I have been experimenting with scratchbuilding using brass. Thus far I have not had any problems with joints melting when I try to attach the next piece, but now I am trying to make some caboose ‘H’ style smoke jacks. Obviously the joints are very close together (HO scale). I can get the first two joints OK but when I try to do the third the whole thing loses its alignment. Therefore, I need solders that melt at significantly different temperatures. The first solder has to have a higher melting point and the second has to have a lower melting point so that the first joint is not melted when the second is being made. Sorry if that is stating the obvious.
I have found charts that show what temperature the various formulas melt at but I have had some difficulty actually finding the different melting point solders.
So, I am turning to you. Can anyone give me specific brands and temperature characteristics that will suit my needs?
In situations like what you describe different techniques are employed. One method is solder paste, where everything is held in a jig, with solder paste at the joints, and the whole assembly is placed in an oven to melt the solder. The other method is resistance soldering, which can produce very localized heat very quickly.
One option you have is silver solder. It has a much higher melt point than lead/tin alloys. With various lean/tin and their replacement alloys, you will need very accurate temperature control, otherwise the work will get hot and the other joint will melt, plus you have to work fast.
One place that’s handy to find silver-bearing solder (64-035) is Radio Shack. In fact, it’s my go-to solder for most things. I haven’t seen a melting point, which seems to be omitted as it is for many solders in retail situations.
I used standard soldering irons for much of the work on the PSC brass DL-535E kit, but I also have one of the Radio Shack digital soldering stations (64-053) that provides 3 adjustable, pre-set temps, selectable via pushbutton. That would make it easier use multiple types of solder in a situation like that described above. It’s tip is very narrow and pointed, allowing form more precise placement of heat. It doesn’t have quite the power that soldering irons do, but is great for small, delicate work.
Aside from that stuff, if possible try using heat sinks. This can be a small metal clamp, like a pair of locking tweezers or a hemostat. You can also try assembling such items on a piece of metal bar, essentially the same idea, i.e. add some more mass to be heated between where you’re working and previous solder joints.
Using some flux will help make solder joints happen more quickly, as will tinning both parts to be joined. The best solder joints are made quickly, then get the heat away. Keep practicing, as it takes some work to get the hang of it.
One brand of solder with a very low melting point is Tix. I have done a lot of scratch and detailing work on brass and have used about every type of solder you can buy. But, if you are really serious and work a lot in brass, a resistance soldering unit will open a whole new world to you. Kind of like using an airbrush for the first time. Won’t completely replace the good old iron but is indispensable for certain jobs. If you are old enough to remember Bill Schopp who did articles for RMC, he would chop up brass Locos to yield a particular prototype. He would then use the leftover parts and create some Frankenstein-models like a 4-6-8-2. He raved and raved about his resistance soldering unit. I corresponded with him and we did some parts swapping. He was quite a character. I bought my resistance unit from P-B-L.
I don’t think I can justify the cost of a resistance soldering unit because I don’t have a huge amount of work planned, but I will look around.
I do use flux and I do tin all the parts prior to assembly. I also have a number of different solders including some 2% silver solder. I will do some experimenting to see if any of the solders seem harder.
I will also try to come up with some sort of jig to hold the bits in place. I have a ‘third hand’ (the thing that has the aligator clips on swivel arms) which I have not tried to use, but I will give it a go too.
I use wet tissue or paper towels as heat sinks. Usually, a wad of wet material can be moulded to stick in place, but I also use alligator clips, clamps, or locking tweezers to hold the wet tissue where it does the most good.
I rebuilt this old Akane brass steamer into a model of a particular prototype for a friend.
I used a propane torch to assemble and install the Kemtron (PSC) cast brass cab, then various soldering irons to add the details. These included, where appropriate, 25 and 45 watt pencil irons, and a larger 85 watt model and a 200 watt model for the bigger stuff.
The rear ladder on the tender was built on a homemade jig, and is pinned in place on the plastic tender, as are the footboards.
The front ladder on the tender is also pinned in place, but because the rungs are curved, it had to be assemble in-place. The two ladder stiles, with holes pre-drilled and mounting pins soldered in place, were first installed on the plastic tender shell, then wet tissue was applied to all points where the ladder contacted the plastic. The pre-cleaned and pre-bent rungs were then installed and individually soldered in place. As each was finished, it got an application of wet tissue, to prevent further movement while the next one was being soldered. No damage at all to the plastic. [:D]
The plastic turret cover (just ahead of the cab, atop the boiler) did get damaged by a s
I have used needle nose pliers with their handles held shut with elastics. The problem with the caboose smoke jacks is that the pieces are all very small. I don’t cut the stack off of the main pipe until all is assembled so that gives me something to hang on to.
Another handy way to hold small parts for soldering is to use a sheet of 1/4" balsa and some straight pins. Assemble everything on the balsa so that the parts are held in place by the pins, then solder at each assembly point and cover that work with wet tissue, soldering and covering each joint as it’s made. Sometimes it’s easier to pre-tin all parts, pin everything in place, and use a larger-capacity iron to make all the joints at the same time.
Although they were simpler to make than smoke jacks, the railings on the loading dock were assembled while pinned to a sheet of balsa, with each joint covered with wet tissue as it was made, I pre-clean the brass wire by dragging it several times through a folded piece of #1200 wet/dry sandpaper, then cut and bend it as necessary before pinning it in place. A touch of flux at each joint just before the iron was applied made for quick and strong joints.
If you need to make multiple similar parts, it’s often worth the effort to make a jig which will hold some or all of the parts in alignment. When you’re finished using it, label it and put it away until you need it again. I’ve used maple and basswood, put together using yellow carpenter’s glue, to create simple jigs for constructing ladders, handrails, multi-piece grab irons and other such details.
I have found a solution to my problem soldering the very small pieces together to make ‘H’ shaped caboose smoke jacks. A while ago I had purchased some solder made by TIX SOLDER. I can’t remember were I bought it however MicroMark has it available.
It is labeled as " The Hardest Soft Solder on Earth". Anyhow, this stuff has a very low melting point. It melts almost instantly.
My procedure is to first tin all the pieces. I put them on a piece of wood and hold them down with my exacto knife, apply some flux and then put a spot of solder where needed. Next I put the cross piece of the ‘H’ shaped jack up against a couple of pins pushed into the wood and hold it down with the hot iron. The pre tinned main pipe is then put up against the cross piece and the solder melts almost instantly. As soon as the main pipe is put in place the iron is removed. Note that I have not cut the main flue to length yet so I have several inches of tube to hang on to, and I will not cut the stack to length until all finishing has been done.
The first two pieces are the easy part. For attaching the third and susequent pieces I do the same thing - pre tin and hold the third etc. piece down with the iron and touch the assembly to it, immediately removing the iron. The previous joints don’t melt if you are quick to remove the iron.
Just so you know, I tried the suggestions offered such as using wet paper towels and building a jig using pins. Those are great ideas but in my case I found the joints to be so close together that they didn’t work. When I had everything pinned in place the pins were so close together that I had a hard time getting the tip of the soldering iron to make contact with the work. The joints
Thanks - I have a total of 10 cabooses in the works (none of which will match your level of accuracy) and I want to make them a little different by using the ‘H’ style smoke jacks. Up until now I have been frustrated in regard to that specific detail, but now its full steam ahead!
Your input is really appreciated, as well as that of the other members of course.
While I can appreciate the satisfaction of making your own details, the “H”-style smokejacks are, as far as I know, still available from Juneco, or at least can still be found in hobby shops. I’ll check next time I’m at the two stores which are nearby.
I use them on a lot of my cabooses, but seem to recall reading somewhere that they’re intended for oil stoves, not the coal ones which would have been more common in my late '30s era.
While it’s not an “H” stack nor a caboose, they should be easy enough to fabricate in styrene, too, as was this one on a crossing tender’s shanty:
While these were likely made from styrene tubing, I’ve made quite a few from sprue material, too. Obviously, only the sections where the smoke would exit need to be open, and I usually start with a drill bit smaller than required, then work my way up using increasingly larger bits. I also use suitable bits to enlarge the passageway in the tubing, and it’s surprising how thin it can be made. I use lacquer thinner to assemble the parts, then leave them at least 24 hours before using files to do any required clean-up work. They’re strong, cheap, and easy to build.
