[PSUBS-MAILIST] PVHO rules

[Alan via Personal_Submersibles]

Hank,
Spelling mistake. Pressure is going to be HUGE.
Alan

> On 22/04/2019, at 8:28 AM, Alan <alanlindsayjames at yahoo.com> wrote:
> 
> 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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