proxlamus© Posted January 16, 2012 Share Posted January 16, 2012 Welp.. after close to 3 years of trying to strip all of the under coating and crap from off my Z so I can seam weld the body panels and reinforcements.. ranging from chemical stripping, to wire wheels, to soda blasting, to nickel slag blasting, to grinders, to dual action sanders and dentist picks and a heat gun.. my car is ready for seam welding the over lapping panels. After welding today.. I learned that no matter how hard you try to get rid of seam sealer.. when welding, the seam sealer from underneath melts and flows into the molten puddle, contaminating my welds. It sucks.. it really really sucks. I talked to a local shop and they recommended getting 1/2" strips of metal to overlap the seam and stitch weld around that to prevent seam sealer from melting into the weld.. sounds like a good idea.. but holy cow I am not looking forward to attempting this. Any advice.. or is it inevitable that seam sealer will ruin my welds. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 16, 2012 Share Posted January 16, 2012 Where are you having trouble? I had most trouble in the rear wheel well area inside the car and I pried up the 3 or 4 layers of steel there and scraped the seam sealer out with a pick. Dirty work, and if I had it to do again I might have just skipped that section. Rockers have a ton of sealer in them too. Everything else was pretty easy as I recall. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted January 16, 2012 Author Share Posted January 16, 2012 Currently.. where I am at.. is behind the frame rails, along the rear sub-frame as it enters the rear wheel wells and the differential mounting area's... I'm having a tough time describing it. That's not a bad idea to pry the panels up and scrape it and hammer it back down. but.. yowza.. that sounds very time consuming. Patience patience patience. Quote Link to comment Share on other sites More sharing options...
RB240zDET Posted January 17, 2012 Share Posted January 17, 2012 Why not try a torch and heat the areas and pre-melt the area and try and get the seam sealer out? If not, then go with what JMortensen suggested as I have done the same technique. It sucks but it works. Quote Link to comment Share on other sites More sharing options...
jt1 Posted January 17, 2012 Share Posted January 17, 2012 The torch works, but then you have another mess to clean up. jt Quote Link to comment Share on other sites More sharing options...
redneck1545 Posted January 17, 2012 Share Posted January 17, 2012 I blasted mine with coal slag and didn't have any problems except for the wheel well archs in the passenger compartment. I scrapped all of the sealer off that I could get to before I blasted though. Quote Link to comment Share on other sites More sharing options...
RB240zDET Posted January 17, 2012 Share Posted January 17, 2012 The torch works, but then you have another mess to clean up. jt That's the point. He wants to remove the seam sealant before he starts welding. As when he welds the sealant is melting out and contaminating the welds. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted January 17, 2012 Author Share Posted January 17, 2012 great idea with the torch rb240zdet Quote Link to comment Share on other sites More sharing options...
RB240zDET Posted January 17, 2012 Share Posted January 17, 2012 great idea with the torch rb240zdet No problem, hope it works well for you. Seam sealant is a pain to deal with. Both removing and applying it. Quote Link to comment Share on other sites More sharing options...
johnc Posted January 17, 2012 Share Posted January 17, 2012 You can actually get a 1" bead down before the seam sealer starts contaminating the weld by: 1. Using 023 wire. 2. Turning up the heat as if you're welding 1/16" thick sheet. 3. Put a spot weld at the start and at the end of the bead. 4. Spot 4 times in between your start and finish spots. 5. Do all the above quickly (under 4 seconds). It takes the seam sealer time to melt, ignite, and smoke. If you can get the short bead down quick enough you can beat that. And move to different areas of the seam to keep from heating up a large area of seam sealer. Quote Link to comment Share on other sites More sharing options...
redneck1545 Posted January 17, 2012 Share Posted January 17, 2012 ^^ i second that. I stitch welded all my seams with about a 1" "tacked" bead every other inch and I never really got any contamination. I did pretty much what john said. Found out what seam I wanted to stitch weld. Added a tack at the beggining of where I wanted to start the stich weld and then another tack at where I wanted to end the stitch. Skip two inches and start the process all over again. When I was done "tacking" I went back with a wire wheel just for a final quick clean-up before I added the stitched bead. I was using .023 wire as well with a higher than normal heat and slightly higher feed speed settings. Quote Link to comment Share on other sites More sharing options...
redneck1545 Posted January 17, 2012 Share Posted January 17, 2012 (edited) Found this site for you. Scroll down and play the flash video. I shows you what you should likely do in this scenario. Although I would do as john suggested and speed up the process. The video shown is the type of "bead" you should use but the welder settings are a little low for what you need to do. I just turned up the heat a bit and added a little more wire and started knockin out beads fairly quick. Just dont forget about the duty cycles on lower end machines. http://www.mig-weldi.../thin-metal.htm Edited January 17, 2012 by redneck1545 Quote Link to comment Share on other sites More sharing options...
RB240zDET Posted January 17, 2012 Share Posted January 17, 2012 Very cool technique. I might just have to try that. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted January 18, 2012 Author Share Posted January 18, 2012 (edited) I used a propane torch today and a 90 degree pick... and had some really good success!! I used a heat gun along the inside of the car by the rear quarter panels. I noticed, rather then a seam sealer on the inside of the chassis, they used some white foamy sealant which was much tougher to remove. So a heat gun and a scraper, once the majority of it was removed, I used the torch and burned off all of the stuff I couldn't get! The pick came in handy. Pretty happy with the progress so far. I tried researching the most effective stitch weld technique and found varying answers. My beads so far are about 2" with a 2" gap or so. Im not using a template or measuring these beads.. rather doing it by eye. I'm considering changing this method. I've only really done the Bad Dog frame rail capping and stitching the existing frame rail flange to the chassis. But a 1" bead followed by a 1" gap seems like a good idea. Edited January 18, 2012 by proxlamus© Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted January 18, 2012 Author Share Posted January 18, 2012 Hey .. neat Quote Link to comment Share on other sites More sharing options...
RB240zDET Posted January 18, 2012 Share Posted January 18, 2012 Glad it worked for you. Post up some pictures of your progress! Quote Link to comment Share on other sites More sharing options...
redneck1545 Posted January 18, 2012 Share Posted January 18, 2012 (edited) I really wouldn't worry about getting all that stuff out with a torch and scrapper. I hit the "teardown itis" bug a long long time ago too but stopped after I blasted the chassis and removed all seemingly appropriate seam sealer. The reasoning behind not wanting to remove ALL the sealer as you are doing now is that your not going to have any way to fill that area back in when your done. There will be exposed metal between the layers of crimped sheet metal that will start to rust over time no matter how much sealer you coat the top of the actual seam with. I would follow johns advice and try a different welding technique to get the desired outcome. I followed the same procedure as outlined above and my welds penetrated the seam without contamination. As far at the 1"-1" bead/gap ratio I would lean more towards the 1"-2" bead/gap ratio due to the cost of welding material and gases and amount of work for a given result. Stitch welding all the seams is alot of work as it is, no need in making it take longer or cost more than it has to. Your not going to get the chassis THAT much stiffer by adding a bead ever other inch. Lay a stich about an 1" long with a 2" gap between the stitches and that will be plenty. Trust me, your going to be systematically stitching every seam you see and when your admiring your work and thinking your done there pops up another seam that needs to be welded. Its a ton of work, adding a bead every other inch is only going to make the job last longer and cost more in the end. Let us know how it turns out! Edited January 18, 2012 by redneck1545 Quote Link to comment Share on other sites More sharing options...
johnc Posted January 18, 2012 Share Posted January 18, 2012 Lay a stich about an 1" long with a 2" gap between the stitches and that will be plenty. Agreed. Quote Link to comment Share on other sites More sharing options...
headmechanic Posted January 26, 2012 Share Posted January 26, 2012 A guy told me he used dry ice and it worked perfectly. Quote Link to comment Share on other sites More sharing options...
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