At that size (3/32"), does it need to be a tube? A solid rod would be much easier to bend, not having to worry about tube flattening, kinking, or collapsing. Of course, at that size, perhaps solid plastic fishing line that fit closely inside the tube would be sufficient to keep the tube from collapsing. You could even try using an aluminum rod that fit inside the tube closely, though it might be more difficult to remove successfully. If there is no reason for the material to be hollow, I would strongly consider using a solid rod of the same diameter since it would be much easier to fabricate the rings with.
As far as a “go to” solution, I am not aware of any for that size of tube or wire/rod. However, if you have various kitchen pots and pans, you might measure them to see if any fits the sizes you are looking for. Perhaps a very large can or small bucket could be used. Even if the sizes are slightly under the diameters desired, you could wrap tape around them to bring up to the proper diameter(s). Don’t overlook even flimsier round objects because they can be filled with Quickcrete to make them hard and strong enough to act as a forming mandrel.
Of course, if you have a router or a Dremel, you could rig up a compass attachment to cut a perfect circle to your exact specs out of plywood.
Regarding the small butane torch, I suppose it depends on just HOW small it is. Propane burns hotter than butane, and MAPP gas burns hotter than propane. Given the small diameter of the tube or wire, it just might be possible to braze it though barely, and it might take a long time, which would be OK if the tank is big enough. However, butane might do well for soldering. And I suspect soldering might be sufficient. The best joint for soldering a tube in your case is to insert a short, matching curved piece of wire of a similar material into each end of the tube. Perhaps 1/2" or so is enough. This can be a little tricky to do, but still possible. If, instead, you are using solid wire/rod, the best solder joint would be a scarf joint, i.e., each end of the wire are cut at a matching slant, and the slanted faces are mated up and the wire clamped to hold their positions. Make sure to allow for the scarf by cutting the wire longer. With the ends overlapped, the slanting cut can be made across both ends simultaneously. The idea here is to increase the surface area the solder will flow into, thus insuring a strong connection. I wouldn’t go steeper than a 45º angle, and 30º would be better (pointier ended scarfs).
Mark
Thanks for the info!
I think I have the bending technique understood. I just need to find circles that size to bend the tube over. As for brazing, I may be using the term out of context.
The tubes are 3/32" diameter. So very small. Most of what I find when googling is industrial grade for higher end applications. Is there a "go to" solution for tubes of this diameter?
I have a small butane torch from Harbor Freight, I was hoping to use to braze or solder the ends of the tube together to make a circle.
thanks again,
-Eric
