I have a can of it.
Might have opened the can twice in 20 years.
Never used any of it.
Looks like no one makes No. 3 flux anymore.
I came across an unopened NCG can of No. 3 flux recently, the owner did not
want to sell it. It must really be old.
What is the difference between No. 1, 2 and 3 fluxes??
Well for one thing if you've only got one can then you've only got
half the flux. Peterson #3 is a two part flux with a mixture A and
Peterson #1 is made for brazing steel and other materials that are
easy to flux.
Peterson #2 is made for cast iron and malleable iron at medium and
high heat. I've been forced to try this lately since I can't find any
of the #3. It seems to work almost as well as the #3 on castings that
haven't been soaked in oil. I've not had a chance to try it on the
really difficult castings yet.
Peterson #3 is made for cast iron and malleable iron and low and
medium heat. In other words it works at a lower temperature than the
other fluxes allowing less heat to be put into the work piece. My
former employer wouldn't use any other kind of flux on cast iron. I do
know it works very well even on dirty castings.
If anybody ever finds any #3 and wants to sell it let me know. I
need some more. I've got one set of cans left at the moment. But I
have discovered that the #2 works almost as well on clean castings so
I'm working at saving the #3 for the hard jobs.
From the label there only appears to be a few differences in #2 and
#3. One that I can remember off hand is the addition of limestone to
the #3. One of these days I'm going to do some experimenting and see
if I can just add a few things to the #2 and make it work as well as
Front of the can
NO. 3 SPECIAL
for brazing cast and malleable iron
at low and medium heat.
Instructions on the back of the can read as follows:
Take from the can, Two ( 2 ) envelopes only
of each color, and mix the contents together
throughly in a small flux container or can.
Small flux container may be left open when
not in use. ---For low heat brazing: Bevel
by grinding and heat the casting to a red heat
on edges before applying flux. Apply flux
with a wiping stroke, using the side of the rod
so that you can completely wet and
coat the metal with the melted flux as far
as bronze will flow.
CLEANS FASTER------- BONDS STRONGER
Bronze can be applied from a dull red heat
up to the molten point of the cast iron. Rusty,
greasy, burned castings easily brazed with No.
3 Special. Cracks may be veed out with high e
xcess oxygen flame or electric arc.
I tried to open it again today to look inside, but did not open it. Kinda
rusted shut. Might open it later if I am feeling lucky.
Actually now that I think about it the first cans of this stuff I
saw where that way. That was when I first started working at that shop
and the next set we got came in separate cans as have all the others