Resistance Soldering Questions

[Straightliner59]

I picked up a Wassco resistance soldering power unit for $25. I am putting together the rest of the system. I am curious as to whether anyone else has put a system together. More specifically, I am interested in handpieces and probes, and, if anyone has fabricated them. I'd like to see what you did to construct them. I think I have enough info to build either, but, I am interested in ideas, and other approaches. Thanks!

[Ace-Garageguy]

I'd like to see too...

[Straightliner59]

Right now, I'm thinking that, for the probe (I'll do that, first, and fabricate the tweezers, later, since the probe and a clamp, for the other "side" should be pretty easy), I'll use an old soldering iron. I'll replace the tip with a length of welding rod and replace the two-lead power cord with a single-conductor cable that I can attach to the power unit, opposite the ground clamp. That should get things rolling!

[Flat32]

Seems the probes are carbon, so solder doesn't stick I assume.  Check out Micro-Mark link.

https://www.micromark.com/Resistance-Soldering-Unit?gclid=Cj0KCQjw5J_mBRDVARIsAGqGLZDMeBonlQuHT6LN-wAIeQgItui89czMPXh4W-xCWJXlIjSIDp5WyOMaAjMDEALw_wcB

 

[aurfalien]

1 hour ago, Flat32 said:

Seems the probes are carbon, so solder doesn't stick I assume.  Check out Micro-Mark link.

https://www.micromark.com/Resistance-Soldering-Unit?gclid=Cj0KCQjw5J_mBRDVARIsAGqGLZDMeBonlQuHT6LN-wAIeQgItui89czMPXh4W-xCWJXlIjSIDp5WyOMaAjMDEALw_wcB

 

Now that is awesome.

Funny I was just soldering some LED stair lights and constantly tinning my stupid soldering iron with a damp sponge.  Man I hate that thing.  The solder sucks, it sucks etc... it's from Michaels.

It sure would be cool to make roll bars, roll cages and car frames using this.

[peteski]

Resistance soldering has its place, but it is not really geared for soldering electronic components. Stick with your wet sponge and standard iron.    And you are doing well if you keep your tip tinned.   But you also get what you paid for.  The iron is probably not temperature controlled and has simple copper tip, and it is running way too hot.  You can get a nicer, temperature-controlled soldering station with a pencil irons and a wide selection of iron-clad long lasting tips for less than $80.  Keep the temperature under 700 deg. F and the tip will not get gunked-up very much. But you still need to use some sort of tip cleaner (like wet sponge), and keep the tip tinned.   It should really become a reflex action you don't even realize that you are doing.

[Straightliner59]

9 hours ago, Flat32 said:

Seems the probes are carbon, so solder doesn't stick I assume.  Check out Micro-Mark link.

https://www.micromark.com/Resistance-Soldering-Unit?gclid=Cj0KCQjw5J_mBRDVARIsAGqGLZDMeBonlQuHT6LN-wAIeQgItui89czMPXh4W-xCWJXlIjSIDp5WyOMaAjMDEALw_wcB

 

Thanks, Ray. I kept eyeing Micro Mark's RSU, and even tried to order it, once. They didn't have one in stock, and were supposed to email me, when they resupplied. They never did. One of the hand built systems I read about, the guy used stainless steel welding rod for the contacts. I reckon that would be for the same reason. My investment is fairly minimal, anyway! I can take a little time to build the tweezers, and the probe should be a piece of cake. I've already ordered a foot switch and a ground cable/clamp. I am looking forward to trying it.

[Straightliner59]

5 hours ago, peteski said:

Resistance soldering has its place, but it is not really geared for soldering electronic components. Stick with your wet sponge and standard iron.    And you are doing well if you keep your tip tinned.   But you also get what you paid for.  The iron is probably not temperature controlled and has simple copper tip, and it is running way too hot.  You can get a nicer, temperature-controlled soldering station with a pencil irons and a wide selection of iron-clad long lasting tips for less than $80.  Keep the temperature under 700 deg. F and the tip will not get gunked-up very much. But you still need to use some sort of tip cleaner (like wet sponge), and keep the tip tinned.   It should really become a reflex action you don't even realize that you are doing.

I've been soldering stuff, for years! I am interested in using it for 1/25 scale dragster chassis construction, especially in places where joints are close together. That's why I'm doing it inexpensively--It's an experiment. You know--mad science meets modeling!

[peteski]

43 minutes ago, Straightliner59 said:

I've been soldering stuff, for years! I am interested in using it for 1/25 scale dragster chassis construction, especially in places where joints are close together. That's why I'm doing it inexpensively--It's an experiment. You know--mad science meets modeling!

That's ok by me.   I was replying to Brian's post - should have quoted it. 

I think for what you want to do, resistance soldering is a good fit.

[aurfalien]

5 hours ago, peteski said:

That's ok by me.   I was replying to Brian's post - should have quoted it. 

I think for what you want to do, resistance soldering is a good fit.

Thank you peteski.

My iron is adjustable and pictured below.  I'm not crazy about the tips and have never used flux.  I think that if I've some better tips and use flux, I may in fact like my soldering iron?

It's 25 watts and can heat up to 950°F

 

 

Edited May 1, 2019 by aurfalien

[Flat32]

14 hours ago, Straightliner59 said:

You know--mad science meets modeling!

Uh, it's more like science meets mad modeler.  Carbon may work better because it has lower resistance than the brass you're soldering while the welding rod has higher resistance.  Then again who knows without trying.  Another thing to consider is the flux just might want to cause solder to stick to the stainless welding rod somewhat.

[peteski]

11 hours ago, aurfalien said:

Thank you peteski.

My iron is adjustable and pictured below.  I'm not crazy about the tips and have never used flux.  I think that if I've some better tips and use flux, I may in fact like my soldering iron?

It's 25 watts and can heat up to 950°F

 

 

25W is a good wattage for general use.  Not sure if you can actually dial up the tip temperature and keep it constant, or if the knob is just like a dimmer switch that simply reduces the power going to the heating element.  I rarely set mine over 700 deg. F, and I use 60/40 solder most of the time.  These tips have strange coloring. Usually the would be silver color.  It is probably just for looks and they are copper under thin layer of brass or gold plating.  Unless the literature states that these are iron-clad tips (for long life).

Flux is absolutely vital for good solder joints. Even with rosin core flux, it is good to use extra flux.  For electrical work I recommend electronic paste flux (non-caustic).  My favorite is Radio Shack Rosin Paste Flux  .

For non-electric soldering (like brass or even steel items) you can use more aggressive acidic fluxes like Tix Flux, or even flux used for soldering copper pipes.  Those usually contain Zinc Chloride or even Hydrochloric Acid.  Make sure to clean the joints well after soldering to remove all the caustic flux remains.

I had been a computer tech for years and had to rework thousands of circuit boards, so soldering is a second nature to me.  Not surprisingly I also own a professional rework station.  Keeping the tip cleand and tinned is very important, and like I said - if you do it for a while, it shoudl become a reflex action. 

[Straightliner59]

59 minutes ago, Flat32 said:

Uh, it's more like science meets mad modeler.  Carbon may work better because it has lower resistance than the brass you're soldering while the welding rod has higher resistance.  Then again who knows without trying.  Another thing to consider is the flux just might want to cause solder to stick to the stainless welding rod somewhat.

Good points, Ray. I found these tweezers on Ebay. Got them for $36, shipping included! Micro Mark wants $159, for something comparable. I got a foot switch for $15, and the power unit for $39, shipping included. I can use my Dremel speed control for greater adjustability, as, several of the sites I've been reading suggest that. Once this stuff arrives, I should be good to go! When I build the probe, I will use copper-clad carbon "gouging" rods, as recommended due to cost-effectiveness, for the contact/tip. The "mad science meets modeling" was  a play on the old Oakley  drag racing campaign, "Mad science meets nitromethane".

Edited May 2, 2019 by Straightliner59

[Straightliner59]

Here is what I have, so far. It works well, and it's pretty quick to heat a joint. I acquired the power unit, the tweezers and the foot switch, in separate transactions, for about $90. I used some 3/8" brass rod, to taper the plugs 2 degrees. The larger ends were then bored to create a solder cup, in each, for the cords. I will repeat that process, when I build the single electrode/probe, and the ground cord and clamp. I'll be replacing the electrical tape with heat shrink, as soon as I pick some up, in the right size.

I found this site to have the most comprehensive, user-friendly, information, in regards to building your own system. They're the guidelines I'll use,  building the aforementioned probe:

https://technitoys.com/diy-resistance-soldering-outfit/

Edited May 17, 2019 by Straightliner59

[Pete J.]

When you get a chance dig up Gerald Wingrove's The complete car modeler.  He shows how he built his own resistance soldering unit.  I've been doing this for many years now and have always used a tweezer.  It allows you to better control where the heat is applied as it will always be between the two electrodes.  It also allows you to grip two pieces together such as photoetched. 

The best units(and yes they are quite expensive) are made by American Beauty.  They have several differant types of probes that are relatively cheap to buy.  I use a copper coated steel, but they also have stainless and carbon tips.

  You may want to wander through their website as they make a range of soldering equipment for industrial use.

https://americanbeautytools.com/Resistance-Tweezer-Systems 

I have their 100 watt unit and if I were to do it again I would buy the 250 watt unit. 

I've been doing some very low melting point soldering lately(woods and rose metal) to solder white metal.  I bought a 220 volt soldering iron from them.  I use it with 110 volts to get the temp down were I need it.  This was their recommendation.  Good people. 

Edited May 17, 2019 by Pete J.

[Codi]

I have to echo Pete's comments. I've used the American Beauty 250 watt model for 5+ years now.  It allows me to do a lot of different work and has a finesse that I couldn't (others can) master with a standard soldering iron.  As you gain experience with it you'll wonder how you ever did it any other way.  Not a cheap unit as you described though.  I've learned to file tips down and shape them for a given job.  Even bent the electrode ends in varying degrees to get at hard to reach places.  I use Tix solder and flux whether resistance or flame soldering and the absolute BEST BOOK on the subject of soldering (IMO) is "Model Building with Brass" by Kenneth Foran even though they don't discuss resistance soldering per se.   Have fun experimenting!! 

[Straightliner59]

Thanks, Tim and Pete. I have both Wingrove books and Foran's book, so, I am good, there. I agree with you, both, that I may want to upgrade to a unit with more wattage, later. I first wanted to get my feet wet, and, for that, this cobbled-together system will definitely work. I'll check out AB's site for probes. Thanks for your input!

[Harpo]

A Weller soldering gun in either size (100/140 watt or 200/260 watt) works great for resistance soldering too, just cut the end off and bend the tips to cover the area:

 

[Straightliner59]

4 minutes ago, Harpo said:

A Weller soldering gun in either size (100/140 watt or 200/260 watt) works great for resistance soldering too, just cut the end off and bend the tips to cover the area:

 

 

Good idea! Makes perfect sense.