Hands down, best/ favorite brazing flux
#26
framebuilder
Yes, Gasflux makes both a powder Type B and also a powder type G that I like using for silver on stainless steel because it has a bit higher temperature range. I put the powder type B in one of those old powder flux cans that the LWS store used to sell. Just like John, I heat up the end of the rod and put it in the can so flux will stick to the end and then I can apply it to where a bit more is needed while the joint is hot. The can had a little hole in the lid that the short used ends of the brass rod could rest waiting to be used. I don't think those cans are available in more but my rusty one from the 70's still works.
Gasflux sells 56% silver for less than $20 an ounce too.
Gasflux sells 56% silver for less than $20 an ounce too.
#27
Senior Member
Join Date: Mar 2012
Location: santa barbara CA
Posts: 1,087
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 96 Post(s)
Liked 30 Times
in
21 Posts
Thanks for explaining that.
__________________
Brian
Brian
#28
blahblahblah chrome moly
Join Date: Apr 2009
Location: Seattle
Posts: 1,989
Mentioned: 92 Post(s)
Tagged: 0 Thread(s)
Quoted: 1176 Post(s)
Liked 2,572 Times
in
1,074 Posts
Bill Davidson used to get some Japanese flux for brass that was noticeably better than Gasflux. Late '80s, early '90s. It came as a powder that we mixed with water. It was ground extremely fine, and made a white slurry kinda like pancake batter that stayed where you put it. I don't know what the secret ingredient was but it stuck really well while cooking the water out. Good heat range and wetting action for liquid brass, all the things you need flux to do, and it soaked off well too.
Unfortunately the supply dried up, no pun intended, or Davidson's connection (through Takahashi probably, or maybe Tange) stopped selling it or something. Either I didn't ask or I don't remember the answer. But one day we started using blue Gasflux brand. It was a big disappointment after being spoiled by the Japanese stuff.
I mention it here in case anyone knows what that stuff was. The words on the box were in Japanese characters (Kanji?) that I can't read. We had to buy some large amount like 20 or 50 kg at a time, but a US distributor (Nova?) could make some money selling it in smaller tubs. If it still exists and it's still as good, people would pay.
But of course the brazed bike frame biz in Japan isn't what it used to be, so some companies have gone out of business and some product lines have been dropped.
Anyone here got friends in the bike or brazing business in Japan that you could ask?
Mark B in Seattle
Unfortunately the supply dried up, no pun intended, or Davidson's connection (through Takahashi probably, or maybe Tange) stopped selling it or something. Either I didn't ask or I don't remember the answer. But one day we started using blue Gasflux brand. It was a big disappointment after being spoiled by the Japanese stuff.
I mention it here in case anyone knows what that stuff was. The words on the box were in Japanese characters (Kanji?) that I can't read. We had to buy some large amount like 20 or 50 kg at a time, but a US distributor (Nova?) could make some money selling it in smaller tubs. If it still exists and it's still as good, people would pay.
But of course the brazed bike frame biz in Japan isn't what it used to be, so some companies have gone out of business and some product lines have been dropped.
Anyone here got friends in the bike or brazing business in Japan that you could ask?
Mark B in Seattle
#29
Randomhead
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 24,398
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 3,698 Times
in
2,518 Posts
did the Japanese flux soak off easily without near-boiling water?
I'm a little curious what characteristics made it better. My main concern is that the flux comes off easily when I'm done.
In retrospect "rolling paint off a brush" is an art technique that I have heard of. But it's not stored in any neurons that are commonly fired. Probably heard of it watching Bob Ross or something
I'm a little curious what characteristics made it better. My main concern is that the flux comes off easily when I'm done.
In retrospect "rolling paint off a brush" is an art technique that I have heard of. But it's not stored in any neurons that are commonly fired. Probably heard of it watching Bob Ross or something
#30
blahblahblah chrome moly
Join Date: Apr 2009
Location: Seattle
Posts: 1,989
Mentioned: 92 Post(s)
Tagged: 0 Thread(s)
Quoted: 1176 Post(s)
Liked 2,572 Times
in
1,074 Posts
Yes, ISTR it was about the same as gasflux that way. This is from memory of almost 30 years ago. I don't remember the soak tank temperature, but it was in the "uncomfortably warm" range if you reached in -- wouldn't scald you. We didn't generally reach in though, we lifted individual frames out with a hook, or if there was a batch, we had a rope hoist attached to the ceiling.
The flux would soak off in cold water eventually, but steel rusts faster in cold water. We had a little Oakite in the water, weak solution but between that and the hot water, frames came out rust-free. And then went straight into an oven for force-drying.
The flux would soak off in cold water eventually, but steel rusts faster in cold water. We had a little Oakite in the water, weak solution but between that and the hot water, frames came out rust-free. And then went straight into an oven for force-drying.
#31
Junior Member
Join Date: Jan 2014
Location: San Francisco - it used to be nice
Posts: 75
Bikes: 1970 Alex Singer, 63 Hetchins, 75 Motobecane Townie, more . . .
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 10 Post(s)
Likes: 0
Liked 8 Times
in
5 Posts
Pre-Heating Flux ?
On my last frame I put some silver flux in a stainless measuring cup on a small hot plate. The flux water boils off and you're left with a thick syrupy liquid that worked well.
I didn't have to worry about trying to out-think boiling water in expensive flux paste while I inevitably watch it fall off the tubes onto the floor. Boiling water is clearly smarter than bicycle frame builders.
In the past I have placed clean aluminum sheet metal pieces under brazing areas to catch the inevitable flux fall-off for re-use. And yes, I do try slow-heating and all the other attempts to deal with
boiling water. I have largely given up with that nonsense - boiling water is too smart for me to fight.
Brass flux = Gas Flux blue works well enough for most folks. If you want utter misery, try using the powder fluxes (Brazo) offered at welding supply stores.
I haven't used the Cycle Dynamics LFB flux. Their other stuff seems to be good, and I doubt they would offer something that worked poorly.
I've used quite a few silver fluxes. Can't remember which framebuilder suggested mixing a little black flux in with the white stuff gives you some of the best of both worlds. Easier to see through and
gives you a little longer life / higher temp ceiling.
I have a lot of respect for the Gasflux company, but I didn't like (hated is probably more accurate) the regular white flux compared to Harris or (my fave ) Superior 601. Superior seemed to work well and stick better than the alternatives. System 48 flux worked well, too. I am curious about the Stainless Light flux, will order some next time I do an order with them.
One personal observation I can pass on is that choice of flux is important, but I've blamed the flux for problems that were more because of my poor technique, inadequate cleaning, or drafty workshops.
Be careful about sand-blasting with dirty media. I was using a blaster once in a shared workshop environment. Thought it was clean until I saw a guy stick a bunch of greasy motorcycle parts in there.
Keep in mind that no brand of flux is going to help you with THAT.
Small diameter silver brazing rod is a mess. 1/32" melts too quickly for anything other than really small braze-ons. 1/16" works so well for most everything for bike frames. I once tried 1/8"diameter 45% EZ-Flo silver with cadmium. Thought it wouldn't be a big deal, but it definitely took a much more concentrated effort to get it to melt compared to 1/16".
I didn't have to worry about trying to out-think boiling water in expensive flux paste while I inevitably watch it fall off the tubes onto the floor. Boiling water is clearly smarter than bicycle frame builders.
In the past I have placed clean aluminum sheet metal pieces under brazing areas to catch the inevitable flux fall-off for re-use. And yes, I do try slow-heating and all the other attempts to deal with
boiling water. I have largely given up with that nonsense - boiling water is too smart for me to fight.
Brass flux = Gas Flux blue works well enough for most folks. If you want utter misery, try using the powder fluxes (Brazo) offered at welding supply stores.
I haven't used the Cycle Dynamics LFB flux. Their other stuff seems to be good, and I doubt they would offer something that worked poorly.
I've used quite a few silver fluxes. Can't remember which framebuilder suggested mixing a little black flux in with the white stuff gives you some of the best of both worlds. Easier to see through and
gives you a little longer life / higher temp ceiling.
I have a lot of respect for the Gasflux company, but I didn't like (hated is probably more accurate) the regular white flux compared to Harris or (my fave ) Superior 601. Superior seemed to work well and stick better than the alternatives. System 48 flux worked well, too. I am curious about the Stainless Light flux, will order some next time I do an order with them.
One personal observation I can pass on is that choice of flux is important, but I've blamed the flux for problems that were more because of my poor technique, inadequate cleaning, or drafty workshops.
Be careful about sand-blasting with dirty media. I was using a blaster once in a shared workshop environment. Thought it was clean until I saw a guy stick a bunch of greasy motorcycle parts in there.
Keep in mind that no brand of flux is going to help you with THAT.
Small diameter silver brazing rod is a mess. 1/32" melts too quickly for anything other than really small braze-ons. 1/16" works so well for most everything for bike frames. I once tried 1/8"diameter 45% EZ-Flo silver with cadmium. Thought it wouldn't be a big deal, but it definitely took a much more concentrated effort to get it to melt compared to 1/16".
#32
Randomhead
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 24,398
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 3,698 Times
in
2,518 Posts
I'm afraid to mix fluxes because it's possible they aren't chemically compatible.
#33
Senior Member
Join Date: Sep 2017
Location: Eastern Shore, MD
Posts: 2,107
Bikes: Road ready: 1993 Koga Miyata City Liner Touring Hybrid, 1989 Centurion Sport DLX, "I Blame GP" Bridgestone CB-1. Projects: Yea, I got a problem....
Mentioned: 24 Post(s)
Tagged: 0 Thread(s)
Quoted: 753 Post(s)
Liked 737 Times
in
422 Posts
Here is an exercise to try to see how independent your hands can move. It is similar to pat your head while making circles around your tummy. Point a finger from your left and right hand towards each other. Now make a circle with one finger around the other. Once you get that circle started, do a circle in the opposite direction with the other finger. 90% of people can't do this at 1st. The 2 fingers will go in the same direction like pursuit cyclists on a track. If and when they can go in different directions their circles will be more like ovals. Try it and see. This lack of independent hand motion is at the foundation of problems learning to braze.
#35
framebuilder
I happen to have the fine powered flux but I don't know if it matters much the way I use it. Back in the 70's when I started, brass flux came in these 1 pound tin cans that were similar to paint cans - except it also had a small 2nd hole/lid in the middle. This small hole was handy to keep partly used rods. The lid surrounding it kept junk out of the power. 40 years later I'm still using mine (after dumping out the old flux and adding powered Gassflux).