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ANH trooper · Master Joined: 20 Oct 2005 Posts: 305 Location: UK

It seems lately that whenever I form anything using my smallest frames (24"x12") that the HIPS is going kind of bubbly only on the area where the plastic first hits the mould.The inside of the plastic is smooth after I have released it,but the outside looks 'dimpled'.

I think I might be overheating the HIPS slightly but wanted to know if anyone has had the same,or similar experiences when forming HIPS.

The guage I'm using is .100 btw.

-Paul.

jegner · Posted: Thu Apr 20, 2006 9:33 pm Post subject:

Hey, that sounds like the beginning of 'orange peel' You might try raising the plastic away from the heater a few inches and see if that helps.

ANH trooper · Master Joined: 20 Oct 2005 Posts: 305 Location: UK

Jim,it's not like orange peel,I have gone through that stage before Wink

It's more like a slightly pitted/dented look in the plastic only where it first hits the highest part of the mould and the rest is fine.It's strange......

jegner · Posted: Fri Apr 21, 2006 7:43 am Post subject:

Ah, I see now. The plastic is being unevenly heated, so parts are stretched and pulled but at different rates. I have seen this with recycled HIPS and with HIPS made from a bad process. Usually in the thicker grades. AS the plastic starts to stretch it sort of spiderwebs, as if you can almost see the laters of material that make up the plastic.

ANH trooper · Master Joined: 20 Oct 2005 Posts: 305 Location: UK

I am thinking it is the heating too.

I have just bought some new heating elements to try out and replace my gas system.The gas has served me well in the past but it is now time to upgrade and heat with electricity.