Does anyone make kits to add gas to a flux core welder, or should I plan on buying a new set up entirely? I want to be able to try some aluminum welding... Maybe Santa will bring me the right parts I need...

if the welder is made for it, its not hard... just buy the kit from whoever makes the welder.

generally this "kit" consists of nothing more then a hose, and regulator... you just go buy/rent a bottle (about $100 with gas)

hopefully you have a cart so you can move the thing around.... if not, then you need one...

then swap the polarity according to the instructions that come with the welder, change the wire and thats it... you're cooking errr, welding, with gas!

Some welders have kits, some don't.

Before you look into it, what is the maximum amperage your "flux core" welder will do? If it's only a 90 amp unit, you're not going to get much welding done on aluminum.

Aluminum takes a much higher temperature to weld, which is why it is welded on ac (alternating current).

I bought a Lincoln unit that's 130 amps, and they don't recommend welding more than 1/8" aluminum in a single pass, with their aluminum kit.

How much you can weld on a multipass is hard to say. For cosmetic purposes, you can weld as thick as you want until the material is too heavy for the weld to hold I would think, but for structural purposes, you're not going to be able to push a 130 amp very far before your bead is only penetrating on the surface. Preheating helps, but only a bit.

If you really want to weld aluminum, invest in a 220 unit and get a spool gun, unless you go TIG, but you don't have to have a TIG welder to weld aluminum.

Mathius

Thanks Mathius. Yes, it's only a 90 amp flux core welder. Time to wander through some pawn shops it sounds like. I couldn't find a kit for the Chicago Electric welder I have anyhere.

The welding I'm wanting to do is cosmetic for the most part... I've done most of it with aluminum brazing rods and acccccc acccssssss... dang, you know, that cuttin torch gas... An 1/8" in a single pass would do me more than fine though if I could find gas to go on it.

As for a cart, yes, I have one. I made a welding table with gas bottle holder on one end as my first welding project. Problem is that it's a cutting torch set up right now. Time for a converted two wheeler...

BTW, why do you have to reverse polarity?

the newly accepted terms are DCEN (Direct Current Electrode Negative) and DCEP (Direct Current Electrode Positive). Depending on what type of welding, one will provide better penetration and one will me more cosmetically appealing.

To weld Al you will need a propane torch for a little preheat of the Al at least a 135 amp welder, .035'' 5356Al wire and Argon shealding gas to weld 3mm 6061Al (the most comon alloy for most project stock).
To weld Al it likes a lot of ESD like about a full 1/2''.
To weld thiner Al 1mm you might want .030'' 4043 wire. With my welder it burns 1mm up with .030 5356 wire and I think 4043 will work better but I dont have any yet.
I'm geting a laser pointer thermometer gun so I can preheat the Al to a spific temp for good weld starts.
Because when you start a mig weld on room temp Al the bead bunches up and stays on the surface and you get no penetration at first and if you don't speed up your bead speed you will melt throught the Al.
Welding Al is a pain.

Usually it also has a gas valve and electrical goodies.



buy the biggest bottle that you can legally buy in your area. You should be able to get the bottle filled for between $30-50 depending on bottle size (I’m figuring an 80, which is the biggest you can buy in most areas), and what the gas actually is.

Renting is not worth it unless you go through a lot of it.



Much more importantly, something to keep it strapped to. Having one fall over and break the valve off with 1000psi or so behind it would not be pleasant.



No.

With a TIG it is welded using AC because the positive current cleans the weld, and oxidation is a major issue when welding aluminum. AC actually puts much less heat into the weld and more into the torch, which is why you usually need a much beefier torch (and possibly water cooled) to properly weld aluminum.

You can also TIG aluminum with DCEN if you add some helium to the shielding gas.



The thing with aluminum and a MIG is that 3/32” is about the minimum that you can weld well with mig, and about the max that you can do in a single pass with a small 110V welder.



The ultimate thickness that can be welded multipass is usually up to the technique and the welder (guy holding the gun). I’ve welded as heavy as 1” steel with a 110V welder that passed destructive testing. A smaller welder will not prevent you from welding something heavier, but will limit what you can do in a single pass and how long it will take to run the bead.

Cosmetic appearance and penetration is mostly up to the wire you’re using, in most cases flipping the current doesn’t allow you to adjust this, but ends up being a it works/it doesn’t work thing. Try flipping the connections on whatever wire you have in the welder now, usually the weld just seems to bounce off the base metal with the current reversed from what was intended with the wire.