Will PR bond to it?

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PSNCO

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I cast PR in PVC pipes. I've always used corks to plug the bottom of the pipe. To keep the PR from bonding and gunking up the corks, I've always slip a finger tip from used nitrile gloves.

Well over the winter, my stash of corks have been misplaced or thrown. I went to my usual local source to find they no longer stocked the size cork that I use.

Looking online, I can get a cork for 38 cents each and continue to "slip on protection" or I can get a stopper and quit with the glove finger processes.

EPDM Rubber stoppers are 63 cents each and silicone stoppers are 96 cents.

I have no doubs that I'll have any issues with PR and a silicone stopper, but what about the EDPM Rubber stopper? It's right in the middle between price for cork vs silicone. Would heat from the PR be any issue with EDPM Rubber?
 
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I think you'll be alright with rubber, but the craft stores still sell cork. I buy mine from Pat Catans.
 
glenspens said:
i put blue tape on the bottom of my pvc.......workes for me
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How many blanks do you make? I make a couple hundred a month, and the time it takes to redo the tape can really add up. Plus blue tape isn't cheap. I have stoppers that are almost 2 years old, and I suspect will last several more years. While the initial cost is high, I think in the long run, it's cheaper than blue tape if you cast a lot.
 
At some point I'd like to get something a bit more convenient than what I use. I don't cast much and have been using perhaps the cheapest duct tape I've ever used, courtesy of Harbor Freight. I don't trust it for much, but it does keep PR from leaking out of PVC pipe. It does get sticky as all getout when demolding the blanks.
 
ye ole penmaker

since you having this problem with corks, can you tell what you do to get the casting to release from pvc pipe? I've use small, medium and large hammer and big bolts. Any suggestions
 
I get corks from Specs Liquor for free. They have a drop off barrel for people to bring them in. It's usually half full and they have been happy to give me some. Don't hurt to butter them up with some free pens after...to keep a free source :)
 
Ye Ole Penmaker said:
since you having this problem with corks, can you tell what you do to get the casting to release from pvc pipe? I've use small, medium and large hammer and big bolts. Any suggestions
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16oz hammer and a 5/8" wood dowel. Remove them too soon and they'll come out rubbery and you have to make sure to get them laying on a flat surface to keep them straight. (I'm still up in the air if the force of the hammer and dowel causes any integrity stress to the still curing blank.)

There shouldn't be any issues after 16-24 hours with light taps from a hammer.
 
PSNCO said:
Ye Ole Penmaker said:
since you having this problem with corks, can you tell what you do to get the casting to release from pvc pipe? I've use small, medium and large hammer and big bolts. Any suggestions
Click to expand...

16oz hammer and a 5/8" wood dowel. Remove them too soon and they'll come out rubbery and you have to make sure to get them laying on a flat surface to keep them straight. (I'm still up in the air if the force of the hammer and dowel causes any integrity stress to the still curing blank.)

There shouldn't be any issues after 16-24 hours with light taps from a hammer.
Click to expand...
I've found that tapping the side will usually help them release easier. You can hear the sound change when the blank is free. Sometimes you have to tap near both ends to free them. I have a wooden hammer handle that I use for this. About 1 in 20 will require the use of a dowel and hammer to persuade them. I will usually let them spend some time in the toaster oven before resorting to the hammer & dowel method.
 
I got some rubber stoppers from ACE for this.

They only had 1 variety, but they seem to work fine. I don't make hundreds of blanks per month though!
 
I've used epdm and latex rubber stoppers in PR for tube plugs and they pried out just fine.

Silicone does come out easier, however.
 
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