Re: [PSUBS-MAILIST]request

Hi Hugh. Sorry I didn't answer sooner, I didn't see this one till I started deleting spam from the list of e-mails.

Anyway, the gas flow to the cover box on the back needs to be minimal, just enough to be positive pressure. A 1/4 inch tube taped onto the box, and enough gas flow so it leaks out a little. The weld tape you mentioned....never tried it.

The weld gap depends on what process you're using. With stick, it should be about the same as the stick size. 1/8 inch is common. Weld joints will pull together as you weld them, so a gap is good. It allows the weld puddle to flow to the root. With TIG it's a smaller gap. 1/16 inch works good if you have a good beveled joint and can reach the tungsten down to the bottom. Many people use "backing strips" for critical welds. Tacking a scrap piece onto the back side, welding the joint, then removing the back strip, grinding, then welding the back side. I do that when I stick weld heavy stuff requiring multiple passes and it's fairly easy to get to the back side to remove the backing. It's especially useful when the "fit up" is not so good.

As for wire speed and amps, that depends on your machine and how thick the joint is. Generally, .035 and .040 is the most common for a home welder set up using flux core. The amps used depends on what the weld bead is used for. You can use a lower setting to weld regular stuff, or a higher setting for spray transfer like hard facing. Too many variables to explain here. Better to read the book that came with the machine, and most of all, practice on scrap until you get it "dialed in" for the particular weld. MIG machines are harder to set for a particular weld because you have to adjust amps ( tied into wire speed) and volts. It's a balancing thing to get the weld you want. With stick and TIG you generally just adjust the amps. turn it up until it burns in deep, but not hot enough to burn through. After all is said and done, practice is the key. Frank D.