vertical casting

[jimskio]

I tried my hand at vertical casting today. I have a couple hundred feet of cast acrylic tube and was hopeful. Well seems that this cast acrylic does NOT like PR poured into it. The tube just started cracking like crazy. The cast itself looks good it's just the tube looks terrible.





Jimskio

 

[jimskio]

Sorry, seems the pictures get rotated when I upload from my phone.

 

[frank123]

Try using PVC, CPVC, or PEX.

Don't know of anything transparent to use, but there probably is something.

 

[mredburn]

there are transparent tubes you can use but they are tend to be expensive. Even more so when compared to the cost of pvc pipe from home depot or lowes etc. Of course if your cast tube is free and you just use it once and discard it then it wont matter.

 

[navycop]

Try using PVC, CPVC, or PEX.

Don't know of anything transparent to use, but there probably is something.

there are transparent tubes you can use but they are tend to be expensive. Even more so when compared to the cost of pvc pipe from home depot or lowes etc. Of course if your cast tube is free and you just use it once and discard it then it wont matter.

You can try these:
http://www.penturners.org/forum/f43/vertical-tube-casting-104616/

 

[Darley]

I tried my hand at vertical casting today. I have a couple hundred feet of cast acrylic tube and was hopeful. Well seems that this cast acrylic does NOT like PR poured into it. The tube just started cracking like crazy. The cast itself looks good it's just the tube looks terrible.

View attachment 88394



Jimskio

The heat of the PR crack the tube change for a silicon mold will be cheap in a long run or may be you got plenty of those tubes to use so then no worries :biggrin:

 

[NewLondon88]

I tried my hand at vertical casting today. I have a couple hundred feet of cast acrylic tube and was hopeful. Well seems that this cast acrylic does NOT like PR poured into it. The tube just started cracking like crazy. The cast itself looks good it's just the tube looks terrible.

How sure are you that this is cast acrylic and not extruded?
I know extruded acrylic has a tendency to craze from contact
with solvents, but cast is less susceptible to it. The crazing is
usually caused by stress in the material, either from cutting or
shaping.

But since you already have it (no sense wasting it!) you can try
annealing the tubes before use. Seems to me it is something like
1 hour at 180°F for each mm of thickness for cast. Extruded is
170°F. These are just below the deflection temps.. so accurate
temp control is important. Also, cooling too fast can cause stress
fractures too, so let them rest with the door closed after heating.