Back Purging

[Ironken]

Gentlemen, I have a quick TIG project that's coming in. It is a 2 stroke flattrack pipe supposedly made of SS and brand new. I need to weld mounting tabs on it. I can't get inside to apply Solar Flux and I haven't ordered my dual flowmeter yet and only have one K cylinder of Ar on my TIG.

Question is....I know this is NOT the correct method but, can I use C10 to get me by on this job to back purge? Weld integrity is important due to vibration and thin section materials.

What do y'all think?

[Oldgrandad]

A couple weeks ago was having a bad day and I grabbed the wrong bottle for purge . Instead of argon I grabbed 75/25 argon/CO2. After finishing the weld I opened up the pipe and took a look the burn thru had some sugaring and was an odd green color. Material was 3" sch 10 316L S.S. pipe, I cut it back apart and did it again with pure argon for the purge. I think C10 would be a bad choice for purge. Back in the day when I didn't have ANY extra cash I used a 'Y' and ran purge and torch off 1 bottle. Didn't do much purging back then so gas usage wasn't an issue.

[ryanjones2150]

You'll probably need to figure a way to pack purge with argon.

[Ironken]

Thanks for sharing your experience gents! I just brought home my new lathe and am tapped. I done broke the bank! A Y isn't a bad idea but, as luck would have it....the pipe is mild steel. Very easily identified once it was in my hands. The customer THOUGHT it was SS.

I will purchase a dual flow meter and some Western quick connects when I build up the bank again and do it right.

Thanks again.

Now its time to go strain my milk and unload this heavy POS.

[xryan]

Argon is heavier than air. Cap one end, turn it upright to fill from other end, cap it. You should be fine.

You don't need dual regulators, just a "T" fitting and two flow meters. $15.

[RobC]

... A Y isn't a bad idea but, as luck would have it....the pipe is mild steel. ...
I will purchase a dual flow meter and some Western quick connects when I build up the bank again and do it right.

I guess you'll see when you look at it ...

The "Y" will take Shielding Gas from your Torch unless you set it up:

Tank ➡ "Y" ↗ Reg1 ↘ Reg2

Reg1 ➡ Torch
Reg2 ➡ Purge Hose

To TIG Weld (correctly, if that's what you want to do) you will set the Regulator to provide sufficient Shielding Gas to both protect the Tungsten and the welded area, in addition you also want to protect the Filler Wire as soon as it gets hot.

In order to regulate the Shielding Gas correctly and repeatedly people use a Regulator, it regulates the Gas flow, otherwise you could just hook the Hose directly to the Tank.

Similarly adding a "Y" after the Regulator (only using one Regulator) and connecting two Hoses doesn't guarantee as certain amount of Gas to either Hose, the only guarantee is a regulated amount of Gas to both Hoses - which if connected to both ends of the Pipe would be the same, but now your still short one Regulator for your TIG Torch.

Solutions without 2 Regulators:

1. Do in using GMAW.
2. Use the why oh "Y" idea and crank the Gas way up.
3. For MS use no "Y" or Backpurge (just like GMAW) and simply increase the Gas Flow to your TIG Torch - you 'know' you are properly protecting your Tungsten, have plenty of Shield on the side facing you and your hoping enough goes under to protect the other side (which it would with MS, because there is no Chromium to 'sugar').

None of those three suggestions are best practice but number 1 and 3 are easiest and number two is the poorer choice (unless you really crank it, but then your wasting time and money to set it up that way, wrong, when you could do it wrong an easier way).

Best results will come from properly regulated Shielding Gas on both sides and an Inert Gas MUST be used on the Tungsten side (the Torch's Hose), for MS you can use less than straight Argon (any Shielding Gas that is suitable for MS, C25 being the worst and used often for GMAW on MS) as the purge - use C25 and the inside will look like you used C25 on MS, use Argon and it will look like you used Argon (assuming no leaks).

So to do it wrong and cheap just block the ends of the Pipe, use the TIG Torch to fill the Pipe (without welding, just preflow), and with the Regulator turned twice as high you'll have enough Gas to weld MS with less than perfection. DO NOT do that with Stainless, etc. only MS; and only if it's not to be perfect.

[ryanjones2150]

What lathe did you get?

[Ironken]

What lathe did you get?

Sorry for the late response Ryan. I'm not getting email notifications anymore???

Anyhow, it's a tiny one.....10x30

http://www.machinetoolonline.com/PM1030.html

and my little mill....

http://www.grizzly.com/products/VS-M...ce=grizzly.com

BTW, I saw your comment on the Youtube weld.com channel regarding "where's Mr. Tig". I go by Kenny Fowler on there. I didn't know they let you venture out of the Miller forums...lol

[ryanjones2150]

Ya, I've been critical of "mr. tig" in the past. Sometimes I think he gives really bad information.

What do you think about that little mill? I'm hunting one, but I tend to go for the old iron. But grizzly is the right size for my shop.

[Ironken]

Ryan, I like the mill and it performs very well BUT....there is a but!

It had a bad vibration from about 900-1500rpms. After fighting with Grizzly, they were convinced it was the motor and sent me a motor. Problem still existed! I requested to simply swap out the entire head stock. This would have been the easy fix but, no way. So I requested every rotating part in the head stock including bearings. Long story short, my mill is fine now and I can rebuild the headstock on a Tiwanese mill in my sleep. In Grizzly's defense, they sent parts fast and at no charge. In my defense, that whole ordeal sucked!

I have had good experiences with Matt at precision Matthews. If I had it to do over, I would look at one of his machines.....like this for nearly the same price.

http://machinetoolonline.com/Jet836MIll.html

[ryanjones2150]

Great advice.<br />
<br />
I've seen that brand in action. Was looking at an old Bridgeport at a fab shop a few hours from here...that's where I bought Helga....they were selling the Bridgeport because it was too big for they needed it for and went with that PM stuff. Said they get better support from the salesman on their stuff. <br />
<br />
I'm glad grizzly made it right with you. That's a lot of money to spend and have a vibration problem. What did it end up being?

[Ironken]

Great advice.<br />
<br />
I've seen that brand in action. Was looking at an old Bridgeport at a fab shop a few hours from here...that's where I bought Helga....they were selling the Bridgeport because it was too big for they needed it for and went with that PM stuff. Said they get better support from the salesman on their stuff. <br />
<br />
I'm glad grizzly made it right with you. That's a lot of money to spend and have a vibration problem. What did it end up being?

The vibration was in the pulley (which has a balanced, weighted sheave) and the spline shaft.

You refer to a "Helga"......is that your new mill? A Bridgeport by chance? ****, I'm jelous!

PM does stand behind what they sell with one of the best warrantys in the Chicom machine world...3yrs.

[ryanjones2150]

Nah, Helga is my big momma 1974 airco 3A. <br />
<br />
My new/old Southbend 13" needs a name next. <br />
<br />
Haven't found the right old iron for a mill yet.

[Ironken]

Holy ****, that Airco is as old as I am!

[ryanjones2150]

Easy....she's sensitive about her age and weight...870lbs....she's big boned.