Critiques?

[laguna80]

Hey y'all, like so many others posting for the first time, I'd like to get some opinions (expert or not) of my welds. I've been welding for a few weeks off and on now. My welder is a hobart 125 running 0.30 flux core wire. My application is auto sheet metal 16-18 gauge. I know of the benefits of running gas, but it's so windy here that's not really logical for me. Anyway, I've been slowly improving over time. My penetration is very little as you can see from the pics. The first pic is topside and second pic is bottom. 1st, 2nd, 3rd runs are from left to right. I get very little penetration when tack welding too. I've been playing with the settings a bit and get a nice buzz but still can't seem to get it perfect. Welds are pretty high, well higher than they should be. I'm open to all suggestions, opinions, critiques. Thanks a bunch. Oh ya, I've been lurking on this forum for a while, there's some great stuff here. Oh and the settings were 1 (out of 1-4) on the voltage and around 20 (10-90) on the wire feed. This was on 16 gauge sheet.

 

[laguna80]

Little update: got some tips, played with the settings and did a run of tack welds, then a run of half inch welds, then a run of better tack welds. (that's all from left to right) Penetration is much better since I bumped up to #2 on the power settings. Wire feed a little bit slower. I tried to weld in a patch on my truck, but the piece didn't fit quite right and I was blowing holes. It is damn hard to cut my truck up to easily measured sizes. Here's the pics:

 

[malcolm]

You must think we're ignoring you here. The first set of welds do look a little light on heat. Sounds like the second setting is much closer. Ideally you'd want the slowest wire speed that works with a nice steady sound, though you can increase penetration by increasing the wire speed.

I'd try to avoid doing the whole weld with tacks. Continuous welds will be stronger. If the truck metal is slightly thinner or if you have a gap try the lower power setting again to reduce the chance of blowing through. Make sure you clean off the metal until it's shiny before welding to it.

For an accurate fit of patch make a template by placing a sheet of card over the hole and running your finger around it to trace the edge of the metal into the card. Cut a metal patch out the same size and grind it to shape - it will be spot on. Or leave a slsight overlap to prevent the gap and blowing through.

 

[laguna80]

Thanks for the reply. I think I'll have to go to a lower power setting to weld in new patches. I've also got to learn to cut more accurate shapes. The ones I've cut are a bit on the curvy side of straight.

 

[laguna80]

Got some more practice in. First I cut a rusted patch out of a fender from a 74 Landcruiser. Then I used that as a template for the replacement patch. It almost fit lol. The curves in the fender made it hard to cut a flat piece out that would fit, so I bent the fender flat and then put the piece in. As you can see, I burned through in the areas that had too large of a gap. Why does it do that? Is it because there isn't enough gas to protect the weld so it gets too hot? Anyway, I've got in more or less welded in. I tried to get extra small pieces in where the gaps are. That's why there are giant blobs in some places. I'm going to grind it down and have another go tomorrow. Cheers all.

 

[laguna80]

Sorry here's the pics: I got another patch in today.

 

[scarecrow]

Hold the torch with all hands and keep the weave a little bit smaller your practice weld is better than the patch weld so just keep practising

 

[laguna80]

another patch welded in. Before it was 16 gauge going on 20 gauge, but this time I used 20 gauge mated to 20 gauge. It went a lot better than before. I did all tack arounds around the weld area. I felt that the metal was too thin to use longer welds than tack. As you can see I blew through the metal a couple time when I left the torch on too long.

 

[Sparkey]

you could fill those holes quite easily you know?
just nice and easy, take your time, put in small tacks, one ontop of the other... i'm sure you'll do fine!
Sparkey

 

[laguna80]

Is it really that easy? I'm a little worried about making the holes even bigger. How about the backside? Would it be better to grind it smooth? I am going to be painting the backside as well. Should I use some kind of heat sink just to be safe or is it cool to fill those little holes without one? BTW thanks for all the advice! It is greatly appreciated.

 

[peterd51]

Hi,

you need to use very short burst of power, maybe 1/2 a second or less.

Try to put a ring of small 'blobs' around the hole to give more material that you wont burn through.

Then you do a 1 - 2 second burn (or possibly longer if it's a bigger hole) and swirl your torch in a spiral moving in to the middle. Keep the torch moving and if the metal glows red then stop until it cools.


To practice you could use a nail and punch a few holes in a 16 - 18 guage scrap sheet.

Regards
Peter

 

[Sparkey]

Thanks for the backup Peter! i felt sorry afterwards that i hadn't more time to explain this properly...
really important laguna, take your time for those welds, sure when you just start out as a welder...just practise and you will get the hang of it!!
I think i woulden't recommend it to weld up all of it if the gap's too big...
Sparkey

 

[Stuggi]

If you need to fill pinholes in rusted metal you can always drill the hole bigger, fit a small piece of 1,5mm-2mm sheet behind the hole and do a plug weld. When you then grind the plug down you have a nice and smooth fill. The only problem is that you need access to the backside, and the backside needs to be inside the car, otherwise water will get in between the sheets and rust out an even bigger hole.

 

[marknotgeorge]

An easier method would be to clamp a piece of copper behind the hole. The copper supports the weld pool, but doesn't stick to the steel. A flattened bit of copper pipe works.

 

[Robotstar5]

An easier method would be to clamp a piece of copper behind the hole. The copper supports the weld pool, but doesn't stick to the steel.

Try telling our Robot welders that!, we've tried copper, brass, aluminium and various exotic materials for our workpiece supports but still they manage to get the weld to stick to it.

 

[Sparkey]

Again you must have very good acces to the back or side to clamp something on it... if not, weld it up i say! jiehaah!
hé robo copper works good in our factory......tackers huh?

 

[laguna80]

Thanks for all the advice people. I can fill the holes ok now as long as I'm really careful. I should be able to post pics of the finished fender later on today.

 

[laguna80]

Hey peeps, thanks for all your help/advice. My welds are looking a lot better and I've moved on to rebuilding the inner rockers and floor supports of my cruiser. I've been wondering about painting these parts. Now the floors are going to go on top of these and they are tack welded in. However, if I paint these parts and then weld the floor down, I'll ruin the paint won't I? What do you all do to protect these areas? Any suggestions? That first floor support in the pic is what I mean. The floor rests on top of that.

 

[laguna80]

bumpity-bump. Anyone got any ideas? What do you all do to protect areas that will be inaccessible to painting after you weld in metal?

 

[marknotgeorge]

Spray it with zinc-rich primer, masking off the areas where you'll be welding. There are weld-thru primers you can use, but most people don't bother. After you've finished welding, you can fill the box-section with waxoyl, or the equivalent US stuff.