Yeah, I've already found good flux over here, I was just wondering what you used, since you didn't mention it. I forget the brand of mine, the tub is at the shop. I do remember it's a powder that you mix up with water. Goes on looking about like skim milk. I also mentioned it because the new guys need to know that you can't torch weld aluminum without flux. Gotta have something to lift the oxide layer before you do the fusing. I hadn't seen it spelled out like that yet, and didn't want someone to get discouraged by failure without it. I say that, 'cause it didn't occur to me that you'd need flux when I first picked up torch welding. Since you don't need it with TIG, I failed to realize it was necessary until I started doing my due diligence research prior to buying a welding torch of my own. I never tried it without flux, but I'd imagine that it would turn out looking a lot like a TIG weld done without shielding gas.
Lifestylz - Thank you, I have been doing this for quite a while but its nice to be appreciated. CoolHand - I had not intended to give a lesson in gas welding aluminium but I am happy to do so. You are right the flux should be mixed with water into a thin past and the edges of the sheet should be cleaned with scotchbright or steel wool to remove any oxides, The flux should then be brushed on the edges prior to the weld being done. You should also treat the filler rod in the same way. I have some youtube footage which shows a little of this but I think it would be against the rules to post it here because it is an add for my DVD.
When welding sheet metal using a MIG, leaving a gap only increases the area that can move while the weld is cooling/shrinking. This in turn will cause the panel edges you have lined up to move (if the location of your patch is on an edge). IMHO, guys are welding like this to fill in the gap because their machine is not set hot enough to get a full penetration weld on panels that are butted tightly together. You need to have your panels fitted tight, you need to set your machine hot (so the "dots" we are welding will have full penetration welds the first time, every time), and the machine will need the wire feed set up a bit to prevent blowout (too much heat and not enough feed, something's gonna burn....hence, blowout). If you're welding dots and not getting full penetration welds, well that helps contribute to cracking when you planish. The welds and the sheet metal need to become one. Welding the front side and still seeing the joint on the back won't cut it. Here's a 55 quarter I was shaving the gas door on, nice tight fit on the patch.... weld dots on the front: Weld dots on the back side (full penetration weld): After I get it tacked in, I'll planish each dot slightly, just enough to relieve the shrinkage that causes the buckling. With a weld dot proud on both sides, as seen above, you can now planish with your hammer and dolly and not have either tool touch the sheet metal. This will eliminate knocking the metal all around, causing more deformity. Now grind down the dots to flush or just above the surface of the sheet metal, so they will be out of the way for planishing the next set, which should overlap the last weld dots. And just like shampoo, lather, rinse, repeat. I purposely went a couple passes without planishing to better show the buckles that appear from the HAZ shrinking: With only planishing the three welds adjacent to the buckle, you can see it quickly eliminates the shrink and the buckle flattens back out. This is using standard HTP brand ER70S, .035. I've never used ez grind anything, and haven't found a need to. I've never experienced any weld cracks when planishing a full penetration weld, using the above method. For those that think welds are harder than sheet metal, sure they are. They can be up to 4x or better the thickness of the sheet metal so they will be harder. But by planishing one dot at a time I think you'll find them much more manageable.
Very nice sir. Thanks for the right up. The only thing that I seen that might help you is over lap each tack 1/2 of the width of each tack.
TIG is for panel work and mig is not,at most tacking sections in place.Mig in my opinion is for structural work.
Here's a good rule of thumb for all, If you can see daylight thru your joint..it's too wide. If you can tack weld using only fusion(No rod), it's perfect! JJ-you done with that truck yet?
I'm gonna try the gas weld thing, been a long time since i've gas welded and have to round up some of my stuff that i've loaned to 'good friends'. I'll try some samples next week and post it on this thread, you guys can have some fun telling me what i'm doing wrong. Later, oj
I seem to find that adding a touch of 023 filler gives the bead a better 'flow'. Am I doing something wrong?? I will never again move as fast as I have before, seeing all this information, patience will now be at my side . I find this thread most impressive on all counts, thank you all for contributing your time!! Cosmo
( It all depends on what tools you have and what you are comfortable with. ) Pretty much say's it all. I mostly TIG steel sheet - and use O&A now and then. For Aluminum - 50% TIG - 50% O&H. For Copper - TIG - 100 % I have used heat to help shrink & shape steel, but never used a burn off aneal on it. For Aluminum with lots of shape I almost aways Aneal the blank. O&A soot burn off or Big Fat Sharpie marker & a MAP torch. It's not hard to do - It Don't take long & the Material is SO much easyer to shape & form - for sure on the thicker sheets like .080 & .100
Well, are you using .023" wire from a roll(mig wire)? I use .035" ER70S2 rod. I just finished welding 33" on a door, basically took me 2.5 hours, welding an 1 1/2" increments and hammering each weld as I go, as always thou, it takes longer to do things right but, the results are worth every penny!
I agree with you and your statement but some people only have mig and I have seen some pretty good results look at Johnny Arieal's photos earlier in this thread. I just think it must take forever! Seeing as you are English too I am surprised you dont use gas welding, I know you learned your trade here and most people here gas weld. Tig is ok for steel but I will not use it on ally, makes for hard work. I have seen some of your stuff and you do great work.
Mindover,i definately see what your saying and i did as an apprentice (90-94) learn the art of oxy acet gas welding at college.But after my apprenticeship i was lucky to learn Tig ac/dc and to be honest never looked back to oxy acet. In any kind of welding its all in the prep. ,then dressing the joint ,then welding and cooling in stages.Yes it takes time but when you come to metal finish the panel zero bondo/filler is needed primer straight onto metal. i only use oxy acet for hot spotting (shrinking metal)now. But anyways power to everyone on here working metal.As you know there s more than one way to skin a cat! .....and keep up the great work yourself!
This thread is why I came to the Hamb ..great stuff ..you will never know how much I have learn from this.
It is my resolution for the coming year to park the MIG in the corner, and leave it there. By then, I will have TIG'd together every loose piece of metal left over in my shop. It is time for me to step-up.
The main reason I use gas to weld sheetmetal is mig and tig welds mark up my wheels. Here is a '36 fender I did a while back welded with gas There's more in the album. I've always left a little gap in the initial fitting and tacking of the panel and found after you tack weld the peice in the gap goes away. Then I guess I've used John Kelly's philosophy and let the panel do what it wants and fix it when I'm done. I do hammerweld as I go, and you just get used to stretching the welds. Same with this rear fender I made from scratch. Sorry Johnny I said I would take a few pictures gas welding, but never got to it. I had to make some door skins and had a buisy weekend (picked up another coupe). I'm not sure I could explain with pictures and text. It's something you need to see in person. Jeff Very good topic Johnny!!! Thanks for starting it up.
Hi Jeff, That is the advantage of Gas over any other method the weld is so easy to dress (or wheel) out. The method you show is what the hot rod mags I read as a teenager always called hammer welding, this is a good method and I used it for years before I learned the traditional method used by coachbuilders of old here in England. You will get on a lot quicker with no gap and no filler rod. You will get much less distortion and you will not need any clamps when you tack up, this makes the whole process so much easier you can tack the panels together in less time than it takes to clamp them! Welding is so much quicker, I will try to post some close up photos of the results soon. David
Below is a photo of a weld done in the way I describe, you can see how even the HAZ is. No filler rod is used in this method and the weld is done in one run. This is the underside of a weld done in this way you can see that there is perfect penetration and the even HAZ again. because the HAZ is even very little distortion is caused. if you don't cause distortion you don't have to take it out, that has got to be a good thing no matter how good you are at dressing it out. No grinding is needed either on the outside or the inside. No clamps are used in tacking, progress is quick along the weld and little distortion is caused. The only slight downside is that when the panel is finished you are left with a slight undercut which is not a problem if the panel is being painted. It can be dressed out completely but this is a lot of work. If I am making something that is going to be chrome plated I use hammer welding but I use very little filler rod because although it takes a lot longer the extra metal from the filler rod allows dressing the weld until it completely disappeared with less work. Below is a photo of one the 1938 BMW wings that these photo are of. I don't wan to take credit for work I did not do so I must say that these were restored and modified by my employee James.
I did both of those fenders before I saw your video. I've tried your method, and it works. I find it takes more time to fit the panels using your method, but they should be fit perfect anyway right? Your method just dosn't leave any room for error, and the undercut weld spooks me. I plan on trying your method on my next fender. I have a good start on the fender now, I've just been getting sidetracked. Jerry I picked up this from partsdawg here on the HAMB It's just what I need to fix the coupe I have that was chopped up and made into a pickup. Bob really treated me good on it!!! Nice guy..... Edit: David you are correct, the method I use has been used by the traditional hotrodders here in the USA for many years as well It's how I was taught.
Hi Jeff, the undercuts do not effect the strength of the weld, If you look at the photo of the underside of the weld you will see that the metal of the weld penetration is still slightly proud and as I say you can dress it until it all disappears, doing that just makes for unnecessary work. When I teach at college I test a piece to destruction by clamping it in a vise and using pliers bending and twisting it 'till it breaks - it never breaks on the weld. I have restored wings (fenders) which were made using this technique seventy years ago and no problems have been caused by it. For most of us time is important and the time to dress this weld out is little compared to any other method I have tried. Below is another photo of the same car, you can see the HAZ is very even and there is very little distortion. If you follow my instructions on the DVD getting the panels to fit perfectly is simple. By the way that 'A' body looks very sound! I have restored (read that rodded) worse. I have answered the question you asked me on metalmeet about the superleggera frame for this BMW. David
Here is a link to the post David is talking about on Metal Meet: http://www.metalmeet.com/forum/showthread.php?p=160902&posted=1#post160902 I'll give it a try this week David. Just have to clean the shop, finish some doors, and do a brake job first.......
The Jalopy Journal
