Friday 21 February 2014

First time soldering photo-etch

I already mentioned in an earlier post that I was very impressed by the latest workshop at the local IPMS meeting : soldering photo-etch parts. So much, in fact, that I ordered the necessary tools and materials to try it myself. My current project (the German panzerjägerwagen, i.e. tank on a railroadcar) has a complete assembly around the turret consisting of many photo-etch parts and I wasn't eager to start glueing them all together.

When do you apply this technique?
When you need to assemble multiple brass parts together.

  1. Because I don't like fiddling with CA glue
  2. Because a soldered bond is many times stronger than a CA glue bond
  3. The bond is reversible by applying heat again

I'm not gonna try this on some actual part of a kit, until I get the hang of it, but I have some left-over photo-etch fret from an earlier model to experiment with.

The first try
On my first attempt, last monday, I didn't have anything to stabilize the parts while soldering. You need at least 3 hands (preferably 4) to hold both parts, the soldering iron and the tin wire. I could easily attach 2 pieces together, but they would occasionally move when touched with the iron.

A second try
I bought a so-called "third hand", which is usually a stand with 2 alligator clips and an optional magnifier.

The proces is extremely simple :

  • attach both pieces in an alligator clip (one each), maneuver them against each other and free your hands to hold other things.
  • apply some flux at the join (a liquid that cleans the metal and makes the bond easier and better)
  • place a smal strip of the tin wire
  • place your soldering iron against the bottom (!) of the pieces to be joined, alternating every few seconds from one piece to the other
The flux will start the sizzle first, then the wire will suddenly liquify and run against the length of the join through capillary action. Withdraw the iron and you're done.

The resulting bond is instantly as strong as it's gonna get, which is VERY strong. I pressed down on the resulting piece and the surrounding metal is more prone to bending, then to breaking the bond.

I continued attaching several more oddly-shaped bits and was very happy with how quickly it all went. I will need to learn to use only exactly enough wire to make the bond. Any excess will need to be cleaned up with a file or something.

I will experiment more later and report my findings.

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