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  • HO RacePro
    started a topic Ed's Excellent Soldering Thread

    Ed's Excellent Soldering Thread

    Soldering is a very basic skill. Fortunately it is easy to learn. You need:
    - Metal parts that CAN be soldered, primarily copper, carbon steel and brass
    - A means to clean same -- a chemical 'flux'
    - A suitable solder -- usually electronic grade
    - A way to hold the parts together -- fixturing
    - HEAT -- from a soldering iron, gun, or a small torch

    I ignore all advice concerning rosin fluxes. I only use acid fluxes -- either liquid or paste. You can count on them to clean and activate the metal surfaces. Rosin fluxes, in my highly qualified opinion, are frustrating and useless.

    Acid fluxes are not all that acid. They do boil, smoke and spray droplets during the soldering process. You want to protect your eyes from the spray. Breathing the smoke isn't recommended. And it may be wise to clean any excess flux off your finished part. But as industrial chemicals go acid soldering flux isn't going to eat your face off. Not for a while.

    I also 'tin' the end of my soldering iron or gun -- I often need to start by filing the tip to bare metal to remove any grunge, then I'll dip the hot tip in acid paste flux, and then apply solder to coat the hot tip of the tool. Once tinned, I will often dip the hot tip of my soldering tool in acid paste flux to clean it again. When the tip gets grungy I'll file it clean and start over.

    I will apply a bit of solder to the tip of my soldering tool to help conduct heat to the metal I am soldering. Just so a drop of solder clings to the tip of the soldering tool, so it can form a bridge to the 'work' when the tip of the tool touches it. For light soldering jobs that little bit of solder may be enough to make the joint.

    Often it helps to 'tin' both parts you want to join. This is especially helpful when wiring or making fine, precision joints. Apply flux and solder to each of the parts independently, so their surfaces get a bright solder coating. Then when you go to join the parts it will be easy to get the added solder to 'wet' the tinned parts and form a joint. On some small assemblies the solder on the two tinned parts will be enough to form the joint. Just a quick touch with the soldering tool will be all that is needed to form the joint. This is especially useful when soldering metal parts -- such as brush tubes -- that are in contact with plastic. If you keep the heat quick and local you can often avoid damage to the plastic.

    Applying enough heat to the metal to be joined is critical. That, and adequate flux. If the joint is properly heated and fluxed the solder will flow into the joint. If that isn't happening, the metal is not properly cleaned or heated.

    Small parts, especially wiring, should be heated with a low wattage (25 to 35 watts) soldering iron. Larger parts may require a soldering gun (100 to 200 watts) or a small propane torch. I will jump up to a torch for some chassis soldering. It will do the job quickly when other tools won't.

    The operative word there is 'quickly'. Don't use any more heat than needed to get the solder to flow. Also be aware you can SET FIRE to things if you aren't careful! BE CAREFUL! Really, be careful!

    Good fixturing is a terrific help. Sometimes it takes ingenuity to figure out how to hold the parts in place, but that is worthy effort. Good fixturing can make a precision soldering job easy. Especially if you are going to make more than one such joint.

    Am I an expert on soldering? I am NOT! There are real, bona fide soldering experts in the world. I'm just telling you what has worked for me. It should help you get off to a decent start and help you develop your own skills.

    Ed Bianchi

  • HO RacePro
    replied
    Love your stuff EM!

    You can win a race. And then there are Concours d'Elegance. Dammit, there should also be a competition for artistry in fabrication! Take that body off! Let's see what's underneath!

    Ed Bianchi

    Leave a comment:


  • Wet Coast Racer
    replied
    Keep them pictures coming, EM - your workmanship is an inspiration.

    This sure is an excellent thread.

    Leave a comment:


  • Ecurie Martini
    replied
    I use high temp silver solder occasionally when I need a strong joint in a small area like attaching stub axles to a dropped front axle body
    gallery_99_579_13040.jpg


    Again, the resistance soldering rig can generate enough heat to do this

    Leave a comment:


  • HO RacePro
    replied
    My soldering experience led me to brazing, a very similar technique except performed at a higher temperature, and with stronger "solders" -- metals such as brass and silver. It is typically used to join steel parts.

    A brazed joint has strength similar to a welded joint, but does not involve any melting of the parts being joined. It does take much higher temperatures -- typically in the range of 1000 degrees Fahrenheit (540 degrees Celsius). Hot enough that brass melts and those steel parts will glow red or even yellow. A propane torch won't get you those temperatures. I have used MAPP gas -- propane's big brother -- for the small jobs I've done. Professionals use oxy-acetylene.

    Nobody should ever need brazing to assemble slotcars. I have used it in repairing motorcycle accessories, with great success.

    Brazing is not as widely known as soldering and welding, but it is a truly valuable technique with its own advantages and disadvantages. And you know what? I taught myself brazing too. No genius required. Some intelligence and real respect for how hot the work gets. Play safe.

    Ed Bianchi

    Leave a comment:


  • Ecurie Martini
    replied
    Very much on the mark. Part of the problem is that eBay has changed - much more focus on being a marketplace for new stuff - like the American Beauty soldering rigs. They are the biggest dog in the game and, levering name recognition, they command absurd prices. A resistance soldering rig is basically a large multi-tap transformer. Mine cost me about the equivalent of a nice RTR slot car. (The internet is full of DIY resistance soldering threads)

    My main purpose was to emphasize the idea that, one way or another, adequate heat is key.

    I actually had the good fortune to have a bit of "training" My father and I were very much into HO model railroading. In those days everything was in kit form and often involved the assembly of heavy casting. We had a family friend who was a dental technician and soldering was his life's work. I've never gotten to his level but he gave me a good start.

    EM

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  • HO RacePro
    replied
    EM, you are making me jealous (or is it envious?) with your resistance soldering setup, and masterful work.

    What I want to emphasize is that soldering is a skill with an easy entrance ramp. You can achieve success early with basic jobs and advance, if you choose, by small steps and at your own pace.

    I learned how to do basic soldering when I was a teenager, mostly self-taught, but with an intro from my older brother who used it for his electronics hobby. Over a lifetime I have developed some more advanced skills, but nothing I'd brag about. My heat application, fixturing and solder application is better these days, but I still don't consider myself anything more than an amateur.

    If I wanted to advance further I'd probably invest in a resistance soldering rig. I've looked at them. They're a pricey investment, though EM may have gotten a great deal on one off of eBay. To date I've been able to do my soldering jobs without one.

    Admire gorgeous work like in that photo by EM, above. But don't let it intimidate you. There are a ton of useful soldering jobs you can do with a basic understanding of the techniques and inexpensive tools. All it takes is a willingness to try, and practice.

    Ed Bianchi

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  • Ecurie Martini
    replied
    OK, let's take it up a notch and reinforce the issue of adequate heat. One of my most frequently used soldering tools is a resistance soldering system that I found on eBay:
    gallery_99_685_6222.jpg

    It works by passing a current through the joint and heating it directly, rather like a spot welder. The unit that I have can generate more than a kilowatt. In use, you attach a ground clamp to the work and then touch a carbon electrode to the joint, turning the system on and off with a foot switch.
    gallery_99_685_1514.jpg

    The electrode will not stick to the solder so you can hold it in place after the power is turned off and the joint cools. It's very good for heavy work like soldering 0.050" steel to 0.0625" brass:
    gallery_99_685_106080.jpg

    and, conversely, it is also ideal for fiddly jobs like soldering suspension detail. The power is adjustable in many steps depending on tap connections (1-2, 1-3, 2-3) and a rotary switch. With the proper adjustment, the joint is heated so quickly that there is no time for the heat to travel to an adjacent completed joint and undo it.

    EM
    Attached Files

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  • model murdering
    replied
    The number one fail point for soldering with an iron is a simple, but somewhat inter-related, set of problems; that revolve around heat transfer, or more specifically, the lack of it. Inadequate heat wont transfer period; nor will adequate heat, if you dont have proper contact between all the players. The iron is not a magic wand that you wave and flutter somewhere near the vicinity of the intended work, with the expectation that flow will magically occur. Ya gotta stick it to the work and hold it there until the work smokes and heat waves. YOU are required to pay attention and watch, and only feed solder when the work will readily accept solder.

    The critical component of this failure loop is your set up. Beyond light electrical work, even small mechanical work must be securely clamped, key-holed, or abutted in order for heat to transfer. Without adequate mechanical support during the heating process, the iron cannot be held steady; and therefore the heat will not migrate through the intended joint.

    The second, and equally intertwined fail point, is not having the patience to do the aforementioned. Curiously it cannot be taught. It is a self-learned skill. It is not the iron or the solder's fault.

    Heat, steady, and patience. Repeat.

    You will improve.





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  • NicoRosberg.
    replied
    I'm only responding to Wheelszk's assumption he is the only guy who cannot solder. He isn't.

    I'm not sure any fabrication skill is 'easy' to acquire if you just don't happen to be handy that way. Some people aren't.

    In some hobbies that would be a major drawback. In this one it isn't.

    The help you offer is extensive, and welcome.

    Leave a comment:


  • HO RacePro
    replied
    Deane, you are on the record as not having a use for soldering.

    For anybody who does see value in learning to solder, it is one of the easier fabrication skills to acquire. I'm here to help those folks.

    Ed Bianchi

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  • NicoRosberg.
    replied
    Originally posted by wheelszk View Post
    I think I am the only person left that can not solder to save my soul.....
    I suspect there are many of us out there. At least in our hobby it need not be a major deal

    Leave a comment:


  • HO RacePro
    replied
    If you are having problems soldering there is a rather short list of things you might be doing wrong:

    - The metals you are trying to solder aren't suitable. Copper, brass, and steel solder easily. Other metals may require special solders, fluxes or tools.

    - The material isn't clean or the flux isn't strong enough. Use a wire brush if needed to expose bright, clean metal. Then use an appropriate flux. I use acid flux exclusively. Lots of people don't recommend acid flux. Your call. Regardless, with any flux, always wear eye protection and avoid breathing the fumes.

    - The soldering tool you are using isn't right. Usually the problem is not enough power. For light electrical-type soldering you can get by with 25 to 35 watts. For light structural soldering 100 to 200 watts should work. Heavy structural soldering usually requires a propane torch.

    - Your soldering tool tip is dirty. If the tip is cruddy, remove said crud with a file until you see bright metal. Then apply flux and solder to the tip and "tin" it. Your soldering tool tip should always have a bright "tinned" surface. In the middle of a job I will often dip the hot solder tip into my can of paste acid flux to get it bright again.

    - You have poor heat transfer. Even if your soldering tool tip is bright, sometimes the heat just doesn't want to transfer to the work. A small drop of molten solder on the end of your soldering tool tip will often help bridge the gap and make for good heat transfer.

    - The solder is not appropriate. Most solders will work on copper, brass and steel. Beyond that you may need a special solder.

    - Your fixturing is no good. You need to have a way to hold the parts in place while you apply solder and heat. Time and effort spent on proper fixturing is well spent.

    If you still can't solder, what can I say? You are cursed. Make an offering to the Soldering Gods. They like jelly donuts.

    Ed Bianchi

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  • wheelszk
    replied
    I think I am the only person left that can not solder to save my soul.....

    Leave a comment:


  • Al's slotracing
    replied
    Originally posted by HO RacePro View Post
    ...... the pins, being stainless steel, are also flame-proof. Better yet, ordinary solder won't stick to them. ..............
    The ceramic plate is a great tip, I've got one on order

    Pins that ordinary solder won't stick to is good, it's important they are made of the right grade of stainless steel



    Many grades of stainless steel can easily be soldered using ordinary solder and the flux used for ordinary (not stainless) steels. Indeed many modern chassis are made of stainless steel and are soldered with ordinary solder.

    Leave a comment:

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