First Cast

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Boz

Member
Joined
Jun 21, 2008
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371
Location
St. Louis, MO.
I bought a resin casting kit from PSI and a resin saver mold. Mixed up the resin yesterday a nice 75 degree day and added the correct number of drops of hardener. Poured it in and let it sit over night. Went to take it out of the mold this morning and it is still tacky on the outside. Kind of like a circuit board pen blank but a little more so. Should I let it sit, get an old toaster oven and bake it, or clean it with some solvent.
Any thoughts from the pros out there would be welcome.
 
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Boz said:
I bought a resin casting kit from PSI and a resin saver mold. Mixed up the resin yesterday a nice 75 degree day and added the correct number of drops of hardener. Poured it in and let it sit over night. Went to take it out of the mold this morning and it is still tacky on the outside. Kind of like a circuit board pen blank but a little more so. Should I let it sit, get an old toaster oven and bake it, or clean it with some solvent.
Any thoughts from the pros out there would be welcome.
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If you have a toaster you can post cure it but if you have any sun, place it in the sun and it should clear up quickly. The tackiness is normal for most PR.

If you decide to post cure, no more than 135-150 degrees or you will cause your resin to get brittle.
 
Mine do that but they are hard inside and usable if you let them sit they do dry but they are also usable as that turns away. I know my first ones were all a little tacky.
 
All the ones I have done are like that when I take them out of the mold. I usually do 30 minutes or so in the toaster oven at 150 and when they come out, they are no longer tacky.
 
75 degrees ... I'm jealous! :)

Toaster oven has worked for me .... barely reached 50 at noon here yesterday. My second cast. Placed it in front of a 100 watt bulb inside an open cardboard box setting on end. Once it had set up some I placed it in the toaster oven for 20 mins. at about 130. Turned my first blank from it this morning and got nice ribbons. :)
 
OK I put the blank in the sun yesterday afternoon. When it was in the full sun I noticed small white specs in the clear resin. I poured it clear over a painted tube with a decal on it. I thought I noticed small white specs in the resin when I was mixing it. Do you need to filter this stuff when you pour it into the mold?
 
It's common with pr. If it's real slimy and sticky it could be that your resin and hardner weren't mixed real well. The top of the mold would be what came from the bottom of the cup. It's hard to get the bottom stuff mixed real well without leaving the resin full of bubbles. I put mine in the sun for 30 minutes and it's good to go. In the winter I just let it sit in the house for the day and it sets up. Good luck.
 
It's 89 degrees here today. I have the opposite problem of trying to get the catalysed resin into the mold before it starts to glob.

If you let the mold sit in the sun today, that should eliminate the sticky top.
 
Boz said:
OK I put the blank in the sun yesterday afternoon. When it was in the full sun I noticed small white specs in the clear resin. I poured it clear over a painted tube with a decal on it. I thought I noticed small white specs in the resin when I was mixing it. Do you need to filter this stuff when you pour it into the mold?
Click to expand...

This sounds like one of three things. The first thing I would check is to make sure that any pigments used (especially mica powdered) were mixed until a consistent liquid form.

The second thing is that all shops get dusty. I always wash and then COMPETELY DRY my mixing cups just before use.

Third thing to check is to make sure that your MEKP is tightly stoppered until just minutes before use. Air in the catalyst will cause a "crud" around the top of the catalyst bottle. This crud will not dissolve in resin and appears as tiny white spots.
 
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