alumilite casting nightmare

[splinter99]

For Christmas I asked for a 2 gallon set of Alumilite crystal clear casting resin. So far I have not had much luck with it. It seems that it boils and foams if you put anything in it. I tried pine cones and it foamed. Today I tried dry white rice and it foamed up. If I don't use presure it comes out full of bubbles. The part "A" is very thick, about twice the thickness of corn syrup.
I am using pearl x pigments and have never had a problem with this before..could I have gotten a bad batch of alumilite? Is it a temp thing (I keep it in the house and heat up the shop before I use it) I have tried using it in the resin saver molds but it seems to lose adhesion with the tubes.

Here is a pic of todays casting cluster @#$%

Thanks in advance

 

[NewLondon88]

Ouch! That looks like moisture to me. I'm not sure where it would come from with
white rice (assuming it isn't cooked, right?) but I've learned to put anything I plan
to add on a cookie sheet and pop it in a warm oven for a while before adding it.
You'd be surprised where moisture will linger. The pine cones don't surprise me,
they're usually moist inside and also contain pitch. I don't know if that would react
or not. I clean the pine cones with kerosene, let them air dry for weeks, then I still
put them in the oven.

It doesn't sound like a temp problem, but when you say you bring it out to the
shop, is there much of a temp differential? If the mold is cold, it wouldn't surprise
me to see a condensation issue, but I don't know. And I've never had an adhesion
problem with the tubes (Resinsaver or otherwise) if anything, the cured resin grips
TOO well. (I'd love to slip the tubes out of failed castings to re-use them)

 

[David Keller]

That looks pretty gross.

Save it... maybe next year there will be an ugly casting contest as part of the bash... that's a winner.

 

[wolftat]

Usually part "B" will be the thick one and when it gets cold, it gets even thicker. The problem that I see with the rice is that rice attracts moisture and that is a problem with Alumilite. If it is part "A" that is thick, call Mike or Carol at Alumilite and discuss it with them, they have been extremely helpful to me in the past.

 

[MesquiteMan]

Definitely moisture. Remember, they put rice in salt shakers to remove the moisture in the salt and keep it dry. Rice is a natural desiccant.

 

[JerrySambrook]

Gee, almost looks like an early 80's version of MRE's

What you think wolftat?

 

[mywoodshopca]

Sell the blanks as handcrafted "maggot blanks".. You can make a fortune :biggrin:

 

[splinter99]

I'm wondering if the moisture is coming from the air line. Do any of you use a moisture trap
or air water filter?

 

[NewLondon88]

Ah.. wouldn't know .. I don't use pressure or vacuum. (or Alumilite.)

 

[MesquiteMan]

I do have a moisture trap on my air line but I do not think that is your problem. Alumilite HATES moisture. Things need to be really dry. The thickness of the part B is not a problem. That just means that it has been subjected to temps less than 40 degrees I believe (not positive on the temp). If you heat up the part B in 120 degree water, it will return to the proper viscosity and stay that way until it is cooled below the temp mentioned above.

Try drying your rice in an oven as suggested. Set it for 150 or so degrees and let it dry for an hour. Then cast away. Also make sure your pearlex is not picking up moisture from not being sealed when not in use. If you have a humid shop, it could be picking up moisture too.

 

[JayDevin]

colder months I heat my part "B" in the microwave to thin out the Alumilite....works Fine....

 

[workinforwood]

I only had this happen once, it was with pine cones, and the cones were simply not dry enough. I had run out of cones and collected a ton and being in a hurry, I tried baking the cones and using some. That wasn't good enough. Now I just let the cones sit out for about 6 weeks..they dry fast, especially in the winter. I'm sure that rice just isn't dry, because I've cast some rice and it was fine.

Part A shouldnt' be thick. My part A I keep in the shop and it never gets gelled. The Part B though..that can get really thick in the colder weather. I don't heat up my thick part B and I don't have any problems..I just stir it a lot more, let it sit a minute and I feel it start to warm up and then I stir it more and pour.