Made a couple patch panels now. They all fit really well. I'm trying the cut and butt method. Each time the patches end up real low. I'm tacking in basically a star pattern, using air to cool the weld after each spot. Really Taking my time to fit it all flush and not get heat, yet after I grind the weld down its low every time. Anyone have an idea on why it's not staying flush? I'm at a loss at this point. Trying everything I can not to use filler. 47 dodge steel, 20 gauge patches. Thanks
Pics added below. You can see where the welds are it dropped, but the middle stayed true. I literally blew off every tack. I could touch the weld and paned with bare hands the whole time with warmth, buy not hot
Don't cool the welds! let them cool on their own. Patience! When you heat the metal by welding, it shrinks as it cools. When you blow on it it shrinks more. After every tack, bump it back up from behind if you can. Also keep your gaps as tight as possible.
What you need is a teacher, but you could settle for a instructor. You Tube has plenty of those. I'm not going to offer much because quite frankly, I'm sure it won't matter. Really, if you can tack you can weld it, so the question is, is it really possible to weld that much and not get shrinkage or distortion? Sure, just few will obtain it. That said, if you want help, spill the beans as to equipment, wire, shielding gas, your experience and knowledge, do an actual weld, show us you gun tip assembly. While its mostly true that 100% of welding troubles can be traced back to the guy/gal welding, every now and again it is the scalpel not the surgeon.
Try fitting the whole patch to the hole, not cutting as you go. Buy a sharp scratch awl and a left snip and right snip. With practice you can make the patch fit exact, and won’t need to add so much heat to the panel as when you were filling a gap.
75/25 Lincoln 140 HD. I'll get the specs for ya when im out in the shop again tomorrow. Experience (as you probably figure already) is very limited. No formal training. I'll watch Fitzee and Carl fisher on the tube, then go in the shop and try it. I'm 100% sure it's lack of experience, not the machine.
Patience and practice, and absolutely don't cool the welds, in body repair language, that is known as shrinking. @RMR&C is spot on with his advice, and don't expect perfection without a ton of experience, and don't give up either.
Will do. I'll cut this one out and try that way. The cut and butt seemed to make the most sense to me, but the gaps are rugged
Will do. Not trying to argue, just understand. Why does alot of the good builders on the tube suggest to use air? Example - Carl fisher
I don't know Carl, but he may have a ton of experience, and knows how to cool to get what he is after. The metal will shrink on its own without cooling, that is why it needs to be stretched with a hammer and dolly, preferably while hot.
David Gardener has a DVD or two, that have some good instruction. He used to be on here, but darned if I can remember his username.
Because it's faster. I used to do that too, but it makes the weld really hard, and hard to work. You need to get good weld penetration and minimize shrinkage. Practice practice.
I think I'll invest in the 3 day class at Lazze's this spring, unless anyone knows of a class in Washington or Oregon that's worth it? None I can find, anyway
Make a panel Fit the panel Scribe the panel edges Cut along the scribe lines. I like to use aviation shears to cut butt weld areas. I hate cutoff wheels unless it’s a rough cut. Tack weld. No forced cooling. Hammer and dolly the weld area to relieve stress.
https://www.jalopyjournal.com/forum/threads/finally-starting-on-the-wife’s-56.1135206/ Here’s some cheap tool patch panel making
Carl Fisher is a very talented metal worker but he also does a lot of hammer and dolly work on his welds to strech them some.
Helps if you have someone on the backside ready with the dolly. It's one of those things that really won't wait on you to get yourself situated just right.
It doesn't matter what welder you use (MIG, TIG, gas). It won't help to force cool it with air, or water, or anything else (dry ice????) The only thing that matters is that welds shrink the metal. The only solution, is to stretch the weld seam, with hammer 'on' dolly work. It is an art, and not easy to master. Takes lots of practice, and also a good eye for what's going on while you are welding, and then stretching. MIG makes a pretty hard weld (and force cooling makes it harder). You can still H & D the weld, but you need to grind the weld proud first, and hit a bit harder. It is also a bit more prone to crack when doing so. TIG and gas make softer welds, easier to stretch and planish. That's why the real metal pros use them, not MIG
Someone posted a video, damned if I can recall the guy who made the video, but he makes his patches larger than needed, not by much, but the cuts the patch and the area with a cutoff wheel at a 45 degree angle, clamps it and spots it in as he goes. I’m a bit fuzzy on the details, but looked really good when done. Also, as mentioned what you’re doing with the air is the same folks do when shrinking metal, heat and cool quickly.
Your weld will shrink the same amount if you cool it fast of slow , heat always shrinks metal ! “Always “
Personally I like to feel the panel and the shrinkage/warping before I hammer on it. I haven’t really found any benefits to hammering the hot weld. So after I tack, let cool, tap into place, weld about half, grind the weld, tap and stretch if required, then weld the rest. Let it cool naturally, then grind the rest. Then you can feel all of it and tap into place and stretch any areas that need it. Sometimes you will be really surprised what area needs stretching or leveling. And, if I can only get it to within a 1/16 inch from level, that is great for me. I’m not going to over work the steel or risk making oilcans to get so close to perfection when we all know it will need some surface leveling anyway.
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