Ask your WELDING questions here.

I have a pretty interesting question that my brother-in-law posed to me last night...

He is a gun collector and restores old guns that previous owners have drilled for scopes, etc.

On late 1800 to early 1900 Winchester sporting arms, he has had weldors in his area fill the non-factory holes with TIG. Then he takes the factory blueing down to bare metal and then re-blues the entire gun. The repair cannot be seen in bare metal, but is very evident after blueing. Plus, he says that the filled hole is a harder metal than the proof steel of the rest of the gun.

So, anyone run across this? What would be a proper TIG filler to take the blueing like the rest of the metal?

Next time use extracting rod, you have a tig, assuming it can do stick too.

Look for X-Tractalloy rod, I use it all the time and the stuff is like pure voodoo magik.

Matching the receiver material would be the best. At least find out exactly what its made of.

I have etched some of my welds to see the penetration. Its similar to bluing.

The metal could be harder than the rest because of the heat treat from welding.

The filler could take carbon from the parent metal to make it harder too. Depends on what was used as filler.


Better luck would be if he had the part heat treated after the weld.

David

I am not a professional, but I am daily driving a solid axle swapped S10 that hasn't given me any problems :

I would find a way to take the load off of that joint, by way of design. If I HAD to butt-weld that and it was structural, I would sleeve it, and rosette weld the sleeve AND full perimeter weld the sleeve to the bar. If the pieces are hollow, I would sleeve internally like I do when making a rollcage

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Get an auto darkening helmet. Made a world of difference for my welding

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Not to argue that, but do you have any more info on their DC TIG use?


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Many old Mosin-Nagant rifles that were formerly used as sniper rifles were welded and rearsenaled in like fashion to what you describe. I don't think you will find a perfect blued match. If this is a huge concern, I would duracoat the area and call it done. Duracoat is MUCH better than bluing, anyway

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AC tig cleans the oxide off aluminum as you are welding. You can not weld through or to aluminum oxide.
Its the + side of the AC wave that blows the oxide off. This is why wave balance is adjustable on the newer machines. The less cleaning needed, the more heat can go into the weld.

When you clean aluminum oxides off, they start forming immediately.

IF you could get the oxides off and KEEP them off until the aluminum is being welded it is possible to get a nice weld with DC tig electrode -.

In my world, I weld for a living, AC tig is the only way to go. For DC a spool gun works great, even better with pulsed spray.
IF you ever got a 110 mig to feed aluminum wire through the whip it would not have enough power to weld much except foil.

Strong Bad IS talking about rocket science. I live in the real world closer to the hobby side of welding. He is correct it can be done and is in certain areas. Just not on my level. I have seen pictures of DC tig on aluminum. Even tried it my self and all I keep running into is the oxide floating on top of the molten aluminum. When a job comes in the door, I don't f around, I weld the part with AC tig or if its big, a spool gun, charge the customer and move on to the next episode.

To weld an aluminum engine part or casting, it would be near impossible to get it clean enough for DC tig welding.

Some one earlier mentioned an Thermal Arc Arcmaster 185. I have had one for about 6 years. I use it only as a TIG machine, AC or DC with a water cooled torch. Nothing hobby about it. It just works day after day.

Last year I added a water cooler and torch set up to my Lincoln V350 for bigger tig jobs and long duty cycles. This is DC only for carbon or stainless steel.

Both are sweet machines.

David

Got any good example pix of this process or any links for more information??

Moreover what are the advantages to DC over say an Inverter in AC?

Not sure what you're price range is. A Miller Diversion 180 has been working out well for my first TIG machine. Works up to 115 amps on the standard 115V wall socket. Got mine practically new on CL for $1250.

The AC weld doesn't care if your welder is an inverter or not. The DC weld process is exactly the same as a AC weld. The DC advantage is purely for the depth penetration for the amount of energy poured into the work. And yes it is impossible to be too clean.

Interestingly enough several more modern inverter TIG sets come with AC/DC mix function, which provides the advantages of both wave forms when welding non ferrous metals.

Although I see where you are coming from, this is actually not true. Inverter technology has allowed a very wide range of customization for the characteristics of the AC wave. There are so many parameters that can be tweaked by the operator, many of which may be specified on a WPS or PQR including balance, wave form, frequency and more. An old school copper wound AC welder will give you nothing more than a sine wave.

The action of the operator may be similar, but the WPS, PQR, and subtleties of technique are different between AC and DC TIG. Most notably, DC TIG is almost only done using very high purity Helium as a shielding gas, and DCEP with a water cooled torch when welding non-ferrous metals. Argon and DCEN work great for steels.

This is partly true and mostly due to the Helium used as a shielding gas. On the other hand, DCEP puts about 80% of the heat in the tungston and 20% of the heat in the base metal, so penetration is not as good as AC for non-ferrous. For steel with DCEN the penetration is much better.

True, Very True.

What he said and I will add...On Aluminum...a Miller 700 Dynasty..in AC kicks ass on any DC machine...

I was thinking of the Miller Aerowave and had forgotten that it was a hybrid. Nothing like wave form shaping for uber control.

I need a length of 7" ID tube or pipe. Everything I find seems to skip from 6" to 8". Any suggestions?

What material, what sort of application?

I mean here is one example, http://www.onlinemetals.com/merchant.cfm?pid=14699&step=4&showunits=inches&id=71&top_cat=60

But I am not sure you really wanted 8 inch aluminum with a half inch wall thickness, but hey it is 7 inch ID tube.

Eric

Sorry, steel, 1/4 wall or thicker.

8" schedule 140 pipe (0.812 wall) will = 7.001 bore.
But it will have a "ridge" where it was welded and being pipe it will not be perfectly round.