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    First go hunt up that tin of acid flux soldering paste you have lying around the house somewhere. Look good I know you have it! Now take it firmly in hand and walk over to the trash can and drop it in!! Unless you are soldering plumbing, never use acid core solder or soldering paste!! Why, you ask? First the flux leaves acid deposits in the joint, these over time, can destroy the joint. If you used this to solder an electrical wiring joint or worse yet an electronic circuit, you have my sympathy!! The exception to this rule is the use of silver solder, on nonelectrical connections, where extra strength is required.

    Regular solders come in either rosin core solder or solid solder that needs a separate rosin based fluxes. The best (only) place I have found to get a rosin based flux is Radio Shack (below). This comes in a plastic tube and you just squeeze it onto the area you are interested in. It has a petroleum jelly carrier so it sticks to the spot (and you) once applied. Between the petroleum jelly and the rosin this can make a sticky mess so be careful. I have found that turpentine will clean it from your hands nicely.

    There are three main types of soldering done in our hobby: Light wire and circuit board soldering, heavy wire soldering, and soldering brass (fittings, sheets, and tubing). I recommend that you invest in at least a 25 watt electrical soldering iron (pencil) and a heavier soldering gun of 100 watts or so. I would strongly recommend you also buy a propane torch kit. If you are really flushed with cash, a portable butane powered soldering iron is ideal for field electrical repairs.

    The 25 watt iron is used for the light electrical and circuit soldering as well as soldering small brass assemblies. The soldering gun is used for soldering the heavier electrical wires in the power leads for the batteries and motors, as well as the larger brass assemblies. While the gun can be used for the larger brass assemblies the propane torch is a better choice. You can position the assemblies and heat them without worrying about moving them with the tip of the gun. Of course if you are heavy handed with the solder you defeat this advantage. Also the torch will more quickly and evenly heat the assembly. One advantage that the gun does have is that it is safer than the torch if you are working close to the ship itself, for instance during the repair of an installed stuffing tube. There is nothing like the smell of burning ship to ruin your day.

    A few other items you need are: Q-Tips (aids in applying flux), a damp (not sopping) kitchen sponge on a plate, sandpaper, a sopping wet sponge or small towel, a brick or two (used as fireproof support pads), and some clothespins or other disposable clamp/holders. You also need some sort of cleaning solution to clean the residual manufacturing oil film off the brass pieces. The best I have found is zero residue electrical parts cleaner in a spraycan. This cleaner has fairly benign fumes, is safe on most plastics, and evaporates rapidly off the parts. Do not use Tuner Cleaner, this leaves a lubricant film on the pieces. I have found the electrical cleaner at some auto parts stores. A usable substitute is zero residue brake cleaner. The brake cleaner, however, does not evaporate off the parts as well and generally has to be wiped off to speed the process. Also it may attack plastics and has a high fume content, use it only outdoors.

Now on to actual soldering.

    Rule number one is use the right solder. All electrical soldering should be done with electrical solder. This is available at any electrical supply store or Radio Shack. Get the rosin core variety. For most of the brass assemblies we build this solder is also fine. For more strength in a joint use silver solder, in either the medium or high strength types.

    Rule number two is that the materials being soldered should be hot enough to melt the solder! Do not use contact between the solder and the heating device to melt the solder. This can leave glob of solder on the surface that has not actually bonded to the materials. Heat the material and keep touching the solder briefly to the material, until it starts to melt, then keep feeding solder until done. With larger assemblies you can often remove the heat source after the solder starts to flow and the assembly will retain the temperature long enough to finish. A good joint will be shiny and smooth, with a feathered edge. Be sure to heat all the parts at the same time. Heating just one part will not work. For electronic parts touch both surfaces with the iron, then add solder

    Rule number three is to use only enough solder to do the job! For instance when soldering two tubes together one inside the other, if you add so much solder that a large glob is left outside you have created one or two problems. One you have a large glob on the outside to cut, file, or grind off. The second possible problem is that there may be another glob INSIDE! Add solder until it just starts to build up and then stop.

    Rule number four is use the right heat source and do not overheat the joint. This can (especially with electronic parts) damage the materials and even burn the solder. You can tell if the solder has been burnt by the finish. If it is dull and grainy, you may have evaporated some of the alloys in the solder, weakening it. Electrical components can easily be damaged by excess heat, so be careful. With brass assemblies if you see the brass suddenly glow red you have overheated the joint and removed the temper (hardness) from the brass. This leaves the brass softer (more easily bent) and has burnt any solder you had in the joint. This can be used to advantage in the initial forming of assemblies, but is not good when soldering! A little discoloration in the brass after soldering is normal, however.

    Rule number five is that solder is not a structural member. Try to always have the assemblies fitted together and relatively self supporting (for example twist wires together first before soldering). For a strut butt joined to a stuffing tube, either wrap it around to form a broader joint, if flat stock, or drill into the side and insert, if a rod. I will admit to not always following the last rule with brass assemblies, however. Do always follow this rule for electrical wiring. With electronic parts bending the leads slightly after inserting them in a circuit board, soldering, and cutting off the excess is fine. For integrated circuits insert them, turn the board over while supporting the chip, solder opposite corners, and then release the chip and solder the rest of the leads.

    Rule number six is have clean joints and in the case of an iron or gun a clean tip.

    First the proper way to care for the tip on an iron or gun. Heat the iron (gun) and after it has warmed up wipe it across the damp sponge several times to remove the grunge on it. Do not leave the tip in contact too long each time or you will cool it down and have to wait for it to come back up to temperature. Some steam will come off the sponge, but this is normal, if you start to burn the sponge you need to add more water. Next take some solder and melt it on the tip to form a shiny liquid blob. With a snapping motion flick the glob off the tip, leaving a shiny coating. DO NOT DO THIS ONTO THE LIVING ROOM RUG, or your spouse will put an end to your hobby!! Always be careful where the HOT solder will end up! Now wipe the tip on the sponge again to remove any excess that may be left. This serves two purposes. The first is to provide a good surface for heat transfer. The second is to protect the tip, which other wise would oxidize and erode away. For the soldering iron I recommend that at least the first time you use silver solder. If the iron will not melt the silver solder, use a torch to heat the tip. The silver solder will last longer due to the fact that it melts at a higher temperature than the electrical solder. The soldering gun gets hot enough to also melt the silver solder so does not benefit as much. If your tip is badly eroded file it smooth or replace it before treating.

    To clean electrical or electronic assemblies just spray the parts with the cleaner so that the liquid runs off the part, and let it evaporate. For brass assemblies sand or file the contact surfaces if possible, clean with the cleaner, apply the rosin flux, and assemble. For smaller assemblies the rosin core in the solder is sufficient without additional flux.

    If your soldering gun does not seem to be heating properly loosen the nuts that hold the tip and then tighten them again. The tip is heated by current flow through the tip and the nuts make the electrical contact. The copper surface can oxidize at this connection and the loosening and tightening cleans the contact points for better current flow. If this does not help, replace the tip, it may be cracked or otherwise damaged.

    When soldering with the torch use a small flame to avoid overheating the assembly. First light it and run a standard flame for a minute to warm up the burner then turn it down to a smaller flame. Play the blue part of the flame all over the area to be soldered. By using the blue part you help to reduce the contaminates that would build on the joint if you used the dirtier burning orange/yellow area. The blue area is also hotter so will heat the area faster. Touch the solder, on and off, to the area as you heat it until it starts to melt readily. Remove the flame and continue to feed solder to the area, from several spots if large. If the solder melting slows or stops before the joint is complete play the torch over the area again, and then add more solder. The reheating of the area should not take long. Do not melt the solder onto the joint by playing the flame on it.

    The only exception I make to this rule is when I am using silver solder. Its melting point is high enough that you can easily overheat the brass. I heat the assembly until about what I feel regular solder would melt at. I then touch the silver solder to the joint and just touch that area with the very edge of the flame. If the solder immediately melts and flows into the joint, I then move the flame along the joint with the solder just outside the flame. If the solder does not melt and flow properly I heat the joint some more and try again.

    When soldering a piece of tubing inside another or when soldering a broad joint heat the whole area and as the solder starts to flow move the flame to the far side of the joint. This causes the solder to wick into the whole joint rather than staying near the front. Also run the solder around the joint with the flame removed to insure that all areas have been fed solder. If you are soldering two or more tubes inside each other, cut the inner tube(s) progressively longer and when you assemble them leave an appropriate amount exposed in a stair step arrangement. This exposes the joint(s) so that you can heat the inner tube(s) more efficiently and add the solder easier. When the parts cool, simply cut off the excess. This also aids in the initial placement as you have something to hold onto.

    I use the sopping wet sponge or towel to test for the temperature of the assembly before picking it up. Do not use this method on electrical parts!!! If the joint cools slowly it will be stronger, so let it air cool. After a while, however, it will have cooled enough for the solder to solidify, but still be too hot to touch. I then squeeze the water on it to finish the job. The towel/sponge also is used to protect previously soldered areas when heating new joints. Just cover thoroughly those areas or a section between old and new so that the towel absorbs the heat. Do not place the towel so close to the area being worked on that you can not heat it sufficiently. Strips of wet paper toweling are good for this masking. The towel can also be used to carefully wipe off an excess blob of solder.

    This brings us to rule number seven - Let it cool down (or cool it down). The larger assemblies will retain the heat for several minutes. If you move them to soon you stand a good chance of burning yourself and/or causing the joint to shift or separate!

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