casting information needed

[chiefgreen]

To be honest, until I joined IAP, I didn't know it was possible to cast your own acrylic blanks in the shop. From what I read, the fumes are really "thick", I am allergic to paint, urathane and other chemical odors. However, I am not bothered by the turning, sanding of the blank.
Whew, finally to my question; Is it possible to pour measured amounts of different colors on top of each other and the colors NOT mix? For example; I need a 4inch blank, starting at one end, 1/2" of red, then 3/8" of white, then 1/2" of red, then 1/4" of white and so on untill the 4 inch total is reached. Can it be done repeatably no matter how thin some of the segments are? IE: 200 blanks exactly the same size.

Thanks,
chiefgreen

 

[soligen]

I'm no casting expert, but I dont see how that kind of accuracy is possible. Maybe an expert caster could do it, but as a rookie, it sounds not practical/feasible to me.

I think it is much more practical to cast solid blanks then cut and glue them in a traditional segmenting way.

 

[ldb2000]

Yes it is possable . When you pour your first color let it set then pour your next color and so on . The casting resin we use is designed to stick to previous pours with no problems
Edit:
From what you are saying you will need to use a vertical mold , PVC pipe will work .

 

[PenMan1]

Castiing this blank can be done with pinpoint accuracy. I perfer a horizontal mold because I can "see" the pour. To use a horizontal mold. you need dividers. I use a shop made horizontal mold. I measure the distance with a caliper (in your case, 1/2 inch for the red), then slit the mold on either side and insert the first divider made from a thick "report" cover or back of a CD case (a little pam spray or peteroleum jelly will make the divider release from the cured PR).

When the first pour dries, remove the first divider, then slit the mold for the second divider and pour the second section, etc. THE IMPORTANT PART IS THE DIVIDER MUST BE STURDY ENOUGH NOT TO BULGE FROM THE PRESSURE OF THE PR!

Others I know don't use dividers, but instead insert shorter blanks in the mold that will not stick to PR as a "dam" for the PR. The problem here is that the insert blank must be a tight fit in the mold or the PR will "leak" around the insert and must be made of something that will not adhere to PR (two part silicone).

This method is VERY exact if you continue to use the same mold. In fact, it is so precise that several blanks poured in the same mould can be then glued together without a seam. I use this method to make "checkerboard" blanks without all the cutting and glueing.

 

[soligen]

Ok scratch my comments - i know nothing LOL. But If I had to do 200 identical blanks this way ...... Shudder.