HDPE Casting Molds

[BillyBoy63]

Working on learning to make my own pen blanks
from Alumilite
Have a question when filling a mold how far do you go past 3/4 of an inch
to create a full 3/4's of an inch
I guess what I'm really asking is how much will the Alumilite shrink when in the pressure pot curing for it set time?
Billy Boy63

 

[eharri446]

According to everyone I have talked to or read on here, Alumilite does not shrink.

 

[chartle]

it wouldn't shrink but it will have a meniscus so make sure your 3/4" is at the bottom.

 

[Marmotjr]

it wouldn't shrink but it will have a meniscus so make sure your 3/4" is at the bottom.

I spent a bit of time doing large scale molds and castings (1800 lbs per cast, every 30 minutes), and while it's technically a meniscus, in the industry, it was referred to as a "funnel" after the casting had set up. The funnel was the raised part of the casting that was unusable and had to be machined off.

Just an FYI.

 

[chartle]

One other issue is if you are doing tube in casting with clear, the resin acts like a lens and distorts how much you have covered the tube so make sure you have some way of measuring exactly how much of the tube is being covered.

I've sometimes mixed what I think is just enough, I hate wasting resin, and look at the mold a go "its covered I'm fine". I start to turn it and start sweating as I start to round it because that the only time you really know you have enough resin.