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Post Options Post Options   Thanks (0) Thanks(0)   Quote General Eisenhower Quote  Post ReplyReply Direct Link To This Post Posted: 14 Feb. 2021 at 1:21pm
Originally posted by otto otto wrote:



Direct and indirect damage: 


Direct damage= the obvious bent and crumpled part; 

Indirect Damage= the not so obvious damaged part, usually further back from the direct damage without bent and crumpled parts, but still dimensionally out of spec.


I have seen many times on enthusiast forums where folks are attempting to repair a damaged vehicle by simply cutting off the damaged part and replacing it with a new section. I rarely see anyone make any pulls to first correct the damage. If you pull out the direct damage, there is a good chance you will correct a lot of the indirect damage and your parts will fit better.



I'm almost 100 percent sure that my frame still has some damage from my accident, the passenger side front hit a 7 inch tree so hard it cracked the tree in two, but it was enough force to roll. So there is some frame twist lingering. You can see when the wind shield folds down, the passenger side is higher than drivers.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote otto Quote  Post ReplyReply Direct Link To This Post Posted: 21 Feb. 2021 at 1:34am

I was removing the toolbox from my jeep’s tub today and thought I might talk a little bit about dealing with spot welds. Because the toolbox will be reinstalled, I had to carefully drill out the spot welds; I used a ¼” drill bit to cut through the first layer of metal and cut out the weld.  A lot of people use spot weld cutters to cut out the welds holding panels together but I don’t. I’ve never liked them and ruined every one that I’ve bought; usually in an afternoon. The Blair cutters I especially have disdain for- I hate them for a number of reasons: they’re expensive, they cut a huge hole that needs to be welded up, the spring loaded pilot is designed to fail and the teeth will break off the cutter easily. All the shops that I worked in would stock the grinding wheels as materials, but not spot weld cutters- it was like getting a free tool!


If a panel is to be reused, you really don’t have a choice other than cutting the welds out. This doesn’t happen very often because if you’re removing a panel there’s a reason (bent, broken, rusted, etc.) and it will just get tossed in the scrap pile. This is the case with most of my experience and in a body shop no one gives a second thought about the old panel and we need to work quickly. So for removing panels to be discarded, we would deal with the spot welds this way- using a grinding wheel:

I use the stripper wheel tool to uncover the welds.



Put the wheel on end perpendicular to the panel.



Grind the weld until you grind through the first layer of metal; you will see a “ring” around where the weld used to be.



Wiggle the scrap piece a little and it should pop right off.



Using a grinding wheel works fast but throws sparks. These sparks can imbed themselves in glass if not protected. It just takes some masking paper to protect glass from sparks. If you do spark the glass, you can use a razor blade to scrape off the sparks, but you will end up with pits in the glass so be mindful before using this technique.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 21 Feb. 2021 at 4:00am
Thanks!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote otto Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb. 2021 at 1:45am

I forgot to mention this tool earlier, it’s my hole punch tool. It says Made in Denmark on it and uses arm power to punch a 3/16” hole. I find the 3/16” hole too small for making spot welds and usually drill them out to ¼” or maybe 5/16. If you drill from the inside out (or toward you) the side of the panel meeting the body stays smooth and the drill flashing will be on the top side so when you weld it the flashing gets melted into the weld- you learn a few things over the years.



I’m working on some ideas for a metal working discussion but struggling because it’s such a huge topic and every situation is different. If folks have specific questions it may help me put something together. There are many videos on YouTube that feature metal working craftsmen displaying their skills, some are actually good- others are amazing! The ones that work metal on English wheels to make curving, swooping panels from flat sheets blow my mind. I won’t be doing any of that, after all I just used to fix wrecked cars.



hjh
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gerrym Quote  Post ReplyReply Direct Link To This Post Posted: 28 Feb. 2021 at 3:40pm
Very good. Thank you for doing this. I look forward to more. Smile
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Post Options Post Options   Thanks (0) Thanks(0)   Quote otto Quote  Post ReplyReply Direct Link To This Post Posted: 01 Mar. 2021 at 3:06am

Here’s a body shop tip of the day: I like to use these Roloc discs for finish grinding; both 2” and 3”. When the 3” discs get dull, I just trim off some of the outside edge creating some points. I’ll put the trimmed disc on the smaller mandrel and keep grinding. The points really get into the metal without digging a ditch and you’ve extended the life of your abrasives.

This works with larger grinding discs too. Some shops had a cutter that would put a wavy edge on the 9” discs.







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Post Options Post Options   Thanks (0) Thanks(0)   Quote bobevans Quote  Post ReplyReply Direct Link To This Post Posted: 02 Mar. 2021 at 2:18am
Great tip.  I've been trimming my dull discs for years, but had no idea that could have points!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sandusky Quote  Post ReplyReply Direct Link To This Post Posted: 05 Mar. 2021 at 1:55am
I too trim Roloc Discs. I usually crank my right angle air grinder up and hold an old file too the back side of the disc. The cutoff generally leaves at about the Speed Of Sight 😉
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Post Options Post Options   Thanks (0) Thanks(0)   Quote otto Quote  Post ReplyReply Direct Link To This Post Posted: 31 Mar. 2021 at 5:04am

Working metal:


I’m not sure how to offer help on how to work metal over the internet, it’s the kind of thing that’s really helpful to see in person but we’ll give it a shot. I’ll try to share some techniques and try to reinforce that with photos that support the discussion. A lot of people ask about shrinking metal, and sometimes that’s necessary, but I would be willing to bet that a lot of shrinking could be avoided by working the metal better. Most of the issues with working metal arise from having too much of it in one place and/or not enough in another. 


Forgive me if this is too pedestrian but I haven’t gotten much feedback and this can be a huge topic. The photos are exaggerated- and because I don’t have three hands.


On dolly/off dolly:


On- dolly:like it sounds, working the metal between the hammer and dolly; striking with the hammer in line with the dolly so that it makes contact with an audible “ting”.  Remember, everytime you smite the metal with the hammer on-dolly, you are making the metal thinner in that spot and creating more of it. 

Another on-dolly technique is to hold the dolly lightly against the panel so that when you hit the panel, the dolly will bounce from the impact. This is good for getting metal to move without trying to iron out wrinkles, like bringing down high spots.




Off- dolly: striking metal with the dolly offset to  where the hammer is landing. A lot of off- dolly work involves putting a lot of pressure on the dolly (like bringing up a low area) and striking the metal with the hammer on the high areas where you are trying to “move” metal on the panel. This can involve a lot of arm pressure or using a bar or piece of wood or lumber on the low spots to bring it up while you work the high spots or maybe get the metal to “stay”. 




Using a slapping file can be substituted for a hammer in any of these instances if you prefer, it will allow you to spread the blow out over a larger area and may help flatten out wrinkles or wadded up metal with less stretching. 


You can also use the dolly as a hammer too, just by grabbing the dolly and striking the panel. Sometimes this will work in a space where a hammer won’t reach and you need the mass of the dolly to move metal. 


I have a lot of metal work to do on my project so when I get to that stage, we’ll have a lot of material to work with. But for now I’m doing panel replacement and will straighten stuff out later.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote nofender Quote  Post ReplyReply Direct Link To This Post Posted: 31 Mar. 2021 at 10:49am
Just catching up on this. Excellent info. keep it coming! 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote otto Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr. 2021 at 4:42am

Since my project is in the panel replacement stage, maybe a few thoughts on that topic. I mentioned my methods of spot weld removal, so that’s covered. So how I do things may be a little different than others- and that’s OK, I learned how to do this work under a flat-rate pay scheme so I am always looking at how to do stuff the quickest or at a minimum involving the least amount of work. I haven’t done production collision work for over twenty years, but I can’t seem to shake that mentality. You can take the boy out of the country…


For panel replacement, I’ll generally weigh splicing vs. total replacement. Total replacement usually involves cutting spot welds and sometimes some surgical work, splicing means replacing a section or partial replacement and involves some cutting and welding, controlling warpage, working metal, etc.

 

Total replacement is cut and dried; cut out the welds and replace the entire panel. Splicing takes into consideration a number of things: where the splice will take place, will the splice be seen from the inside?, layers of metal, etc. A lot of the splices I’ve had to do on my jeep project will be seen from the inside so they’ll have to look good and rely on a solidly done butt weld. I had to direct my splice around the holes in the cowl gusset because it would be very difficult to finish grind the weld inside the hole.




So for splicing, I’ve learned over the years- much like patching drywall, making my patch first and then making the body fit the patch works much better than the other way around. Create your patch, then trace the edges that you’ll section in, and cut along those lines. It doesn’t even have to be a straight line because it will match the edges of the patch.




You can also overlap the patch and the panel on the body and cut through both, but that will consume a lot of cutting discs or blades plus takes longer. I would do this when replacing ¼ panels up through window openings because it was a smaller splice to make. Painters don’t like it when you make splices up high because then they have to blend into the roof.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote otto Quote  Post ReplyReply Direct Link To This Post Posted: 21 Apr. 2021 at 5:00am
There are all types of clamps you can use to hold your patch in place while welding it in. Clecos, Vise Grips, drill point screws, those little clamps with the wing nuts, etc. Or, a lot of the time I just hold it in place where it fits well and start tacking, making sure the two pieces are perfectly flush. I’ll continue to fit and tack until there is a tack weld every inch to inch and a quarter.





Then I generally pulse weld between the tacks, bouncing around not welding contiguous sections until the section is welded completely. Leaving a tiny gap between your patch and the panel seems to aid in getting a better weld with more penetration rather than butting them tightly.


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Post Options Post Options   Thanks (0) Thanks(0)   Quote otto Quote  Post ReplyReply Direct Link To This Post Posted: 28 Apr. 2021 at 5:49am

To add to the previous installment on panel replacement, I wanted to elaborate on the welding aspect of it. I’m using a MIG welder for this project; it’s a tool that I’ve had a long time and have gotten used to how it performs, but the results could be better. There are two tools that I wish I had before starting rebuilding my tub: a sheet metal brake and a TIG welder.


A MIG welder will join metal and allow work to progress pretty quickly, but it leaves a thick, blobby weld that must be ground down. I hate grinding- it’s noisey, messy, time consuming, requires costly abrasives (especially on the weekends when I run out of them), and is a lung hazard. A TIG welder, if used properly, leaves a small, flat bead with good penetration that only needs a light pass with a grinder to dress the weld. You can get a small, flat bead by using an oxy/acetylene torch, but the excessive heat creates a lot of warpage (see my hood hole repair in the Parts Jeep thread). 


But, I don’t have one so it’s run what you brung. I put the heat setting on my MIG welder a bit hotter than normal and pulse weld short, intense beads (kinda like a series of tacks) for about an inch to an inch and a half. Looks like this:



And on the back side:




I’ve tried a hammer welding technique while MIG welding a short bead where you use a hammer and dolly on a weld while it’s still red hot to flatten it out and draw the metal back out where it should be. It didn’t really do anything. Hammer welding works well with oxy/acetylene or TIG welding. 


MIG welds need to be ground down to the same thickness of the metal being welded before it is easily worked. If you don’t grind down the weld, the thicker weld metal will be more difficult to work than the surrounding steel and make your life harder than it needs to be. Try to grind just the weld and not the metal right next to it as that will make a thin spot next to a thick one. I use a grinding wheel to grind welds almost completely flat and then finish with a 24 or 36 grit disc. I don’t recommend using flap wheels to grind welds as they seem to follow the surface and just polish the metal. 


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Post Options Post Options   Thanks (0) Thanks(0)   Quote uncamoney Quote  Post ReplyReply Direct Link To This Post Posted: 28 Apr. 2021 at 9:37am
Fine tune your machine. I did all of the body work on my3B using 0.25 wire in my MIG. I had a friend that asked me if I wanted a job welding. An afternoon  a week is a hobby, every day is a job.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ggordon49 Quote  Post ReplyReply Direct Link To This Post Posted: 28 Apr. 2021 at 3:38pm
I really enjoy reading this thread, just wanted to say thanks! Thumbs Up
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Post Options Post Options   Thanks (0) Thanks(0)   Quote otto Quote  Post ReplyReply Direct Link To This Post Posted: 02 May 2021 at 6:02pm

Dear readers, 


You’re probably wondering why I keep rambling on and on about welding and grinding body panels. Well, mostly because this happens:




I don’t know what happens to metal molecules when introduced to heat, but they don’t like it. The welded area usually draws together and will “sink” causing a low spot and warpage. To make things right again, the welded area will need to be worked back up on- dolly style so that the warpage is reversed, the metal thinned and stretched back out. 


Since all the splices done on my jeep’s tub will be seen on the inside, I want them to look good so I’m going to have to work the metal back into shape. And to do that, the metal needs to be a uniform thickness so it will react like one piece of sheet steel- hence proper grinding. We’ve properly welded the metal together so that it will withstand hammer and dolly work and can be brought back to its original configuration. Jeeps have thick sheet metal and it’s generally fairly easy to work; the thin metal on newer cars- not so much.

Also if the thick, blobby weld ends up being a high spot later when you are trying to finish your filler, it won’t be as easy to just pick it down as the virgin metal.




Edited by otto - 04 May 2021 at 8:10pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote drhodes Quote  Post ReplyReply Direct Link To This Post Posted: 07 May 2021 at 6:52pm
Definitely interested 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote otto Quote  Post ReplyReply Direct Link To This Post Posted: 20 June 2021 at 6:28pm

Long overdue update:


After being welded, the metal is affected by the heat and has warped somewhat. The warpage can be minimized a bit by going slow and spacing out the welds a bit, but it’s still going to happen. I’ve drawn some contour lines on this panel to show what’s going on here. If you are familiar with reading topo maps you’ll see the highs and lows in the metal. Along where the two pieces were joined by welding, the metal dives down and is low. Another low spot here is along the fuel filler pocket hole. I don’t know the story why it’s low here but to put the new pocket in, the panel will have to be a near metal finish without filler because I can’t straighten the panel with filler and then weld the fuel pocket back in. Or if that doesn’t work out, I suppose some panel bonding adhesive might work here.




I’m going to try something new here and I hope it will work.




I’ve always been curious about these things and thought it might be interesting to give it a shot. The claims seem too good to be true but I’ve watched YouTube videos of the discs being used so it must be true! Never did I see any bodymen use one of these in any shop I worked in, or knew anyone who would admit owning one, but what the hell, I’m open minded.





Edited by otto - 20 June 2021 at 6:29pm
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