Investment

[Jubiler]

Hello Everyone! What kind investment are you guys using to cast platinum( name company)?
Also for gold too?
Thank you.

[darrinfry]

We use Invest RP

http://www.stuller.com/products/21-7060/?groupId=118383

Its a phosphate bonded investment that does very well with high temperatures. It sets very fast, so use it cold. We have our powder and liquid in the fridge (be careful not to let it freeze as this is bad) and we also set our flasks in the fridge as well. This gives us close to 7 minutes working time. With this investment you will need a flask liner ( http://www.stuller.com/products/21-7976/?groupId=118645 ). Also, break out can e bough if you are not prepared. It doesn't quench. You will need to take a mallet and hit your flask a few times to break the investment apart, and then will need to sandblast the small stuff off.

That being said, it is very reliable. So much so that we use it on our gold as well.

I got sick of fighting with "adding this", or "changing that", etc. with the standard investments. Our customs are higher end and we can afford to use a more expensive investment. If we where doing large productions of silver pieces this would not be the case, but for our gold and platinum we don't use anything else.

Our flasks are smaller size, but this is the burn out i use with this investment for platinum:
Full Ramp to 800f
Set flasks into preheated oven.
Hold for 1 hour (two if i am not in a hurry)
Full ramp to 1625f
Hold for 2 hours
Cast

For gold we use this burn out:
Full ramp to 800f
Set flasks into preheated oven
Hold for 1 hour (two if i am not in a hurry)
Full ramp to 1425
Hold for 2 hours
Ramp at 350f to casting temp
Hold for 1 hour (or longer)
Cast

Let me know if you have other questions about his investment.

[wawatobi]

I boil the castings in sodium hydroxide for a couple of hours to remove investment. Comes right off in the ultrasonic after that.

[M-Williams]

https://www.romanoff.com/j-break-platin ... azmat.html

Excellent Investment Remover.

[darrinfry]

This is today's platinum casting next to a grown model. Sorry for the poor photo quality, it was a quick shot with the cell phone.
Milgrain is .25mm. Honestly it was just to see how it would do, it will be reapplied my hand the real way.

[M-Williams]

Indeed. "poor photo quality" for a beautiful work. What did you use to clean you Investment.

[darrinfry]

Indeed. "poor photo quality" for a beautiful work. What did you use to clean you Investment.

After letting the flask cool for about 30 minutes i use a rawhide mallet to break the investment. Then i give it a quick sandblast to clean it. I am not a big fan of the chemicals, they work great, but i would just prefer to stay away from them if possible.

[artificer]

Beautiful! What is your casting system for platinum? I've wanted to give it a try.

[darrinfry]

Beautiful! What is your casting system for platinum? I've wanted to give it a try.

We use an EC12 http://rdoinduction.com/easycast.html And bought ours from Stuller http://www.stuller.com/products/22-2160/?groupId=119752

Great machine. Great results with all precious metals.

[artificer]

Interesting, thanks!