Tig welder

[fusername]

yeah as long as it doesn't fall through my floor, I am pretty happy about it, although not being able to find a <100 $ tank is cramping my style a bit, I may have already found some work to help offset the cost. Welding new sled tin tabs on rotted T1 blocks, and some bell housing ears.

[Piledriver]

my local welding supply has a new 80 for $250 full of gas, 30 bucks a fill. Any larger and you have to rent he says. He also says a MIG cyiinder lasts the same or longer than TIG, do you agree? Because I have a 60 on my MIG and am happy w/ the lifespan of it. My TIG machine is NOT portable, so a big cylinder has no draw backs aside from price.

man I can't believe I forgot to add a cylinder to my budget, this is adding up.

Shop around. A Lot.

Find the guy that delivers CO2 and balloon helium.

[fusername]

so it is a modern pedal, he modified the plug on the machine and replaced the pot in the pedal to match what the machine expected. So I am using a nice 'modern' pedal and what looks like a DIN connecter on steroids w/ about 9 conductors, but he says only two are wired straight to the pedal, nothing else is live in there.

[Piledriver]

Measure the current going through the pedal at MAX current setting.
No need to actually weld.
(should be 4 wires, 2 are probably 24v, remote contactors)

I don't do much bench welding, and that's the only place a pedal is useful.
(visualize squeezing the pedal between your knees for current control while trying to weld something inside your car)

[fusername]

fill a 80 cf = $50 swap
fill a 120 cf = $50 wait a day


hmmm...

[Steve Arndt]

Our bottles are 50 pound bottles. What does that convert to in your units? Is that for 100% argon?

[fusername]

uhhhh not sure, here is a chart that Pile linked to earlier, but I don't see anyone using mass
http://www.airgas.com/content/details.a ... 0000000234
oh wait, if the tank weighs 50 lbs, that chart says a 80CF tank weighs 50 lbs

and yes, pure argon. I have both a 20 and a 60 75argon25CO2 mix bottles. Time to sell the baby one methinks.

[fusername]

450 CF = 50 lbs? maybe? .111 lbs/CF

either way this is the tank I am looking at buying, anyone see a problem w/ it? Fresh cert and full, surprised they are allowed to ship like that, but hey who am I to argue. And its only 30 bucks more than an empty 125 CF!

[Piledriver]

A 450 is a freaking ginourmous bottle.. Those are typically leases, but hey, if you can get one legal and refilled cheap and move it by yourself, its all good. Should last for ages.

[fusername]

according to that other page, a 80 CF tank WEIGHS 50 lbs, I suspect taht is what he meant.

[Piledriver]

A 330cf is about as large as an average human can move safely IMHO (even a few feet/wo a trolley) and I move gas bottles all the time. It is also a bear to pick up and put on a welder.

(a newer design welding trolley/running gear from Miller etc has almost zero ground clearance for this reason)

[fusername]

can I mig weld w/ 100 argon? I am thinking in a pinch I can top up my 25/75 tank w/ the tig tank and keep going should I run out on a weekend, which we all know is the only time you run out.

[Piledriver]

Yes, for aluminum MIG you MUST use Ar or an Ar/He mix.
For steel, will usually work fine, depending on the wire.

For steel, the small amount of CO2 actually acts as a reactive gas with the alloy in the wire.
Most wires will work fine with straight Ar, will look better than straight CO2, which is the "standard" MIG gas many places.

Ar costs a bit more than C25 and considerably more vs. 100% CO2, but if you are tapping from a huge bottle, you'll likely still be saving money.

Home Depot distributes up to 125 CF bottles around here if you need a quick exchange, also sells them.
(service by Praxair)
125cf is probably the largest easily movable/transportable bottle, and 80cf+ sizes do have a safety cap.

[fusername]

I only weld steel MIG w/ 75/25. So I can top up my bottle in an emergency w/ a pigtail from the Ar tank and do steel as usual? I don't quite inderstand the CO2 as a reactive gas comment. I am using a super standard wire that is escaping me right now. I don't know if I have ever done MIG w/ straight CO2, since I am often near the upper limit of my 100 amp machine, I was told 75/25 helps a bit with penetration, I figured it was my doall.

[Piledriver]

Straight Ar will work, but may require some adjustment in technique, and the area you are welding will need to be super clean as for TIG, Ar acts as a shield gas only.
(Short: may not be able to weld rusty crap as MIG w/ C25 sort of allows)

The arc breaks down the CO2 in the mix into free O2 and carbon, acts ~as a cleaning agent.

Google for the details, they are out there.