MIG and TIG

[MI2600]

I often see references re the use of TIG for various gun repairs. Is there a compelling reason why MIG rather than TIG couldn't/shouldn't be used?

 

[Lee Roder]

Precision and heat control. Try MIG welding something small and delicate and you'll understand

 

[BBBBill]

MIG is brute force compared to TIG precision. Heat can be controlled much better with TIG. There's really no comparison. TIG is far more useful for gun work.

 

[SuedePflow]

Some people will use MIG because it's all they have available. The machine is cheaper to buy and the process takes less skill in general. But as mentioned, the user has much more control with the TIG process, which results in a better looking and far more quality weld.

 

[MI2600]

Yes, I already have a MIG and can't see spending a herd of money for a TIG. I also understand TIG is hard to learn.

I only have a couple internal pieces.

 

[Sam1911]

Very likely worth taking them to a shop and having the work done there, then.

 

[tbk5]

I am not sure where you are located but check http://pullmanarms.com/gun_smithing_services/ . They do some amazing repair/restoration work.

 

[SuedePflow]

I would take the project to a TIG weldor and pay for their services before I'd tackle the job myself with a MIG. For a firearm, its worth spending a little bit to get nice TIG welds. What exactly needs to be welded, btw?

 

[beeenbag]

If you are welding small pieces, you do not want to use mig (Gas Metal Arc Welding is the correct terminology now). Using gmaw or gmaw-t, varies a lot between different processes. You have globular transfer, short circuit transfer (most common), and spray transfer. The most fusion between filler metal and base metal for an initial arc would be using spray transfer with 98% argon and 2% oxygen mixed shielding gas. This transfer type does put down a lot of filler metal at a higher current, so it wouldn't be ideal for a small piece. Short circuit transfer, which is most likely what you have, would be hard pressed to fuse the base metal with the filler metal "tacking" small pieces without a prolonged, established arc.

Tig (Gas Tungsten Arc Welding) allows you to establish a plasma column (arc) without applying any filler metal at all. Filler metal is applied at the welders discretion. The arc can be established even at a very low current, in a very small heat affected zone, making this welding process ideal for small or thin base metals.

In my opinion, if your welding something for your firearm... Don't. Let a professional do it.

 

[MI2600]

My intention is/was to very slightly build up a "ledge" on a 1901 Colt DA 38 hand.

 

[jmorris]

This is one of the better "eye opener" examples of what we are talking about heat control.



TIG is really not too hard to learn because you have 100% control of the heat with your foot or thumb (at least you should). Control of the filler material by diameter and feed rate.

I would say, getting quality (can pass x-ray) stick welds is more difficult, same goes for oxy/act welding.

 

[Trueno]

MIG used to plug axis holes on a Saiga.



TIG used to relocate the charging handle of an AKM.

 

[Sam1911]

Why is the charging handle on backward now? I get switching it to the other side, but backward?

 

[BBBBill]

Sam1911, I'm guessing that the winking smiley at the bottom of his post is some how related to that backwards charging handle.

 

[Trueno]

some owners request that mod, makes it much easier on the palm when slapped after a mag change.

t

 

[bluekouki86]

TIG (GTAW) will also allow you to weld almost any metal on earth. I realize most of our firearms don't contain exotic metals, but some people just go overboard when the right equipment is at hand.

Just as an example of how much more controllable GTAW is, the guy who taught me how to TIG weld is an ex NASA welder. He welded not only exotic materials on the space shuttle, but also materials as thin as .005 (that's right 5 thousandths) of an inch. He could weld two razor blade tips together in his sleep.

 

[Longhorn 76]

Another plus for TIG, that I cannot do with oxy/acy, is overlay a harder metal on a softer base.

I had a guy fix a Python trigger, and he used Hastalloy filler. It was a bear to shape, but smoothed out to make the smoothest trigger I had ever done.

 

[WALKERs210]

With my hands shaking so much and eye sight not what it was my days of precision welding are long gone. Around 73 myself and one of my senior petty officers were sent to a welding school at the Naval Research Center in DC. Both of us were certified weldors and felt this was a waste of time, after the first day we both came out of class with our tails between our legs and a double dose of humble pie to boot. The TIG welding there was amazing, we were given a task of welding two razor blades together without distorting. TIG welding is a method that can be learned in one day but takes a lifetime to master. Find a super good shop to do the work and if possible ask if you can watch. Nothing like watching the metal flow and be worked by a craftsman.

 

[justashooter in pa]

beanbag,

as a certified weldor, certified welding inspector, and a welding engineer i have to remark that you have globular transfer and short circuit transfer confused. globular is the most commonly used, if ER70-S then usually with 100% CO2. short circuit is a low heat application that is used for filling voids, and is rarely seen. you are correct in your description of spray arc. it is the altered gas mixture that allows for the conversion. another form of interest is "square wave", which is useful for high volume application in lighter materials, but it is also of little value in gunsmithing. also of interest, ER70-C6M, commonly known as metal powder core tubular, though it is usually found in .045 and larger sizes, so is of little interest to gunsmiths.

the most common application in gunsmithing is GTAW, but oxy-fuel and carbon arc have been used in years past effectively. personally, i have used FCAW and SMAW in gunsmithing, but then i'm just a hack FFL gunsmith building semi-automatics.

 

[beeenbag]

I too am a CWI, the most common gmaw transfer type I have been in contact with has been short circuit using 75% argon and 25% co2. Then again, I am not in contact with many fab shops, mostly heavy construction where SMAW is the preferred welding process, GMAW being secondary for overlaying and such.

 

[Lee Roder]

The structural cert (AWS D1.1) I had for mild steel of limited thickness used short circuit transfer (GMAW-S). GMAW-S is more than capable of adequately fusing such base metals (Xray qualified). Globular transfer in out of position welding is a nightmare, and spray is such a high heat process that little parts would simply disappear into the puddle if you're fast and down the hole if you're not.

MIG is a production process, TIG or brazing is more aligned with art

 

[HankC]

Tig has much higher investment and take some practice to do it right. If you don't do it frequent enough, every time you weld, you need to practice your skill and you better have a large tank since it will go fast. Cheaper just send it out and have professional do it for you. That is what preventing me from getting a Tig.

 

[cfullgraf]

Tig has much higher investment and take some practice to do it right. If you don't do it frequent enough, every time you weld, you need to practice your skill and you better have a large tank since it will go fast. Cheaper just send it out and have professional do it for you. That is what preventing me from getting a Tig.

It depends on your definition of "much higher investment". There are some budget priced tig welders on the market today that probably do a fair job on lighter weight steel and aluminum. These are a bit more expensive than the big box hardware store 110v mig welders but not what i would class as "much higher".

I consider myself a hobby welder. I build stuff in steel like some folks work in wood.

While I do not have experience with the budget priced tig welders, my 110v mig welder does a good job within its limitations. The limitations can be frustrating though. I am sure the budget tig welders have similar limitations and frustrations, particularly when it comes to delicate work.

But, what you get when spending more money is a more capable and flexible welder, both tig and mig.

I have what I would call a medium priced transformer tig welder and I rarely fire up the mig welder or do oxy-acetylene any more.

Roger, if you weld only once in a blue moon, your skills will atrophy regardless of the mode. But, the tendency with tig welding is to do more delicate welding making the loss of skill more critical.

I figure you do not get really good at welding until you have laid down 1000 pounds of filler rod.

At least for the foreseeable future, I would still take my gun smithing welding projects to a professional.

 

[dprice3844444]

if you can gas weld/braze,you can tig weld

 

[dubbleA]

I figure you do not get really good at welding until you have laid down 1000 pounds of filler rod.

....or make you tired, have done more than my share of laying down 125lbs of wire a day

if you can gas weld/braze,you can tig weld

Yes, in theory it's just an extension of using a "electric torch" instead of one than uses a actual flame.

Cleanliness of weldments is paramount though as you do not use a flux.

In the end its just a lot of practice with eye, hand and foot coordination and of course using the correct parameters with the machine/equipment setup.