Using PCV pipe molds for blanks?

[PTsideshow]

While reading either a tutorial in the library or some threads or both.

Somebody said something about using PVC pipe for molds and one type of the resins having slight shrinkage that releases the blank from the pipe?

Does anybody clean up the inside of the pipe, as some of the stuff I have seen and used over the years isn't always smooth in the interior of it? Or just make sure there isn't any major hang up points.

And which type of resin is used Polyester or Acrylic? And do all the assorted brands of that resin shrink?
:clown:

 

[sumterdad]

I use pr. I also use 3/4 pvc pipe and o cut it at around 6-61/2"s and use a cork with a piece of plastic covering it. Wait till it is cured and tap it out with a hammer and ram rod. Usually a couple of light taps and it pops out. The other mold I use is baby soda bottles but I have never had to clean after them usually leaves nice and clean

 

[Jim Burr]

I use 1-1/2" PVC 3" long for Stopper molds. I'll mix extra resin (PR) and toss it in after pouring the pen blanks.

 

[navycop]

I too use the 3/4" PVC with nothing done to the inside. My pieces are alittle over 5". I just use painters tape (blue or green) on the bottom. I made a rack to hold six pieces at a time. When dried/cured I use a 3/4 dowel to tap the blanks out. I have only did a dozen but they all came out great.

 

[SSobel]

Ditto

I do almost exactly as Chris. Use 3/4 PVC, Pour the PR, and use a wood dowel to pop out the cast. I made a small set up with a dowel that fits down in the pen tube and is centered in the cork. That way, I can keep the tube centered in the PVC while keeping the PR out at the same time.

 

[Florida Marine]

I learned after one batch that stuck hard, to hit it with mold release....now they slide right out.

I am using Silmar.

 

[el_d]

Polyester resin(PR)will shrink and pull away for the mold in theory. Doesn't always happen that way. I will use a sheet of parchment paper to keep the sidewalks of the PVC clean.
Alumilite will stay in you PvC.

 

[PTsideshow]

Thank you one and all.
Some more to ponder before I jump into that area.
:clown: