLAY.

Also, depending on the nature of the part you are molding, you will need to decide if you are going to make either a slit mold where you create a box around your part, fill the box with silicone, then slit one side with a razor knife to extract your part and create register points to re-align the mold. Or, does your part require a 2 part mold? A box is built around your part and it is set half way deep in a bed of clay ( sulphur free of course) silicone is poured over your part and allowed to set. The box is the turned over and the clay removed. Because silicone WILL STICK TO SILICONE, a release agent must be applied to the cured silicone if you want the halves to separate. After that, more silicone is applied to complete the mold. Keep in mind when doing a two piece mold that it completely encases the part. This means in order to cast it, you will need both a fill hole AND A VENT HOLE. A vent hole is a place for the air inside the mold to go when you fill the mold through the fill hole. These holes are usually made with a cylinder of clay.

[TK bondservnt[501st]]

In 2 part mold making you can make the 2 halves with a hinge by not applying mold release to the hinge part of the second pour.

this creates a 'glove' style mold.

[trooper96[501st]]

Thanks for the advice, everyone!

[trooper96[501st]]

OK, I have decided to go in a completely different direction. Today I ordered this...

 

http://www.apexgunparts.com/submachine-guns/sterling-l2a3-mkvi/sterling-l2a3-smg-parts-set-9x19-nato-4833.html

 

I'll put my blaster back together and start a new thread when my kit arrives. Thanks again for the great advice!