User Tag List

Results 1 to 8 of 8

Thread: So what is Gasflux GF-72?

  1. #1
    Join Date
    Jun 2021
    Posts
    3
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default So what is Gasflux GF-72?

    Hey guys,

    I took a frame building course a few years back where we used GF-72 Nickel Silver for tacking tubes and an initial joint which was then covered with brass filler.

    I really enjoyed working with nickel silver, but whenever I go to do an order from BFS or other places it is sold out, being in Canada I would rather not do an entire order just for some filler.

    So my question to you guys, is what exactly it is? It is impossible to find anything with a similar make up from any of my usual brazing suppliers up here. I have recently read about Aufhauser A-56T, which doesnt look to be the same but the properties description sounds very much like it.

    Hoping to get some more generic terms to search for, the welding suppliers don't seem to be too much help in finding out an alternative.

    Thankyou for any help!

    JB

  2. #2
    Join Date
    May 2008
    Location
    Better to be ruined than to be silent atmo.
    Posts
    20,858
    Post Thanks / Like
    Mentioned
    8 Post(s)
    Tagged
    0 Thread(s)

    Default Re: So what is Gasflux GF-72?

    With little experience past the course itself, I'd suggest not fixating on the rod alone, or itself, and simply get some brass. I'm assuming this is for lugless frame building. I've never heard of using two separate and different filler metals on the same task. I use the C-04 exclusively. For lugged joints, it's the BAg-7 alloys for me.

  3. #3
    Join Date
    Jun 2021
    Posts
    3
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: So what is Gasflux GF-72?

    Thanks Richie,

    I have been getting by with just generic brass rod for the last frames / forays into brazing, its more just trying to get my hands on it for the sake of having some around.

    I was however able to get some good leads on it over the past couple hours of digging through some catalogues, it looks like it is the same as Harris Alloys 170 or Aufhauser C773. That being said none of the suppliers are willing to get less than 50 lbs of the stuff for me.

  4. #4
    Join Date
    May 2008
    Location
    Better to be ruined than to be silent atmo.
    Posts
    20,858
    Post Thanks / Like
    Mentioned
    8 Post(s)
    Tagged
    0 Thread(s)

    Default Re: So what is Gasflux GF-72?

    Quote Originally Posted by JBanderob View Post
    Thanks Richie,

    I have been getting by with just generic brass rod for the last frames / forays into brazing, its more just trying to get my hands on it for the sake of having some around.

    I was however able to get some good leads on it over the past couple hours of digging through some catalogues, it looks like it is the same as Harris Alloys 170 or Aufhauser C773. That being said none of the suppliers are willing to get less than 50 lbs of the stuff for me.
    hmm must be a canada thing.

    i've never bought 50 pounds of anything.
    50 ounces of silver, yeah.

  5. #5
    Join Date
    Mar 2009
    Location
    South Haven, MI
    Posts
    54
    Post Thanks / Like
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)

    Default Re: So what is Gasflux GF-72?

    The only problem with the nickel silver is that some folks report developing an allergic reaction to the nickel in the filing and sanding finishing procedures.

    I have used both the Gasflux and Cycle Design rods and flux. All worked as expected.

    These suppliers will sell you a pound of bronze or flux.

    https://www.bikefabsupply.com in Arizona carries Gasflux rod and flux (on vacation this week)

    https://framebuildersupply.com/ in Portland carries the C-04 bronze and blux from Gasflux (also on vacation this week)

    https://www.cycledesignusa.com/ Sells there own line of bronze, nickel silver and silver.

    Ceeway in the UK also sells the Cycle Design line
    Ralph Ellis
    South Haven, MI

  6. #6
    Join Date
    Dec 2009
    Location
    Niles, Michigan
    Posts
    529
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: So what is Gasflux GF-72?

    One of my framebuilding colleagues tig tacked his frames with spots of steel rod before fillet brazing. The idea I suppose was that the frame would move less (or the spot would not break) when the brass was being applied.

  7. #7
    Join Date
    Feb 2009
    Location
    State College, PA
    Posts
    5,658
    Post Thanks / Like
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)

    Default Re: So what is Gasflux GF-72?

    GF-72 is their in house designation for RBCuZn-D, which is UNS C77300. Ask your local folk for those later terms. The gasflux bronze rod that everyone seems to love is RBCuZn-B, which is also high nickel bearing, and may be easier to find. Most major alloy suppiers will offer their version. It's a more widely used alloy in bikes than RBCuZn-D, and will work for everything save stainless. Nickel silver will work with some stainless, but both are picky with heat and flux, and most people have better success there with real silver bearing alloys.

    In the past I've done fillet and lug tests with RBCuZn-B and -C back to back, and both worked fine for me. -C is regular low fuming broze, and some folks prefer it to sweat joints. As Richard mentioned, at this stage it's more about learning heat control than the particulars of the filler. Nickel Silver, Nickel Bronze and Low Fuming Bronze are all close enough in working temp and flow characteristics that, provided you have decent flux and heat control and are working on regular steel, can all be substituted with a moment to get a feel for the rod in hand. Buy a couple lbs of one, and get it worked out. Good luck!
    Last edited by Eric Estlund; 06-22-2021 at 02:50 PM.

  8. #8
    Join Date
    Jun 2021
    Posts
    3
    Post Thanks / Like
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Default Re: So what is Gasflux GF-72?

    When I was doing the aftermentioned course I tried this as well, by the time you got it all setup it was quicker just to tack with whatever you were going to be using to fillet braze.

Similar Threads

  1. Fillet-Pro and Gasflux Type U paste
    By David Tollefson in forum Mentor
    Replies: 0
    Last Post: 10-28-2016, 08:28 AM
  2. Gasflux 69T and Oxy Propane
    By timto in forum The Path
    Replies: 13
    Last Post: 08-31-2015, 01:56 PM
  3. Gasflux Type T silver flux
    By Curt Goodrich in forum The Path
    Replies: 11
    Last Post: 12-03-2009, 11:21 PM

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •