1st Coffee blanks

[Daddy1]

I mixed up the coffee and resin and poured in the mold. I am not using a pressure pot yet. My first issue was the coffee rose to the top and I had a "blank" strip on my pen. There was an area that did not have any coffee. My next issue was it was really thin and the ends chipped. Yesterday was a "learning" day. I learned what NOT to do ALL DAY LONG--Anyway can someone tell be how to avoid the separation?

 

[Hello]

I don't actually know...but I might guess a higher coffee to resin ratio?

 

[Daddy1]

I tried that. I poured 4.5 oz of resin and mixed in 3/4 of a cup of coffee thinking that would avoid this problem and it still has separation.

 

[Hello]

did the cofee that seperated end up hardening into a usable blank?
I might try getting the attention of PR_Princess or Ed4copies with this question

 

[SuperDave]

Are you casting in one single cube or in separate blank-sized cavities?

Without a pressure system, you might keep stirring the mixture until it starts to gel up fairly good (gotta be ready and quick) and then put the "batter" into the mould... hopefully, then, it will stay together better.... but air pockets could be an issue... so maybe some waxed paper and added weight compressing the "batter" while it sets[?][?][?]... just thinking outside the mould...

 

[Stevej72]

I used equal amounts of resin and coffee. Also the last time I used 3/4 inch PVC pipe about 3 inches long. It still floated but I had plenty to work with anyway. I used CA to glue the PVC to a board and then cut it off with the band saw. After the resin cured I was able to push it out.

 

[leehljp]

I did whole beans on most of mine and on these, I put the beans in first and poured the mix on top. Before they could float, I placed wax paper on top and a weighted board on top of that. One other note - I made sure the mix was about 85°to 90° which lowers the number of bubbles and allows them to get to the top quicker than at 70° or so.

I did one ground coffee blank and mixed the grounds in with the 85°+ mix and poured it into the mould. I put wax paper and weighted it down. On this, I knew that I would have to mix enough coffee so that it would not have the room to "float" up. The weight of the board on top keeps it from rising out of the mould.

Both sets of these were with resin that sets within 5 minutes and do not allow me time to pressurize a take to keep bubbles down. But the warm temp eliminates most of that. I tried two sets on the 24 hour resins in pressure and still got more bubbles than with the warmed quick resin. I haven't done but about 8 batches of coffee (24 blanks) and these were my first foray into casting. I have done 8 red pepper blanks and they turned out the same as the coffee beans.

 

[Jarheaded]

With Alumilite, you can make the blank in stages. Just make a thin layer at a time. I like the round mold idea also, but not everyone has them.

 

[Daddy1]

Thanks for the advise. I will try it again. I did try some blanks poured in to round molds. I found some ice trays that are used for making water bottle ice cubes. So they are elongated and round. But I can't get them out of the mold. They are stuck.[}]

 

[sbell111]

Originally posted by Daddy1

Thanks for the advise. I will try it again. I did try some blanks poured in to round molds. I found some ice trays that are used for making water bottle ice cubes. So they are elongated and round. But I can't get them out of the mold. They are stuck.[}]

I've had the same issues with casting PR in the two-part walmart ice cube molds. This is what I do:

When the PR is good and hard, I peel off the bottom piece of the mold. I then grab a short 3/8 socket extension and use this to press the hardened PR out of the mold. Sometimes, I've had to use a few taps of a rubber mallet to get it started, but I try not to do that for fear of creating fractures within the blank.

 

[Jarheaded]

Try using a mold release agent on the ice cube trays and it should pop right out.

 

[Daddy1]

How can I get the release agent in after the fact? The blanks are stuck in the trays already. Hind sight is a .......

 

[Daddy1]

I tried the hammer and a transfer punch. I hit it so hard it flattened the end of the punch. It moved 1/4" but would still not release.

When I do something I do it BIG!!!!

 

[Stevej72]

I've had some cast in PVC that just wouldn't come out so I set the table saw to a depth the same thickness of the PVC and then made a cut on each side, then I could pull the rest of the PVC away.

 

[sbell111]

Originally posted by Daddy1

I tried the hammer and a transfer punch. I hit it so hard it flattened the end of the punch. It moved 1/4" but would still not release.

When I do something I do it BIG!!!!

Please don't be insulted by this post.

As I recall, the walmart ice cube molds are slightly thicker on one end than the other. Are you sure that you are trying to make them come out the right end?

 

[Daddy1]

I will give it a whirl. Thanks

 

[Daddy1]

You know sometimes you are so close to something you can't see your way out. SBell was right on. When I look at the ice cube tray now it is obvious the top is wider. I flipped it over and have 3 more chances at a coffe blank. I still have some separation at the top but if I cut off the top I should have enough left to make some pens.

Thanks SBELL.

 

[ed4copies]

Originally posted by Daddy1

I tried the hammer and a transfer punch. I hit it so hard it flattened the end of the punch. It moved 1/4" but would still not release.

When I do something I do it BIG!!!!

I would be surprised if there were a mistake we have NOT made. This is one of my favorites that has not been solved, by us. I believe it relates to temp and humidity and therefore, curing time. Cause lots of people swear this works (round pipes). Well, I have used the transfer punches and wooden dowling, usually get the blanks OUT, but there are hairline cracks in them that make turning a pen a problem.

As far as HOW to use coffee. Dawn has not made coffee she likes yet. So, I don't know YET!.

A suspicion - use more hardener, so it sets faster, it will help separate from the pipe, but it will be more difficult to turn, because it will want to shatter.

So, what do I KNOW???? Darned little!