Brazeing 316 stainless
Jason Byrne
Hello,
I am building a rack for my touring bike out of
316 stainless. Although I have a means of building
it with threaded rod and nuts, I would like to
braze a couple points if possible.
Is it possible to braze 316 stainless with bronze?
I have a MATT gas torch for which to do this.
Thanks,
Jason
Gary Helfrich
Jason Byrne <jason...@analog.com> wrote:
: Hello,
The important thing to keep in mind when brazing stainless is speed.
Don't dilly dally around, nuke the joint and do the job quickly. The
reason for this is the chrome in the stainless will begin to oxidize and
form a black-grey crust on the surface of you work. There is no flux (or
none that you would want to be in the same room with) that will remove
this oxide.
Is your setup MAPP/Oxygen, or just straight MAPP gas? Straight MAPP is
kind of under-powered for the quick heating that is required for good
brazing. The flame with straight MAPP becomes too big for good control
when you turn it way up. If you can afford it, the MAPP/O2 system is a
nice upgrade, and will get the job done far better.
Gary Helfrich
Arctos Machine
Joshua_Putnam
>I am building a rack for my touring bike out of
>316 stainless. Although I have a means of building
>it with threaded rod and nuts, I would like to
>braze a couple points if possible.
>Is it possible to braze 316 stainless with bronze?
Most brass fillers will not wet the surface of stainless, and if
they do they will produce low-quality joints. Brazing stainless
steel takes more practice than brazing ordinary steels, and in
some cases special filler alloys are needed to prevent corrosion
between the filler metal and the base metal. A small amount of
nickel is added to the filler alloy to prevent this sort of
corrosion, which can otherwise cause rapid failure of joints
continuously or repeatedly exposed to water. The filler with
nickel also resists corrosion better itself, so you don't get
tarnished black silver on exposed joints.
If you don't have a good local brazing supplier, try Henry
James: he makes stainless lugs, dropouts, etc., stocks the
proper fluxes and fillers for brazing stainless, and charges
less for silver filler than any local suppliers I've found.
He's also an excellent source of information.
Henry James Bicycles, Inc
704 Elvira Ave.
Redondo Beach, CA 90277
310/540-1552
--
Jo...@WolfeNet.com is Joshua Putnam / P.O. Box 13220 / Burton, WA 98013
"My other bike is a car."
http://www.wolfenet.com/~josh
Gary Helfrich
Joshua_Putnam <jo...@WOLFENET.COM> wrote:
: In <33560CB3...@analog.com> Jason Byrne <jason...@analog.com> writes:
: >Is it possible to braze 316 stainless with bronze?
^^^^^^^
: Most brass fillers will not wet the surface of stainless, and if
: they do they will produce low-quality joints.
The most important aspect of "wetting" is the condition of the two
surfaces to be joined. Flux, cleaning, flame chemistry, and heat input
all play a part here. Phosphor-bronze alloys will create joints that are
far stronger than annealed 316 stainless. The poster was asking about
brazing with bronze, which is not the same as brass.
: If you don't have a good local brazing supplier, try Henry
: James: he makes stainless lugs, dropouts, etc., stocks the
: proper fluxes and fillers for brazing stainless, and charges
: less for silver filler than any local suppliers I've found.
: He's also an excellent source of information.
Fillet brazing with silver is not a good use of this material. In lugged
construction, silver produces a very strong joint. It does not have a
desirable set of properties for fillet brazing.
Gary Helfrich
Arctos Machine
John Getsoian
In <33560CB3...@analog.com>, Jason Byrne <jason...@analog.com> writes:
>Hello,
>
>I am building a rack for my touring bike out of
>316 stainless. Although I have a means of building
>it with threaded rod and nuts, I would like to
>braze a couple points if possible.
>
Jason;
I recently had occasion to join some 1" heavy wall 304 stainless tubing
(not bicycle related). I ended up using 56% Ag solder and SodiumBorate/
SodiumFlouroBorate flux. The joints came out quite nicely and this is a
strong solder. The key with high Ag solders it to get a very close mechanical
fit however, as this material does not fill volume very well. I would think
that this method should work just as well for 316 and would have more
than adequate strength for a rack as long as you design your joints with
adequate contact area.
This solder melts below 1100F and so I was able to use MAPP gas in an air
aspirated torch. Aside from metallurgucal concerns wih bronze and SS, bronze
usually requires working with an oxygen torch.
-regards
John Getsoian
[jget...@compuserve.com
or sls...@umich.edu]
Melissa & Jim
Gary Helfrich <lap...@wco.com> wrote:
>Jason Byrne <jason...@analog.com> wrote:
>: Is it possible to braze 316 stainless with bronze?
>: I have a MATT gas torch for which to do this.
>The important thing to keep in mind when brazing stainless is speed.
>Don't dilly dally around, nuke the joint and do the job quickly. The
>reason for this is the chrome in the stainless will begin to oxidize and
>form a black-grey crust on the surface of you work. There is no flux (or
>none that you would want to be in the same room with) that will remove
>this oxide.
Gary,
I'm surprised. I was under the impression that SST couldn't be bronze
brazed. I remember trying this years ago and not getting it to work
to my astonishment. On the other hand this was probably 304, but as I
recall I found a reference that just said that SST couldn't be bronze
brazed.
SST can, however, be brazed with most of the silver alloys or the
so-called nickle silvers. There are a number of good fluxes for this.
Jim
---------------------------------------------------------------------
Melissa Kepner Jim Adney
mgke...@facstaff.wisc.edu jim....@mpcug.com
Laura Kepner-Adney
Madison, Wisconsin
---------------------------------------------------------------------
Melissa & Jim
Gary Helfrich <lap...@wco.com> wrote:
>Joshua_Putnam <jo...@WOLFENET.COM> wrote:
>: In <33560CB3...@analog.com> Jason Byrne <jason...@analog.com> writes:
>: >Is it possible to braze 316 stainless with bronze?
> ^^^^^^^
>: Most brass fillers will not wet the surface of stainless, and if
>: they do they will produce low-quality joints.
>The most important aspect of "wetting" is the condition of the two
>surfaces to be joined. Flux, cleaning, flame chemistry, and heat input
>all play a part here. Phosphor-bronze alloys will create joints that are
>far stronger than annealed 316 stainless. The poster was asking about
>brazing with bronze, which is not the same as brass.
You are correct in the fact that brass and bronze are different.
Classically Brass is an alloy of copper and zinc while bronze is an
alloy of copper and tin. I have no doubt that Gary already knows
this.
In present day brass (bronze) brazing the distinction has been lost.
I am under the impression that modern day brazing alloys have both
zinc and tin in them in some amount, as well as manganese and a few
others in small amounts, thus making the distinction between them
pointless. My experience in not being able to braze to 304 SST was
with a present day "manganese-bronze." Are you saying that SST can be
brazed with bronze, but not with brass?
If so, what are you using as a "bronze" alloy and what are you using
as a "brass" alloy. I looked a long time for a simple high zinc
content brass rod or wire for brass brazing, but failed to come up
with such a thing in the US. Is there something available now?
Andy Dingley
The moving finger of Jason Byrne <jason...@analog.com> having
written:
>I am building a rack for my touring bike out of
>316 stainless.
Is 316 not a little soft ? How about 304 ?
Stainless can't easily be brazed, but if you make nice tight-fitting
joints you can silver solder it. You're trying to solder the joint,
not build up a fillet.
--
Smert' Spamionem
Joshua_Putnam
In <5jdfgu$3n...@news.doit.wisc.edu> mgke...@facstaff.wisc.edu (Melissa & Jim) writes:
>Gary Helfrich <lap...@wco.com> wrote:
>>The most important aspect of "wetting" is the condition of the two
>>surfaces to be joined. Flux, cleaning, flame chemistry, and heat input
>>all play a part here. Phosphor-bronze alloys will create joints that are
>>far stronger than annealed 316 stainless. The poster was asking about
>>brazing with bronze, which is not the same as brass.
>In present day brass (bronze) brazing the distinction has been lost.
>I am under the impression that modern day brazing alloys have both
>zinc and tin in them in some amount, as well as manganese and a few
>others in small amounts, thus making the distinction between them
>pointless. My experience in not being able to braze to 304 SST was
>with a present day "manganese-bronze." Are you saying that SST can be
>brazed with bronze, but not with brass?
>If so, what are you using as a "bronze" alloy and what are you using
>as a "brass" alloy. I looked a long time for a simple high zinc
>content brass rod or wire for brass brazing, but failed to come up
>with such a thing in the US. Is there something available now?
My AWS brazing manual says, "Of the copper base filler metals
only those in the BCu classification are recommended for brazing
stainless steels. They are generally used in high purity
reducing atmospheres of low moisture content. The RBCuZn and BCuP
filler metals are not recommended for use on stainless steels."
It does say BCu, BNi, and copper-manganese-nickel alloys will
work, but that BCu needs to be used in high-purity reducing
atmospheres with low moisture content, and that the BNi alloys
tend to erode thin base metals.
The Harris-Welco catalog filler selection guide only shows
silver alloys for joining stainless to stainless, while the
Handy & Harman catalog shows either silver alloys or some of
their Hi-Temp alloys, which are Cu-Mn-Ni alloys. The All-State
EASB catalog also recommends nickel silver for stainless.
If anyone could recommend a common bronze alloy that works on
stainless, I'd love to hear it.
Gary Helfrich
Brazing stainless seems like teaching a dog to walk upright on its hind
legs. Nice trick, but what is the point? Tig welding seems like a whole
lot less trouble. (Note: Tongue is somewhat planted in cheek)
Gary Helfrich
Arctos Machine
Thomas H. Kunich
In article <5jlnfr$p8h$2...@news.wco.com>, Gary Helfrich <lap...@wco.com> wrote:
>Brazing stainless seems like teaching a dog to walk upright on its hind
>legs. Nice trick, but what is the point? Tig welding seems like a whole
>lot less trouble. (Note: Tongue is somewhat planted in cheek)
Hmm, nonmagnetic stainlesses are mostly nickel are they not? What is
wrong with soldering nickel together with silver?
E Bolton
I've been told the difficulty of brazing 300 series stainless is an
oxide coating that forms quickly on the surface, and prevents an
interface alloy from forming. Similar to aluminum but not as bad. That
is consistent with the recomendation for a reducing atmosphere. Sounds
like you need to be very good if you want to try this.
E.J. Bolton P.E.
John Getsoian
>Hmm, nonmagnetic stainlesses are mostly nickel are they not? What is
>wrong with soldering nickel together with silver?
>
304 is 18Cr/8Ni and there is nothing wrong with silver soldering
it except that nowadays we are now supposed to call the use of
hard Ag (mp >800F) solder "silver brazing". I've worked with
a lot of SS in the chemical industry and the fact is that it is virtually
never brazed at all, but TIG welded. But for a home garage mechanic
Ag brazing should work OK and doesn't require an acetylene rig.
Joshua_Putnam
>In <tomkE93...@netcom.com>, to...@netcom.com (Thomas H. Kunich) writes:
>>Hmm, nonmagnetic stainlesses are mostly nickel are they not? What is
>>wrong with soldering nickel together with silver?
>>
>304 is 18Cr/8Ni and there is nothing wrong with silver soldering
>it except that nowadays we are now supposed to call the use of
>hard Ag (mp >800F) solder "silver brazing". I've worked with
>a lot of SS in the chemical industry and the fact is that it is virtually
>never brazed at all, but TIG welded. But for a home garage mechanic
>Ag brazing should work OK and doesn't require an acetylene rig.
Lots of food service stainless is still brazed, not welded. For
food service work the usual filler is silver, without cadmium of
course. Using non-cadmium filler would probably be a good idea
for the average home tinkerer, too. No point poisoning yourself
with overheated cadmium fumes.
Joe Yannie
I have seen a bike made by Rhygin(sp??) that was SS.
I was at the VW/Trek race in Boston adn they had one
in the booth. Maybe they could answer a ? or too.
yann...@pilot.msu.edu
Joe
John Getsoian
>Lots of food service stainless is still brazed, not welded. For
>food service work the usual filler is silver, without cadmium of
>course. Using non-cadmium filler would probably be a good idea
>for the average home tinkerer, too. No point poisoning yourself
>with overheated cadmium fumes.
>
That's interesting. Am I right in assuming that most of the equipment
you see is relatively thin gauge sheet? Most of what I come across are
fabrications of 1/4" plate or thicker. I don't pretend that my welding
knowledge is that extensive but I could see a couple of ways why silver
brazing might become the preferable technique as the stock gets thinner.