Pressure Pot to Test DIVE LIGHTS!

[DimitrisV]

You cut that big old tank without any support?

A friend of mine cut the cylinder on lathe and also the aluminium ring (i didn't find any othe word to describe it)
He remove 0.5 -1mm from the cylinder to take away the paint and the scratches.

How much pressure do you think those 4 latches can hold back?

I hope to hold 10bars. I haven't test it yet to 10bars bacause i need a better oring. Till now only to 2 bars
If I see that the latches cant;t hold 10bars I will replace them with stainless steel.

BR
Dimitris

 

[350xfire]

A friend of mine cut the cylinder on lathe and also the aluminium ring (i didn't find any othe word to describe it)
He remove 0.5 -1mm from the cylinder to take away the paint and the scratches.

I just noticed on the pics he did use a live center on the end. That's a pretty nice big lathe!

 

[DIWdiver]

I just noticed on the pics he did use a live center on the end.

Yes, but then he cut the end off!

 

[SmokedCPU]

I agree that trouble occur in shallow water.
The only recurent light trouble i got was happening in the beggening and deco of the dive, since there was only few drop in the light, for a 90min dive around 75ft. If it was occuring at depth, it would have filled the can completly

 

[gasdiver]

What is the wall thickness of an AL 80 after you cut the top off of it? I'm thinking about making a pressure pot out of an old AL 80 and need to know how much room I have to work with.

 

[350xfire]

Not a lot. I threaded my holes to 1/4"-20 and there really is no room for an oring.

 

[gasdiver]

Here is why I'm asking: I need to know how deep to cut the groove around the outside for my clamping blocks. I have a buddy with a large lathe who's going to face the cylinder and cut the groove.

 

[lucca brassi]

that design will made you some fun with nuts when you want to seal pressure pot :devil:

 

[350xfire]

Gasdiver, that is similar to what I did except I used a gasket and threaded 6 holes with 1/4"-20 into the thickness of the cylinder. Like Luca said, it does get tedious tightening 6 nuts. But it works.

 

[gasdiver]

I've got some knobs that will spin down pretty quickly. My concern is will the clamp blocks stay in the groove or slip out. I may need to put a cam band on them. If you don't mind, can you measure the wall thickness of your AL80 pressure pot? I'm assuming the wall is 1/2" and the groove I cut will be 1/3rd of that. If the wall is thicker I can cut the groove deeper and the issue of the clamp blocks slipping out becomes less. I've Googled until I'm blue in the face and I can't find the standard wall thickness of an AL80 anywhere.

 

[350xfire]

I've got some knobs that will spin down pretty quickly. My concern is will the clamp blocks stay in the groove or slip out. I may need to put a cam band on them. If you don't mind, can you measure the wall thickness of your AL80 pressure pot? I'm assuming the wall is 1/2" and the groove I cut will be 1/3rd of that. If the wall is thicker I can cut the groove deeper and the issue of the clamp blocks slipping out becomes less. I've Googled until I'm blue in the face and I can't find the standard wall thickness of an AL80 anywhere.

Yes, I was going to mention that, looks like those bocks may be an issue. Get a couple of hose clamps around them! I think 1/2" is about right. There is just a bit of metal left on each side of my 1/4"-20 bolts. I'll measure tonight.

 

[DIWdiver]

After turning the OD smooth and clean, I have exactly 1/2" left.

And why go to all the trouble to make those lid launch trigger mechanisms, er, I mean clamp blocks?

I turned the ID smooth and fit the o-ring totally inside the ID, leaving the full 1/2" for the 1/4" bolts.

I use socket head cap screws and an allen wrench. Makes fast work of driving in the screws.

 

[gasdiver]

Thanks DIW, that helps me a lot.

 

[DIWdiver]

If you really want to use bolts external to the tank OD, I would mount a permanent ring to bolt into. Much safer and easier to work with. Not that there's much energy stored in the system when pressurized (assuming you get all the air out), but the tank is somewhat elastic, as are hoses, etc, so there's enough energy there to pop the lid and make a mess, maybe even hurt you.

 

[SmokedCPU]

you guys are making strange plans to make complicated pots ... should make a shooting session with mine someday

i got a damn big 6'' steel pipe heavy wall, plate for flange, bottom (12x12'') and lid are .5'' steel
i dont know why, but i dont move it when its full of water... I got evrething weld and then faced the flange, and grooved for the Oring, used in pool filter ... a big one, bought 3 .... should be enought for life .... then i use 8 bolt grade8 to hold this togheter.
Hand tight is enought to bring 3 canister mag and a bottom timmer to 130psi.
Evrething is paint scuba RED, its nice, and also warn you that if you hit your legs you will remember, eventought, we fit well toghether since one year.

can somebody show me the maths to know the pressure that i should not exceed with bertha ?

 

[gasdiver]

If you really want to use bolts external to the tank OD, I would mount a permanent ring to bolt into. Much safer and easier to work with. Not that there's much energy stored in the system when pressurized (assuming you get all the air out), but the tank is somewhat elastic, as are hoses, etc, so there's enough energy there to pop the lid and make a mess, maybe even hurt you.

I agree with you, but my problem is that I don't have a lathe or mill big enough to make this myself. I've got some other ideas on how to simplify the design, so I'm still on the drawing board with this...

 

[lucca brassi]

you guys are making strange plans to make complicated pots ... should make a shooting session with mine someday

i got a damn big 6'' steel pipe heavy wall, plate for flange, bottom (12x12'') and lid are .5'' steel
i dont know why, but i dont move it when its full of water... I got evrething weld and then faced the flange, and grooved for the Oring, used in pool filter ... a big one, bought 3 .... should be enought for life .... then i use 8 bolt grade8 to hold this togheter.
Hand tight is enought to bring 3 canister mag and a bottom timmer to 130psi.
Evrething is paint scuba RED, its nice, and also warn you that if you hit your legs you will remember, eventought, we fit well toghether since one year.

can somebody show me the maths to know the pressure that i should not exceed with bertha ?

++1

 

[wquiles]

Guys, my apologies if this has been asked before, but can THIS Paint Pressure Tank be used for testing flashlights? The construction looks pretty strong (at least from the web site!).

Will

 

[DIWdiver]

It's rated to 60 psi, only 4 bar. It would certainly go somewhat higher than that, but who knows how much?

The problem is it's got a big diameter, and only four points for keeping the lid on. That puts a lot of force on each one.

 

[eh4]

so some of you take lights down below 130+ feet of water (60 psi paint pot for instance) ?
I can hardly imagine.
Would minimizing the quantity of gas space inside of a light or other container make it more resistant?
Say for instance if the same seal is only protecting a cc of compressible gas instead of 2 cc?