Welding questions

   / Welding questions #1  
mjncad

mjncad

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A couple
I have a couple of quick welding questions.

My MIG welder's tri-mix gas is down to about 500PSI. I'm still running the original cylinder with it. At what PSI should I take it to be refilled?

Also, my timing is bad as usual; CCM is in the middle of hay season, so getting a sidelink for my 4200 from them is quite a ways out. I'm thinking of ordering a cylinder from Surplus Center and making my own. Any tips on welding custom mounting brackets to hydraulic cylinders so as not to fry the seals? I'm thinking the rod should be extended as far as possible away from the area to be welded, and a damp rag placed on the cylinder walls where the piston rod seals would approximately be. I use the damp rag trick when soldering up copper tubing to ball valves.

Thanks!
 
   / Welding questions #2  
you can run a gas cylinder to zero. When the gas flow drops it is time to change it. I would change it anywhere below 100#, or when it works best for me. don't want to run out during the weekend project.
 
   / Welding questions #3  
mjncad

It would be best if you had a small/large spare. If you exchange it, you will not get credit for what is left in the tank.

As far as welding on the hydraulic cylinders, Baileynet.com could best answer, or even make you a custom cylinder. If you did weld anything on the cylinder, I would try and measure the inside of the tube where you welded to see if there was any significant warp-age. The o-rings might allow some deviation from true round.
 
   / Welding questions #4  
500psi is still a lot of gas. But it depends on what size cyl you have. even if you have a small 80 cu ft cylinder. 500psi is about 1/4 of max therefore you have about 20 cu ft of gas left. @ 20cu ft per hour on the regulator thet is about one hour of straight welding. I agree with others, just wait until it runs out and then go get it filled.

As far as the sidelink, I cant picture what your talking about. Pic would help.

But is their any way to make your bracket and then bolt to the cylinder. Or buy a cylinder that comes appart easialy, like a tie-rod cylinder, and take it appart to weld.
 
   / Welding questions #5  
Distorting the cylinder can be a problem; I'd have a pro shop fabricate additions to my specs. As for running out of gas, a second cylinder would be the better way to go. Cylinders come in 20, 40, 60 CU Ft capasity and larger. You could always side step running out of gas by using Flux Core wire.
 
   / Welding questions #7  
Matt,

You can weld ends on the cylinders without a problem. Just extend the seals away for the heat and the wet rag as you suggest and all will be fine. I understand that the TnT setups have POV's so you will want to include that also. I believe that Rob (of 3RRL fame) made a TnT set up for his Kama. he of course went super fancy and machined some parts for it, but it might give you some ideas.

Mike
 
   / Welding questions #8  
I came across a very interesting welding forum with a link to a well-documented discussion about the performance of 110-120 volt Mig welders, a real eye-opener.
The low-end Mig's by name brand outfits are just about all hype. Surprisingly, older models, say 10 yrs or more do as advertized, the later ones are all plastic and gutted.
This could help explain why some of us with older units get better results than the latest ones off the shelf. Pay attention to pages 3 and on, that is where you will find the meat. It is amazing what is being palmed-off.
I liked the part where they went under the covers; I was surprised that the capacitor bank was missing, after all a constant voltage unit should have a good cap-bank, 100k Microfarads or more


Welding 3/8 with a 110 mig - WeldingWeb™ - Welding forum for pros and enthusiasts
 
   / Welding questions #9  
Just a footnote:
Running cylinders out completely isn't really that good for the cylinders, so if you own the set and have them re-filled, stop when there is still a positive pressure in the tank. It doesn't tank much, and 500 is way too much to stop at. More like 25-50 pounds depending on the size of the tank. It has to do with humid air getting into the cylinder.
As far as Oxy-Acetylene, never run them completely out if possible, as it is possible for the other gas to backflow thru the torch and put the wrong gas into the othe cylinder. It can be a disaster at the time, or when the tank goes to be filled. If you stop the oxygen level at above 10, the acetylene won't flow, etc.
David from jax
 
   / Welding questions #10  
They are welded all the time, I would TIG it and stitch weld it, if you don't TIG you can mig it as well. I would also use a 500deg heat crayon and make lines about one inch from the weld, if the mark starts to melt stop and let it cool. Of course it is best to never see it melt.

Any other questions? Fire away.

Bob
 
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