PR Hardening

[charliekap]

How long does it take the PR to harden? I cast a picture on Monday and left it in the silicone mold until today. It's was stored in the basement (about 60 degree temperature). Just took it out of the mold and the PR is still not hard. The ends are gummy and the surface will still easily capture my fingerprint. I used about 6 drops of hardner with approximately one once of PR.

charlie

 

[carpblaster]

blanks

How long does it take the PR to harden? I cast a picture on Monday and left it in the silicone mold until today. It's was stored in the basement (about 60 degree temperature). Just took it out of the mold and the PR is still not hard. The ends are gummy and the surface will still easily capture my fingerprint. I used about 6 drops of hardner with approximately one once of PR.

charlie

All the ones i poured the ends were still tacky till taken out of mold, and the outside sticky, I just set them aside to harden, and they all came out ok after that, some put them in a little toaster oven,but i never tried that,

 

[Justturnin]

I spoke w/ a PR manufacturer and they said a post cure in a toaster over at about 200* is ok.

 

[Dale Allen]

Too cold!
The temp of the resin needs to be warmer and the work area needs to be up to at least 65 for good results, IMHO!
I had some that I could actually bend in a curve after I sawed them into blanks.
Put it on something flat and set it in from of a heat register for a day or two and it should be fine.

 

[jmbaker79]

usually any surface, usually the top, exposed to air remain tacky for me. I usually hit them on a belt sander, or just turn off the tacky part. I am sure they are fine underneath

 

[CaptG]

As mentioned above, air temp is to cold. I use a toaster oven from Goodwill I paid $8.00 for and post cure ALL my resin blanks at 150 for one hour.

 

[Jim Burr]

As mentioned above, air temp is to cold. I use a toaster oven from Goodwill I paid $8.00 for and post cure ALL my resin blanks at 150 for one hour.

+1...works everytime.

 

[theidlemind]

As mentioned above, air temp is to cold. I use a toaster oven from Goodwill I paid $8.00 for and post cure ALL my resin blanks at 150 for one hour.

Good advice from the Cap'n.
watch your temperature at first though, when I set mine at 150 it gets hot enough to cause the glue to fail.

 

[charliekap]

I appreciate all of the feedback...

As far as glue failure... I poured the PR so no glue. Now off to my local Goodwill. I am beginning to feel like I own a boat (always finding new uses for my money)

Charlie

 

[plantman]

I looked in the dictionary under BOAT. It said, "Bring Out Another Thousand". Been there, done that !! Jim S

 

[its_virgil]

Don't trust the temp dial on the toaster oven. Use an oven thermometer and find exactly where 150 is on your dial. 200 degrees may be too hot for some materials clear cast on the tube. I've heard that snake skins can shrink
Do a good turn daily!
Don

As mentioned above, air temp is to cold. I use a toaster oven from Goodwill I paid $8.00 for and post cure ALL my resin blanks at 150 for one hour.

 

[CaptG]

I appreciate all of the feedback...

As far as glue failure... I poured the PR so no glue. Now off to my local Goodwill. I am beginning to feel like I own a boat (always finding new uses for my money)

Charlie

I looked in the dictionary under BOAT. It said, "Bring Out Another Thousand". Been there, done that !! Jim S

Amen to both comments.

 

[CaptG]

As Don said, I also use an oven thermometer and when I found where 150 actually was on the dial (the dials are seldom accurate) I marked it with a sharpie.

 

[Wood Butcher]

Just curious, where did you get the PR and, if it's Castin Craft, what is the date on the bottom of the can? I just got another quart from Michael's with the 50% off coupon and the date is 02/25/2012. That's a year old with a shelf life of 3 to 6 months. The sticky surface is a given if the stuff is old but the toaster oven will make it work. Too hot and it will be as brittle as glass. I use a heating pad with newspaper over it to keep the mixing part of the operation heated to speed the cure a bit. My experience is not as vast as a lot of folks on here but they have tutored me without knowing it....thanks \.
WB

 

[charliekap]

PR

I recently purchased my PR from Arizona Silhouette. Barry Gross is local to my area. They were just filling the containers so the PR was fresh.

charlie

 

[Lenny]

When I cast, and the temperature is only 60 degrees, I set up some clamp on lights to aid in warming the resin as it sets up. I would never think of using PR inside though without some form of ventilation. Once it has set up but is still tacky, as others have said, 20 mins in a toaster oven at 150 will do wonders for it.

 

[seamus7227]

Don't trust the temp dial on the toaster oven. Use an oven thermometer and find exactly where 150 is on your dial. 200 degrees may be too hot for some materials clear cast on the tube. I've heard that snake skins can shrink
Do a good turn daily!
Don

Ask him how he knows that:biggrin:, sorry Don, I couldnt resist!

I recently purchased my PR from Arizona Silhouette. Barry Gross is local to my area. They were just filling the containers so the PR was fresh.

charlie

I too have used and like the resin that Barry sells!

 

[Pjohnson]

casting in the basement.
what kind of heat do you have? i place my molds on top of the boiler ... works like a charm

 

[Dale Allen]

Just curious, where did you get the PR and, if it's Castin Craft, what is the date on the bottom of the can? I just got another quart from Michael's with the 50% off coupon and the date is 02/25/2012. That's a year old with a shelf life of 3 to 6 months. The sticky surface is a given if the stuff is old but the toaster oven will make it work. Too hot and it will be as brittle as glass. I use a heating pad with newspaper over it to keep the mixing part of the operation heated to speed the cure a bit. My experience is not as vast as a lot of folks on here but they have tutored me without knowing it....thanks \.
WB

Bill, I recently emailed a question about the can date to the place where I bought mine. They said the date that is on the can is the date the can was made. They said the cans are filled from a large drum and it seldom gets more than a month old before it goes out due to the fact that the vendor also uses it extensively.
Now granted, I did not buy from the same place as you did but since the stuff still worked great, after I got the room and resin warm enough, then I'm inclined to believe them.

 

[Wood Butcher]

Thanks Dale. I didn't know that and it makes me more confident. When I think about it, I have bought from Michael's before and the can date was later than the most recent one. You have cured my paranoia.
WB

 

[Dale Allen]

Actually it's quite funny when you think about it. :laugh:
Why would you need to date the can?
How old would a can need to be before it is no longer usable? :rotfl:

 

[Lenny]

casting in the basement.
what kind of heat do you have? i place my molds on top of the boiler ... works like a charm

What kind of precautions do you take for the fumes ... Oh, I am making a presumtion here... if you are using alumilite NO worries! PR on the other hand has toxic fumes. Just wondering ?