Confused over which gas for welding...

[sixdogs]

There is plently to search on this but I am still confused.
My wire welder is a Lincoln 170T (220) that I have used with flux core wire for farm welding and rusty metal welded outside.
Now I want to do attractive welds on new metal or clean hot rod frames or other new metal than is in the area of 1/8" yhick. Maybe thinner, maybe some thicker.

I do not understand which gas I should use and know little about it. Which wire size? What size bottle to buy for infrequent use? The kit I bought has the regulator, etc and says I can use different wre sizes. I presumed I would just use argon and was not aware of blends.
The welding class I took covered all this but I need some practical application. Thanks in advance.

 

[mbohuntr]

I have always perferred .035 hardwire with C25 gas. Probably 1/8" is max with one pass. CO2 will leave you with worm holes, but it is cheaper. I don't trust mig enough to weld hot-rod frames, even though I have been certified in it.

 

[sixdogs]

I have always perferred .035 hardwire with C25 gas. Probably 1/8" is max with one pass. CO2 will leave you with worm holes, but it is cheaper. I don't trust mig enough to weld hot-rod frames, even though I have been certified in it.

So you would use stick for hot rod frames? What is C25?

 

[jayste]

I have always perferred .035 hardwire with C25 gas. Probably 1/8" is max with one pass. CO2 will leave you with worm holes, but it is cheaper. I don't trust mig enough to weld hot-rod frames, even though I have been certified in it.

I'm with mbohuntr. I prefere .035" hard wire and C25. I'm not sure what size of bottle I rent. It's in the pic below.

 

[LD1]

c25 is 25% CO2 and 75% argon. It will work well in your welder. The higher % arogon and less CO2 is more expensive and wont penetrate quite as deep, but can give better quality welds. I thing a 90/10 mix is required to do spray transfer welding, which is a whole other topic that you shouldn't be concerned with.

The bottle in the pic loos to be the 125 cu ft. I think that would work for no more welding than you'll do. They also make 85 cu ft bottles, 24x bottles and like a 320.

035 wire is also a good bet. It is the "norm" around here. However if you plan on doing really light stuff like auto body repair, you may need much smaller wire. But for ~16ga up to 3/8", I like the 035.

If you are confident in your welder and your welding skills, I wouldn't be afraid one bit to use it on hot-rod frames for several reasons.

1. Car frames are mig welded already. (by robots though, but the process is the same)

2. A good Mig weld (or any weld for that matter) will be stronger than the base metal. So in theory, if you are a sound welder, the frame will break before your welds

3. Many custom fab shops that build chassis cars and roll cages use Mig. Some of the high-end ones use TIG, but many still use MIG. and IMO a roll cage on a drag car is a little more critical than what you will probabally be welding.

 

[paulinkansas]

Buy the 10 lb spool of .035 solid wire, not a 2 lb spool. You'll go through it alot quicker than you think. I bought a Hobart 187 last year, and got an 80 cubic ft tank of C25. I've gone through 3 spools of 2 lb solid wire, and have maybe used 1/3 or less of the gas in the tank. Get a good brand of wire, nothing from Horror Freight.

 

[AlanB]

For what you are describing .035 and C25 gas as the others have said would be my start point.

Some additional thoughts.

Figure out who your gas supplier will be, then see how they are doing the bottles. Some rent, some lease, some sell, some do it many different ways for different sizes. Pick your supplier and then just go along with how they do it.

I tend to like big bottles, but it takes a while to empty them and it is not the most convienient to roll around at times. The price pr cuft is often substantially lower on the larger bottles, but again, that varies with the supplier.

If you have someone in the soda business C02 is behind all the fountains. Can make for a ready and easy supply.

I run straight CO2 in my MM 250 and run C25 in my MM 135

As was said, the mix is more expensive, but gives a cleaner / better weld although for me, 95% of the time the straight CO2 is perfectly acceptable.

If you decide to mig Aluminum you will need straight Argon.

Stay away from the really small bottles as they almost always will leave you frustrated and empty.

I swear, all the welding gas suppliers got together and insured that none of them referred to their bottles by the same names to keep the end user in the dark as to how to compare them. Go by cubic Ft. and write notes to keep straight that you are comparing apples to apples.

 

[mbohuntr]

In expierenced hands, mig is great, My woodsplitter was welded with core wire. I have also watched a welding school graduate watch his root and face bend tests fall apart before they even bent. I would weld the frames with a sleeve insert and a 3/8" gap so the welds go into the sleeve. People tend to weld mig cold, or try to weld thicker material than they should.

 

[crusty 1]

I persnnally like 023 wire as it penitrats deeper[imo].I use a40 cf cyl. and I get alot of welding done with it.

 

[crusty 1]

bye the way I use 25/75 most of the time.