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Millermatic 200, GA-20c gun update

6.9K views 7 replies 3 participants last post by  guajilloweld03  
#1 ·
Bought a MM 200 and the GA- 20C gun is beat up. The nozzle and the defuser and insulator need replacing. Profax has defuser, nozzle and tips. The insulator is harder to get. The Profax catalog list the thread sizes for these parts.
Put a miller Roughneck gun on the MM200, the Miller defused is 1/4" NPT thread. Thought how hard can it be to convert the GA-20C to accept miller Rough neck parts.
The GA-20C has 7/16-14 female thread.
Got a 3/8" barb x 1/4" NPT fitting( Milton). On the 3/8" barb side ran a 7/16-14 die to make threads. Then cut fitting to length.
Now can attach Miller Roughneck parts.
Bernard center fire parts are 1/4" NPT and Miller M25 are 1/4" NPT . Some of the Tregaskiss are 1/4" NPT.
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#4 ·
View attachment 1702811
Going put heat shrink tube to cover gooseneck.
Need to find a liner for this GA-20C gun.
Miller Spoolmatic 15 and 30 A use the same parts as the Roughneck gun.
You will find that liners are very expensive for the GA-20C gun. The cost of liners and the fact that new switches for the GA -20 are not sold anymore is the reason I finally switched guns on my MM200. I still have the GA-20 hoping I might find a switch . I did find one on ebay once but they wanted $69 for it. I replaced the liner in mine and a few days latter the switch went bad. Good luck but I feel your putting money in a dead horse.
 
#5 ·
Your right about putting money on a dead horse. Already had the parts from my other guns. It was fun getting it together and simple getting it to work. The liner looks like a miller # 194010 ($ 11.00) can be bought on EBay and made to work. The old liner has a bushing with a set screw, so cut new liner and fit it on. Think I have a spare liner some where, will have to look.