T3D Re: underwater housings

[Tom Deering <tmd@xxxxxxxxxxx>]

On 9/14/98, john bercovitz wrote:

Hey, it this THE John Bercovitz?  Cool.  :^)

>>My plan is to build one out of plexiglas.  The stuff is easy to cut and
>>glue, and will withstand any amount of pressure if thick enough.
>
>That's a nice choice - it will allow you to diagnose problems visually.
>Polycarbonate fails more gracefully than acrylic, and cuts and joins
>about the same, but it does have a color cast so you would have to put
>optical ports on the front of the housing.  Probably not a bad idea
>anyway.

I noticed that plexiglas comes in a blue-ish tint that looks like real
glass, as opposed to the greenish tint you usually see.  If that doesn't
look right.  I was thinking of sealing a thick piece of glass to the front
of the box with silicone.

>>Maybe my biggest questions are about water-tight controls and maximum
>>depth.  I assume I will build a special camera that has motorized
>>functions, and a controlled depth of field.
>
>For watertight controls, I would recommend magnetically-operated switches.
>No seals to fail.

That's funny, I bought eight reed switches the other day for this purpose.
I figure I can find some way to trigger them with magnets from the outside.

>For maximum depth calculations, I would recommend "Roark's Formulas
>for Stress and Strain", McGraw-Hill, any edition.  If you find it slow
>going, I can help you with the formulas in that book.

Great.  Math has never been my strong suit.  Thanks.

Tom



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