I want to make 1/64 scale models of construction equipment. I have
looked at using brass and soldering it together, but it doesn't stick
together well. I can break it apart at the solder joint. Is this
normal or is it my soldering skills? I also want to lay a bead of
solder along a 2" joint and then grind it smooth. Is this possible?
Should I braze it instead of soldering it?
I have thought about using sheet metal and a mig welder instead. Will
this work with very small parts and thin metal?
Thanks for any ideas.
There needs to be a soldering FAQ.
If you have a good solder joint with enough overlap (4 to 8 times the
metal thickness) then on a new joint you should break the metal as often
as you break the solder.
The solder joint needs to be ever so clean before you start -- scrubbing
it to a shine with steel wool is not a bad idea. Fingerprints will
tarnish badly, so for an intricate part you should probably start with
clean metal and always wear rubber gloves during handling.
Use good acid flux (_not_ just acid-core solder) and solder sized to
match the sheet. I like to use electronics solder as it is very fine
and the rosin doesn't seem to mess up the acid flux. Pretinning the
parts is a _very_ good idea.
Make sure your parts are hot enough -- you should be able to melt the
solder on the part, not just the iron.
MIG is not the answer here.
Get some Harris Staybrite silver-bearing solder. It works just a
little above usual soldering temperatures, and it sticks very well to
brass, also to steel and stainless. You can use a small torch, a
soldering gun or a soldering iron. Strength is about 24,000 PSI
IIRC. It's not as strong as a braze or weld, but it's considerably
stronger than ordinary lead-tin solder -- and it is very easy to use.
For flux, use Harris Staykleen, or ordinary tinner's fluid.
You don't "lay a bead" with this material. It wets and flows like
water when it melts. It will "follow the heat". If you want a
bead, lay brass wire or narrow strip where you want the bead and
solder it in place.
I'd braze the joint, or possibly use silver solder.
Ordinary soft solder is simply not suitable for what you are trying to
I have an Oxy/Acet torch available, but I normally just use an
inexpensive MAP gas torch on jewelry and small items. Silver soldering
is arguably a bit easier than brazing, but either technique should work
for your application. Both require specialized fluxes to do a good job.
The flux should be available from the same place that you purchase your
silver solder or brazing rods.
Hope this helps.
I think the metal will expand a lot and cause problem during the
heating. I tried making a small windmill by silver soldering
brass rods together. I could not keep thing straight do to the
expansion during soldering and the cooling afterwards.
FWIW - silver-bearing solder is available at Radio Shack. You might want to
try there rather than purchase a larger quantity as it is normally sold
through welding supply sources. It comes as a "cored" solder similar to
soft solder with contained flux. IMO, the flux core is not good unless you
use some other agent for cleaning prior to soldering. AFAK, the shack
doesn't handle recommended special flux such as Harris StayClean. It is
available in 4 ounce quantities through welding supply places.
Incidentally, silver-bearing solder appears to be about the same stuff
jewelers use. I recently "sized" an old ring by cutting it open and
soldering in a small piece of similar material (14k gold) from a junk piece
OTOH, silver-bearing solder is fairly strong. For a test, I sawed open a
brass tube and then silver-soldered it back together in a butt joint
configuration, preserving the internal contour of the tube. Then many
passes were made in the lathe, taking the tube down well below original
diameter. The silver-soldered joint held up with no problems taking fairly
light cuts. The joint appeared to be nearly as strong as the native brass.
Consider a resistance soldering unit ... they're hard to beat for 90% of
light structural soldering like you propose. almost all the real quality
constuction models are made of soldered and cast brass. How much
strength do you need? Something the size of this (1/64) can always be
easily bent or broken, even if solid sheet or cast metal.
Use the correct solder, use the correct flux, and, as others have
stated, **CLEAN** the metal before soldering! Also, lear the various
types of joints, and how to reinforce them for added strength.
For examples of the miniature structural soldering art look at any of
the fine quality brass model railroad models available ... and the COST!
even in HO scale, $2000 plus for a model is now common.
Also, it's your model, but why 1/64? 1/64 is common for farm tractor
models, but not construction models. Cnstruction models are usually in
1/87, 1/48-50 (most common of all), 1/24, or 1/16. A vast number are
commercially available, including some parts, like working metal link
tracks, winches, lights, etc. Most are diecast metal, but the better
ones are either resin/diecast combination, or all brass construction.
Again, a nice 1/24 scale D8 Cat is about $1700!
for a starter, see:
... Buffalo Rd. Importers
Caterpillar Classic Toys
Not the same stuff, Bob. The RadioShack stuff is 62 Pb36Sn2Ag.
Staybrite is about 96Sn4Ag. It's considerably stronger than
lead-based solder like the Radio Shack stuff. I did misremember,
though; it's more like 14,000 PSI, not 24,000 PSI. Still
considerably better than 64Pb36Sn which is about 5000 PSI. I used
it last week to repair a decorator light fixture made of very thin
sheet steel, this for my daughter-in-law who was delighted to have
that old pieca-- uh, piece restored.
The silver-bearing lead-free plumbing solder sold at Home Depot is
probably much closer to Staybrite, probably being mostly tin. I
don't think it wets as well as Staybrite.
There is a Staybrite 8 with higher silver content that has a plastic
range so it can "build" a little in loose fitups. I haven't used it.
The Radio Shack stuff is handy in that it's small -- .022 dia.
Staybrite can be made into thin ribbon with a hammer. Welding
stores do sell small quantities of it in blister packs that include
a little bottle of flux.
I ordered a 1 lb roll of Harris Staybright from a local welding supply.
I don't remember if it was 20 or 40 bucks. I compared the price to MMC
catalog and the price per pound was about the same.
I also ordered 1 oz of true silver solder 56% silver (melt at 1200) for
about 20 bucks. A good mapp gas torch will work on small parts. I was also
surprised to fine that 1 oz of thin silver solder is pretty long, over
Did you use a hard silver solder or staybright?
Staybrite is about 95% tin and 5% silver. It would surprise me
to hear that stay bright is that strong.
Staybrite is available in several different sizes diameters from very
thin to fat and in several package sizes as well. I found it on
their web site and then ordered it via a local welding supply company
via the phone.
PM research will sell you 1 oz and a bottle of flux for 8 bucks.
One oz is considered enough to solder one of their boilers!
When you say that you can pull the solder joint apart, do you mean just tap
it and the joint falls apart or that you can do a joint and then rip the
joint apart, bending the brass as the joint comes apart.
Soldering of small pieces like you are discussing in 1/64th scale (basically
S scale in model railroading) shouldn't be any problem. The first thing is
to clean the brass so that the solder sticks to the brass and forms a nice
thin "tin coating" type surface. If you have places where the solder
doesn't flow then you don't have a good coat of the solder. Then clamping
the two pieces together and heating the joint with the addition of a little
bit more solder will make a very strong joint. The edges of the joint
should be nice fillets rather than a convex bulging looking interface.
Another thing is that you don't want to overtemp the solder as this just
doesn't help with the metals involved. 400F is hot enough to melt solder
and that is a good enough temp to work with for the actual joint.
The use of flux in doing large area joints is also a positive thing as the
flux will allow for the solder to flow properly over the metal before it
The soldering iron is a very important part of the heating equation. I
prefer Weller temperature controlled irons for my work as you can control
the temp of the iron and keep the iron from getting red hot which just makes
messes of things. There are other brands out there that offer temperature
control. Hot irons heat the metal so hot that it usually oxidizes the brass
before the solder can flow over the brass. It also burns the flux off of
the metal which is a bad thing to have happen as the flux then becomes
contaminants in the solder.
I usually pass my file over any joint surface just before soldering to
insure that there is no oxidation on the surface.
For solder, eutetic (63/37 solder) is probably the weakest but works very
easily. Then there are, on the other end, silver bearing solders with a few
percent of silver in them that are more than strong enough for your work.
With the silver bearing solder, I will do butt joints in low to medium
stress joints without any problems.
Why isn't there an Ozone Hole at the NORTH Pole?
"> Not the same stuff, Bob. The RadioShack stuff is 62 Pb36Sn2Ag.
If this is true, then RatShack is lying on the product descriptions on their
The latest silver-bearing solder I purchased from RS says on the package:
64-026 E, Silver-Bearing Solder, Lead Free, 96/4. The sales type said that
the 96/4 referred to the percentage of tin and silver. It comes in a 0.5
I have a much older package of Silver-Bearing Solder from RS, maybe about 10
years old, packaged in a blister pac with a small roll of material inside,
0.46 ounce. It says on the front: Kester Solder, Silver Solder, Alloy 4%
Silver 96% Tin, High Strength For jewelry, Antique Silver, Melting
Temperature 440 F, Special Flux Core Included.
That sounds like the right stuff, all right. The melting temp also
jibes pretty well; staybrite goes at 430.
My roll of RS is part number 64-013E, sez 62/36/2. It's only a
couple of years old. It's better for elex work, particularly
surfacemount, because of the lower temperature.
This effect is largely a result of uneven heating.
If you carefully clamp the work properly and heat it evenly, you will
not have a warping problem. If you simply lay it on a flat surface and
only heat the area that you are soldering, then of course it will warp
like Hell becaue the area that you are soldering is hot and the rest of
the object is cold.
A Silver-Bearing solder PASTE called Solder-It melts at 430F,
and amazed me with its strength. I tossed all my AG4 and AG2%
stuff from Rat Shack, which may or may not be only slightly
better than "ordinary" Pb/Sn stuff.
The paste also has excellent flux. Hypodermic type container,
about 7 bux Canadian at Canuck Tire, likely at most hardware
stores although I haven't seen it at Home Depot. / mark
As when welding castings, sheet metal parts can sometimes be heated in
an oven to just below soldering temperature, then taken out and quickly
soldered. This will reduce warpage, as the entire part is at nearly the
same temperature. When working with preciously solder-assembled parts,
avoiding a too-high temperature is critical. It's one place where a
variety of solders with different melting points can be useful.