MG Sports Cars

How thick is that? I'm starting to think my HTP is a pretty good machine.

Yeah, or maybe you're a pretty good welder? .032" thick, same as MG body panels.

I'm doing a little better with the short stitches, about 3/8" long. Any less than that and I get globs sticking up. I'll have to set up a butt weld and see what I can do with that.

Jim

Jim

Sometimes if the wire is bouncing off, the metal isn't clean enough try to sand the area or sand blast a little and see if that helps. Also like Bill said when you are Welding sheet metal don't go any more than a half inch long at a time I usually make spot weld like in 1 second burst's then move to a different spot

Keep practicing you will get it

Joe

JIm,

I have found with body sheet metal at 032" to use the smallest wire you can find. I found some 023" wire that worked the best and also used a 023" tip in the mig welder. The cleaner your metal is the easier the welding is ( less contamination). Bill and Joe are spot on with stitch welds. If you try to do a long weld, it will heat up the metal to much and you will blow through. Stitch weld about every 2" or 3" and then come back and fill in the gaps. Some times you can get away with a long weld but most of the time I ended up sewing it together for my firewall and inner fender work. If I scewed up, always had the grinder close by. Also every welder is different but I ended up using about 17lbs of gas seemed to work best for me. On my mig 80%Argon mix.
Tig 100% Argon. Yes! short 1 second blast works well once the mig is dialed in. I put my tip at a 45 degree angle or more, it helped not to blow through my work, and sometimes I layed the outer tip right on my work so the gas for sure gets to the metal to sheild.

Good luck, the more you do it the more you will find your own comfort zone with it.

Hope this helps,

Calvin

Biggest problem I have right now is consistency. I did get it so that I could lay down some 1/4" beads that looked pretty good, but when I slit the metal and then tried to weld it together all I could get was a bunch of goobers stuck on top and no penetration. I did find laying the nozzle over helped but right now I'm getting real cold starts. That would make for an awful lot of grinding and real bad strength. I'm going to try more tension on the drive wheels tomorrow, but at this point I'd be a lot better off sticking with the gas torch.

Jim

Same here spot weld or up to about an inch bead. Do that a few inches apart & then come back & do the same in the middle of those & repeat till its complete. Not only helps avoid blow throughs, but more importantly minimizes the heat build up & subsequent warping. Also slight circular motion as you weld if you're doing a bead.

All that is good advice, but when I strike an arc it takes a second or two for it to stabilize and while it's doing that there is no penetration so all I get is a blob. Then if I'm on an edge like you'd be welding two pieces together it just goes from blob to hole. I'm really starting to think there's something wrong with the welder.

Jim

RE: ..."I'm really starting to think there's something wrong with the welder."
I'd bet on it being the welder - you shouldn't be having that much trouble. Can you borrow another well-functioniong MIG and see if you have more success.

Jim, it sounds like you're getting close, try increasing the heat a bit and leave the wire speed alone. Then just trip the trigger for an instant on some sample sheet and check the back side for a red spot under the weld. You want enough heat to make a nice little cherry spot at the weld without leaving your wire too short. You then can start increasing the wire speed so that it leaves about 3/8 to a 1/2" of wire clear of the tip when you release the trigger. Start by making very short welds, one second or less, just enough to tack the pieces together with good penetration. Then just repeat the process all along the seam. It's time consuming compared to a continous bead, but much easier and results in much less warpage from the heat. If you have clearance on the back side for a welder's spoon to back up the seam that will help reduce any tendancy to blow holes as well. HF sells a nice little spoon for about $6 last time I checked.

Jim,

Some welders on the drive wheel feed you can flip it over 180 degrees, the slot (idler wheel not drive wheel) on the wheel will have a wide groove and a small groove (2 grooves on the wheel) depending on the wire size (.035 for wide groove .025 and under for small groove).

If the weather is very cold you may want to heat up the metal first before welding, it may help.

Thanks everyone for the help, lots of good tips and advice. For the time being I'm going back to the torch though. I can get darn near perfect welds with it every time without even thinking about it. Warpage is a bit more of an issue, but the same approach works there too, tacks and then start closing 'er up, use the hammer and dolly and shrink as I go. I can lay in a tack almost as fast as a mig. Fire is a bigger concern which is a pain on firewall work, but if I haven't figured it out by now there's no chance I'll suddenly become competent enough to do the welding that's needed on the Roadmaster body. Sometime when I get a chance to try someone else's mig maybe I can find out what the problem is. But I can't spend much more time trying to get to the bottom of this when there's so much else to do. If I had a likely cause to go after, like a component in the controls causing the waveform to go haywire it would make sense to look for that, but I don't have any way of checking the output to see if it's correct. No scope for instance and no references either.

So I guess that's it for now. Park it in the corner.

Jim

Jim, If I might add my 2 cents: Back in 88 I started building my 67GT with the 215 engine. The body of the car was in pretty bad shape which meant I had a lot of panels, floorboards etc to replace. My wife bougth me a little Cebora MIG welder along with instruction booklet etc. I experienced the same problems you are having. Welding the floor panels wasn't a bit deal since the metal was fairly thick. However when I got to the body panels all hell broke loose. I burned holes warped panels and generally was about to give up. I found the stich method to be slow but a whole lot more effective. I futzed with the feed and heat thinking I had hit upon the right solution to find the next time I went to use the same welder on the same panel it would turn to crap. I have since used a more expensive Miller welder that makes me look like I know what i'm doing. You have to keep adjusting, changing the tip angle. Keep the wire lubed and the arch area as clean as possible. Sizzle is fine on thicker metal but if you have constant sizzle on light material it is likely to be warping as you go. So as has been sugested I would sitch every 3/4" or so let it cool down and go back and stich some more to narrow the gap. My2c Tom

Jim, before you give up on the welder, try Bill's advice. Before I got the hang of doing short bursts I had the power set too low to avoid blowing through. You don't get any penetration that way. turn up the heat & do short bursts -- tacks to maybe 1/2 to 3/4" max. And do the little circular motion or you'll get roll-over on the edges.

I don't know, Rob. I think it's the welder. I mean welding machine. :)

Those welds look like crap. Jim's waaaay too talented not to take to it like a duck to water. I had very little stick welding experience welding when I bought my HTP MIG unit. I still can't weld, but I can sure make metal stick together.

What wire size are you using, Jim?

The little stuff. .023 I think. And the rollers are the right way up. Problem seems to be that it takes a couple seconds or more for the arc to stabilize. That makes an ugly goober. I know how to weld, I've been doing it for 40 years and have used practically every type of welding equipment at one time or another, but this thing has me buffaloed. I know it's wrong to expect it to be too easy, but it really should be easier than this. Maybe there's a good reason the guy wanted to sell this machine. Does Snap-On have a warranty you suppose?

Jim

For the price of snap-on stuff they should! Maybe have the local dealer check it out or get it checked out at a local welding shop.

I usually spot things in like Bill said. What do you get with it set on #2 and a really slow wire speed?



Edited 1 time(s). Last edit at 03/16/2009 01:14PM by t.lay.

Steve DeGroat and Tom Caine were here this weekend and played with it while I went to the house. They both said it definitely is not right, and they both have mig welders. I believe them. (I did the welding on the Roadmaster this weekend with gas and stick btw) So next is to try and find out if Snap-On can or will fix it and for how much, then Weld-Plus, them probably pull the cover off myself.

Jim

Years ago I lent a friend my Deca Mig (brand of mig welder) to put quarters on his Chevelle, I included my 30' extension cord with it. When I go the welder back I put it in my shop asked how it worked and he replied great.

I didn't use it for a couple of months but when I did it was all messed up wouldn't weld at all so I took it in to the local Carquest as they dealt with the Dealer for this brand of Welder. So they sent it in and they gave me an estimate of like a Million Dollars it seemed I don't quite remember but it was more than I could buy a new one for, they said it needed the whole circuit board, so I brought it home and put it in the corner, I will look at it someday.

A couple of years later I decided to mess with it so I drug it over by the 220 plug plugged it in and gave it a try it welded perfect I messed with it for over an hour perfect, I figured the rest did it some good:)

The next time I have a car in the shop for body work I pull out the welder plug it into my extension cord to work on the other side of the shop and its back to welding like Crap, what gives. It took me a little while but I figured out that my Buddy had put a different end on my extension cord for his shop and when he put my end back on he wired it incorrectly.........changed two wires and it was back to Perfect....End of Story

Good Luck Jim

Joe