Subject: Re: Buiilding a resistance solder machine

From: [email-masked] (Wes Barris)
Date: Thu, 15 Dec 1994 17:02:10 GMT

In article <[email-masked]>, [email-masked] (Jon R. Stroud) writes:
|> > I have heard that it is possible to build a resistance soldering rig 
|> using....
|> 
|> Is it possible to build one using a RV power supply?  i.e. Something that 
|> converts 110V AC to ~ 12 V DC with 20 amp output?

The following information is from the model railroading FAQ:

Subject: FAQ TECHNIQUES 1, 11/21: Soldering, resistance

SOLDERING, RESISTANCE
Any recommendations for a resistance soldering unit?

	Go to your local friendly electronics supply house and buy a
	transformer with 110v primary, 6.2v (? or there about) secondary and a
	4 to 6 amp output on the secondary.
	
	Go to your local Radio Shack and get an insulated box big enough to
	hold the transformer.
	
	Wire a 110v plug to the primary of the transformer. (Do I need to
	remind you to use a grounding plug and take care not to electrocute
	yourself???)
	
	Run the secondary to two wires, one with something like an alligator
	clip, and the other to a clamp making a good connection to a carbon
	rod.
	
	Where do you get a carbon rod? one might ask. Go somewhere where you
	can wash some chemicals away, and cut up an old flashlight battery or
	two. I have had good luck with both C cells and AA cells.  The center
	contains a carbon rod. Make a point on the rod with some sandpaper, or
	a pencil sharpener, or something, and clamp the second wire from the
	transformer's secondary to it. Radio Shack will have conenctors that
	will do the job.
	
	Now, when you plug in the transformer to the wall, and you connect the
	alligator clip to something metal connected to what you want to
	solder, and touch the sharp tip of the carbon rod to where you want to
	solder, the metal right around the tip of the carbon rod gets REALLY
	hot. Sounds kind of like one of those $250 dollar units to me.  If you
	really make it fancy, you might spend $25 or $30 building the thing.
	
	How to make it fancy??
	
	First, I like to put a control on the 110v side of the transformer.  A
	normal light dimmer works well, although I have also had good luck
	with a sewing-machine foot control. These do not really have the
	current rating, but are ok for light duty work. I like having both
	hands to set up the work (the rod holds stuff in place) and then Zap
	with the foot.
	
	Second, I use large stereo-type plugs to connect to the secondary side
	with the clips and rods. This lets me have several different rod-size
	and clip configurations that are easy to switch.
	
	Third, Fancy handles for the carbon rods...
	
	Fourth, whatever else comes to mind. For the price, and ease of
	construction, you can afford to experiment.
===============================================================================
Wes Barris                                                   PH: (612) 626-8090
Minnesota Supercomputer Center, Inc.                         Email: [email-masked]