Cheap spool gun mod

[Frank S]

Needing to do some aluminum mig welding I first tried using the 12 ft gun on my welder. This wasn't going to happen I found out very quickly. Not with 4043 0.035" wire and not with a 12 ft gun, 0.045" 5356 possibly. A 4ft gun with the 4043 maybe.
So going to amazon I found the MBC 200 spool gun completely bare no cable or hose for $29.00 free shipping.
If it works really well fine if not I'm not out a whole lot, I was sure I could at least make it work well enough to do the job required.
IE Ramp mounts on the rear of an Aluminum stepdack trailer
In order to make it work first I hooked up a 16 ft cable, hose and the control wires.
The problem was the gun came with a little spool of its own that I would have to wind the wire on 1/2 lb at a time. the 1 lb standard spool would not fit.
SO about all I had to do was grind a bolt to fit in the mounting hole on the gun find a suitable sleeve to fit the spool and bend the spool brake out of the way enough to accommodate the larger spool

[ibdennyak]

Frank
Thanks for the tip. I've wanted to go with mig instead of TIG for some of my projects, but the spoolgun cost kind of got in the way. Now I have to try it.

Denny

[Tooler2]

Are you powering it with a mig welder or a stick welder? I imagine it is AC for aluminium?

[Frank S]

Are you powering it with a mig welder or a stick welder? I imagine it is AC for aluminium?

No, No no never Ac for a mig of any kind.
My miller mig has a spool gun port for the control and a 2nd gas sol. so I can actually weld with either just depends on which I pick up. but it would require 2 tanks of gas 1 pure ARgon for the spool gun for aluminum and 1 CO2 or 75/25 mix for the mig.
If you have a mig machine that doesn't have a 2nd port you would have to create one You could install a switch inline with the mig motor to switch from it to the spool gun then connect the trigger of the spool gun where the trigger wires go into the machine.
For the spool gun you need a gas hose a cable for the weld current. What I used was a 4ga cable I wanted 2 ga but that was what I had on hand. The Chepo MBC 200 requires 24v control for the motor a lot of mig machines use 12 v for the feed motors My Hobart 135 for example uses 12v
and you need the trigger wires to close the contactor and activate the gas sol.
Now here is a hack if you have an old 110v mig machine that no longer works but has a good feed motor if the voltage of it is the same as you mig machine you need at least a 200 amp machine for welding aluminum even the 0.30 wire is going to suck in 150 amps.
Anyway you can remove the feed motor and rive wheels assembly from an existing small machine and fashion a spool gun out of that by making a handle a mount for the spool and a short gun tube that is essentially all there is to a simple spool gun.
A more complex one could be made and used on a DC stick welder providing you connected a contactor to interrupt the weld current and a transformer to give you the gun motor voltage a couple of resisters and a potentiometer to control the motor speed right at the gun connect the gas valve to the aux contacts of the contactor and you would be in business.
Had this 29 dollar thing I bought not worked that would have been what I was going to do by salvaging a feed motor out of an old dead baby mig machine.

[DIYer]

Thanks Frank S! We've added your Welding Gun Spool Modification to our Welding category,
as well as to your builder page: Frank S's Homemade Tools. Your receipt:

Welding Gun Spool Modification by Frank S

tags: welding, modification

[Tooler2]

A friend of mine used to rent a spool gun, pretty sure he only had an AC stick welder to run it. I got one with my Linde 305 stick/tig but never tried it, I will try to figure out how it is wired. Most of my mig feeders are 120v, but the voltage running up to the trigger may be less for safety reasons.
Rob

[cmarlow]

Have you tried it with flux core?

[Frank S]

Have you tried it with flux core?

The only thing I rigged up the spool gun for was to be able to run 0.030 or 0.035" aluminum wire without it constantly bird nesting at the rollers like it will do when trying to feed through a long gun hose. welding aluminum using a conventional mig gun can be accomplished when the guns are around 6 ft long with nylon liner tubes and the stem of the gun connection is super close tot the drive rollers. My mig gun is not.
If by flux core you are referring to the gasless wire the answer is no I have not tried it with the spool gun. I see no reason for doing so for my purposes.
I have used the gasless flux core through many other long guns But I really don't care for it all that much, for most things that I weld I prefer to run duel shield flux cored wire with CO2 shielding gas the difference between the 2 types of wires are like comparing 6011 trash rod with 7018 low hydrogen rods.
Even 7018 low hydrogen rods will not achieve the same quality welds as the duel shield wire will do.

[cmarlow]

Thank you for a decent response. Sometimes I use cored wire with my cheap little house current mig. I agree it is not the best for quality but it can be plugged into any 120 power supply and tacks things together enough to get them to a shop.
I bought one of the cheap spool guns like you did and wired it to run off two12v batteries, obviously it is not being connected to bottles. I have not tried it out yet and I expect it to be really rough.

[Frank S]

Thank you for a decent response. Sometimes I use cored wire with my cheap little house current mig. I agree it is not the best for quality but it can be plugged into any 120 power supply and tacks things together enough to get them to a shop.
I bought one of the cheap spool guns like you did and wired it to run off two12v batteries, obviously it is not being connected to bottles. I have not tried it out yet and I expect it to be really rough.

If you are driving the feed motor from a pair of 12v batteries have you worked out how you will control feed speed?
Possibly with a Rheostat to reduce the voltage?
And are you thinking about using the batteries to supply the weld current as well?
a company named Forney used to make a self contained mig welder that ran off of 2 batteries When they first came out in the mid 80's they sold for around $250.00
Wasn't a bad price for a machine you could toss in the back of your pickup and head out to the field for a quick get you home repair.
But I had something even better all the way back as a teenager on the farm it was called a pair of jumper cables a lot of our equipment had 2 batteries in it just to start it with simply disconnect the positive then hook the batteries up in series and use 1 lead of the jumper cable with a rod to weld up what ever was broken or at least as you say tack it together well enough to get from the field to a welding machine. Never had as welding helmet on the tractor but all of the tool boxes had a #10 shaded lenz wrapped up and stored.