Defluxing

[fpavao]

Hello again,

I've used the search button but didn't come up with anything interesting.

How do you guys get flux out after brazing? Any tips on this or is it just old fashioned brushing?

Regards.

[echelon_john]

H20, preferably hot. That's it.

[Mtblucas]

My flux is water soluable. Like the last guy said, warm/hot water and a wire brush helps get the chunky stuff off. I'm sure some flux is still stuck inside the tubes of the frame that I can't get to. Not sure how to remove that, but I can't see how it could hurt anything if it stays there.

[Will Neide]

My flux is water soluable. Like the last guy said, warm/hot water and a wire brush helps get the chunky stuff off. I'm sure some flux is still stuck inside the tubes of the frame that I can't get to. Not sure how to remove that, but I can't see how it could hurt anything if it stays there.

If you have all your vent holes properly drilled, a complete submerge of the frame in hot water should get it out.

[fpavao]

Thanks for the replies. Unfortunately, I don't have hot water in my workshop and heating on a stove or something would be too much time consuming.

For the time being, I'll stick to what I'm doing.

[Bill Bryant]

Hot water works better, but cold water will do the job if you have time. If your shop doesn't have water, find a way to haul in a few gallons and make a soak tank. Brushing/sanding it off is too much work and won't be as good as using water before you start doing the finish work.
Water is your friend.

[igor miyamura]

I use in my workshop one electric water boiler.
where I live it costs the equivalent of $ 5.

1298654455_1.jpg

[afwalker]

Just get a coffee pot and dump some hot water into your soak, it'll work fine.
Lucky folks in Europe get 240volts, takes like 1 minute to get boiling water:)
cheers
andy walker

[NBC]

if only we did get boiling water in a minute over here ! who wants a prototype 415v 3 phase kettle ? HAHA !

for all you guys making forks, where do you drill vent holes ? and do you fill them after ?

i made a fork the other day, and it's got little bits of flux that rattle in the bottom, but it's all sealed up, would you put up with it and leave alone, or make some vent holes ?

thanks

nathan

[Andrew R Stewart]

Vent holes go at the top and bottom of the stays/blades without overlapping the actual joints. Nails make good pins/plugs. Wrapping a joint with wet rags can help soften flux. Andy.

[veryredbike]

Vent holes go at the top and bottom of the stays/blades without overlapping the actual joints. Nails make good pins/plugs. Wrapping a joint with wet rags can help soften flux. Andy.

I've noticed that some folks drill the top vent through the fork crown after brazing (using the bottom one to let out pressure then both to let water in/out), and some drill it in the blade underneath that. Is there a specific reason you don't go through the crown?

[fpavao]

Thanks for the ideia, Igor! I'll look into that.

Great to have someone elso from Brazil here. (:

[NBC]

with hollow fork crowns, is it ok to drill vent holes in the base of the steerer tube ? i don't particularly like putting holes in lightweight fork blades, scared i'll do something silly and make one unsafe !

nathan

[Jonathan]

with hollow fork crowns, is it ok to drill vent holes in the base of the steerer tube ? i don't particularly like putting holes in lightweight fork blades, scared i'll do something silly and make one unsafe !

nathan

yes. its a fine way to vent and most modern crowns allow for it.

[steve garro]

I have a stock (like cows, not soup) tank with water that has not been changed in years - braze it up, drop it in, leave for hours or even overnight - why rush?
There is plenty to do in life.
Don't chip flux - I got a shard in my eyelid that had to be lanced out from the inside when it got super infected = mega no-fun.
- Garro.

[shirk]

How long should you let a joint cool before dropping it into the water?

[ToddFarr]

^ Should be completely cool to the touch.

I do the same as Garro


Soaking by Todd Danger Farr, on Flickr

If I'm in a hurry or have a small portion that needs defluxing, I use a 5 gallon bucket with piping hot water.

[fpavao]

Thanks Garro and Todd.

I've got a small tank were I can put half a frame inside and let it soak. It's what I've been doing already. The ideia of having another small bucket with hot water seems good to me. I'll try that.

I've also got plenty of shards in my eyes to (not as serious though) to the point were even for brushing flux I'll use safety glasses.

[steve garro]

Yep - my dunktank is just a little longer, it fits all but the biggest 29ers in one dunk.
- Garro

[igor miyamura]

I had not realized that was the fpavao Brazil too.
good to know that we have more people becoming interested in framebuilding here.
stream quality for brass found in Brazil is very different from the U.S. for example. works, but is more difficult to remove ... the imported out much more easily. almost 20 years as a framebuilder the best brand I've ever used is manufactured in Brazil's brasdak. waterborne hot for some time is the best solution. removes better than a full day immersed in cold water.