POLYMER CLAY AND MOLDS

[seawolf]

I have a different idea for PC. I wanted to cast a few pens with crosses on them. I am not a scroll saw person so cutting the crosses from wood or acrylic is not a good option. Enter the polymer clay, I rolled a small bit until it was workable then formed a rod about 1 ½ long by 3/8 diameter I pressed it down on a piece of glass then pressed my pen tube (Wallstreet ll) into the clay. Using the sculpty knife I cut the excess from each side of the tube then used the knife to release the clay from the glass. I now have a piece of clay flat on one side and fitted to the tube on the other. I carefully cut the cross with the knife. The extra clay from pressing the tube in I cut two small pieces to set the tube on in the toaster oven and baked according to instructions. I gently removed the cross from the tube then I sanded the sides with 400 and 600 grit paper glued to a small piece of wood to remove any blemishes.
I will glue the flat side to a piece of glass and make a silicone mold of the cross. When the mold is ready it can be poured with any color of resin or the small amount of resin left in the cup from a regular pour.
This will work with any size tube for the pen of your choice. Paint or treat the tube in your preferred manner then with a drop of CA attach the cross to the tube the back is pre formed to the tube (no air bubble) set the tube in a resin saver mold and pour the blank with the cross up. The cross is about 1/8 thick above the tube. When cured round the corners and turn to fit your pen. This should work with almost any shape to make your own custom molds.
I am still working on this and may have to work out a few bugs.
Have fun, Mark

 

[RAdams]

pure flippin genius! That is an awesome idea! Please keep us informed as to how it works out for you! I can think of lots of shapes that could be done this way! Stars, flames, all kinds of stuff!

 

[el_d]

Very Nice Mark. I like your approach. Lots of possibilities....

 

[Russianwolf]

the only downside I see is the change in consistency between the clay and resin.

May make turning a bit difficult.

 

[KDM]

the only downside I see is the change in consistency between the clay and resin.

May make turning a bit difficult.

If I understand the other wolf guy correctly, the PC is no longer part of the equation. Rather, it was used as the mould positive to make the mould negative and has now been discarded.

 

[jason_r]

If I understand it correctly, he'll end up with a polyester cross in a PR blank, so
change in consistency shouldn't be a problem.

There might be a small problem with a weak bond and/or the 2nd PR cast pulling away from the pre-cast cross.

 

[KDM]

If I understand it correctly, he'll end up with a polyester cross in a PR blank, so change in consistency shouldn't be a problem.

That's what I think, too.

My slight concern would be the shrinkage. My PR square mould is about 20x20mm cross section. After curing there's a good 1mm gap all the way round. (Ummm.. is that 10% shrinkage? Surely not?)
I hope the force of the second PR pour shrinking is not enough to cause the first one to "crush" and crack.

 

[JohnU]

I've double cast silmar many times with no problems. The shrinkage will be around the moldedges and not your item inside. Never had a bond issue either. Should be fine.

 

[workinforwood]

I see no reasons why it won't work. The downside is the amount of prep work and cost of making the mold, but once that is done, it should perform perfectly. The cross however may need to face down in the resinsaver and not up, unless you are not using any pressure. If you are using pressure, then the pressure will push on the edges of the cross just like it does on the edges of a mold and thus cave down the resin around the cross if you follow what I am saying. It's like if you have a square mold, then you pour and pressurize and when you take it out of the mold, the square corners of your finished block are round because the air pressure pushed the liquid down in the corners and around the edges. Otherwise...like John says, the PR will not shrink inside the mold and will adhere perfectly to itself..it only shrinks on the outside of the mold.