A PVC housing idea based on Formufit table caps

Waterproof Housing, Frames, and Buoyancy Methods.
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EKMallon
Posts: 28
Joined: Jan 31st, 2015, 3:12 pm

A PVC housing idea based on Formufit table caps

Post by EKMallon »

I recently came up with a new underwater housing design that is very easy to construct, so I thought I would post a link here as many people on this forum use PVC in their builds. The Formufit table caps that this design uses are available in diameters between 1 to 2 inches, and if you combine this with the underwater cable connectors I posted last week, you might have a good way to package batteries for an ROV.

http://edwardmallon.wordpress.com/2015/ ... -for-2015/

Links to all the parts I am using are embedded in the post. Most are from Zoro tools, as they are cheapest supplier I have found so far. If anyone knows of an equally reasonable supplier for 5/32 o-rings with an inside diameter of 2-3/8 inches, I'd love to hear about it.

cheers!
rossrov
Posts: 383
Joined: Feb 28th, 2013, 5:01 pm
Location: Australia

Re: A PVC housing idea based on Formufit table caps

Post by rossrov »

Good find. Lots of other interesting bits on the Formufit website.
EKMallon
Posts: 28
Joined: Jan 31st, 2015, 3:12 pm

Re: A PVC housing idea based on Formufit table caps

Post by EKMallon »

Yes, and it looks like some folks have started selling ROV kits using their colored PVC parts:

http://www.marinetech.org/pufferfish/
dtrip
Posts: 28
Joined: Jan 25th, 2015, 10:01 am

Re: A PVC housing idea based on Formufit table caps

Post by dtrip »

They look good, thats for sure!
What pressure do you expect them to withstand ?
EKMallon
Posts: 28
Joined: Jan 31st, 2015, 3:12 pm

Re: A PVC housing idea based on Formufit table caps

Post by EKMallon »

Not sure on the total pressure yet. They are about 4-5mm thick on the ends (while the older pvc end caps I was using were 6mm thick), and they have a big flat surface, so I expect there will be some flexing. Since that is also where I have the epoxied pass-throughs, this might give me some grief. Most of our research sites are at the 20-30 meter depth, so I will find out on the next deployment if they are good to those depths. I also know a fellow who has bodged a pressure chamber together from an old scuba tank, and the next time I am in his town I will pop in. His DIY rig can pressurize to about 90m. (he makes dive lights..) But it will be a few months before I know if they will last long enough..
gsisrov
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Joined: Aug 7th, 2014, 9:36 am

Re: A PVC housing idea based on Formufit table caps

Post by gsisrov »

That looks like a brilliant simple way of making a seal if it works.
EKMallon
Posts: 28
Joined: Jan 31st, 2015, 3:12 pm

Re: A PVC housing idea based on Formufit table caps

Post by EKMallon »

The first generation of the formufit underwater housings has just come out of the water, and all of them survived more than 4 months at 10 m depth.

http://edwardmallon.wordpress.com/2015/ ... e-strings/

Once we had the data off them, they were put back in for another stint, in addition to 6 more units in systems ranging from 5 to 25 m depth. We will probably go back to retrieve them early next year.
EKMallon
Posts: 28
Joined: Jan 31st, 2015, 3:12 pm

Re: A PVC housing idea based on Formufit table caps

Post by EKMallon »

Hi again everybody.

I hope this is not spamming the thread here, but I thought people might be interested to see how I put the electronics into the PVC housings. Most of my 'surface to shallow water" loggers use a simple rubber Quik-cap, and some of them have survived months at 5m depth, although the rubber flexes so much that I rejected that idea from applications like the flow meters, because the flexing throws off your buoyancy control as you go deeper. Still it was interesting to note that those things can withstand far more pressure than they are rated for, and that might be good for fast prototyping while you work on a hard shell.

I threw my little project into the ring for Hackaday's contest this year. After looking at it I realized that the listing turned out to be a pretty good 'short' summary of where I'm at with the entire project. So I thought I would post a link to that here so that people don't have to wade through my entire blog if all they want to see a few quick photos.

http://hackaday.io/project/6961-the-cave-pearl-project

cheers!
EKMallon
Posts: 28
Joined: Jan 31st, 2015, 3:12 pm

Re: A PVC housing idea based on Formufit table caps

Post by EKMallon »

Happy to report that the first generation of 2" form-u-fit table cap housings have all successfully passed 8 months at depth, with some of the earliest builds now approaching 12 months. The deepest deployment so far was ~22m.

http://edwardmallon.wordpress.com/categ ... r-housing/

Sorry about the previous link being behind a login wal, I did not realize that Hackaday was trying to keep people from seeing their project site.
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