Alumilite and ambient air temps...

[Marko50]

I have a question for all of you Alumilite users out there. Does the ambient (the air surrounding you) air temperature have an effect, positive or negative, on your casting, especially when casting clear blanks?

My shop, on average, hovers around 55 degrees. I'm not sure what internal temperatures inside the pot climb to due to compression but I would imagine they are probably negligible. I'm just curious if my clear castings would be better if I did them inside a warm house. The wife will go ballistic on me if I start dragging my pressure pot into the kitchen. Ya know what I mean?

 

[HamTurns]

Hi Mark - My basement shop is a bit below 50*F and I cast Alumilite.

I've found the cold to be a benefit because it gives a little more working time. More time to mix and pour and swirl.

I'm pretty sure that all of the heat generated is by the chemical reaction between the A & B parts. I don't think any heat is introduced because of the pressure we put the casting under, that just shrinks the air bubbles for a better casting.

I always pour my extra resin into a small cup on the workbench and I leave it set until hard. That gets warm just sitting there from the chemicals mixed.

The colder it is the more working time you'll have.

Happy turning
Tom

 

[crabcreekind]

Hi,
I normally cast around 70*, but that is because I am spoiled with heated shop. But you can cast at lower temps such as 55*. You will get a longer working time, but the disadvantage of that is the resin will be more viscous. If you are using pressure, after you pour your resin in the mold, you should have no problem with bubbles. However, since alumilite is a thermoset resin (correct me if I'm wrong) the hardening of the resin is caused by the reaction between the A&B parts which puts off heat and cures it. Also, since the ambient temp of you shop is lower, the set time will be longer than stated on the alumilite website.
I hope this helps,

Edit: If your shop is too cold, the resin will not set. For example if you tried to pour the resin at freezing point the resin would have a hard time setting and probably be screwed up and no good to turn.

James

 

[BSea]

I just did my 1st sub 60 degree cast the other day. I weas surprised that after 3 hours, the blanks were still tacky. That's a 1st for me with alumilite. Before, they always come out fully cured after 2 hours. Next time I'll heat my mold before pouring. But it wasn't an issue anyway. It just took longer than I'm used to.