Tig Welder

[1hand]

Hello All,

I looking to pick some of you tig welding pros out there. As some of you know I've been working on a prosthetic wrist and tools over the last few years. I have my quick change wrist right where I want it, but my wrenches need a little help. I've been milling a slot in an aluminium blank and inserting the tool, then using 2 set screws to hold the wrench in the holder. What I've found out in the last 2 weeks as working as a mechanic for 10hrs a day, using these wrenches exclusively, is that they loosen up after a bit and move some.

What I want to do is get a way from the aluminium blank and use a stainless steel bolt tig welded to the wrench.

Question is what kind of tig welder would I need for this? Could I get away with one that operates on 110volt?
What sort of gas would I need?

Matt

 

[jslocomb]

You might get away with a little 110 volt dc tig. You might have to pre-heat a little. Argon would be my gas of choice.

All that said .... a plain ole buzz box and stainless rod would work just fine.

 

[Maryak]

If you just want to glue them together MMA will do the job.

If you want a slick no mess, no splatter charlie finish then TIG and the gas is Argon which in Oz is pretty pricy.

Hope this helps

Best Regards
Bob

 

[ShedBoy]

If you don't have a tig already Weldall rods will be the cheapest and easiest to get the job done. Really good for joining dissimilar metals and can be made to look quite pretty with no grinding. Google Weldall Rods you will find them nearby.

Brock

 

[shred]

I got one of the little DC-only TIGs a month or so ago. After going through 2 40 cu-ft tanks of Argon putting down practice beads and welding rough stuff together I'm slowly getting the hang of it-- it's not a quick-learning thing. I have to crank mine pretty much all the way up (140 amps) to do anything useful with 3/16 or 1/4" steel plate. I don't know if the 110v units will go that high. Are you planning to make a TIG-torch-hand attachment? TIG is pretty much two-hands-and-foot type operation (the cheap TIGs don't all come with foot pedals, but have a button on the torch or lift-start).

 

[1hand]

I got one of the little DC-only TIGs a month or so ago. After going through 2 40 cu-ft tanks of Argon putting down practice beads and welding rough stuff together I'm slowly getting the hang of it-- it's not a quick-learning thing. I have to crank mine pretty much all the way up (140 amps) to do anything useful with 3/16 or 1/4" steel plate. I don't know if the 110v units will go that high. Are you planning to make a TIG-torch-hand attachment? TIG is pretty much two-hands-and-foot type operation (the cheap TIGs don't all come with foot pedals, but have a button on the torch or lift-start).

Ya I talked to a salesman today at work bout my deal. He did the math on the materials I'll be working with and I need something up around 200 to 225 amps to get done what I want. Might be able to get by with a 175, but will have to bevel and preheat. So that means getting a 220v plug-in in the shop. I have laid down well over a pallet or 2 of 40# spools of wire MIG welding in the last 20 years, but only puddled a couple stainless tubes together with TIG, and didn't use fill rod. I'm right handed, so the torch will go there. I figure I'll run the rod out of my clamping hook on the left. It will be a learning experience for sure.

I would rather just MIG them together, but its such a small area of a work envelope, that on the smaller wrenches the MIG nozzle is twice as wide as the area being welded. That and they need to be pretty for my customers.

 

[aheg1220]

JB-Weld or other metal epoxies are always an option. Same with brazing.

 

[RonGinger]

As some of you know I've been working on a prosthetic wrist and tools over the last few years.

Would you care to elaborate some on this? From what I can figure you have been developing a prosthetic had for yourself. This just amazes me, and Id like to understand how you are doing it, what control you have with it, etc.

I hope this is not to personal a question, but It really amazes me that you re doing this. Maybe you could open a topic on this?

 

[steamer]

I think thats a great idea Ron, if Matt is willing. We'll leave that up to you Matt as long as Marv and Chuck don't mind.

Dave

 

[1hand]

Hey thanks guys!

Here Ron there is bits and pieces of the story through out this thread
http://www.homemodelenginemachinist.com/index.php?topic=7936.0

A few different attachment vids


http://s1216.photobucket.com/albums/dd366/midwestprocad/?action=view&current=DSCN1325.mp4
If you click on albums off the video site you can see other pics.

Necessity is the mother of all invention
Matt ;D

 

[jonesie]

matt my hat is off to you for the idea and work. i would be careful that the welds do not become to hard and brittle, causing one to break off,causing further injury.again nice work and good luck. jonesie

 

[Entropy455]

TIG welding does not require as much current as MIG welding.

To TIG weld a stainless steel bolt to a carbon steel wrench, you’ll likely need somewhere between 110 and 140 amps current (DC Electrode Negative), with 2% throated tungsten electrode. You’ll need 100% argon shielding gas, set for about 25-CFH (depending on the cup-size). The filler electrode should be 309L, which is specifically designed for joining carbon steels to austenitic stainless steels.

Make sure that you have proper ventilation, as you do not want to breathe chromium vapors.

Clean parts with soap and water prior to welding. Do not use spray cleaners.

 

[velocette]

Hi this is my two pennies worth on welding stainless to Carbon-chrom vanadium steels

GRIND OFF ANY CHROMIUM PLATING IN THE WELD AREA This can lead to an EXTREMELY BRITTLE weld

Preheat and slow cooling will improve ductility

Stainless is very pretty looking but can suffer from 'Galling " on threads with constant use.

I make the assumption that you will fabricate new adapters for this project

Quote from Self (((Assumption is the Mother of all Misunderstanding)))

An alternative would be to use a "Chromium Vanadium Tool Steel" it can be machined relatively easily

Another option is to use a "Flux Coated Silver Brazing Rod" suitable for "Stainless Steel" You local welding supplier would be the best adviser on this as terminology for this process varies widely

My hat goes of to you Matt this post is an inspiration to us all with your "Can Do" attitude to getting things done

Hoping to be of some use Eric

 

[1hand]

TIG welding does not require as much current as MIG welding.

To TIG weld a stainless steel bolt to a carbon steel wrench, you’ll likely need somewhere between 110 and 140 amps current (DC Electrode Negative), with 2% throated tungsten electrode. You’ll need 100% argon shielding gas, set for about 25-CFH (depending on the cup-size). The filler electrode should be 309L, which is specifically designed for joining carbon steels to austenitic stainless steels.

Make sure that you have proper ventilation, as you do not want to breathe chromium vapors.

Clean parts with soap and water prior to welding. Do not use spray cleaners.

Your thinking I can get away with a 150amp 110v unit?

 

[1hand]

Hi this is my two pennies worth on welding stainless to Carbon-chrom vanadium steels

GRIND OFF ANY CHROMIUM PLATING IN THE WELD AREA This can lead to an EXTREMELY BRITTLE weld

Preheat and slow cooling will improve ductility

Stainless is very pretty looking but can suffer from 'Galling " on threads with constant use.

I make the assumption that you will fabricate new adapters for this project

Quote from Self (((Assumption is the Mother of all Misunderstanding)))

An alternative would be to use a "Chromium Vanadium Tool Steel" it can be machined relatively easily

Another option is to use a "Flux Coated Silver Brazing Rod" suitable for "Stainless Steel" You local welding supplier would be the best adviser on this as terminology for this process varies widely

My hat goes of to you Matt this post is an inspiration to us all with your "Can Do" attitude to getting things done

Hoping to be of some use Eric

Thanks Eric,

The wrench is cut off, then it will be welded on top on of a 1/2-20 X 1/2" long SS bolt. Then this is threaded into a SS bushing that goes in and out of my Quick change wrist end. So once the tool is threaded into the bushing, that's it for using them threads. A one time deal. Hope this makes sense.

Matt

 

[1hand]

matt my hat is off to you for the idea and work. i would be careful that the welds do not become to hard and brittle, causing one to break off,causing further injury.again nice work and good luck. jonesie

Thanks Bud!

 

[1hand]

Hi this is my two pennies worth on welding stainless to Carbon-chrom vanadium steels

GRIND OFF ANY CHROMIUM PLATING IN THE WELD AREA This can lead to an EXTREMELY BRITTLE weld

Preheat and slow cooling will improve ductility

Stainless is very pretty looking but can suffer from 'Galling " on threads with constant use.

I make the assumption that you will fabricate new adapters for this project

Quote from Self (((Assumption is the Mother of all Misunderstanding)))

An alternative would be to use a "Chromium Vanadium Tool Steel" it can be machined relatively easily

Another option is to use a "Flux Coated Silver Brazing Rod" suitable for "Stainless Steel" You local welding supplier would be the best adviser on this as terminology for this process varies widely

My hat goes of to you Matt this post is an inspiration to us all with your "Can Do" attitude to getting things done

Hoping to be of some use Eric

Preheat both bolt and wrench? How hot? Will my propane turbo torch heat enough for this? Weld it when its hot then cool?


Matt

 

[Tin Falcon]

Matt a turbu torch would be fine but an old oven is a wonderful thing . pre heat to about 400 degrees do the weld and then pop the next one out of the oven.
post heat will relieve streses as well.
tin

 

[Entropy455]

Chrome Vanadium is often classified as medium carbon tool steel (0.55 to 0.65% carbon content). It is heat treatable, and can achieve a hardness of between 35 and 59 on the Rockwell C-scale, depending on temper. It is a great steel for making wrenches.

Chrome Vanadium steel contains small amounts of chromium (0.80 to 1.1 percent), which is similar to that of typical chrome-molly steels. If need to weld Chrome Vanadium steel to itself, or to ordinary mild steel, 70S, 80S or 100S filler material will work fine.

The chrome content of typical 304 stainless however is between 18 and 20 percent. The problem here is that if you attempt to weld 304 stainless steel to Chrome Vanadium steel using 70S filler rod, the chromium will migrate out of the 304 and into both the 70S' lattice structure, and also into the Chrome Vanadium's lattice structure. This causes the stainless to lose appreciable strength. It will be brittle, and very susceptible to corrosion along the heat affected zone.

To combat this, you use 309L filler rod, which has over 35% chromium, and 14% nickel. The high nickel content, together with the excessively high chromium content, will work to stabilize the 304 base material during welding operations. It saturates the weld joint with high levels of chromium, which is required for successfully welding stainless steels to carbon steels.

Thus if you're welding a Chrome Vanadium wrench to a regular steel fastener, with 70S filler material, you would certainly want to remove the chrome plating to prevent weld contamination. However when joining a 304 bolt (20% chromium), using 309L filler rod (that contains over 35% chromium), I’m not sure that a thin layer of chrome on the wrench is going to cause problems.

I suppose it could weaken the toe of the weld. . . .? I would recommend taking the Pepsi Challenge. Weld a 304 bolt to one side of a Chrome Vanadium wrench with 309L rod, without removing the chrome plating - then weld a 304 bolt to the other side with 309L rod, with the chrome plating ground away. Then clamp the wrench in a vise, and beat the crap out of it with a 5 pound hammer. If the weld joint with the chrome plating fails first, then you know to remove the chrome before welding. I’m thinking you will not see an appreciable difference in strength, if any difference at all.

If the wrench was electroplated in copper and/or zinc prior to chroming, all bets are off. . . .

 

[1hand]

The bolts I have are 18-8, if that makes a difference.

You think a 150amp 110v unit will work if I do a small bevel on the wrench and pre heat?