curing PR castings

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cwolfs69

cwolfs69

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i believe i read somewhere that PR casting can be helped by curing in an oven for some period of time. can anybody help me with what temps to use and how long to cure.
 
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Careful there, lots of pitfalls ahead.
It's a good way to stink up your oven and house, and a good way to ruin your blanks (especially castings like carbon fiber, feathers, and labels).
Putting them out in the sun for a day or two is the safe way. The last castings I did I left on the dashboard of my truck with the windows up while I was at work.
Too much heat will cause the glue to fail and can cause brittle blanks.
 
I imagine it depends somewhat on what brand of PR and how much catalyst you're using, as well as what kind of blanks you're making, but I usually put them in a dedicated toaster over at somewhat under 200 for an hour or so and have had not problems doing that.

Of course, I'm not all that experienced and just playing around with stuff to use getting more experience.

Cast some small blanks to experiment on and see what works for you.
 
Same here. I use a crappy toaster oven set on 200-250 but I use around 30 minutes. right after I mix the colors the mold goes in.
NOTE: mold will deteriorate faster with repeated heating's.
 
I'm with Lenny on this one. Hotter is not good for clear casting things glued to the tube. Can't comment on solid castings with pigments and colors since I don't do those. Don't trust the settings on the toaster oven. use a good thermometer and find the dial setting for 150 degrees.
Do a good turn daily!
Don


Lenny said:
Toaster oven .... outside of the house ... 150 degrees for 20 minutes has worked well for me.
Click to expand...
 
My utility room has an outside vent. I put mine on top of the hot water tank and let them sit overnight. But first they spend most of the day in the garage with the main door left open a few inches.
 
I let mine cure a good 12 hr then put put in sun for another few hours.

What is your problem are they still soft or are they just tacky. How much MEKP did you use, how long have they set, what is your ambient temp.

As others said a longer cure time is better if you choose to use heat don't use more then 150 for an hour or 2 at most then let set. More heat (faster cure) = a more brittle product like glass.

Good Luck
 
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My girlfriend has been pouring lots of blanks lately, and she discovered that putting them under a 60w lamp accelerates the cure, without having to go buy a toaster oven. She sets the molds in my photo tent, so the heat is trapped in better, points the lamp at them, and they are done quick. It's enough heat to speed things up, but not fumigate us out of the house.
 
bruce119 said:
I let mine cure a good 12 hr then put put in sun for another few hours.

What is your problem are they still soft or are they just tacky. How much MEKP did you use, how long have they set, what is your ambient temp.

As others said a longer cure time is better if you choose to use heat don't use more then 150 for an hour or 2 at most then let set. More heat (faster cure) = a more brittle product like glass.

Good Luck
Click to expand...

no, i have had no problems. just wondering if about people curing them in the oven. i cast and just let them sit in the shop for 3-4 days before i attempt to use them in the summer i will put them out in the sun as others do. was just kinda cuiour about the oven curing. didnt know if i was missing out on something. from what i see here it just speeds up the process. oh well i guess i do not need an oven after all.
 
cwolfs69 said:
bruce119 said:
I let mine cure a good 12 hr then put put in sun for another few hours.

What is your problem are they still soft or are they just tacky. How much MEKP did you use, how long have they set, what is your ambient temp.

As others said a longer cure time is better if you choose to use heat don't use more then 150 for an hour or 2 at most then let set. More heat (faster cure) = a more brittle product like glass.

Good Luck
Click to expand...

no, i have had no problems. just wondering if about people curing them in the oven. i cast and just let them sit in the shop for 3-4 days before i attempt to use them in the summer i will put them out in the sun as others do. was just kinda cuiour about the oven curing. didnt know if i was missing out on something. from what i see here it just speeds up the process. oh well i guess i do not need an oven after all.
Click to expand...

I cast mine early in the morning and am able to turn them at noon. I use 3-4 drops of catalyst per ounce of resin. This is a locally bought resin and much cheaper than what I have previously bought through the 'net. Dries crystal clear.
 
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