Help with PR double casting

[jimmyz]

I need some help!

Made a PR blank (mostly red) with 5 drops per once and let it cure for a couple of days. (No pressure pot, but I did warm the material before doing the pours). Drilled, inserted a tube, and turned the blank to 3/4". Then I remounted it on the lathe and made some "designs" in the blank about 1/8" deep. Did similar designs on a wood blank. Created a second PR batch (mostly goldish) with 5 drops per ounce of PR and poured that into a mold containing the two blanks. Waited a couple of days, cut the blanks apart, trimmed the ends and turned them. Two problems:

1) Some of the second cast material is coming out and creating voids. How do I keep it to stay in? I'm using, I think, sharp tools and light cuts.

2) When I carved the designs in the red PR blank, I noticed some of the material down "in" the design was more light brown vs red. I went ahead and did the second cast anyway because it was a test. Why is the material not red throughout?

Appreciate any help I can get with these casting issues.

 

[BSea]

The 1st problem is that once the resin is cured, the 2nd pour won't bond well with the original pour. The way to keep things together is use CA as you're turning the blank. Treat it as you would a burl blank.

The 2nd problem might be the brass changing the color of the red to brown. The deeper you made the design, the more the brass changed the color. You probably should paint the inside of the drilled blank a red color, and maybe paint the brass tube too.

Hope this helps.

 

[Edward Cypher]

Also the second pour of PR will shrink if not in a pressure pot. Bsea is correct if you are not going to use pressure be sure to soak with thin ca it will get sucked into and between the new and old pour.

 

[Joey-Nieves]

If all you want to do is fill the voids, mix mica and medium CA in a small glue bottle, then fill. The CA will last for a while in the bottle but mica will go to the bottom so a lot of shaking is involved. I use this to fill bug holes ans cracks on wood and it comes out very interesting.

 

[jimmyz]

Thanks for the inputs. Didn't realize PR would shrink. I ended up mixing gold coloring with epoxy and filled the holes with that. May try to mica/CA mixture next time. Sounds like I mix it in a CA bottle, shake before use, and just leave it in the bottle until next time? Make the hole in the CA spout a little bigger?

 

[BSea]

If all you want to do is fill the voids, mix mica and medium CA in a small glue bottle, then fill. The CA will last for a while in the bottle but mica will go to the bottom so a lot of shaking is involved. I use this to fill bug holes ans cracks on wood and it comes out very interesting.

Thats a good tip. Do you have more than 1 color mixed? I can see that costing some money, but still a good idea.

 

[Joey-Nieves]

If all you want to do is fill the voids, mix mica and medium CA in a small glue bottle, then fill. The CA will last for a while in the bottle but mica will go to the bottom so a lot of shaking is involved. I use this to fill bug holes ans cracks on wood and it comes out very interesting.

Thats a good tip. Do you have more than 1 color mixed? I can see that costing some money, but still a good idea.

Yes I mix 2 or 3 colors when I'm in high production mode( Christmas I turned about 300 pens, different styles from slim lines to Majestic s and a few kitless). They last a few weeks in the bottle with a cap, I don't mix very much at a time and the CA comes out the bottle when dry so I reuse the bottle again.
I also apply it as a finish to the pens, it gives light color woods a nice pearl like finish.