If you coat the outside seams on your housing with silicone (RTV) it may help seal better than trying to do so from the inside. That's because the pressure is pushing the silicone against the seal.
Also, think about using the gel from a baby diaper or a gel filled absorbent feminine panty shield to absorb and contain leaking water. The second suggestion may cause some raised eyebrows, but those are about the right size.
You are very talented and skilled. Think about getting a small drill press with an x-y table for milling. You demonstrate quite well what can be accomplished when you stay away from TV and the internet. Gotta go.
Maybe this is a reply to me...
I think I have known your advice well however I would like to say thank you very much for your kindness.
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1) I would like to add somewhat comment about water absorber. I don't raise eyebrows (I know this mean for the first time) because I had used the sanitary pad as water absorber about 8 years ago.
At that time there was a discussion about the water absorber at an U/W digital camera formula in Japan. Many divers taking U/W photos recommended a ladies sanitary pad without evidence. So I had examined how the pad, a facial tissue paper and a silicagel absorb water. The result was uploaded at my HP on Dec 12, 2001 (sorry in japanese).
here and
here.
The polymer in the sanitary pad immediatly absorbed the water but it took a few minutes to intake and fix the water.
2.5g silicagel, half the kleenex papaer and 2x3cm sanitary pad absorbed about 2ml water immediatly. This implys that the sanitary pad is not much effective than silicagel and kleenex in QUICK absorption of water.
My conclusion was that
if the predicted water invasion is much and the inner space of the housing is enough,
a piece of sanitary pad wrapped by the kleenex paper is recommeded.
if the water volume is not so much and the inner space is not enough, a silicagel wrapped by kleenex paper is recommeded.
Actually I use a piece of ADULT diaper wrapped by facial tissue paper.
Because it is cheap and easy to buy and I occasionally use it at a very long time diving with dry suits.
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2) My DIY policy is as cheap, easy and safety as possible.
Really I'm not talented and skilled so I want to get a drill press and lathe but it may be against my policy to use these machines.
The professional produces a housing with 10mm or more thick acrylic plate and bend it by heating. This is very difficult and almost impossible for me.
My method is to use thin acrylic plates (usually below 5mm) and the strength is gained by adhesion of 2 or 3 plates. To make a box some acrylic plates are glued by acrylic adhesive.
This method enabled me to cut acrylic and make a hole very easily with a saw for plastics, mini-rooter, mini-drill and mini-vise. So I could produce my housings at the very small area in front of the PC on my desk while looking at TV and doing internet.
Thank you, again.