Welding Tips and Tricks

ok I've said it before and ill say it again, I'm so noob its becoming ridiculous and I think the local welding supplier punishes the newer employees into serving me so they can deal with my stupid questions.....
So i walked in and told them i wanted to back purge some 304 ss pipe I'm turning into an exhaust and asked for everything i needed... they just sold me a bobbin for argon and through all the confusion i never checked to see if it came with fittings to screw into my reg...which it didn't....
NOW....... I've noticed on the side of my reg there is a hex block off(which you can see I've removed in the pic) so i thought i would buy a adaptor like below, screw it into the red and run my bobbin off that, so i went back to the shop, explained this, and he scratched his head, said i should have got fittings with the bobbin and gave me a second hand one (pictured)

I went home only to realise he screwed me and the thread was different FML. I had to go to my gas supplier today and went through this whole process again and he said i should never use the outlet that i had unscrewed the block off from and that i should use a Y piece and run two bobbins from one outlet to purge...... only catch is that he wants to charge me $70 for a freakin Y piece.... no thanks.


What do i / should i do?

Good morning, ONDGAS-
First, a caveat: I have not used a Y connector to provide both backpurge and shielding gas, so this is all theory for me, but I have worked with regulators. I'm pretty sure there's a WeldingTipsAndTricks.com video that shows the Y connection: I'll look for it (don't have the time just now) or maybe someone else here knows about it and can post a link.

I have not heard the term "bobbin" before, but I think you're referring to the flowmeter in column with a ball to indicate flow: is that correct?

My experience with welding supply shops has been that I need to have a pretty good idea of what I need before I go. There's always a guy who's been there forever and has heard that type of request before so he knows how to respond... but if he's not there, it will be a new guy that can correctly spell "TIG" two out of three tries.

Ondgas,
First things first, make sure you are only adding things to the low pressure output side of the regulator, most are stamped in the housing. If the port you plan on using is less than halfway around the regulator from the inlet from your cylinder, I'd be suspect of it being high pressure. Sending 2500# through a Wye or Tee fitting that's not rated for it can be a shorts staining experience at best and you can imagine the worst.

You can use a standard 1/4" NPT Tee or Wye and 2 (bobbins)flow meters, again on the low pressure side. The easy way to do this if it's something you plan to do in the future and can warrant the cost is to buy a dual flow meter, then nothing else is needed.

If you sent pictures as you noted, they didn't upload. Please get your pictures up before you rig this up and open the regulator so someone with the proper knowledge of regulators makes sure you're on the right port.

Len

I am sure most of us here can help. I agree with Len, do not do anything until we see pics. I (as well as others) have experience with back purge and the necessary fittings needed to get there. Please post up so we can help.
-Jonathan

sorry guys my bad, for some reason my pics failed to upload.

heres some better pics

Im at a loss as to what to do as I'm hoping to get it up and running by tomorrow so i can get welding over the weekend.

I'm sure its an easy fix, just as I'm sure a baboon would have a damn hard time boiling a egg

also i forgot to mention, i have a barbed fitting to go on the outlet of the flow valve......can i just use some cheap rubber hose and tape off the ends of the pipe or would you guys recommend something else

thanks in advance

This video offers some alternatives to argon back purge:
http://welding-tv.com/properties-of-sta ... el-part-2/

This link shows some ideas about adding a T adapter and second valve to the low pressure side of a regulator:
http://www.everlastgenerators.com/forum ... -for-Purge?

Ondgas,
I can't really tell by the picture but if you crack open the valve at the cylinder without anything in that open port you should be able to tell if it's on the low pressure side by the volume of Argon that comes out. The low pressure side of most Argon regulators are usually less than 75# of pressure, that will be easy to distinguish from the tank pressure. If it's on the high pressure side it will scream out of there so keep to the side of it.

As to the hose question, I use old Argon hose that has been cut and is no longer used for the torch, but you can use any clean hose or tubing that you have. Smaller is better in this case so you're not wasting Argon. Make sure it's clean inside, old compressed air line is a bad choice because it usually has oil in it and our goal is to keep contaminants out, not add them.

Len

Thanks for the reply guys
As per usual, I'm more confused now than when i started this whole ordeal!!!!!
Im starting to think my local supplier is a douche bag.... As i said earlier i walked in and said that i wanted to back purge some pipe and to give me what i needed to do the job, at which point i was sold a flow valve and said thats all i would need plus some hose. $70 bucks i think i got bent over for that day

After getting home and scratching my head as to where to stick this thing.....I went to another supplier who said "nahh all you need is a "y-piece, $70 bucks thanks" i nearly fainted and said no thanks surely theres a cheaper way to do this.

Now i went back to supplier #1 who sold me the flow valve, this time i had enough and unscrewed my reg and the whole shebang and took it with me, dumped it on there bench and said "make it work"

This time, the same guy who served me and sold me the flow valve said " Oh I've never ran two flow valves off a reg, i would just do it like this.....(see pics below)

At this point, two more "professionals" had wandered over and i failed to see the irony in the fact that he was contradicting himself and had sold me a freaking flow valve only to tell me i didn't need it after i spent a week losing my Sh1t trying to figure out how to make this whole thing work, i was a bit under pressure with people standing around and didn't stand up for myself (i thought of all this after i left the store so i only have my pea brain to blame.

SO

My question is....like i told the guy behind the counter, with me tapping into the gas flow after its been metered by the flow valve, am i not robbing my tig torch of argon? there answer was no you only using a little bit of gas for back purge..... at which point i politely said, " well then am i not robbing it of a little gas then?" to which they said " oh it won't make a difference.....

I don't know much about tig but in the last few weeks I've learned that if i so much as fart in the same room i get methane contamination in my welds....So how can robbing the torch of argon be ok?

Tell me what you guys think as I'm very shortly bout to lose it and just start welding without back purge, who cares I've like sugar my whole life, why stop now...

And to add to my bitching, I asked the guy to give me a run down on how filler rod part numbers work etc etc and i said i would like some more rod to suit me welding 304 to 304 ss and that i wanted the same that the other guy who works there recommended i buy last time because i don't know my head to my butt when it comes to fig and I'm learning blah blah blah and he said yeahhhh sure ill grab you some 309 rod...... i just got home and saw that the last batch of rod i bought was 316.....
which should i be using ?

Ondgas,
What you have pictured will work, but yes it's robbing your torch of Argon. I've used that exact set up a few times when I didn't have a choice. Only open the valve to your purge line as much as needed to maintain your purge and up your flow about 10 CFH from what you would normally have it set at. It's not the ideal set up but not many things in life are ideal.

Like I said earlier, if you're going to weld Stainless a lot, buy a dual flow meter and be done with it. I have the luxury at work of having someone else pay for Argon so I just use 2 cylinders with their own regulators, but at home I make due with what I have, which is what you have pictured.

Len

Ondgas,
You might be shopping at the wrong welding supply. Do they sell canned goods and bait and tackle? My choice of wire when welding 304 to 304 is 308L, but either of the rods you have will weld it. 309 is made for dissimilar metals and 316 is made for 316.

Len

Thanks for that Len,
Is there a good reference chart or something I can go by for filler rod?

Is there a consequence of having too much gas flow other than wasting gas?

Ondgas,
There is some problems with too much gas flow, like it can cause turbulence and draw in the surrounding atmosphere. This usually isn't a big concern while welding tubing because the shape of the tubing lets the gas flow away without much restriction like you would have in a inside corner for instance. I'd suggest a large cup, say 8 or up for welding Stainless, with bigger being better.

Lincoln and other filler rod manufacturers will have filler rod selection charts on their websites that can point you in the right direction. You can always put it in a search and find all the info you can use, just put in "what filler rod for this metal" and you'll get hundreds of hits. Or you can just ask here. With specifics about what you're doing there will be someone here who has been there, done that.

Len

ok thanks for that,
So do you think its worth me taking back the rod they sold me and asking for 308 or should i not bother for something as non crucial as exhaust?

Ondgas,
The 308L is probably cheaper than the 309 but unless you bought quite a bit of it, it's not going to be worth the gas money to take it back. It should be fine. I personally like the way 309 welds and use it sometimes for even mild steel, but then again I'm not paying for it either when I do.

Len

I work night shift this week, so I am going to leave any further questions to the real welders who get to work only daylight.

Len

I build stainless steel exhausts for my car myself as a hobby and I use such a setup to provide both the torch argon as well as the back-purge (don't like to get sugaring on the back):

http://www.gasiq.com/econtent/235?prod=264



Works pretty well. Basically 1 main regulator to bring the pressure down from the tank pressure and then a 'T' piece on the end where 2 flow meters are mounted with their own output valves to control the flow.

This way both are pretty much independent as long as the main regulator can provide sufficient gas flow to max out both flow meters at the same time.

Bye, Arno.

You can build that yourself.

I have. Several times. Most of our TIG machines at work have my homebrew dual flowmeters so a second bottle is not needed. The dual setup does not let one side affect the other, so the gas usage is well controlled.

I'll dig for the topic with pics, of the first one I built. There are details there. The cost is low on e-bay for the two flowmeters required, and the modifications are on the low-pressure side so hardware store gittings are adequate.

Here's one, at the bottom of the first page of this topic:

http://forum.weldingtipsandtricks.com/v ... ter#p15067

Steve S

I have welded many ss exhaust pipe for cars and bikes using the tig process,I have welded same with and without back purging.Many factory welds are done without back purging, so my advise to you would be to weld without back purging,''but'',I would suggest that you practice on some scrap pieces before the finished part.NOTE,make sure you use a joint with a metal to metal joint, (no gaps) an (no bevel).Practice on a scrap piece till you have little or no burn-through,I.E., (sugar).lastly, keep the joint cool and use smaller diameter filler wire. such as .030 in., hope this helps. NOTE; we all started as beginners, and learned as we go......hope this helps, ron

Where bouts in melb r u?
I'm in bayswater.
But I goto dandy gas when I want proper service.

steeldr. wrote:I have welded many ss exhaust pipe for cars and bikes using the tig process,I have welded same with and without back purging.Many factory welds are done without back purging, so my advise to you would be to weld without back purging,''but'',I would suggest that you practice on some scrap pieces before the finished part.NOTE,make sure you use a joint with a metal to metal joint, (no gaps) an (no bevel).Practice on a scrap piece till you have little or no burn-through,I.E., (sugar).lastly, keep the joint cool and use smaller diameter filler wire. such as .030 in., hope this helps. NOTE; we all started as beginners, and learned as we go......hope this helps, ron

Yeah, some companies that make high end 5k+ systems follow that philosophy too.

I'm no ethics major, and in the end I really don't care, but there is moisture in exhaust, a lot in fact on startup, and for varying amounts of time depending on climate, but yeah.

Whatever is a good attitude for a lot of people.

If you are going to be doing a lot of welding using a separate purge system, I would buy a separate argon tank and reg/flow meter.Cost is not cheap, but well worth it. hope this helps.....ron