Advertise on Bikeforums.net



User Tag List

Results 1 to 8 of 8

Thread: Flux?

  1. #1
    Senior Member Andycapp's Avatar
    Join Date
    Aug 2011
    Location
    Puyallup, WA
    My Bikes
    Tommasini Super Prestige, Kamra Triathlee, Nishiki Tri-A equipe', Sakai 2000
    Posts
    446
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Flux?

    So, I've got my tubing, lugs, and all the other bits and bobs. I also got some strait gauge 4130 from Spruce to practice with. I'll be shopping for my torch handle/tip this weekend. Question: The guy at the weld shop I was in earlier recommended a powder type flux called Marvel- "just dip the rod in there, works great!". Everything I'm reading/seeing shows you guys using a paste type (Harris?) and slathering it on pretty generously. Has anyone used this powder type? Results? Thumbs up or down?

    -Andy

  2. #2
    Randomhead
    Join Date
    Aug 2008
    Location
    Happy Valley, Pennsylvania
    Posts
    12,749
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I have used the powder type flux, and it's a pain to deal with. I used to use it for bridges and dropouts. You can actually turn it into a paste by pouring boiling water on it. At least he didn't try to sell you silver flux

    I think the powdered fluxes are not all that great for you, I would go with Cycle Design

  3. #3
    Extra Medium Member redtires's Avatar
    Join Date
    Jul 2006
    Location
    Louisville, Co
    My Bikes
    Fuji Roubaix 1.0 (Sampson Kalispell Ti GONE); VooDoo Wanga (Specialized Stumpy: GONE)
    Posts
    1,613
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I've always used paste flux. It's true, the powder stuff is really a pain and it does not work very well in reducing oxidation and increasing flow like a paste does, in my own experience.
    Coming to you from and brought to you by:
    Department of redundancy department.

  4. #4
    Andrew R Stewart Andrew R Stewart's Avatar
    Join Date
    Feb 2012
    Location
    Rochester, NY
    My Bikes
    Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder
    Posts
    3,613
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    While brass/bronze is more forgiving of poor prep, cleaning and lack of flux and many just want to get the job done as fast as possible, these are no reasons to not follow best procedures. So most here will suggest that you prep well. Clean by sanding fully down to bright surfaces. Have your fit up as it needs to be, not almost right. And use flux on all brazing surfaces before starting to heat up. Powder won't stick to steel unless the metal is hot, and then the oxidation that flux helps prevent has already started. paste will stay put while heating up and by the time the water steams off the resulting powder will stick and do it's job. Which flux can be debated but many find the GasFlux company type B the best for brazing and clean up. I'll dip my warmed up rods directly into the paste as i feel the need to have more flux on the joint. I do have generic powdered flux and might sprinkle some on (just a pinch will do you) fillets if the flux is getting "old". As you get more proficient you'll find aspects that you can short cut but when starting do the full thing. Andy.

  5. #5
    tuz
    tuz is offline
    Senior Member
    Join Date
    Dec 2006
    Location
    Toronto/Montréal
    My Bikes
    Homemade mixte, track, commuter and road, Ryffranck road
    Posts
    1,159
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I use the Gasflux paste too, it's really great.

    I've used generic powder a little bit too, but I thought it generated more glare under the flame, and didn't soak out very well in warm water. That being said, I don't see why the powder wouldn't work. It's the same as the paste basically, they are active in absorbing oxides at the same temp. range, i.e when it's already hot. I've seen some videos of Zullo and Pegoretti where they heat up the joint, then dunk it in a box of powder. Doesn't look like they use paste? Presumably the flux will flow before the filler to clean the metal ahead if you're sweating a socket... Gotta give it a shot one of these days.
    homebuilt commuter, mixte, road and track (+ Ryffranck road)
    bla bla blog

  6. #6
    Senior Member
    Join Date
    Mar 2007
    Posts
    6,096
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    I haven't been able to make powdered flux work for me. Harris flux is much more straightforward IMO.

  7. #7
    Senior Member Andycapp's Avatar
    Join Date
    Aug 2011
    Location
    Puyallup, WA
    My Bikes
    Tommasini Super Prestige, Kamra Triathlee, Nishiki Tri-A equipe', Sakai 2000
    Posts
    446
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    That's what I was expecting. Thanks guys.

  8. #8
    Randomhead
    Join Date
    Aug 2008
    Location
    Happy Valley, Pennsylvania
    Posts
    12,749
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    I forgot to mention that the powdered flux is apparently made of powdered diamonds, because when you try to take it off again you will have to use carbide tools to chip it. You can't even buy it around here anymore though

Posting Permissions

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