jkelly Posted December 3, 2015 Share Posted December 3, 2015 (edited) Hey guys, I've been posting my build in "Member's Projects", but wanted to get some advice from you guys on my welding and panel/frame rail replacement. The passenger side front frame rail under the battery box was rusted, as well as the firewall. I've cut out most of the rust and have fabricated several panels and welded the firewall panels in. The frame rail section is 16ga and everything else is 20ga. I'm also replacing a portion of the curved frame rail that is spot welded to the firewall, and will be fabricating it myself. Also replacing the passenger side floor pan, but I'm going to weld in the front frame rail first to ensure more stiffness before removing the floor pan. I know this is a critical section of the car as far as overall rigidity goes, so do you guys have any suggestions, concerns, comments, critiques? The last thing I want to do is spend a lot of time doing it wrong now just to create more work later and possibly a hazard to myself or others. I'm using a Hobart Handler 140 with 75/25 Argon/CO2 shielding gas and 0.023" wire. The car is supported by a custom stand bolted to the transmission mount and by jack stands in the back. Engine and front suspension are out. I braced the engine bay like so. Test fit only. Frame rail patches are 16ga. Inner fender section is 20ga. Firewall patches in 20 ga. I've been using the "pulse welding" technique; moving around the panel placing a single spot weld until I've filled the gap completely. Also using copper backing plates because I'm a noob. Edited December 3, 2015 by jkelly Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted December 3, 2015 Share Posted December 3, 2015 That looks like decent work. Are you planning on adding bracing or just repairing stock? I'd also wait for John C for some input since he knows some things about welding these cars up. Quote Link to comment Share on other sites More sharing options...
jkelly Posted December 3, 2015 Author Share Posted December 3, 2015 Thanks. I hadn't planned on any major bracing, other than replacing the forward frame rails I showed with 16ga, the under floor pan rails with 16ga as well as extending them to the rear of the car and possibly fabricating subframe connectors. I'm not opposed to adding more bracing if you guys think it's necessary. Planning to drop in my rebuilt NA L28. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 3, 2015 Share Posted December 3, 2015 You're doing fine. I suggest you get the surface rust off your replacement panels before welding them into the car. Quote Link to comment Share on other sites More sharing options...
jkelly Posted December 3, 2015 Author Share Posted December 3, 2015 Thanks, John. I'll be sure to start cleaning those up before welding in. Thanks again. Quote Link to comment Share on other sites More sharing options...
LSB_11 Posted December 10, 2015 Share Posted December 10, 2015 Looks great, the stock "raills" don't seem to do much at all. I removed the section you are talking about and the floor where the rail runs with Jack stand under the car and it didn't move a bit. I installed "subframe connectors" or rails that I just made up. They made a world of difference in the longitudinal rigidity. You look like you are doing a great job, Quote Link to comment Share on other sites More sharing options...
4.8240z Posted December 16, 2015 Share Posted December 16, 2015 Looks like you are doing some great quality work. I am in the same process now I just finished up my battery area patch panel tonight and will take on the frame rail repair next. It might not be a bad idea to coat the inside of your frame rails with por 15 or weld through primer while you have access through your patch holes. Quote Link to comment Share on other sites More sharing options...
jkelly Posted December 16, 2015 Author Share Posted December 16, 2015 (edited) Thanks for the compliments, guys! I do plan to fab some 16ga rails to go under the floor pans. Floor pans should be coming in today. 4.8240z, I just finished reading your thread and I'm going through the same thing with trying to coat the inside. I sprayed POR15 using a 3M wand down the frame rails and masked off where I was going to weld. Then went back and sprayed Upol #2 weld through primer in those spots. I also used some 3M cavity wax on top of the paint, but not in the weld area. Will probably drill a small hole through the footbox area into the frame rail cavity to finish it up with cavity wax, and then plug it with a rubber grommet or something. That was my idea anyway. Can't seem to find rubber grommets for 20ga panel thickness. Edited December 16, 2015 by jkelly Quote Link to comment Share on other sites More sharing options...
1969honda Posted December 17, 2015 Share Posted December 17, 2015 Would any of these work? They list a few at .03 and thinner panel thickness. Towards the bottom of the page there are some liquid tight ones. http://www.mcmaster.com/#push-in-panel-plugs/=10a1ck6 Quote Link to comment Share on other sites More sharing options...
jkelly Posted December 17, 2015 Author Share Posted December 17, 2015 Good call! Something like that will definitely work. I had tunnel vision looking for the grommet style, but the push plugs should work great. Thanks! Quote Link to comment Share on other sites More sharing options...
4.8240z Posted December 20, 2015 Share Posted December 20, 2015 Did your 3m wand work well to spray into the frame rails? I thought about using one but was afraid it wouldn't works well since I heard por 15 was a weird consistency. I have yet to work with por 15 so I apologize if this is inaccurate. Quote Link to comment Share on other sites More sharing options...
jkelly Posted December 26, 2015 Author Share Posted December 26, 2015 I'll be honest I was a little disappointed with the 3M wand. I had to thin the POR15 way more than the recommended amount and it still didn't spray evenly. The Cavity wax didn't require any thinning, but the wand still didn't seem to spray it evenly. I had to make several passes and I still don't think I got an even coating. Not sure what wand/gun setup would be better. I was using an Astro 4538 gun around 40 psi. Quote Link to comment Share on other sites More sharing options...
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