Cups for casting

[jttheclockman]

Today I ran into abit of unexpected problem when mixing my Silmar resin. I have been using a certain cup for awhile now and have had no problem. Well I tried doing somethiong different by heating my resin while it sits in a bowl of warm water heated to about 125 degrees. I usually have no problem because I heat the resin in the oven to this and no leaks. Today they melted.

My question is what cup do you all use to mix your resins and if you have a product name or number would be appreciated. Or location where you get them. Also state weather or not you heat your resin in this cup. Thanks for the replys.

 

[srf1114]

cant answer your question about type of cups to use, but can expalin the problem.

It takes a lot more energy to heat water to 125 degrees, then it does to heat the air (in the oven) to 125 Degrees. That energy is stored in the heated air/water. Once your cups are added to that heated medium they take the energy out of the medium into them. Since the water had a lot more enregy stored in it, it was able to transfer more energy into your cups, which your cups where not able to handle.

dont think I'm saying that 125 degree water is hotter than 125 Degree air, cause I'm not. But it does take more energy to reach that temperature for water than it does for air. That extra enrgy isnt lost, it is stored and transfered to what ever is inserted into it.

Stan

 

[PTownSubbie]

John,

I buy my cups in bulk from Sams Club. They are the 12oz clear plastic (Member's Mark brand). I have also used the 9oz cups.

The recycle code on the bottom of these cups is "1". I have had no problems with PR eating through them.

I have had some "slight" deformation problems if I add too much catalyst due to the heat but never had a breach of the enclosure. I also heat them in water to thin the PR prior to catalysing but don't know how how it is. I get the hot water from our water cooler/heater (just like you would have in an office).

I have never tried to heat PR in the oven though. I wouldn't think that would turn out very well.

I cast with S40 not the S41 that most people cast with though. Don't know if that would make any difference but I don't believe it does.