Data Sheet. Number: 003 Issue: BASIC SOLDERING TECHNIQUES.

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Prudence Sharon Rodgers
5 years ago
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1 BASIC SOLDERING TECHNIQUES. You will need to practice. Nobody would buy a piano and expect to master the fundamentals immediately. So is it with soldering. The concept is simple. 1. Take two pieces of metal. Position them exactly as you want them to be soldered. Ensure you will still be able to do this, when both pieces are heated. There are various ways of doing this. Hot Tape will bind work together. You may be able to hold them in a vice. In theory you can use a steel base plate and place a magnet on top of the work. In practice however, the steel acts as a heat sink, so making soldering difficult. 2. If soldering delicate electrical components, use a heat sink. Aluminium forceps, sold by hobby shops, are ideal for this purpose. A piece of water soaked tissue will do if nothing else is around. 3. Wet the work with your chosen flux. 4. Touch the area you want soldered with the tip of the iron. Ensure as far as is possible that you heat both pieces of metal evenly, i.e.. so both are at approximately the same temperature. 5. When the flux starts smoking, touch the join between the two metals with a strip of solder. Be sure to touch the metals - not the iron. The solder should flow through the joint. 6. How much solder? Just the minimum that will make a clean joint. Too little and the joint may not form properly. Too much and you will have to spend time scraping the excess away. Think of using ordinary glues. You know instinctively just how much to use. Practice and it will soon be the same with solder. 7. Remove the iron and allow the work to cool - making sure that there is no movement between the pieces of the work. This is important, for the slightest movement will seriously affect the strength of the joint. 8. Replace the iron into its stand. 9. A quick, but not always fail-safe way to test for this is to inspect the joint visually. A good joint will be bright with solder. If it is an electrical connection, testing with an ohmmeter will give a guide to the effectiveness of the joint. 10. Carry out Post Soldering Treatment. If there has been movement, the solder will often appear greyish in colour and exhibit stress ripples. If the joint has moved or is otherwise unsound, it is tempting just to pop the soldering iron bit back on the joint. Re-melt the solder; remove the bit and what usually happens? As you pull the iron away, the solder tends to pull away with it. You have just had a good demonstration of spiking. Now add some flux and try again. This time the solder should stay on the joint. And this is an important lesson: Applying flux is not necessarily a once only act. Solder plus heat plus flux is the recipe for a sound joint. Without the flux, solder will not flow. Practice soldering a couple of pieces of electrical wire. Then move on to some scrap brass. With these, practice soldering two pieces together at right angles. Use varying solders for this and see how different solders produce different fillets at the junction of the two pieces. Now solder two pieces of brass edge to edge, and then solder a small scrap near the soldered joint. Does the first joint start to bubble and become un soldered? Probably, but later in this booklet we will show you how to overcome this. 1

2 Try different combinations of flux and solder. A couple of hours spent doing this will not only give you good practice, but will build up your knowledge base. Think about humming or whistling. You may not be able to read music and probably have no real idea of how we produce the different notes. But we do it and we do it instinctively. This is what you want to achieve with soldering. You look at a piece of work to be soldered and without really thinking about it, you select a suitable iron, bit, solder and flux. This is when soldering becomes ordinary and talk of it being a black art is forgotten. Tinning. Not your soldering iron tip, but the work. The theory goes like this. You tin each piece of the work, fit them together, brush with flux - whereupon it creeps into the joint by capillary action, apply heat and hey presto! You have a perfect joint. In fact, the practice is not far removed from this. In industry, tinning is carried out by dipping the work in Solder Paint. It is then brought together, fluxed and heated. For larger items this still holds good, although the Solder paint can be applied with a brush. For smaller items, especially where you are making up sandwiches of thin materials - Brass or Nickel Silver etches, etc. the easiest and cleanest way, is to wipe the surfaces with the thinnest smear of Solder Cream. This material is slightly adhesive and will hold small items ready for soldering - a typical example being spectacle rings on brass locos. Hold in position, apply heat and you should have perfect joints that require little or no cleaning up. Post-Soldering Treatment. Have we finished? Well, not quite. The fluxes that were so essential to your perfect joint, leave residues that must be removed. If you are using a No Clean Solder, such as Carr s Solder Creams or a resin cored flux and you are soldering electrical components and wires, then no further treatment may be necessary. However, in all other circumstances it will be most unwise to leave matters there. We have seen the importance of cleaning, in the section dealing with Metal Blackening. Also, should you be painting over a soldered joint at a later stage, it is essential that all acidic residues be removed, else your carefully applied layers of paint will begin to bubble and peel. Fortunately the task is not arduous and the most effective way of removing them is also probably the easiest. Simply brush or immerse in Neutralizing Rinse and then wash off with several changes of water. If this is a brass kit, then painting over with Surface Conditioner, followed by rinsing with water and allowing to dry, will not only clean it, but will etch the surface very slightly, which will give you more of a key for paint. De-Soldering. What can be soldered can be de-soldered. You need to equip yourself with some Solder Mop, sometimes also called Solder Wick. This is a braided copper strip, not unlike the car battery earth leads that were popular some years ago. The technique is simple. The end of the wick is placed over the area to be de-soldered and the bit placed on top. Be aware that de-soldering requires more heat than soldering, so you may need to dwell with the iron for longer. Or you can increase the temperature setting if you have an adjustable iron. Copper has a high degree of conductivity, so do not hold the braid with your bare fingers, too near to the iron - a distance of at least six inches is probably about right. After use, cut off the used end of the braid. 2

3 Now solder wicks themselves are subject to the same oxidation that affects brass and nickel silver so, if your braid seems to be ineffective, you can dip it into the same flux you were using to solder the metal in the first place. Some folk do this anyway, as they feel it helps the de-soldering process, but it is not absolutely necessary and may involve more cleaning afterwards. SUGGESTED PRACTICES FOR SOLDERING SPECIFIC METALS. We can almost hear you saying, Well, the above is all very well, but I ve got this metal, which I want to solder to that metal. Which flux and which solder should I use? The serious answer is, it all depends. Not very helpful, but there is a world of difference in say, soldering a brass gear wheel to a steel axle and a brass steam pipe to a steel boiler. For, as we are told in other fields, size is important. The following is intended as a general guide. Please note: 1. Although many modellers mainly use solder creams for nickel silver and brass, the table below lists wire and strip solders as being preferred. This is because solder creams are more expensive and you may prefer to become used to soldering using a cheaper alternative. 2. Many of our other solders will work perfectly in the circumstances listed below. However, to list too many will clearly cause confusion. 3. If your own personal favourites are not listed, but they work for you, then by all means carry on using them. Nickel Silver to Nickel Silver. 145 deg. Nickel Silver to Brass. 145 deg.. Brass to Brass. 145 deg Whitemetal to Whitemetal Red Label. 70 Deg. Whitemetal to Brass Yellow Label Red Label. 7 0 Deg. 3

4 Whitemetal to Nickel Silver Red Label. 70 Deg. Steel to Steel. Green Label. Black Label. 188 deg Solder. 224 deg. 188 Solder paint. Fine Detailing - non ferrous Red Label. Green Label. 145 deg. Fine Detailing - steel Green Label Black Label. 145 Strip Solder. 179 Solder Cream. Tinning Green Label Black Label. 188 Solder Paste. 188 Strip Solder. Aluminium & Mazak Grey Label. - None. 179 Strip Solder. - None. Gap Filling Green label. Black Label 224 Deg. - Material(s) to be soldered: High Temperature Work. Green Label. Black Label. 243 Strip Solder. 224 Strip Solder. Material(s) to be soldered: Electrical Soldering. Orange Label Solder Cream. 179 Solder in Step Solder Kit. 4

5 Material(s) to be soldered: Lead Free Soldering. Green Label. Red Label. 227 Solder in Step Solder Kit. - None. 5

Soldering & De-soldering

Soldering and De-soldering Digital Electronics 04 Soldering & De-soldering This presentation will Review the tools needed to solder and de-solder electronic components. Demonstrate how to tin a soldering