Water proofing a Project

[John Gutmann]

First of all as an idea how about an off topic technical forum for random mechanical, electrical, and programming questions that have no relation to FIRST? LIke the Chit chat but pure technical threads.

Ok, my main point. The other night I was at a friends house when she was showing me the lighting in her pool so I had the idea of making little floating lighting elements. The problem is that I would like to make them totally submersible so you could just leave them in the rain and not worry about how you get them out. The problem is I want to be able to make them so that I can change the batteries in them. So it would need to be some type of box. I was thinking of maybe of just casting the actual control board or whatever I choose to do for the control (whether it be a micro controller or what) is some sort of non conductive resin but then I still have to worry about the battery. Then I though of using vacuum bags, but they are pricey, then I thought of the big sheets of laminate for text books but then how do I seal the box and what if water gets under the laminate?

Do you guys have any ideas?

-John

[Greg Needel]

it is actually alot easier then you think. All you need is well placed gaskets and o-rings. There is a really good chapter in the machinists handbook on them, but the basic gist of things is you have 2 surfaces (like panel that comes off, and the plate it attaches to) and you cut a small groove (dimensioned to the size of the o-ring). When you put the 2 parts together it squishes the o-ring and creates a water proof seal. If you open most any electronics that are water resistant or proof you will see one of these. A good cheap example if you wanted to find one is a shower radio.

[MrForbes]

there is a clear plastic food storage container you can get at Walmart (?) that has a rubber o ring in the lid, and latches to hold the lid on, brand name LOCK & LOCK maybe it would do the job.

[TheOtherGuy]

Originally Posted by squirrel

there is a clear plastic food storage container you can get at Walmart (?) that has a rubber o ring in the lid, and latches to hold the lid on, brand name LOCK & LOCK maybe it would do the job.

This is the one you were talking about. We tested them and they're watertight up to at least 8 ft. (after smearing vaseline on the o-ring)

[ChuckDickerson]

Originally Posted by TheOtherGuy

This is the one you were talking about. We tested them and they're watertight up to at least 8 ft. (after smearing vaseline on the o-ring)

I advise caution using vaseline on the o-rings. I am not sure what material the o-ring is made of in these containers but vaseline is a petroleum product and will degrade some o-rings. There is a special silicone based o-ring grease made just for this purpose. Check a local dive shop and they will know what you are looking for. IIRC what we use at work is "Dow Corning 111".

[John Gutmann]

I forgot all about "tupper ware" type containers. I should just try buying some glad wear and putting a huge bead of silicone in the crease on the top if it isnt water proof right away.

-John

[GBIT]

Originally Posted by DeepWater

I advise caution using vaseline on the o-rings. I am not sure what material the o-ring is made of in these containers but vaseline is a petroleum product and will degrade some o-rings. There is a special silicone based o-ring grease made just for this purpose. Check a local dive shop and they will know what you are looking for. IIRC what we use at work is "Dow Corning 111".

We use the same stuff at the dive shop that i work at we also use a a silicone product produced by trident diving accesories for $4.95 for a half oz. container witch will last you forever if you use it right. the product number is LP21.

[Joe Ross]

Team 842 came up with a rather unique solution for their first entry in the underwater robotics championship. http://www.wired.com/wired/archive/13.04/robot.html

[Jon Jack]

A good reference we use at work for o-ring seals is the Parker O-Ring Handbook. The Parker O-Ring Handbook goes over just about everything you would ever want to know about o-rings. Everything from materials and handling, applications, lubrication, groove sizes for various types of seals, o-ring profiles, etc, etc, etc.

[Dick Linn]

Those "lock and lock"containers are really nice! You could also investigate various PVC pipe fittings and cobble something together. Most of the plumbing stuff at my house is waterproof, LOL!

[Otaku]

If you want something a little tougher than tupperware or whatever people are suggesting, get a small ammunition can from eBay or such, then build the light into that (anywhere on the box is fine really, so long as it can still latch shut). Then waterproof the light and the hole it's sitting in and you're good to go with a military ammo-can light-thing that you can still open up and work on and is perfectly waterproof.

[chris31]

Originally Posted by Otaku

If you want something a little tougher than tupperware or whatever people are suggesting, get a small ammunition can from eBay or such, then build the light into that (anywhere on the box is fine really, so long as it can still latch shut). Then waterproof the light and the hole it's sitting in and you're good to go with a military ammo-can light-thing that you can still open up and work on and is perfectly waterproof.

They did this on a recent episode of Hak5 if you are interested in watching a video of how they did it and how it turned out.

[Otaku]

Originally Posted by chris31

They did this on a recent episode of Hak5 if you are interested in watching a video of how they did it and how it turned out.

I have no idea what Hak5 is, but if you can get me a video link, then by all means, please do.

-Otaku

[Heavy Metal]

y not just cut out a corner of a soccer ball fill in sides with metal to keep from folding in on itself and the cut out corner is the lid and you use superglue to make it waterproof just takes a lot to do it
one more thing
the see-through soccerball hasnt been made yet lol