# Resistance soldering: solder w/ flux or pure solder w/ flux added to work?



## videobruce (Jun 15, 2011)

Background first, questions later:

For those who are not familiar with resistance soldering, it is a lot like 'arc welding' where a current is passed between two electrodes with resulting heat generated in a very small area at a fast rate so as not to heat the surrounding areas. Voltage is only around 6 volts, but current is very high.
Either using a 'tweezers' type of hand held unit or a ground clip and a 'probe' type of hand unit. Depending on what is being soldered would determine the type of hand unit. For our application a 'tweezers' type of hand unit should be ideal. 

You can make one of these yourselves (if you are so inclined since the power unit is nothing but a transformer);
http://www.google.com/url?sa=t&rct=...srTWBw&usg=AFQjCNEC9d3xCIHbYBaBTOpIJGoDpc7GNQ

Or purchase one from these two manufactures (both US made); American Beauty and P-L-B.
http://www.p-b-l.com/

This site is basically a 'ad' for AB, but is helpful;
http://resistancesoldering.com/site/

This is about the cheapest source for the AB 100 watt basic model;
http://www.all-spec.com/products/10501.html?utm_source=amazonshopping&utm_medium=feed

Of course it's hard to justify the cost to solder a few 'power feeders' unless you are lucky to find a unit used as I did. 
I was going to go with the smaller 100 watt unit, but I was concerned that it would limit the usefulness down the road for other applications. The 100 watt is fine for just N scale and fine work, but I now find using their 250 watt step up version I'm running the adjustable 'pot' at half current, which means it would have to be at full if it was a 100 watt station. I talked with someone from AB's tech support and he admitted many buy the 100w version only to find it wasn't enough. (this wasn't a sales pitch either)

Now the question. Since the 'key' is unrestricted conduction between the two tips, anything the hinders this causes a problem. No electrical path, no heat. 
The problem is flux buildup on the tips of the 'tweezer' unit using flux core solder requiring constant cleaning of the tips. 
Would it be better to use pure solder and apply flux to the work first?


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## tooter (Feb 26, 2010)

Thanks for the info Bruce... 

I had no idea resistance soldering even existed. They even make resistance solderers big enough to solder copper plumbing, and one that gets copper hot enough to actually *braze* joints! 

Flux core solder would likely work best as the resistance tips might come in contact with the flux only when the solder was applied.


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## gunrunnerjohn (Nov 10, 2010)

I think I'll stick to my 140W gun, over $300 for this thing is way out of line! If I need to sweat copper pipe, I have a nice propane turbo-torch that works great. 

Oh, and your home-made page link is bad.


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## videobruce (Jun 15, 2011)

Resistance soldering has been around for decades. 

I paid just over $200 for a $475 (new) unit. Yes, it is expensive, but I felt it was worth it.

Do they still make "solder guns"?? 

(Link fixed.)


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## gunrunnerjohn (Nov 10, 2010)

Not only do they still make soldering guns, they work just fine for the tasks I need them for.


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## gunrunnerjohn (Nov 10, 2010)

The home-made one makes more sense, especially to try it. Most folks have a battery charger somewhere they can test out the operation with.


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## videobruce (Jun 15, 2011)

Next you are going to tell me they still make vacuum tubes. 

BTW, there is a older RS model on eBay as I type at $32 current bid.


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## gunrunnerjohn (Nov 10, 2010)

If you've done any buying on eBay, you know the "current bid" means nothing, most of the bidding is in the last five minutes or less. 



> Next you are going to tell me they still make vacuum tubes


Well, yes they do. Here's a list of Vacuum Tube Manufacturers around the world, and I'm sure it's not a complete list.


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## videobruce (Jun 15, 2011)

I know they do John, I was just being facetious (did I spell that right?). Thought I didn't know any were really still mad ehere anymore other than perhaps broadcast xmitter tubes.

Where I worked, they still had equipment that was installed in 1956 that used tubes and the lead tech had to resort to Russian made replacements since none were made here anymore. I also well aware audio purists love tube amplifiers.

I'm just surprised someone of your level of detail would resort to a 'solder gun'. I never liked using those especially since I got spoiled buy using a Weller temperature controlled solder station. It's nice to have a tip that doesn't go from 900 degrees at idle to below 500 when in constant use like those cheap solder pencils do that operate full bore when plugged in.

The station I have is this (actually I have two, the 2nd was picked up in miny condition used when they sold for less than $100);
http://www.amazon.com/WTCPT-Tempera...wer-hand-tools&ie=UTF8&qid=1333795148&sr=1-16

But for the best bang for the buck (and good reviews) this might be worth a look;
http://www.amazon.com/X-TRONIC-MODE...ower-hand-tools&ie=UTF8&qid=1333795148&sr=1-9


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## videobruce (Jun 15, 2011)

I could of suggested this;
http://www.amazon.com/Industrial-Ca...wer-hand-tools&ie=UTF8&qid=1333795279&sr=1-48

or even this;
http://www.amazon.com/Weller-WR2000...wer-hand-tools&ie=UTF8&qid=1333795279&sr=1-37


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## gunrunnerjohn (Nov 10, 2010)

videobruce said:


> I'm just surprised someone of your level of detail would resort to a 'solder gun'. I never liked using those especially since I got spoiled buy using a Weller temperature controlled solder station. It's nice to have a tip that doesn't go from 900 degrees at idle to below 500 when in constant use like those cheap solder pencils do that operate full bore when plugged in.


I have a temperature controlled Weller soldering station, I use the gun for large and crude jobs. 95% of my soldering is using the soldering station.


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## Big Ed (Jun 16, 2009)

WOW! $1200 bucks for this one! 



http://www.amazon.com/Weller-WR2000...wer-hand-tools&ie=UTF8&qid=1333795279&sr=1-37
*

Weller WR2000X Digital Rework Station w/DXV80 Desoldering Pencil*


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## gunrunnerjohn (Nov 10, 2010)

Yep, those are just a bit _*Over the Top*_ and totally unnecessary for anything that anyone here is likely to do.


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## gofisher2 (Jul 19, 2012)

I own a resistance solder (worked in the electronics industry) and a good soldering iron. Both have their purpose and excel in different areas. I mostly use the resistance solder for soldering track and electronic connections where excessive heat is an issue. It solders incredibly fast. Nothing is more aggravating than melting plastic ties with a gun when soldering track (power feeds). With some practice anyone can make either one work and work well in 90% of the things you will solder. I picked up my American Beauty up for $50 and it came with an extra micro solder tip. There is no easy solution to keeping the tips clean other than emery paper. I just goes with the territory. When the tips wear out, buy another set.


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## gunrunnerjohn (Nov 10, 2010)

The iron plated tips last basically forever. I've had the same one on my soldering station for several years, it still looks great and works perfectly.


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## gofisher2 (Jul 19, 2012)

gunrunnerjohn said:


> The iron plated tips last basically forever. I've had the same one on my soldering station for several years, it still looks great and works perfectly.


Your right Gunrunner, I should have said "if". For hobby use, they should last forever.


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## gunrunnerjohn (Nov 10, 2010)

My iron has been used a ton, and I get good life out of the tips. I actually got my soldering station when the company I was working at upgraded all of them to later models. When they used them, they replaced the tips about once a month after 8 hours/day continuous use. I probably use the iron 4-5 hours a week at least working on stuff, so I figure I have a lot of life in the tip. I keep a couple around anyway, and I also keep several sizes.


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