I recently posted about solving a problem of shitty MIG welds by changing the wire, which had developed some rust.
In an attempt to prevent the new wire from rusting, I have made a modification to my MIG. The mod was to build a little sheet metal enclosure for the spool and put some silica gel in it:
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The wire feeds out of it's box through a slot with two rubber flaps as a seal. The box is sealed with RTV on the back and the MIG cover/door has foam weather stripping that seals the front. The silica gel is in a pouch, in the plastic chamber in the upper left corner.
I'll let you know how it works.
Bob