I have a Radius 46 that has a broken "locking tab" or whatever you call the tab that keep the two parts of the box closed. I intend to copy the tab from my Optimus 8, from the remains that is left on the Radius 46 and pictures here on the forum they seem identical. I think I will try to use a 10mm strip of 0.5mm thick spring steel to form a new tab. But how do I fix it to the box? It seems to be spot welded from the factory. Does anyone have an idea how I can spot weld this tab at home? I have a mig welder, but I don't think thats an option. I also have a smal spot welder for making battery packs, but the strips used for the packs are thinner, and from soft nickel steel. I'd love to hear any ideas, or experience, of performing this kind of spot welding. Kind regards Tron
Hi @Tron here is a link to an old thread showing an alternative fix of a closure clip on an Optimus No. 111 case: Optimus 111T rebuild. Best Regards, Kerophile.
Yes, thank you. I hope the photos can explain better: This is the stove The broken tab. The little rustspot is where the spotweld is. I will remove all the paint before I attempt any repairs. Another angle The Optimus 8R tab that I will copy. Kind regards Tron
For auto body repair with a mig, the closest you get to a spot weld is a plug weld - where you punch a hole in one piece and clamp the two pieces together and fill the hole with weld. Not sure whether the stove tin would be a heavy enough gauge of steel to attempt that without blowing holes in it. That may be more a reflection of my welding rather than your gauge of steel! Rivet or nut and bolt, maybe? Or adhesive?
Hello, I would strip paint, clean the joint and just soft solder the new part in place… then respray… otherwise a rivet is the fastest way. Nicola
Thanks for all advice. I am considering brazing it, maybe combined with a small, hammered rivet. On the other hand, this stove will be repainted and never be "original" again, so it would probably wear a small pop rivet with pride as well! MIG welding would burn through, at least with my skills and equipment. Still I feel that spot welding, given the right combination of volts/amps should be possible. Kind regards Tron
@Tron, the trick is to use a block of copper on the backside of the weld. The sheet metal is kept cool by the block to prevent burn through. Murph
Unfortunately if you want to spot weld then you probably want to have a spot welder. I assume you don't want to shell out the cash to make a single spot weld, but I do know that harbor freight sells them. I've used a harbor freight spot welder before and it worked pretty well for what I was using it for.
@Tron your case looks already repainted, sure about that, that’s why I suggested to strip the paint and solder, the case is already not original… brazing would be more strong than necessary imho. Originally the part was spot welded probably because it was the fastest and cheapest thing to do on a production chain… Nicola
I agree with Murph - I'd plug- weld it with MIG. Disclosure : I've just spent the past year and a half teaching myself automotive panel rust repair and patch fabrication to sort out an old Type 3 VW, so I'm pretty match-fit with thin-sheet welding. My welder is optimised for it, with 0.6 solid wire. Use gas - fluxcore is not an option. The very lowest voltage you've got, about a 5mm plug hole, about half a second on the trigger and a nice fat lump of copper or brass heat-sinking the steel from behind should make it doable. Every machine is different, though, so practise on some scrap first to fine-tune your settings/duration. Best of luck...
@Tron as you have a MIG welder, multiple small plug welds are an option. I would practice, practice and do more practice before you attempt the real repair. There are plenty of car restoration channels on YouTube that will demonstrate how it's done. Regards John
Thanks everyone for encouragement and much good advice. It has made me consider dusting of the old mig welder and buy some fresh wire and gas. I will buy some 0.5mm spring steel strips/sheets and practice a little with the welder. Silbrazing is also an option I will consider. Kind regards Tron
@Tron I'm sure you already know this, but in case it helps- use the smallest diameter wire your machine will take (0.6mm)? As mentioned above a non-ferrous block will make a great heat sink to reduce chances of blowing holes. The advantages of puddle/plug welds compared to brazing is that there is less risk of distortion.
I am revisiting this thread, since making this repair this weekend! Finaly the spring steel I ordered came through the mail, plenty to make many locking tabs I have been very preoccupied with the problem of actually fastening the tab to the Radius 46, and underestimated the skills needed to actually form a locking tab from the spring steel. I cut strips of steel from the sheet I bought, using my grandfathers 70 year old steel sheet scissors Then I tried to just bend the strip in to shape. It broke almost imediately. I'm no metalurgist (or whatever a metal expert is called), I ended up bending parts of a strip cold, and the sharpest angles hot, heating the strip with a propane torch. The "trial and error" approach I had to apply, for lack of skills, made the process rather frustrating and time consuming. But after the atempt nbr I can't remember, I ended up with this part, that actually turned out to both look and work as intended I sanded both the tab I made and the freshly primed Radius 46 case to bare metall and dusted of the old mig welder to plug weld the tab to the case, through the hole in the tab. I did take the advice of putting a brass object (a 10x10mm plug) on the opposite side of the case wall. A few minutes with the Dremel and a grinding wheel, and I was honestly very pleased with the result. With the locking tab in place, I could finally give the Radius 46 a new finish, and complete this project. Before and after pictures, the Radius case "as bought": The finished Radius 46, I did go for "full polish": I love this forum, all the inspiration and advice is priceless. Kind regards Tron
Great work Tron. A little more information, in case you tackle something similar in future. To be able to bend it without it breaking, you would need to anneal it, by heating to red heat and letting it cool slowly. As it is such a thin piece of metal it might cool too quickly in air, a guaranteed way of success would be to put in the embers of a fire as they die out. You then may be able to make the bend cold, or you might need to bend it halfway, anneal again, and make the rest of the bend. Working it hot means you do not need to anneal before bending, but such a thin strip will cool very quickly so it will be difficult to work hot, you need to be very fast as I'm sure you found out! Aside- if you work brass or copper, to anneal these metals you heat them, then cool quickly in water, or let cool in air.
Greaat advice, and I might need it for another project. I anneal a lot of brass cases for reloading centerfire cartridges, I put them in water to stop the annealing process when the neck of the case is done. The rest of the case needs to be hard. Kind regards Tron
