Building Up Worn Out Parts


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GlockFu
July 28, 2013, 04:25 AM
Hello,

I have started working on old single action and double action revolvers. I've been basically buying broken revolvers to fix and restore them. They are mostly antiques and the majority of the problems are just due to worn out sears, gears or parts that rub against each other.

What are good methods to build these parts back up as there obviously aren't readily available replacement parts?

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Boxhead
July 28, 2013, 07:12 AM
You must learn the supreme art of TIG welding. Once done all is possible. I hire mine out.

4v50 Gary
July 28, 2013, 08:16 AM
There are two schools of thought.

First is if the gun is collectible, you buy a used or reproduction part and fit it. You save the worn part and return it to the customer. You can also make a part from stock. Make a template and transfer it onto the stock. Cut, grind or file and then stone to fit. You may need specialized files to do hammer notches.

Second school is TIG welding and fitting the old part.

Longhorn 76
July 28, 2013, 08:58 AM
I am certain TIG is better, but I use a small jeweler's oxy/acetylene torch to build them up.

Works well on the old parts, don't know about MIM stuff.


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carbine85
July 28, 2013, 09:07 AM
You can usually find machine shops that will replace metal and do proper heat treatment if its needed. Some can provide a 95% match of the steel originally used. If the part gets blued the finish will match better. If it stays in the white it might not matter.

Jim K
July 28, 2013, 01:44 PM
It is darned hard to find a good welder to work on small parts. Most of the ones around here are not worth a hoot on anything smaller than a new tooth for a backhoe.

Jim

4v50 Gary
July 28, 2013, 02:39 PM
There is no better. It all depends on cost-effectiveness. Sometimes all it takes is a small weld and a lot of filing to make the part work. However, as pointed out earlier, if you have an all matching Colt Single Action Army that has a bobbed hammer, do you really want to alter a part for an otherwise original gun? I would set aside the bobbed hammer and put a replacement on it. That way the owner can enjoy it and still retain its historic value.

Bottom line: What is the customer willing to pay for?

GlockFu
July 28, 2013, 04:12 PM
I know these are newbie question but can someone tell me more about TIG welding and using a small jeweler's oxy/acetylene torch? I've heard of using a TIG welder before but never new exactly how it would work to accomplish building worn out parts.

How exactly does TIG welding work to build up parts? Are you basically melting steel onto the part or are you welding an additional piece of metal onto the part?

When you are done TIG welding, building up the part and then reshaping the weld with a file or stones, do you then have to heat treat the material you added?

How Would you use a small jeweler's oxy/acetylene torch to build them up? Would this be the equivalent to melting more steel onto the part and then reshaping it with a file?

Longhorn 76
July 28, 2013, 05:49 PM
With a torch, I am just building up small areas, like the sear of the trigger. I use steel for this. On Colt parts, I have not had any problems. I can harden them if desired. Then file or grind to fit.

TIG can be better, because it allows you to build up with other metals than steel. I built up a Python trigger with Hastalloy once, and it made the smoothest trigger I ever did. It was so hard and tough that it polished like a mirror.

Old Smith parts were only surface hardened, so I would use something like Casenit to duplicate that.


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Kp321
July 28, 2013, 08:34 PM
A TIG torch is a heat source just like a jewelers oxy-aceteline torch is a heat source. That heat source is used to fuse a filler metal onto the existing metal surface. TIG produces higher temperatures but the small oxy-acet torch will work for most applications.

rcmodel
July 28, 2013, 09:11 PM
The main difference is.

TIG = Tungsten Inert Gas = Tungsten electrode produces the ark welding heat to melt the base metal and rod or wire added to the weld to build up the part.
A flow of inert gas (argon or helium) around the electrode prevents oxygen getting to the puddle of molten metal.

That stops all burning out of carbon from the original steel or rod.
And it also prevents slag pockets and slag from forming on top of the weld.

MIG = Metal Inert Gas welding = Similar to TIG, except an inert gas is injected around the electrode / wire welding rod to shield it from atmospheric oxygen, which also burns out base metal and forms slag on top of the weld.

Acetylene torch welding = Uses Acetylene gas and pure oxygen to produce a high temp flame that melts the base metal and welding rod being added to the weld.

Unfortunately, the oxygen rich flame also is capable of burning carbon out of the base metal, and slag is an unavoidable byproduct that can contaminate the weld.
Regardless of how good you can gas weld, slag on top of the weld will mask defects until the weld is cooled and the slag removed.

Then you may have to go back and weld the weld again to fill in the slag pockets you could not see while the weld metal was a molten pool of steel with slag on top of it.

Still, oxy-acetylene welding is still the simplest and most economical welding method available to me in my home shop.

I guess I have been relying on a acetylene torch for too many years to change now.
Besides, a torch is more often used for hi-temp silver-soldering gun parts.

And gun parts are more often hi-temp silver-soldered then steel welded, by about 99 to 1.

rc

GlockFu
July 28, 2013, 10:20 PM
Thanks for the replies!

So when TIG welding and Acetylene torch welding, are you using a filler material to join the worn out part to another piece of metal or is the filler material the steel that is actually building up the part?

From the above post it sounds like the filler material is the steel that is actually building up the part. If this is true, would you have to harden the steel that's been added?

Also, what happens if the carbon is burned out of the base metal? What does that do to the base metal?

rcmodel
July 28, 2013, 10:34 PM
Yes, you are adding molten steel to molten steel to build up the part.

If you were only adding another piece of metal without melting the orginial part?
You would probably use Hi-Temp Silver Solder.

If you weld on a tempered streel part?
It will be annealed when you get done welding, and need to be re-heat treated or case hardened.


But all this welding theory & practice is well beyond simple posts on a gun board.

Any type of welding, silver soldering, heat treating, or tempering is not something you can learn in 15 minutes on the internet.

Before you will be able to 'build up' gun parts to repair them??

You will have to at least take enough welding and machinists classes to know the different welding methods, different types of steels, and how & when they are used together.

Then a few years of welding practice before you get good enough to say, build up the hammer notches on an old Colt hammer and re-cut them, and re-harden them so they work like new again, for instance.

So I won't even try to explain it any further.
Because I can't.

rc

beag_nut
July 28, 2013, 11:21 PM
With many years experience making surgical instruments may I offer?:
TIG welding is the most versatile, but the machines cost a lot of money, and training. The range of possible size of the objects to be welded are truly astounding, and the control of the welding process is almost unequaled. It is the most suited to gunsmithing.

“Silver-soldering”, as usually cited, can be either “silver brazing”, when the temps are above 800 degrees, and (properly) “silver-soldering” when the temps are less than 800 degrees. “Silver-brazing” is much stronger, but more likely to affect the strength of the parent metals, because the temps are higher. “Silver-brazing” is weaker than any type of welding, but easier to perform, and will less-likely affect the parent metals, especially if a “low-temp” silver solder is chosen. Either torches or induction-heating can be used. “Silver-soldering” is stronger than lead-tin soldering, and used to be how double-barrel shotguns (etc.) were made. Some “silver-solders” will melt around 450 degrees.

Shielded-Metal-Arc-Welding (SMAW) is the full technical term of “stick-welding”, when one uses an inexpensive “arc-welder” to do general-purose welding. This is the least-appropriate form of welding for firearms, unless one is simply making tools for gunsmithing.

MIG welding is Metal Inert Gas Welding, where one uses a special coated wire (from a coil) in a special MIG machine. It is somewhat like SMAW, except that the wires can be very much smaller, easier to control (even with foot-pedal-controlled wire feeding), and one can weld quite small objects. Costs for the machines is in between the TIG and SMAW types. Some gunsmithing applications exist.

Torch-welding requires a lot of practice and experience to do correctly, and can never equal the quality of either TIG or MIG, because of the temperatures used with an unshielded workpiece. The parent metals are unavoidably degraded by atmospheric oxygen. The only gunsmithing applications should be for making tools, or non-highly-stressed parts, like locks for black powder firearms.

BBBBill
July 28, 2013, 11:36 PM
...TIG welding is the most versatile, but the machines cost a lot of money, and training.

There are some TIG machines on the market now in the $1500-$1800 range that several of my friends have bought. They have been pleased with them for gunsmithing use (low duty cycle).

rcmodel
July 28, 2013, 11:59 PM
I'm sure they are.

But my point is.

How many old gun parts can you destroy, learning how to use a TIG welder to build them up with??

Welding is not rocket science.

But repairing old gun parts so they are usable again almost is.

If you don't have a clue what welding is, or how to use any kind of welder.

rc

MI2600
July 29, 2013, 11:24 AM
A timely topic. I just had a friend of a friend TIG weld extra material on the hand of a 1901 Colt to correct "The Colt Wobble". Worked like a charm with a little filing/sanding.

BBBBill
July 29, 2013, 12:02 PM
I'm sure they are.
But my point is.
How many old gun parts can you destroy, learning how to use a TIG welder to build them up with??

I was referring to the previous post by beag nut about the cost of the equipment. Lots of guys who can TIG are unaware of the newer machines. Post will be edited to clarify.

Not suggesting that you buy the skill along with the machine. That would be like the problem with doctors buying Beech Bonanzas. They have the money and a pilot's license, so that must mean that they are qualified to fly a high performance single.... NOT! That's why they are known as doctor killers.

GlockFu
July 30, 2013, 12:28 AM
Thanks for all the replies. I'm not trying to learn how to weld from an internet post, I'm just trying to figure out in what direction to go in. I've now looked up welding classes in my area and thanks to your comments, kind of know what to look for. My problem is that there are no Gunsmithing schools in my area so I have to look for the next best thing.

BBBBill
July 30, 2013, 12:36 AM
Go to your local trade school and take machinist courses. It's been said the you can make a gunsmith out of a machinist fairly easily, but it's really hard to make a gunsmith into a machinist.

Longhorn 76
July 30, 2013, 07:22 AM
I think everyone agrees that TIG is superior at the welding aspect, but the torch also allows you to heat a part for hardening, soldering, or brazing, as well.


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