I’m wondering how strong soldering is. I need to attach some tiny pieces of metal to some larger pieces of metal. But these tiny pieces need to stand up to A LOT of impact. There will be heat, friction and a bunch of kinetic energy.
So how strong is a solder bond?
Would some type of welding be better? Is there a way to weld tiny objects?
Brazing might be more suitable. Brazing is a sort of high-temperature soldering, using brass instead of tin-lead alloy as the filler metal. What are the bits of metal made of, and what sort of stresses do the joints need to withstand?
You ain’t gonna get a sensible answer to your question without telling us what kind of metal you’re joining.
Solder only works properly on a very small number of metals. Brazing works on more, and welding on more still.
And what are you doing anyway? Is there any reason why you can’t use mechanical fixing, like screws, bolts or rivets?
…my girl robot…
The larger bit of metal will be steal. The smaller piece will be similar material - some kind of durable metal. The metals will definitely stand up to the stress. I’m worried about the joint though.
The force applied to the joint itself will be kinda lateral, but a little angular. Imagine the larger piece of metal as the ground. Imagine the smaller piece is a pole sticking up out of the ground. Where the pole meats the ground is the hypothetical weld. Now imagine a car crashing into the pole. However you classify that type of force that’s pushing the poll over, that’s the type of stress on these pieces. I’m not sure exactly how much force it will be. But one main concern is RPM. This thing will have to hold up to this type of stress very, very rapidly. Like 1400 smacks a minute or so.
The size of the pieces? On is about 6 inches long or so and about an inch thick. The other is only about a centimeter or so. It’s tiny, not very thick - like maybe a couple index cards thick.
The little tiny piece is what will be getting smacked around hard. And a lot. And fast.
All of the above are WAY bigger than the piece to be attached.
Keeping with my larger world example, if the weld does not hold, I think I might be able to drill into the ground a bit and place some of the pole under the surface. So the weld wont be absorbing all the shock, just keeping the piece in place.
Heck, rather than attempting a solid connection, it sounds more like you need to join the pieces with a shock-absorbing spring, with the spring bolted firmly to each steel piece.
I’m not sure how RPM is going to figure into this, and now I’m curious.
OK. If it’s steel you can’t solder it. So forget about that.
Your choices are brazing or welding. A decent arc-weld will be as strong as the steel that you’re using. Brazing will be less strong.
Just arc-weld it. It’s not that hard to do.
That’s not entirely true. However, from the sound of things, it wouldn’t be suitable for this application, anyway.
If it’s too small for screws, etc, it’s too small for any conventional arc welder too.
I’m going to suggest aircraft-grade epoxy (heck, they glue fighter jets together), but I have no idea where one procures such an item.
Nah, look at the actual dimensions:
Sounds like he wants to join some reasonably heavy guage steel sheet to something. How would you do that? Put a 90[sup]o[/sup] bend at one end ot the sheet, then drill and screw the bent bit to what Bear_Nenno calls “the ground”.
With the dimensions listed, might it be possible to lay a weld bed on the surface of the larger piece and grind the bead to the required dimension? In other words, make the added piece out of welding rod deposited on the surface. This is done all the time to repair warn metal on cutting edges and the like.
OK, that’s weld bead and worn! Not what I typed.
This is a new part/assembly. Consists of a thin flap like piece sticking up from a larger flat surface 1 cm ~0.40". Right?
Try drilling a hole with a diameter the width of the ‘flap’ and make two semicircular rod pieces to fit in both sides of the hole such that the three pieces fill the hole completely.
A press fit of the assembly would eliminate the need for a welding or brazing operation.
The application of high temperatures for brazing or welding will affect the strength of the assembly which should be avoided.
A high strength silver bearing SOFT solder could be used if necessary on a non-press fit.
What kind of material is smacking this part/assembly at 1400 XPM?
Torque on the solder, weld, or glue will be what kills you. Why not use a ‘pole’ with an end cap, or for that matter, a solid pole? That way you can drill a hole through the sheet steel, and into the pole, thread it, and fasten the thing together with a big old bolt.
Is the small part a flap, or a rod? From your description, I get the impression that you are sticking a rod of circular cross section into the base, correct?
The easiest way to do this with small parts is by interference fitting them. Drill a hole of slightly smaller diameter than the rod in the base part. Heat the base, and cool the rod (liquid nitrogen is best, but if that’s inconvenient you can just bring it to household freezer temperature, and heat the base a bit more). Assemble the two parts, and then let the assembly equalize to room temperature.
Once the parts are assembled, you will want to do something to relieve the stress at the intersection - especially since the assembly will be subjected to cyclic loading (i.e. will be likely to fail in fatigue). Build up a bead of solder, weld or what have you around the base of the part to provide a bit of stress relief.
This is a great idea. And I had pictured actually doing this with the solder. Just laying down a lot of it as a liquid and “sculpiting” it into the right shape. Doing it with the weld is an even better idea. But it’s a pretty small little space. I would need some tiny welding tools. I’ll look into that, though.
Hmmmm. More metal. But with a set ‘breaking’ point. So it will be causing another piece of metal to move.
A flap would imply that it can be allowed to move. The tiny piece is not allowed to move. It must stay planted and eat all the impact. The larger piece is what is moving fast and causing the smaller piece to hit yet another piece repeatedly.
It’s most like a “rod”. But it’s just a tiny little triangle piece. I think a “tooth” or a “BUR” is more descriptive. Actually, yeah, an artificial BUR in the larger piece is pretty much exactly what I’m making.
Thanks everyone. All your posts are helpful. Sorry I can’t be more specific.
In that case, just drill and tap a hole in the appropriate location for the smallest diameter screw you can find (probably a 2-56 or something). Apply a bit of LocTite to the screw threads, and drive the screw tightly and allow the LocTite to set. Then cut off the head to the height you want, and use a Dremel or similar grinder (or even a file) to grind off the threads, and shape the resulting shaft the way you need it.
Neat. That should work, actually. Precision is a must here, so I’ll be at it forever with the dremel. But it will be worth it in the long run.
Provided you don’t think a TIG welder is conventional this is true but otherwise it sounds like the ideal thing for the job. My machine only dials down to about five amps but some of the higher end machines will go down to one amp where a skilled operator can weld soda cans together. Steel is a bit easier but I havn’t really tested the thinnest metal I can work on.