Second Casting – FAIL!

[Triple Crown]

I attempted to do two postage stamp pens. The second one turned out pretty good and I put it in the Show Off Your Pens thread. This is the first one. What I THINK happened is that I got the mix wrong on the Alumilite Clear. I measured equal amounts of A and B, poured them into the mixing cup and mixed well. Put it in the ugly homemade mold and pressurized at 50 PSI. However, when I went to throw away the measuring cups of A and B, I seem to recall that one seemed slightly heavier than the other, like I didn't pour all of it out.

I also had some of the mixed stuff left in the mixing cup. (I actually think I like a little left over - at least so far - to estimate how far along the curing of the casting in the pressure pot is going.) Anyway, the stuff left in the mixing cup took a very long time to cure. As a matter of fact, it was pliable and not very strong (I could break it easily) for probably around 5 hours or more. Anyway, when I took the mold out of the pressure pot, I decided to let it cure for another 24 hours. When I turned it, it was air bubbled to extreme! I'm guessing that since it took so long to cure and was a hard jelly for so long, air got in where it wasn't supposed to. So that's my hypothesis. Do you think that's what happened? Any other ideas as to how this would happen?

For my second postage stamp pen, I measured exactly. I measured the A and B cups before mixing and afterward to make sure that they were equal and it was truly a 50-50 mix by weight. No air bubbles.

Comments and suggestions appreciated! Thanks! Greg

 

[Jim15]

Hi Greg,
I'm not positive but I think it's better to go weight than looking at measuring cups. this is just what I think I have read i have not used Alumilite.

 

[cwolfs69]

if i am not mistaken, alumilite clear requires by weight. even then mine seems a little "rubbery" for 24-48 hours.

Sent from my Galaxi via forerunner

 

[Triple Crown]

OOPS! My measurements were by weight. I didn't weigh the A and B cups after pouring into the mixing cup though. My post does not make that clear - well about as clear as my bubbly blanks. I'll edit it now. Thanks so much Jim and Charley!

 

[Triple Crown]

OOPS! My measurements were by weight. I didn't weigh the A and B cups after pouring into the mixing cup though to make sure that all of it was mixed together. My post does not make that clear - well about as clear as my bubbly blanks! Thanks so much Jim and Charley!

 

[warthog]

I have been using Alumilite in my castings...and I just look at the cup and don't weigh. I have not been having any issues concerning the material setting up like it is supposed to. After I make my pour I put it under 60 PSI for a couple of hours and they are ready to turn.

 

[leehljp]

The bubbles remind me of an experiment that I tried a couple of years ago but could not follow up due to work and time limits.

I deliberately wanted lots of tiny bubbles in a coffee bean cast so that it would look like "Iced Coffee". (Iced Coffee is kinda prevalent in Japan.) The problem was that the layer was too thin to have enclosed bubbles on a finished turned blank (Sierra). As I turned it to size, I cut into the bubbles, destroying that "captured bubbles" in ice like look.

Those bubbles do look like they are "frozen". If someone could capture that in a cast pen deliberately, it would be a "new" craze around here! It might work on the thicker pen kits like Sierra Vista or a custom pen with small tube and large diameter outer blank.

Don't think that your experiment is a waste! You learned something and shared it. Thanks!

 

[Justturnin]

When I mix Alumite I zero the cup, pour Part A in the cup, mix my tint if I am tinting, Zero the cup again, pour part b in the same cup Slowly as to not go over. I have never tried to weigh them seperately becasue I thought about what you were saying and the fact that I would never get all of B out of the cup.

As for the bubbles.......wow, I have no idea. I use 50psi (my pots max) and have never seen that. Could there have been air trapped between the Stamps and the tubes that escaped? I dont see how but it's all I can think of.

 

[PTownSubbie]

Did you cover the stamps with some medium prior to casting?

Some people use Modge Podge to put a protective coating on the stamps.

Alumilite hates the slightest hint of water and I believe Modge Podge is water based......

 

[tkbarron]

Yeah, that looks like a reaction to the adhesive. Let it thoroughly dry and then seal prior to casting.

I'm with Justturnin on mixing Alumilite. I use a digital scale for measuring the weight and only one cup is used unless I'm mixing multiple colors for the same batch.

Also, heat your molds before pouring. That will help provide more consistent results.

Tom

 

[Triple Crown]

Did you cover the stamps with some medium prior to casting?

Some people use Modge Podge to put a protective coating on the stamps.

Alumilite hates the slightest hint of water and I believe Modge Podge is water based......

Thanks! I did spray them with an acrylic clear spray. I don't think it was water from the tubes or spray. My glue was spray mount. If water is present (even the slightest amount), are bubbles the result?

When I mix Alumite I zero the cup, pour Part A in the cup, mix my tint if I am tinting, Zero the cup again, pour part b in the same cup Slowly as to not go over. I have never tried to weigh them seperately becasue I thought about what you were saying and the fact that I would never get all of B out of the cup.

As for the bubbles.......wow, I have no idea. I use 50psi (my pots max) and have never seen that. Could there have been air trapped between the Stamps and the tubes that escaped? I dont see how but it's all I can think of.

Thanks! The way I did it, I used three cups. Probably a waste, but one for part A, one for part B, and then a bigger cup for mixing the two. Then, when I reweigh the A cup and the B cup after pouring them into the mixing cup (which I didn't do in this case, but did on the second one), if they are still equal, then I know that I got equal amounts by weight in the mixing cup. I guess there could have been some air inbetween the stamps and tubes, but I don't think so.

The bubbles remind me of an experiment that I tried a couple of years ago but could not follow up due to work and time limits.

I deliberately wanted lots of tiny bubbles in a coffee bean cast so that it would look like "Iced Coffee". (Iced Coffee is kinda prevalent in Japan.) The problem was that the layer was too thin to have enclosed bubbles on a finished turned blank (Sierra). As I turned it to size, I cut into the bubbles, destroying that "captured bubbles" in ice like look.

Those bubbles do look like they are "frozen". If someone could capture that in a cast pen deliberately, it would be a "new" craze around here! It might work on the thicker pen kits like Sierra Vista or a custom pen with small tube and large diameter outer blank.

Don't think that your experiment is a waste! You learned something and shared it. Thanks!

That's a great idea! I might have to experiment too!

Thanks! I didn't think it was a total waste. I try to learn something each time I have a success or a "fail" (term that my kids use really). Thought that maybe others could learn from my errors as well! Thanks again!

-----------------------------

Thank you all for reading and responding... If there are other ideas for what might have happened or for doing it a better way, let us know. Thanks again! Greg

 

[Triple Crown]

Yeah, that looks like a reaction to the adhesive. Let it thoroughly dry and then seal prior to casting.

I'm with Justturnin on mixing Alumilite. I use a digital scale for measuring the weight and only one cup is used unless I'm mixing multiple colors for the same batch.

Also, heat your molds before pouring. That will help provide more consistent results.

Tom

Cool! Thanks! I like your suggestion! Greg

 

[PTownSubbie]

Yes. If water is present it looks like boiling.....

If you use a water based glue as Modge Podge, you just have to let it sit for at a minimum of 24-48 hours to allow the water to fully dry.

I like to coat the stamps with CA to seal them but as people say, YMMV. Each person does it differently. You just have to figure out how to do it without introducing any water or moisture. Even humidity will cause failures....

Good luck!