View Full Version : DIY RSU resistance soldering

Boyan Silyavski
21-03-2014, 10:26 PM
Hi there,

recently have been visiting a model making club so it got into my head to build a resistant soldering unit.

Here are some instructions how to do it and some info :

DIY Cold Heat soldering iron (http://www.instructables.com/id/DIY-Cold-Heat-soldering-iron/)


Resistance Soldering (http://www.raymondwalley.com/misc/tools/rsu.html)

Basically what it does is heat a graphite stick, while shorting a 5-12v 3-10A transformer. It does not matter if its AC or DC. It works both ways.
So what i did was source an old not working car charger from a boot sale. Usually apart from the fuse the only thing that can burn there is the rectifier. I payed 5 eur and it happened such was the case. I liked the unit as it had graduated steps of power and also 6 -12 v switch.

After throwing the rectifier to the garbage , the fuse if on the 6-12v side should be isolated, cause later will blow and heat!

I decided to make 2 handles which hold 3mm and 1/4 inch graphite. Just for the sake of experiment and as discovered later can serve different purpose.
Threaded bar goes through the handle and screws on aluminium heat sink. At the other side of the heat sink goes the graphite. The heat sinks i fashioned seem to work very well with the purpose of not heating so much the threaded shaft. In the future will make a base plate with some fixtures and tweeters if needed



21-03-2014, 10:51 PM
Thought you had gone to Mars !
We used to use this technique to restore burnt out battery terminals. You use a short piece of welding cable with a battery terminal on one end and a welding rod holder on the other end, using a gouging rod with the copper coating removed you basically short out the battery by feeding the rod into a mould around the burnt out terminal and dropping bits of solder into it. This builds up a new terminal, sometimes you might screw a self tapper into the middle of the burnt out terminal to give it some support.
I'm talking about batteries like this 11894