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What to do with this?
Posted: Wed Nov 12, 2008 11:07 am
by limbeh
Dang.
I sent my minion out today to buy some 2mm thick solid neoprene sheet today (among other things) and he comes back with this:
Some 2mm thick solid rubber sheet or some crap like that with threads woven between the layers of rubber.
Since the threads are there, I'm quite I can't use this rubber as something to provide a seal on the waterproof container that I'm making (i.e. 2 ends of container press down on rubber providing positive pressure).
Its not possible to refund or exchange it for something else, so I got a problem what to do with it. Throwing it away is a huge waste, particularly since this crap cost thrice as much as an equivalent amount of neoprene.
Anyone got any suggestions what to do with this?
Posted: Wed Nov 12, 2008 11:20 am
by Carlman
you can use it for a seal, i have done so before on a 25x15 coax
Posted: Wed Nov 12, 2008 11:32 am
by limbeh
Carlman wrote:you can use it for a seal, i have done so before on a 25x15 coax
For sealing a piston spudgun, the thing should by right have no problems sealing, since you're using the rubber to cover up the hole (i.e. air leak would be perpendicular to the rubber sheet)
On the the other hand for my container, the direction which water is coming from is parallel to the direction which the sheet faces, so I'm not so sure.
The threads aren't waterproof, water seeps through them.
Thanks.
Posted: Wed Nov 12, 2008 11:40 am
by Carlman
can you provide a diagram or more explanation so that i can help you further
Posted: Wed Nov 12, 2008 11:46 am
by limbeh
Here is the diagram. Hope it can be understood.
I didn't draw a diagram of the spudgun, I don't think its necessary.
Posted: Wed Nov 12, 2008 12:22 pm
by Carlman
can you give me a pic of the surface of the ruber as i can see no reason whyit wouod not work
Posted: Wed Nov 12, 2008 2:21 pm
by jackssmirkingrevenge
I would roll it up into a narrower cylinder and use it to beat the errant minion repeatedly,
pour encourager les autres 
Posted: Wed Nov 12, 2008 2:30 pm
by Gippeto
That'll teach em!
limbeh, if you don't cut out the center of the gasket, the water will "leak in one side and out the other", not entering your container at all.
The only way I see a problem, is if there is a significant pressure differential. In which case, the rubber will detach from the fabric, and "bubble" inside the container.
Significant would be in the order of 50psi (~115 feet). How deep are you planning to go?
Posted: Thu Nov 13, 2008 2:19 am
by limbeh
Max depth: (actual) 3m (swimming pool use for research project), (plus insane safety margin) = 10m.
I had some 3mm thick neoprene sheet for the seal, but then and again I drilled the holes for the latches wrongly. As a result, I need to get thinner sheet.
Diagram error:
The container is made of acrylic. Lid, container walls, everything except for the rubber.
The threads in the solid rubber sheet runs parallel to the horizontal, not very sure how to draw that on the diagram.
I'm scared that water leaks through the threads to get into the container by this method.
The rubber sheet is in school now, getting the same minion to take more pictures of the thing......
Anyway, I already went back to the hardware district and bought some more 2mm neoprene sheet (in addition to the 3mm sheet which I already have), so I won't need to use the solid rubber sheet.
Posted: Thu Nov 13, 2008 2:32 am
by limbeh
Sorry, double post, can't delete post.
Posted: Thu Nov 13, 2008 2:42 am
by Carlman
make a few piston cannons to sell maybe
Posted: Thu Nov 13, 2008 2:55 am
by limbeh
Sorry for double post earlier, hope an admin or mod helps me delete the repeat.
Sounds good.
Once I get my first piston cannon up and running. Hope I can find the time to, since I have a swimming competition to prepare for.
If I can get the first one to work, I can start teaching my science club people how to make spudguns - as part of official curriculum........
Then, I'll make them construct cheapskate ones for practice and sell them at rip off prices to innocent sec 1s (junior students) to raise $$.
I was just thinking about selling it off as dirt cheap car mats too.
But not before I whack my minion with it....