OK, I know I bought the cheapo wire fed MIG at Harbor freight...$99 Thanksgiving special. It has two settings low and high. On heavier metal its fine, but trying to use it on our cars is a real trick. Even on the low setting, I'm having a difficult time learning how to fill with the weld........if I'm not careful, my hole gets bigger not smaller.

Are there any tricks/techniques welding with such a unit? I have to admit, this is my first welder, and I'm sure experience, or lack of, has a lot to do with it.

Anyway, I have a newfound appreciation for you guys and gals that weld

same problem here.

if you burn a hole, i welded a little, stopped..let it cool for 3 seconds, then went back. kinda pulsed the welder to fill in holes.

If it's only got two settings, then I'm sorry to say that it's probably not adjustable enough to work on sheet metal. My MIG welder has four power settings and a infinitely adjustable wire feed speed, and that's not NEARLY enough for me.

Also, if you don't have a gas bottle, your using flux core wire, and that stuff is even harder to work with.

Britt's got it right though. Filling in holes is a pulsing action.

Yep...it has a variable wire feed, but no gas...and yes flux wire feed! Well, looks like a nice day for a bbq here in sunny CA...I'll just have to experiment.

Putting a chill plate behind it is an old trick. The plate keeps the metal a little cooler and the weld hits the plate and solidifies.

I use a few inches of copper pipe, pound one end flat and ram a wood dowel into the open end. A nail to secure and you have a portable chill plate. Or a block of copper held behind works well too.

The weld won't stick to copper.

Ken

Get a copper or brass plate to back up your hole. It works well and the weld should not stick well to the backing plate. (I have a couple pieces of 1/4" brass plates that I use for this when I need them.)

Britt's method works well too. Pull the trigger and hold just briefly.

I wouldn't want to try to weld sheet metal without a 2 speed welder and no gas. But that's just me.

Love my Miller 175 with variable wire speed and voltage.

Hey computers4kids I seen your car the other day at the 7 eleven. I was going to say hello, but you sped off.

I just recently completely rebuilt my outer longitudinals and installed the Restoration Design clamshells using a Hobart 135 (110v) Mig unit (cost about $500, 5 years ago). It has 4 amp settings and infinite wire speed.

I am definitely a novice but got better as I went along (a lot of practice pieces). I tried using flux coated wire and could not get it to work. Fortunately the Hobart allows the use of gas so I swiched and it helped a lot. I also found that even with 4 settings, it was not really enough to deal with the various thickness during the rebuild. Yes, I blew open more than a few holes. I found the most important parameter was to make sure the old OEM steel welding areas were very, very, very clean. The newer steel replacement patches were a little more foregiving.

Depending on what you are trying to do, 2 amp settings and not using gas is going to be a problem, especially as others pointed out, in trying to weld sheet metal. Best thing to do with what you got is to practice, practice, practice with some scrap pieces.

jjs3rd914

I have the same $99.00 HF welder. What you are doing is holding it in one spot too long. As stated above you can pulse the trigger to put a tac spot. or you need to practice and adapt your torch speed to the level of heat or wire feed speed. also adjust your helmet lens so you can see the metal puddle flow.

I just welded the new front apron to my race car Thursday worked great.

I have a similar welder, and it can be a problem with automotive sheet metal. I've found stitch welding works well. Just a spot tack weld move an inch and do it again. Once you get to the end, stop and steel brush the work you just did, then do it all again. After many passes it's will be a complete weld. Lap welds are easier, while butt welding thin sheet metal is next to impossible. If I make my own patch panel, I usually try to use 14-16 guage, that way it's a bit heavier and easier to weld. Practice, GOOD LUCK.

you may also be to close to the work.
If you slowly move away from your practice piece you will see the difference.

About 1 inch away up to 2 inches can be done.
I have the craftsman flux core, no gas.
I have figured out how to weld 22 gauge with it...
Its timing and distance.
The thinner the metal, the farther away you need to be.

There is an odd trick that I use on really thin 22 gauge.
Turn on another piece of equipment that has a large draw of amps.
Like a compressor, or a large saw.
This will lower the amount of amps going into the welder, thus you get less coming out.

Rich

Lots of great advice...chill plate, pulsing, very clean OEM metal and possibly even turning my 60 gallon compressor on while I'm welding on low to even further lowering the amperage.

I successfully welded up my tornado mirror holes, and a few others today...just got to take it real slow, grind. touch up.

The real test will be when I spot weld my replacement trunk panel in. It's all fitted ready to be tacked...hopefully I won't be blowing holes.

PS "MR.C"...I don't think it was me at 7-11. I haven't been driving my car much lately, I'm waiting to get my MPS back from Geoff (Bleyseng)--he's fixing a blown gasket. I do have my spare in but it doesn't work too good, so I don't drive too much.

Ahhh, well then there is another nice red one in town. I've seen it alot lately. Never could catch up with him though.

One trick I've not seen is to start adding material far enough back from the edges that you are more likely to be in thicker metal, then work your way toward the joint after the weld material is there to absorb the heat. Doing this in passes to allow cooling is best.

You really can't weld 914 body panels well with that...

The inevitable will be a sale and a purchase of a real MIG (ask me how I know)

It is a nice medicine ball though.

Agree with Eric........get a real welder with infinite adjustable voltage. It will pay for itself in frustration alone. Go 220 versus 110. More bang for the buck. Avoid the Home Depot specials. Avoid the Lincoln HD's. Get a Miller 180. It will do everything you ask of it and more for $800 plus a tank of C02/ Argon.

Watch out. Pulling back on the gun will decrease penetration and increase porosity. Adjusting voltage is recommended.......1 to 2 inches of sickout even with flux core will not produce an acceptable weld. Stick out should average a 1/4 to 1/2 inch at most. Excessive stick out will only leave a bead a 1/8 wide on top and not penetrate properly to the next layer of metal. By the time you make your next weld you will hear your last spot or pass popping loose. (pop, ting, tin canning)

For thin sheet metal always use a MIG or TIG. If you do not have infinite control of voltage tap the trigger with short bursts. More heat is still better than not enough. Avoid flux core wire for autobody sheet metal repairs altogether. Flux core should only be used for 1/8 inch and thicker metals. Flux core welds also produce more oxidation using reduced voltage when welding thin gauge sheetmetal.

Panel fitment is the key to a good weld. Avoid bridging large gaps with liquid metal filler. Clamp, cleco, vise grip whatever it takes to get two pieces as close as possible and then weld. Make sure your metal is clean. Anything with paint or rust will create more resistance and the possibilty of blowing holes and creating a dirty weld zone. You want to strike a fast hot arc in the shortest time possible. Anything inhibiting those three things makes for trouble. If a Ball- O -Weld starts to form stop now and let go of the trigger. Once a ball of dripping liquid steel forms you cannot fix it, its too late. Let it cool and get out the grinder.




"When you successfully can weld inverted it's like losing your virginity all over again. When you get second degree burns from slag on the fold of your forearm to bicep you have become educated. When you no longer get second degree burns you have become a professional welder although occasionally you will hear ear wax sizzle!"

A quick suggestion... check your local equipment rental shops. Every few years they sell off their rental equipment. The gear is often replaced on a depreciation schedule rather than just when it's ratty.

I scored my rig for a fraction of "new" price. It was cosmetically challenged, but every bit of it worked just fine. I don't weld enough to justify an 800-1000 dollar setup, so it's been a great value.