twodoorgaz Posted February 7, 2023 Share Posted February 7, 2023 (edited) I’ve just ordered myself a new spot welder (nice thing, a Tecna 7902P - does 2x2.5mm steel and has a pulse setting). It was ordered primarily for non-LR projects and steel bodywork repair, but I keep coming back to the trick on YouTube of using it for aluminium by sandwiching the panels between two thin pieces of steel. I do have lots of Series bodywork repairs to do (tubs, seatbases, etc) for a couple of rebuilds and have already got an AC/DC tig set but I’m only just learning how to use the kit and expect it to take me years before I’m vaguely OK with ally. Using the spot welder would be infinitely easier and would be more in keeping with factory. so the question is: while I know that using the steel sandwich truck, that I can now spot weld aluminium (and it’s alloys), has anyone used this trick themselves and if so - how does the strength of the weld compare to factory spots? Im debating whether to rely on the tricked spot welds as direct replacements for factory, whether to put them down twice as frequently or even whether to do spots in the factory position and use some panel bond epoxy in the gaps to guarantee at least factory strength. Edited February 7, 2023 by twodoorgaz Quote Link to comment Share on other sites More sharing options...
smallfry Posted February 7, 2023 Share Posted February 7, 2023 Always meant to but never got round to it. Unfortunately where I live now, the electricity supply is not up to it. My spot welder needs a dedicated 32 amp supply from the fuse box. I have wondered if, instead of the sandwich, steel contacts would work. My spot welder works really well on steel, but to make full use of one, you will end up spending a fortune on different arms. Quote Link to comment Share on other sites More sharing options...
twodoorgaz Posted February 7, 2023 Author Share Posted February 7, 2023 Thank you - on the arm front I’m sorted. The chap I’ve bought it from reconditions and upgrades them and also makes arms - he told me how to do it and if you have a lathe, which I do, and make a simple rod bender then you can make them in any shape you need for the price of 12mm copper rod. That was the thing that tipped me over into buying one. 1 Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted February 14, 2023 Share Posted February 14, 2023 What's "the trick"? Quote Link to comment Share on other sites More sharing options...
landroversforever Posted February 14, 2023 Share Posted February 14, 2023 On 2/7/2023 at 8:21 PM, smallfry said: I have wondered if, instead of the sandwich, steel contacts would work. I assume not, as it needs the arms to have as little resistance as possible. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted February 14, 2023 Share Posted February 14, 2023 1 hour ago, FridgeFreezer said: What's "the trick"? Add a thin piece of steel either side of the aluminium and heat the aluminium through that. Quote Link to comment Share on other sites More sharing options...
landroversforever Posted February 14, 2023 Share Posted February 14, 2023 Anyone here actually tried it? I really can't see how it helps as I thought the issue with ali is how quickly it wicks the heat away from the weld area. A bit of steel each side doesn't change that bit? Quote Link to comment Share on other sites More sharing options...
Peaklander Posted February 14, 2023 Share Posted February 14, 2023 I did, on my 88 rebuild. I don't remember having much success but that was the advice given. If I can find pics I will post them. Quote Link to comment Share on other sites More sharing options...
smallfry Posted February 14, 2023 Share Posted February 14, 2023 6 hours ago, landroversforever said: Anyone here actually tried it? I really can't see how it helps as I thought the issue with ali is how quickly it wicks the heat away from the weld area. A bit of steel each side doesn't change that bit? As I understand it, it is actually to increase the resistance, to intensify the heat in the contact area, or as you say, the heat is conducted away, as the ali has little resistance. Spot welding is a resistance welding process, which is why I wondered if steel electrodes would be any good. Quote Link to comment Share on other sites More sharing options...
twodoorgaz Posted February 14, 2023 Author Share Posted February 14, 2023 Quote What’s “the trick”? It’s this: but I’ve never tried it, so don’t know if it’s as strong as a factory weld or if it’s more decorative. 9 hours ago, FridgeFreezer said: 1 Quote Link to comment Share on other sites More sharing options...
landroversforever Posted February 15, 2023 Share Posted February 15, 2023 16 hours ago, smallfry said: Spot welding is a resistance welding process, which is why I wondered if steel electrodes would be any good. It’s a resistance welding process in that that’s what causes the heat. If you’ve got the resistance in the arms I don’t think that will help, just mean less power getting to the actual joint. Given the price difference in steel vs copper I’m sure they’d all come with steel electrodes if it was a benefit. Quote Link to comment Share on other sites More sharing options...
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