Alumilite Block Casting - Rounded Corners

[VODesign]

I keep getting these rounded corners on my block mold castings. Is this common when using the silicone molds?

I'm using the ptownsubbie 6"x 5 1/4" x 1" silicone block molds. I've got a flat surface in the bottom of my pressure pot since its concave and I always make sure the mold is sitting flat.

 

[Wagner11]

I don't use alumilite or silicone molds so take thos for what it's worth. I've heard that warming the molds prior to casting helps prevent this issue

Sent from my SM-S260DL using Tapatalk

 

[VODesign]

I don't use alumilite or silicone molds so take thos for what it's worth. I've heard that warming the molds prior to casting helps prevent this issue

Sent from my SM-S260DL using Tapatalk

Thanks! I'll give it a try and see it if makes a difference.

 

[RobS]

I'm in Southern California, and things tend to be warmer, and the edges are a lot less round.

 

[MRDucks2]

Yep. Preheat your molds for about 10 minutes at 150 or so. They don't have to be hot but should still be warm to the touch when you pour your resin in.

 

[drise]

How thick is the flat surface in the bottom of the pressure pot? If it isn't very sturdy, the air pressure will deform it to fit the contour of the bottom of the pot. I would try something thicker or put a shim in the middle so it won't deflect downwards.