I made a soldering jig (fixture, actually) with clothespins to hold a wire and small part, similar to a helping hands but with an aligned orientation. The easiest way to build one is to epoxy the clothespins in place on a wooden board, but I wanted to be able to set up a variable distance. So, I made a brass plate with tapped holes at various locations.
By placing holes towards the back and towards the front, this allows parts to be held in midair or to rest on the metal base.
The underside of the base has a bar screwed onto it (see below), so the entire fixture can be held firmly in a vise. The bar can be removed if the base needs to lay flat on a desk or bench.
Bottom of base to be held by vise
I took a little extra time to countersink the screws to ensure the screw heads would not interfere with the vise lead screw or any other method of holding the base.
Countersinking vise mount bar screws
I chose brass because it is nonflammable, is easy to machine, and I had it in stock. Aluminum might be a better choice, because solder has a difficult time sticking to it. However, aluminum is relatively soft and the threads will wear out faster from repeated fastener insertion and removal.
Drilling holes in brass base plate
I usually drill and tap more holes than I expect to use. However, sometimes I overdo it.
So many holes to tap
After tapping, the burrs and other protrusions can be removed by sanding the brass surface. This also removes discoloration from the brass stock (not that it matters because this is going to get gunked up with solder splatter).
A great technique for sanding a flat surface is to place sandpaper on a flat glass cutting board. The brass plate is then slid around on the sandpaper. By using large grit paper followed by finer and finer grit, you can quickly get an attractive and smooth base.
Sanding brass face on glass cutting board
I’ve already used the wire-holding fixture to successfully rejoin tiny LED strands connected with magnet wire. A fixed setup (as opposed to adjustable) also increases efficiency if you have a bunch of parts or wires that need to be soldered in the same manner.