K1 project page INCLUDING publically-available files

Genesis

As soon as I can write it up...

__________________
"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
http://www.denninger.net
http://www.diversunion.org/liability.htm - Fix the Diving Cert racket

Genesis

Thought you guys might like this....

I've gotten increasingly tired of the "plumbing parts" T-pieces. They work, but they're big and bulky.

So I decided to do something about it. Ordered up some rectangular HDPE and some tubular HDPE, and went to work with the lathe and drill press.

Now you can't glue HDPE. But you can heat-weld it! So out came the checkbook and a Steinel Heat Gun arrived at my door - digitally controlled. Set for 650F and you have a nice pinpoint blast of hot air that does a dandy job of welding your HDPE parts together. No solvents, no fumes, no problems. For a joint like this it turns out you don't need a filler rod, provided you have machined things to be a tight enough interference fit - it welds right up - although you could use a filler rod if you wanted to.

Anyway, here's the new and old T-pieces. The O-rings aren't on the new one yet and I have to drill the relief holes and fit the divider plate, which will get done here in the next few days.

The other advantage is that since you're machining down the original rod from a slightly larger diameter you get a much better fit in the bore of the MSR bag's collar. This makes for more stable seal and fit overall.

Its a MAJOR improvement - MUCH smaller and lighter than the one made out of Schedule 80 bits.




Another interesting thought has crossed my mind The heat gun may make it reasonable to fabricate counterlungs out of urethane-backed cordura! Since the usual is to RF weld it, its obviously done with heat. The Steinel, with a pinpoint nozzle, may provide enough precision to make it possible to either take a big MSR bag and cut it down width wise (solving the "too wide and short" problem) or make possible raw fabrication out of the bare urethane-coated stock. I'm doing some experimentation on that now.

We are rapidly approaching the start of our summer diving season, which will afford me lots of "in water" time with the K1....

Rockin' on!

__________________
"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
http://www.denninger.net
http://www.diversunion.org/liability.htm - Fix the Diving Cert racket

fireman

Have some green...great stuff, thanks for sharing.

__________________
Heres to you Capt. Bill
Never Forget, and stay safe everyone.

jmhardingjr

I've been making up CL's out of urethane coated fabric for some time now. It's not as easy as it sounds, and the heat gun increased the instance of weld failure for me. Even heat + even pressure = hard to do with a heat gun. The problem is welding the coating to the coating and having the urethane on the "blind" side. If you are doing overlap welds (like with PVC tarp material) you can do a weld where part of the welded coating is visible. Being able to watch it heat up/melt makes a hell of a difference. Welding urethane coated fabric seems to work better (in my experience) with different equipment.

Good luck,

Jay

__________________


". . . the sea's in my veins, my tradition remains, I'm just glad I don't live in a trailer . . ."

blibecap

What equipment would that be Jay?

jmhardingjr

Hi,

Depends on the specific material you are working with. I use a constant heat sealer for most of my work. It's touch and go until you get the pressure/time/heat ration dialed in, but the results tend to be more consistent. In some cases welds have to be made or finished by freehand welding with a heat gun or some other tool. I just don't have the capital or the market to invest in an RF or Ultrasonic welder, but then, I haven't needed one yet.

Basically, the design and raw material will dictate which methods can be used successfully, economically, and efficiently.

Cheers,

Jay

__________________


". . . the sea's in my veins, my tradition remains, I'm just glad I don't live in a trailer . . ."

Genesis

Here are some more pictures of the new "T" piece......




Need to clean up the chaff on the edges a bit and such, but this is what it looks like assembled. The collar up above the cap keeps it from riding up too far and locates it quite precisely in the counterlung.

All assembly is by heat welding - no solvents. All made out of HDPE.....

__________________
"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
http://www.denninger.net
http://www.diversunion.org/liability.htm - Fix the Diving Cert racket

marekm

Hi Karl,

I can see how the white plastic collar prevents the T-piece from going in too deep into the MSR bag. However, what keeps the T-piece from sliding up and out of the bag? The first o-ring down from the modifed MSR cap?

Cheers.
-Marek

Genesis

There are actually THREE O-rings in there - you can't see the top one.

There are two that fit in cut grooves in the HDPE tube (it comes somewhat rough and has to be turned at two diameters - one exactly 2" to fit into the bore hole of the block, and the second at 1.9" to fit the MSR bag)

There are then two grooves cut into the section that fits into the bag. Those are visible in the picture.

On top of the "top" O-ring in the groove is a third O-ring. This one does not go into a groove - it sits proud on the tube; its purpose is to prevent the tube from being withdrawn. It provides a cinch seal in the taper of the MSR bag and also prevents withdrawal of the "T" piece as the top O-ring cannot pass it, nor can the proud ring pass the collar.

So the function of the bottom O-ring is to provide the actual seal. The top grooved ring and the override ring provide the mechanism by which the tube is locked in the bag against withdrawal, and the collar prevents the assembly from being depressed into the bag to a degree that would disengage the seal.

The collar/cap assembly can be taken apart without tools - you pinch the bottom O-ring out of the groove with your fingers and then, depending on the size of your fingers, you either do the same with the top ring or use a wooden tool to do so to remove it. The cinch ring can then be slid down and once it is off the collar and spacer drop off.

__________________
"A venturesome minority will always be eager to get off on their own, and no obstacles should be placed in their path; let them take risks for Godsake, let them get lost, sunburnt, stranded, drowned, eaten by bears, buried alive under avalanches - that is the right and privilege of any free American."
http://www.denninger.net
http://www.diversunion.org/liability.htm - Fix the Diving Cert racket

teomannaskali

Anythin new? Or some interesitng dives?

Teoman