Making an SMB

[JVM4.0]

Has anyone ever attempted to make their own SMB?

I happened to be at a fabric store the other day (yes, I was holding my wife's purse at the time) and saw some nylon material that looked just like what SMBs are made out of. We bought some to experiment with, and was wondering if anyone else had the same idea.

I've got some ideas as to the construction of the device, but if anyone else has some alternative ideas, or things they'd like to see incorporated into it, I'm listening. Also, what do you do to make the seams air-tight?

If we are successful, I'll be happy to publish the results here.

 

[jonnythan]

I've toyed with the idea, and I still am. It's hard to find bright orange waterproof nylon though. If one side of the nylon isn't "plasticy" then it's not waterproof and won't do you much good. The waterproof stuff has a thick urethane coating on one side. To be sure, pour some water on a plastic chair, then lay the fabric over the small puddle and sit on it for a few minutes. If your butt stays dry your stuff is waterproof

If you have good bright waterproof nylon, use a product called Seam Grip to seal up the seams. You can find it in any good outdoor products store and many marine or craft stores.

 

[jonnythan]

Oh, and btw: be sure you do something to reinforce the point where you would attach something. It wouldn't be a bad idea to sew a 1" piece of heavy duty nylon folded over the edge all the way around the thing, like you see at http://www.diverite.com/products/tools/surfmark.htm

At the very least, put in some metal gromets.

 

[The Kraken]

Hey, John,
Wanna have some fun???
Buy a government surplus army duffle bag, put a plastic garbage bag inside of it, inflate it at depth and hang on . . . !!!!!
Wooooooooooooo Hooooooooooooooo !!!!!!!!!!!!!!

Just kidding. Kids, don't try this at home . . . .

 

[The Kraken]

Actually, I've used this method as a Rube Goldberg contraption to life a very large outboard motor. It was interesting, to say the least.

 

[jonnythan]

LOL Kraken. I didn't have a lift bag when I rescued the Mogwai so I was considering that option. Fortunately a buddy had a nice big one, which we needed for the little guy. 60 pounds by my estimation

The reason I've toyed with the idea is because all the ones I've found are either very expensive or very big. I have yet to find a nice 4-6 foot semi-closed SMB that's more like 5 or 6" wide instead of 8". I bought one from ScubaToys but it's way too huge, especially with teh dump valve, to fit in my pocket. I haven't actually needed one yet, so it's not a priority. I also hate my drysuit and keep telling myself I'll get another so I'm resistant to buying proper pockets too

 

[JVM4.0]

Great idea, Johnnythan. I happened to find just exactly the right fabric. But, they only had about a 9" x 60" piece. She said that they could order more. It's not rip-stop, and it's not "flag material" although those are nylon as well. I found some stuff she called "backpack material". It's dull on one side and shiney on the other. I think that's the side with the urethane coating.

I'm thinking some narrow webbing at the botton to make some kind of bridle (like on a kite), a small d-ring at the top (for a light ? ) and at the apex of the bridle to attach a line (for safety stops), a bolt snap to attach it to the BC.

Construction of the "tube" would incorporate an inverted cone at the bottom to allow air in, but would be harder for it to escape, and would also act as kind of a expansion valve.

Either that, or I go out and buy a gov't surplus duffle bag, and a can of orange Krylon...................

 

[The Kraken]

. . . Krylon !!!!
Damn . . . now why didn't I think of that ????

 

[JVM4.0]

Gees, Kraken...........Krylon is a major part of my tool collection! If I can't fix it with bailing wire, duct tape, or chewing gum, I paint it!

Gotta have LOTS of colors, though!

 

[jonnythan]

Your design sounds good to me.



Krylon...

Oh good Lord.