[PSUBS-MAILIST] PVHO rules

[Alan via Personal_Submersibles]

Hank,
I had a go at forming an acrylic ring out of a straight piece of 1" thick
cast acrylic, using a modified kitchen oven.
At forming temperature the acrylic was like the hardness of eraser rubber.
Maybe there is technical literature on what shore hardness it actually is at
forming temperature. Anyway if you are forming a 5" block the pressure
Required is going to be used.
When I had a 1" thick dome blown for me they had to stop & get thicker
Clamping rings made.
Emile or Greg may like to comment on this as they have had a lot more experience.
You will need a temperature controller for a kiln, & program it for your requirements.
It will be a few days in the oven I would imagine.
If you machine it, can you get away with not heat treating it afterward?
I would imagine the stress would only be superficial.
Alan


> On 22/04/2019, at 2:11 AM, hank pronk via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> Hi All,
> I am looking for the actual PVHO rules for Acrylic forming.  I can find all the references to the rules but not the rules.  I am planning to make a 5 inch thick 60 degree Hemispherical segment either from forming  or from machining out of a thick slab.  I prefer to form it because I will need an oven to heat treat it after anyways, but I don't want to form it without the rules.
> Hank
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