I use the smooth on resin myself...

quick video...

http://www.youtube.com/watch?v=mf6277_ZSXk
I have a couple comments on this video.

First of all the video said to mix until the resin starts to get hot.  This is probably a bad idea.  Smooth-cast 300 has a pot life of 3 minutes.  You pour the parts together and mix vigorously for 30 seconds to maximize the amount of time you have to pour.  Once it starts to get warm it's not long before it starts to gel.  I have literally had it gel up when I was pouring from the cup.

The second thing is that the video said he waited for 5 minutes before demolding.  You need to check the literature for the resin you're using to find the demold time.  Smooth-cast 300 has a 10 minute demold time.  That is for most parts you can take them out of the mold 10 minutes after you mix the 2 parts.  Some thin parts like the open barrel and crate you should leave for 15 minutes to make sure the piece doesn't get deformed when you demold it.  Of course, if you WANT to warp the final piece you can demold it early and bend a block as well.  Resin is an endothermic chemical reaction.  That means that as the resin cures it creates heat which helps the resin cure.  The lack of heat generated is why thin pieces take longer to cure.

You can also avoid scraping resin by using the plate method.  Bruce has a great casting tutorial for resin that I would recommend to anyone who wants to get into casting resin.
Scraping resin isn't like scraping plaster.  You always end up with a concave bottom (at least I always did).

The bottom line is that you need to read the literature on the resin you're using.  Some resins have a longer or shorter pot life and have different demold times.  I use several resins for my business that have pot life between 90 seconds and 20 minutes and cure times of 10 minutes to 90 minutes. 


Itar

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