Rubber molds & Resin Projo's

[KABAR2]

Skip,

Not to steal your thunder but do you mean like this? 



I had promised a write up on this back in April, they have kept me busy

at work and this is the first chance I have had to get my photo's together.

My job requires me to work with silicon molding material & plastic resins

while working with them I decided to play a little.......

here are some 45 acp cast in a rubber mold the resin did a pretty good job,

only a few small casting flaws, I measured each round for shrinkage and found

them to be dimensionally correct. they function through a magazine like the real thing.



the mold even picked up the writing on the base of the cartridge,

it also picked up any small scratches and a small ding in the case.



On to bigger stuff.........................

Do you have an artillery piece that's hard to find Projo's for ? Is Walmart out?

This mold is made nose down with a rod forming a hollow point, it also acts as a pusher

to move the resin out of the mold, the hollow point is loaded with a 50 cal spotter round........

this is for a registered DD Austrian 47mm AT gun WWII.


Simple mold stainless steel rod is hollow point fixture and pusher,
it is clamped it a vise to hold mold steady during casting.


Top of mold

Pusher starting to remove Projo
 
Fresh out of the mold



Here is a fresh Projo next to one with a lathe turned base.

The company that makes the casting materials is called Smooth-On
they are not cheap but there are plenty of possibilities.

http://www.smooth-on.com/


Allen <><

[dan610324]

the world of silicone is amazing, not only for boobs 
put a master half way down in childrens play clay

[dan610324]

add the upper half of the wooden frame and fill it up with silicone

[dan610324]

clean out the childrens play clay carefully

[dan610324]

put back the other half of the frame and fill it with silicone again

[dan610324]

take it apart and you have a perfect mold

[dan610324]

and you can duplicate the master

[cannonmn]

Thanks Allen.  I get that the mould is a slicone rubber two-part mix, but would you elaborate on exactly what the projectile is cast from?

[KABAR2]

Thanks Allen.  I get that the mould is a slicone rubber two-part mix, but would you elaborate on exactly what the projectile is cast from?

I am using A-30® Castable Epoxy is an aluminum filled castable epoxy resin for making vacuum forming molds that resist higher temperatures up to 300° F / 148° C continuous.

I use this for making molds for molding plastic in a pneumatic press it is dense and takes heat well,  so we think it will hold up to being fired out of a cannon, it is not cheap If I remember

it is about 450.00 to 500.00 for the 5 gallon pail full.I will check on price tomorrow. These are for the owner of the company's gun so I can justify experimenting for him.

http://www.smooth-on.com/gallery.php?galleryid=241&cPath=1275

I want to add that some of the other resins do not cost as much and may give similar results