pouring with pieces

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RAdams

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I just finished my first pen with a piece poured blank. I call it that cause i dunno what else to call it. I made some blanks, then smashed them with a hammer. Then i took the pieces and put them in the mold, and poured another color around them. After it was all finished, i noticed a tiny crack in the blank where one of the chunks meets the repour. Is this common? I pressurized it to 50 PSI in hopes there would be no flaws.


any help would be appreciated.


P.S. how do you remedy such a problem? the crack is tiny, but i know it is there, and i don't want it to become a problem spot in the future.
 
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Try a chisel rather than just a hammer

I have had some limited success with this also. The next time I do that type of pour I will make sure that I rough up the edges of the pieces and if you look really closely at the pieces, you will likely find some tiny cracks in them also.
The breaking process causes a lot of trauma to the pieces. I have tried a chisel and hammer instead of just a hammer and have gotten better results.
Just my 2 cents.....
 
it is poly resin.

I also emitted the fact that the blank is now on a finished pen.

I also went with a chisel and hammer for the second round attempt, and didn't think about inspecting / roughing the pieces. this all should make quite a difference, but would also throw the price of those blanks up considerably unless you could mechanise the process. Use a sandblaster to rough the sides, etc. alot of work for some pen blanks.

In this case, it would be worth the work. The pens i am making with these are for my cousins wedding.

speaking of... gonna hijack my own thread... cool idea for wedding pens. use the wedding colors to make the first blanks. break those and repour in two blanks.

pearl white for the Bride.
pearl black for the Groom.

i will post pics of the pair when finished.
 
RAdams said:
Snip

I also went with a chisel and hammer for the second round attempt, and didn't think about inspecting / roughing the pieces. this all should make quite a difference, but would also throw the price of those blanks up considerably unless you could mechanise the process. Use a sandblaster to rough the sides, etc. alot of work for some pen blanks.

Snip.
Click to expand...

Sandblasting the resin shards will generate dust, you will need to wash off the shards, which will be another process step.
 
If you see that tiny crack while the blank is still on the lathe, it would be a good idea to flood it with thin CA so as to not only fill the crack, but also to help avoid a blowout.
 
NewLondon88 said:
Can't do it with Alumilite.. not with a hammer. I even tried it with a
meat grinder. Alton was able to do it with an 8.5hp wood chipper, though.
Click to expand...



so how do you turn it? Diamond tipped tools??? I bet i could break it with a hammer... But then again, my daddy always said i could tear up a hammer!!!
 
RAdams said:
so how do you turn it? Diamond tipped tools??? I bet i could break it with a hammer... But then again, my daddy always said i could tear up a hammer!!!
Click to expand...

It will cut fine, but breaking it up with a hammer would be an exercise in
futility. Alumilite is too elastic to shatter the way PR does.
 
Put it in the freezer over night. Elasticity will be much reduced when very cold. Worth a try if you want to smash it into smaller pieces. Watched a cabbage get smashed after a dip into liquid nitrogen. Cold is a funny thing sometimes.
 
You might also verify that your blanks were clean prior to you smashing them up.

Some time ago, I discovered that my old compressor was getting way too much oil blowby. This wasn't really a problem when using air tools, but it was a real issue when pressurizing a tank full of blanks.
 
Try breaking the pieces with a chisel then use tumbler

I had luck with this years ago. Try using a chisel to break the peices. Once you get the sizes you want put them in a rock tumbler to soften the edges.
 
I've had great success by mixing the PR and mekp first then mixing in the chips then pouring the mix into the mold . By mixing in the chips I'm sure that all surfaces of the chips are coated with PR . I get no voids and just minimal small bubbles doing it this way , and I don't use a pressure pot .
Here's some pictures
http://www.penturners.org/photos/index.php?n=9384
http://www.penturners.org/photos/index.php?n=9385
http://www.penturners.org/photos/index.php?n=8409
http://www.penturners.org/photos/index.php?n=8509
 
I use dry-ice to chill my PR before breaking it up. I cast about 1/8" thick, put it in a styrofoam cooler with the dry-ice and leave it for about an hour. It cracks up real nice, any big pieces go back into the cooler for about an hour and I hit it again.
Hope this helps
 
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