Re: [PSUBS-MAILIST] Open Discussion's Allowed in PSUB's Mailing List

[Jonathan Wallace <jon@psubs.org>]

Hi Brent,

After hearing Dr. Joan Stachiw say it in person, and reading it myself in Dr. 
Jerry Stachiw's book, I can tell you with certainty that ASME PVHO standards 
require annealing for any acrylic component whose surfaces were machined, 
sanded, and/or machine polished.  Now that I have the book myself, I can even 
give you a reference; 15.2.3 Annealing, Page 837, "Handbook of Acrylics for 
Submersibles, Hyperbaric Chambers, and Aquaria".

In my opinion, Stachiw and ASME PVHO, are synonymous.  Stachiw served within 
ASME and wrote many (most?) of the standards regarding acrylic viewports 
because of his extensive research with the material.  If I'm wrong, someone 
correct me, but I believe this is true.

You are correct that Stachiw's book does not specifically reference water jet 
cutting acrylic and his book may be "dated" in that respect.  However, he 
constantly refers the reader to the latest ASME PVHO standards which we 
assume are updated when new procedures are tested, qualified, and adopted by 
that organization.  If water jet cutting acrylic viewports is not singled out 
in the current ASME PVHO standard (I don't have a copy of it), then we can 
assume that the more general description of "machined" applies and annealing 
is required when building to ASME PVHO specs.

So you see, your question would have been answered in that $200.00 book 
because you would have been pointed to the latest ASME PVHO specs.  You could 
have then read those specs to determine if annealing after water jetting was 
an exception.  The reason you sometimes get "pat" answers on this forum, is 
because someone might have already done that research and is merely giving 
you the "answer" you seek in the most forthright manner they know how.

If you are suspect of the credentials of those that might respond to your 
questions, then you should either target your question to that person to whom 
you do trust; or purchase the Stachiw book/ASME PVHO standards so that you 
can find the answer yourself.  After all, if you can't trust yourself, who 
can you trust?

Jon

> I once posted a question about
> whether or not I needed to anneal acrylic, if I only cut it with a aqua jet
> cutter. Since I had reason to believe the aqua jet cutting process wouldn't
> put any heat stesses on the acrylic that would need annealing to take care
> of. I did a PSUB's archive search before I posted my question. Along with
> the speculation that my question wouldn't be answered in a great but
> slightly dated $200 book, (I hadn't aquired yet) since I believed aqua jet
> cutting of acrylics was basicly a new process, I asked the question. I got
> the patt answere of that, all acrylic needs to be annealed after cutting,
> in such a way I couldn't tell if they really knew that, with regards to my
> question, or if they just didn't want to deal with it. 



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