PVC pipe as a mold??

[rtrimyer]

Hey I was wondering about the use of pvc as a mold. Do you traet the inside so that you can pull the casting out, and how do you keep the barrels straight inside the mold? Also, is there a special way to pour the PR so the you do not get voids, or does the pressure help to keep that from happening?

Thank you

 

[stevers]

Heres a few to get you started till someone else comes along.

http://www.penturners.org/forum/topic.asp?TOPIC_ID=26266&SearchTerms=pvc
http://www.penturners.org/forum/topic.asp?TOPIC_ID=25657&SearchTerms=pvc
http://www.penturners.org/forum/topic.asp?TOPIC_ID=23863&SearchTerms=pvc

 

[Stevej72]

To keep the barrel straight with 3/4 in PVC I glue a square piece of wood to the end of the cork that was just slightly less than 5/8 inch. As long as you glue the cork to the middle of the piece of wood it will be perfectly centered.

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[Narwhale]

PVC pipe works great as molds for round castings. No, it does not need a mold release. Just seal one end (a lot of us just use tape to seal the end) and pour the polyester resin in. At the PR hardesn, it shrinks slightly. For me, after an overnight wait, I just knock the molds together and the blank slides out. If the molds were not very clean, the blank may stick a bit. A metal rod let me force the blank out with hand pressure.
I do not put tubes inside the PVC pipe molds but it might make things simpler? But maybe not. Depends on what you are doing.
I like to mix ans swirl the colors in the blank and do not think a tube would allow me to do that.
Bubble and voids have not been a problem for colored PR blanks for me and not pressure or vacumn is used. Just be easy with the mixing and pouring.
Rich S.

 

[Blind_Squirrel]

Originally posted by Stevej72
<br />To keep the barrel straight with 3/4 in PVC I glue a square piece of wood to the end of the cork that was just slightly less than 5/8 inch. As long as you glue the cork to the middle of the piece of wood it will be perfectly centered.

<br />

Steve,

What type of cork is that and where did you get it?