markw Posted October 10, 2022 Share Posted October 10, 2022 Does anybody have an idea of what is required to legally seam weld (or braze) a road car's chassis? I have an old 70's car I have stripped down to a shell. I would love to seam weld structural seams to stiffen it up without requiring a roll cage. However, I hear that you now have to be a certified to weld structures. Can anybody advise? Ta Quote Link to comment Share on other sites More sharing options...
cubastreet Posted October 11, 2022 Share Posted October 11, 2022 Maybe ask the person doing the lvvta cert, which you'll need if you're changing the structure. 2 Quote Link to comment Share on other sites More sharing options...
Nominal Posted October 11, 2022 Share Posted October 11, 2022 You don't need to be a certified welder for that sort of thing. Quote Link to comment Share on other sites More sharing options...
Early jap nuter Posted October 12, 2022 Share Posted October 12, 2022 I’ve done it before and wouldn’t recommend.Seem welding on a road car doesn’t really make stuff all difference without a cage. Just ads more weight and makes it a real bitch to fix if you bend anything major. 1 Quote Link to comment Share on other sites More sharing options...
Muncie Posted October 12, 2022 Share Posted October 12, 2022 You'd be better off getting spot welder and blasting a stack load more into your seams at least then if you stack it you can drill them out easily. If its a unibody car? If its something like a Toyota crown or an impala with a separate chassis its pointless. You could get creative and urethane strengthening panels in no bolts no welds. 1 Quote Link to comment Share on other sites More sharing options...
sr2 Posted October 16, 2022 Share Posted October 16, 2022 From an engineer’s point of view I’d argue that seam welding a monocoque shell unnecessarily strengthens small areas of a structure that is designed to flex when under load. The result adds both stress raisers and excessive localised flexing increasing the chance of structural failure. Short answer is sorry no, don’t seam weld. 3 Quote Link to comment Share on other sites More sharing options...
sr2 Posted October 16, 2022 Share Posted October 16, 2022 On 12/10/2022 at 18:18, Early jap nuter said: I’ve done it before and wouldn’t recommend.Seem welding on a road car doesn’t really make stuff all difference without a cage. Just ads more weight and makes it a real bitch to fix if you bend anything major. +1 re adding a cage. Just a reminder that if you do so you're trading crush zones for structural integrity, 6 point harnesses are a must! 1 Quote Link to comment Share on other sites More sharing options...
markw Posted October 19, 2022 Author Share Posted October 19, 2022 I don't believe that the areas were designed to flex (the flex is likely due to the cost effectiveness of spot welding). However, the flex would have been present during testing. You are correct that the stress would be transferred elsewhere, and strengthening the shell likely pushes the car into untested, unknown territory. The same risk would exist with the installation The value of seam welding cars of a similar category to mine is supported by its continued use by premium restomod companies like Retropower, who state that seam welding of window and door apertures greatly improves rigidty of the cars they do, and Alfaholics. Granted, these shops likely understand the additional strengthening required to mitigate any shift in stress. Quote Link to comment Share on other sites More sharing options...
sr2 Posted October 19, 2022 Share Posted October 19, 2022 23 minutes ago, markw said: I don't believe that the areas were designed to flex (the flex is likely due to the cost effectiveness of spot welding). However, the flex would have been present during testing. You are correct that the stress would be transferred elsewhere, and strengthening the shell likely pushes the car into untested, unknown territory. The same risk would exist with the installation The value of seam welding cars of a similar category to mine is supported by its continued use by premium restomod companies like Retropower, who state that seam welding of window and door apertures greatly improves rigidty of the cars they do, and Alfaholics. Granted, these shops likely understand the additional strengthening required to mitigate any shift in stress. Bit confused with your comment. All steel structures flex, they don't have to be "designed to flex"? (Enjoying the discussion by the way). Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.