PR resin stuck in vertical molds

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CrimsonKeel

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Mar 1, 2013
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Location
Royal oak, MI
So this weekend I cast 5 PR blanks in vertical molds made from PVC pipe. previously with a few good whacks the blanks came popping out. This weekend I had to resort to cutting the PVC and prying the pipe off the blank. it was almost like it glued itself to the pipe. I had been reusing pipes and I figure this is the 4th time i've cast in these pipes. Should i be getting new PVC and using that after a couple casts or do others reuse the PVC? I did buy some mold release yesterday and ill try that for the next few times
 
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Ben, I have had a similar problem in the past using PVC pipes as molds. They can be reused multiple times. every now and then one will not release. I use a 3/4" or 1/2" dowel to knock out the blanks, which works 99% of the time. Have used mold release some but the problem is hit and miss. The PVC is so cheap, 24" for about $1.30 that "stickers" should not be a real problem.
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Everyday I'm vertical is a great day
 
I've reused my PVC tubes many times and fortunately never had a problem with the PR not coming out. I usually wait 24 hours before trying to remove the cast pieces...but that is just me.
 
I agree with Fred. There is no reason that they can't be used a dozen times or more. I do replace mine from time to time, but not nearly as often as I used to. If you use a dowel and a hammer to persuade them out, you will break one occasionally. All they need is a little more time. Or a half hour or so in a toaster oven. Be sure and let them cool after heating them.

Here are some of my typical tubes. Well, Ok, these are maybe some of my older tubes, but you get the idea.
2_PVC_tubes.JPG
 
i leave a little room at the top of my pvc tube then i turn it over place it on something solid then use a pen blank that i turn to fit inside the tube and tap it out.........99.9 % of the time that works.....
 
I use my tubes about a dozen times before replacing (PVC pipe is cheap). Using a release agent like Pam does help.
 
BSea said:
Here are some of my typical tubes. Well, Ok, these are maybe some of my older tubes, but you get the idea.
2_PVC_tubes.JPG
Click to expand...

My first reaction was that these weere some funky looking blanks that would make some awesome looking pens. Then I re-read what they really are. :redface:
 
CPVC is only in the plumbing section, and not carried in all home depot or Lowes stores. It typically is sort of a cream color, and available in smaller sizes. I use electrical PVC, but then I am an electrician and that is my scrap
 
AceMrFixIt said:
Try CPVC pipe. It is rated for hot water and does not deform like PVC. I have not had any problem tapping out my blanks when its done.
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Now that's a good tip. I usually throw mine out when they deform due to the heat of the PR, or when they get a little stubborn. But I'll have to try this next time I buy some.
 
Well a little update on my next batch. I used mold release and some new pipes and was able to push my blanks out with my finger with very little pressure. One I had to do a light tap but the end on that one wasn't fully cured yet. The mold release helped alot.

anyway thanks for the recommendations on different pipe and maybe replacing my pipe now and again. Does cooking spray really work and not interfere with the blank curing or anything?
 
I have not seen a HD or Lowes that did not have CPVC.....I think it may be in the building code for hot water. Look at your water heater output side if you want to see what it looks like. Should be CPVC.
 
I live in the Denver area, and it is hit or miss if they carry CPVC or Pex. I work all over the metro Denver area, and I think it is dictated by the local building codes. There are WAY too many jurisdictions in the metro Denver area. :)
 
I don't get out that way much.....the south is my stomping ground.

wyone said:
I live in the Denver area, and it is hit or miss if they carry CPVC or Pex. I work all over the metro Denver area, and I think it is dictated by the local building codes. There are WAY too many jurisdictions in the metro Denver area. :)
Click to expand...
 
I've not had any issues with pvc. I can pop the blanks out in a matter of hours once they start cooling down and set the to the side to finish curing if needed. The only mold release is pictured below.

 
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