Cracked solder joints

One other thing to consider… Have you recently changed types of
fuel for your torch? I know that acetylene is a very dirty flame
compared to propane or even natural gas and that could cause some
pitting problems also. Just

FYI. Steve


From your post it sounds like you are using plain borax for a flux.
Try using a slightly diluted mix of paste flux like Handy Flux or
Stay Silv and distilled water. They are classified as AWS type FB3A
fluxes if you are not located in the USA you can talk to a welding
supply and ask for a similar flux. Plain borax alone is not the best
soldering flux yes its use dates back to antiquity but it not active
at lower temperatures and may not be providing the protection the
solder alloys need. Borax fuses and becomes an active oxide dissolver
at 743C (1369F) the FB3A paste fluxes become active at 593C (1100F).
Many solders are molten before the borax becomes active. If you get a
good joint with the paste fluxes then you will have your answer.


James Binnion
James Binnion Metal Arts

I have used, to good effect, what is called a KD IGNITION FILE
#2153. this file and others similar to it cost from $ 2.00 to $ 4.00
each and are commonly found in better auto parts stores, Sears, and
on EBay.

The ignition or point files are made very thin and flexible so as to
very slightly remove any dirt, oxidation, or burrs between mechanical
parts which must be very close fitting There are 3 or more styles
available, just get the thinnest and most flexible.

Make your first cut, rough fit the butted ends, and then insert the
( very, very thin ) point file and draw it back out without changing
the angle it was first at. These point files are between 3 to 3 BD
inches long and app. 0.032 inches thick.

Something which might also work is the abrasive plastic films which
can be stuck together with double faced scotch tape. Use these in a
like manner. The operative idea is to get the ring joint well fitted
and then spring it open to accept the file or abrasive (the thinner,
the better).

Cleaning your solder with a glass brush and inserting a thin sliver
of it between the joint ends (like welding platinum with a piece of
its self) might work better as this reduces over heating the solder
before the joint.

In passing another tip for using plastic film abrasives is to stick
them on to a 5 - 6 inch length of hack saw blade which has had the
teeth ground off, sanded smooth, and sanded to make it thinner. With
a plastic abrasive film stuck to it, it becomes the smallest, most
precise sanding stick I have ever used. Super glue could be used as
an adhesive to make it even thinner. The modified hack saw blades are
reusable of course.

Hope this helps. Robb.

Hi all. Darren here with respect to “cracked solder joints” Sorry
for a delayed reply but I wanted to have some news. Thank you all for
taking the time to reply and for the various suggestions. Thanks to
James Binnion for a rather detailed prognosis of my choice of flux I
have ditched the borax cone and and bought some tenacity flux. Not my
favourite but it will do for now till I next do a U.S. order and get
some “Handy flux” to try. I am happy to say that since using the new
flux I have experienced far less problems. So once again thank you
all for your help.

Ace of Diamonds Jewellery

I have ditched the borax cone and and bought some tenacity flux.
Not my favourite but it will do for now till I next do a U.S. order
and get some "Handy flux" to try. 

Please don’t pin your hopes on HandiFlux! I wouldn’t say don’t get
it-- it isn’t costly, and I suppose you may like it, though in my
opinion it is, um, junk. But when you’re ordering, get at least one
or two others and try them all. Prips, Cupronil and Firecsoff (now,
that one IS expensive) all have their proponents, as do others, I’m
sure. My personal favorite is Magic Flame, which has come out best in
my only-somewhat-scientific firescale tests.

What I like best about Magic Flame is that it comes as a thick paste
that you can mix with either water or alcohol, and I much prefer the
latter because the alcohol just evaporates or burns off instead of
boiling away and bouncing my snippets of solder out of position.

I keep several fluxes on my bench and if things aren’t going well, I
switch or even double up. So, try a few, it won’t break the bank.


Please don't pin your hopes on HandiFlux! I wouldn't say don't get
it-- it isn't costly, and I suppose you may like it, though in my
opinion it is, um, junk. 

Not junk, it is a much better soldering flux than the ones you list.
But if you are more worried about firescale than good solder joints
then yes it is not a good firescale preventer. And if improperly
applied it can make spots of firescale fairly intense. But used in
combination with prip’s or cupronil you can serve both needs.

James Binnion
James Binnion Metal Arts

Not junk, it is a much better soldering flux than the ones you

Well, Jim, as you know, I don’t take your statements lightly! I’ve
never noticed any real difference in terms of soldering with any of
the fluxes I’ve tried, only firescale. I do double up if I’m having a
bad soldering day, and will give HandiFlux more attention now that
you’ve endorsed it.


One of the good properties of Handy flux is that it is very fluid
when molten and will flow easily via capillary attraction into the
joint to insure that the joint is clean and well fluxed and also the
solder can easily push it out of the joint as the solder flows in.
However it can also pull away and bead up on flat surfaces as the
work heats up. It will then smooth back out as it continues to heat
but the fire stain damage is done by then. This is one reason it is
not good for fire stain. For work that is likely to fire stain I coat
it with StopOx II (or Cupronil or Prip’s all three are
interchangeable). Then I apply a tiny amount of handy flux while the
work is hot so that it will not spread out too much. Then I apply the
solder if I am doing a job where pallions are placed in advance. I
apply enough heat till the handy flux just starts to liquify then
place the solder. This keeps it from flying all over.


Hello Noel.

I Boric Acid and Alcohol everything I solder, period. As far as the
soldering, Consider the amount you will need by the size of the
object to be welded. Use a fine saw blade, without wax or oil and
make the joint totally flush. I don’t know what type fluxes you use
and I won’t go there because I do not know enough about your welding
skills or the types of metals you are using.

If you have a thick project to solder, start the flow and quickly
turn it over and draw the solder all the way through, don’t loos
your heat, the killer - “Oxidation” - will get you.

If you have to flat sheets to join, you can place solder spaced a
few millimeters apart and with the proper tip on the torch, you can
run the full length by pushing the flame ahead instead of spot

Stephen Wyrick, CMBJ

Another excellent flux is Superior 6. I get mine from H & N
Electronics. It’s a non flouride flux, creamy and smooth. Remember,
your flux should be clean, look like yogurt or sour cream when mixed
properly. If your flux is watery and thin, your work will suffer from
the protective properties of the flux doing its job.

Good company, nice people, excellent customer service.

Karen christians

I use nothing but batterns flux and for 25yrs, had 0.0 problems.


Another excellent flux is Superior 6 

I use this a lot too. But it has the troublesome tendency to creep
out of even a tightly closed lid and build up a layer of crud around
the top of the container. I finally called the company, who explained
what was going on. Apparently there is a special foam lid lining that
stops this, but it’s not easily available. I have a small working jar
of flux that I refill from a larger container. I cut an appropriate
circle out of the center of the foam lid lining of the original
container and put it in the lid of my small one. Problem mostly