Fillet Brazing Newb

[devlin]

First up. To all the guys that have somewhat mastered this technique I tip my hat. That shit is hard.

I started out to day by finally replacing the top tube in my ELOS frame. That went fairly well to script. Went with bronze for all the joints given that's what the frame was originally done with. A bit too much bronze went in so will need some extra clean up.

When I finished that I thought I'd mitre up some pieces and start to learn the art of fillet brazing. My god what a mess. I am pretty sure I used to much heat and when I think about it I may have held the torch too close when applying the rod as it seem too just flow all over the place. I couldn't seem to get any build up on the sides of each joint but could get some fillets going by using gravity so flow the filler down into the closed corners of the joint. Now that I think about it while I type it makes sense that I used too much heat. Maybe my flame was too big. I'm using LPG/Oxy How long should the inner cone be on the flame? I was running about 10-12mm I guess. Do I need a hot flame or run it a bit cooler and go in soft with the heat? I seem to remember that you get in quick and lay the fillet fast but maybe I'm confusing that with lugs brazing. I tried watching some videos to get a sense of timing but as you all know it takes time to get it right.

Some pictures below which I'd appreciate comments both good and bad. I know it's hard to diagnose wit out knowing time on the joint and flame setup. Using Cycle Design products. Thanks.


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[Doug Fattic]

Well lucky you. I’m here in Ukraine (but fortunately not in eastern Ukraine) where I am teaching Yuriy how to fillet braze transportation frames together with propane. You should know that for most people learning to fillet braze is difficult. As Yuriy says as I constantly correct him, his head understands what he is supposed to do (because he has heard me say it many times) but his hands don’t obey.

For starters make sure that if you are using a propane/oxygen flame, that you don’t have an oxidizing flame. It is easy to get a neutral flame with acetylene because the 2 inner cones are so distinctive. However with propane you have to see the slight color change of the inner cone turning from a slightly greenish to bluish. And whatever you do you don’t want it to start getting a bit purple. When I was demonstrating to Yuriy yesterday I noticed that brass didn’t want to stick to the surface of my tubes. What was happening was that the cheap regulators keep changing the flame setting and as I started to get a bit of an oxidizing flame the surface of the tubes got a bit black and brass would have trouble sticking. Everything was fine when I made sure I had a neutral flame.

2nd you need to use a smaller tip with propane when fillet brazing (but probably still bigger than acetylene). I use a Victor TEN-2 but it might even be better for a novice to use a smaller tip so they have more time to realize what is going wrong and make a change. The bigger the tip the faster you have to react.

What is happening in your case is that you are holding the heat too long on your joint. Effective fillet brazing is using your flame as an on/off switch to just keep the brass in the heat zone between melting and solidifying. You need enough heat to add brass and just as it starts to run away to where you want it to go or be, you turn the heat off.

3rd you have to use compact motions. Keep the brass as close as possible without melting the tip off and rotate the flame (instead of moving your entire hand) so the flame is just off of the joint in the off heat position. Students that have to move their brass any distance or take their time getting the flame on and off the joint just make messes.

Actually there are a lot more tips I have but I like to have my framebuilding class students have a real competitive advantage over those that think they can learn by trial and error and reading internet advice. In my case with Yuriy, I find that repeated demonstrations after explanations and then practice multiple times works the best. In other words I demonstrate and he sees part of what I do. Then he tries it and after that - when I demonstrate again - he can see more of what I am doing. There is a lot going on like what is the angle of the flame and how far is the tip from the joint, etc. It looks so easy when a pro does it that the subtleties are missed unless everything is fully explained.

Doug Fattic - now in Bucha Ukraine where things are kinda normal unlike in the east where a pastor was kidnapped by soldiers without any insignia while preaching last week. The members asked what authority they had before they fled and they said their guns gave them all authority they needed. So far nobody has been able to confirm what actually happened because all of them in attendance are out of communication.

[devlin]

Thank you Doug. I do appreciate your advice and yes having now dived in I can see how the subtleties make the difference One thing I couldn't figure out is whether to melt the bronze with the tubes or the flame or a bit of both. Definitely though I could see I was doing what you were saying. Too far away with the rod, too close, too long with the heat, moving the whole arm etc. I think like your student says, seeing is only the start of the learning.

For me it's going to be a case of trial and error as their is no one near by me to go and watch. There also no frame building course of any value in Australia. I have heard one is supposed to be starting up but haven't heard any news of it since. I've tried looking at the local college course but I couldn't actually figure out which course was applicable.

Also appreciate you cannot give all your secrets away. After all your knowledge is your commodity and how you make a living.

[Todd Mosley]

Start practicing some basics first:
1. Practice heating the flux up, keeping it hot, but without burning it. Learn how much reaction time you have on a given setting. Experiment with different tips, long cone, short cone, etc. Start with a small tip then move up to bigger tips. Get really good at this before moving on.
2. Start practicing laying a string of beads on a flat surface. When you practice on a tube you are fighting gravity and you have to speed up your reactions. The flat surface removes gravity from the equation so you can focus on everything else that is going on.

There is a fillet-brazing thread in "the knowledge" section. If you haven't already, read through it.

[devlin]

Start practicing some basics first:
1. Practice heating the flux up, keeping it hot, but without burning it. Learn how much reaction time you have on a given setting. Experiment with different tips, long cone, short cone, etc. Start with a small tip then move up to bigger tips. Get really good at this before moving on.
2. Start practicing laying a string of beads on a flat surface. When you practice on a tube you are fighting gravity and you have to speed up your reactions. The flat surface removes gravity from the equation so you can focus on everything else that is going on.

There is a fillet-brazing thread in "the knowledge" section. If you haven't already, read through it.

Yes, the gravity thing....that sucked......it was killing me on top of the other issues.

[steve garro]

Take a piece of tube & flux it, and heat it up and see how long you can hold the workpiece right at the liquid point of the flux.

You'll see why after you try it.
- Garro.

PS - yep, it's a hell of a way to make a living…...

[emanuel]

get a length of tubing and lay beads along it. You'll see when it's too hot(spreads) and when it's too cold(adhesion probls).

As Doug says, on, off, on, off.

thicker tubing is easier than thinner.

Lay a straight, even bead, everytime.

then go onto tubing.

Basically, it's similar to sewing.

[Doug Fattic]

Thanks for reminding me to have Yuriy practice laying a bead along a tube! I started him with brass brazing dropouts to chainstays and that went fine but when we started doing practice fillets on round tubes things weren’t going so well. I’m here on limited time so I am pushing the time line but this is a reminder that good instruction starts with simple exercises and gets more complex as skills improve.

I suggest when you practice a fillet on round tubes to use one long piece and the other short. The reason for this is that with your one hand on the long tube, you can kept repositioning the intersection so that the top of each tube where you will be putting the brass are an equal distant angle from each other. If one is leaning over more then the other than the brass tends to flow more in that direction so there isn’t an equal amount of brass on each tube. This long/short method isn’t really wasteful since you can cut the practice end off the long tube and do some more with the loss of only a few centimeters each time. Actually you can do 2 across from each other before you need to cut them off.

I’m right handed so I create the fillet going from right to left. As my flame is melting the puddle, I’m adding brass to the bottom left of it. The edge of my flame is just at the very end of the rod. Most likely I lift the rod when I need instead of pulling away to the left. It is a more compact motion and easier to reposition again. It is a very common mistake that rookies place the flame a little more into the rod making it ball up on the end. You need the flame to melt the rod and not the heat of the metal. I can’t emphasize enough that the difference between success and a mess is very small differences in motions. Oh and your on off travel path should be along the fillet so the brass isn’t attracted by your heat placement someplace else.

Because the frames we are making over here in Ukraine use the thick true temper 33mm head tube (which if memory serves is 1.5mm thick) and the outside butted seat tube, we are practicing with the long 1 1/8” tube being .049” thick (1.25mm) and the short 1” piece1.0mm thick. Sorta similar to the real thing. We mitered the angle at 77º because that is what the top tube angles will be.

[PLAIN]

Personally I would avoid using Propane for fillets especially in the beginning of learning curve ,
Propane has a very slow reaction , once everything gets hot its difficult to control the fillet ,
also using lager flame gives greater heat affected area , that might cause a lot of heat distortion
and put you at risk of overheating in tight areas like DT/ST etc.
to my mind it's kind of advanced stuff and only skilled person can do it safely .

[devlin]

I went LPG for cost and storage reasons. Even the oxy bottle makes me nervous but I make sure I am doing everything right and am working on a process for my setup that I can repeat and work things out with. I also realise that it's harder for fillets but am prepared to put in the time to learn and achieve the skills. I'm am confident I can do this but also realise it will take some work. The good thing is I can understand the advice and can see where each point is pertinent.

Thanks.

[Doug Fattic]

Personally I would avoid using Propane for fillets especially in the beginning of learning curve ,
Propane has a very slow reaction , once everything gets hot its difficult to control the fillet ,
also using lager flame gives greater heat affected area , that might cause a lot of heat distortion
and put you at risk of overheating in tight areas like DT/ST etc.
to my mind it's kind of advanced stuff and only skilled person can do it safely .

Propane works fine for a rookie to braze fillets. It is true that it has different characteristics but with the right tips and settings and instruction my students have had no trouble using propane when fillet brazing. I let them choose whichever gas they want. In fact its slightly lower heat results in a slightly longer heat cycle (not a lot longer) which allows the rookie a bit more time to access what is going on and make the necessary adjustments easier. Part of Devlin’s problems are that it all happens so quickly he can’t process what is happening fast enough to react with precision quick enough and then the brass sags and goes somewhere he doesn’t want it to go. And not being exactly sure what to do makes things even worse. Slightly hotter acetylene won’t correct that problem. It is important to use a smaller propane tip when fillet brazing than one would use with lugs. I like a Victor TEN-2 but it might be wise to use a TEN-1 to slow things down even more and have a more focused heat zone. Vladimir is right in that the way many use propane with large tips producing large flames for even heating of things like fork crowns doesn’t work for doing fillets.

[devlin]

I think what you described was right on the money. Too much heat, too big a tip, not knowing how to react to the issue and happening at lightening speed. I somehow had in my mind to heat the tube so the tubes melted the bronze. That is now an obvious major error. I've already pick up heaps out of this thread so all is not lost. Hopefully I can remember it all in the heat of the battle but that's what the practice is for.

Thanks guys.

[emanuel]

Don't fuss about tips, gas, anything. sure smaller is easier. I started with a 3 tip, took six months of daily practice to click.
But it did.
Use what you have, get used to one thing.
keep at it.
practice daily.
Read what we say, but don't fuss over it, we're all saying the same thing, in completely differnt ways.
you'll only really understand it when you won't need to understand it.


that's it.

oh, and get someone with loads of experience to look over what you do. until you realize what you're doing wrong, and can self correct.
You'll be in a circle, not a spiral.

don't be afraid of heating, but be gentle. brazing is like stroking a cat.

Or woman you've had an argument with.

[devlin]

I hear you. Unfortunately I'll only have weekends for a while but as you said I'll make do with what I've got.

I used a smaller flame today. Center cone was about about 4-5mm long and the heat was much more manageable. There were times when I could see a nice puddle and I could feed the rod in and it's was peachy. I found the the tube easier as I could flick off easier than the flat. I did the tube first. One thing I noticed is my torch is heavy for this type of thing, I have strong hands and arms from rock climbing but it was still noticeable and the tip is along way from my hand which I can tell slows things down a little. I could see some difference and learned some more. I'm under no illusion that this will take some time and I'll stick to lugged frames for the meantime.

Thanks for the advice guys, I really do appreciate it.

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[emanuel]

Take a piece of tube & flux it, and heat it up and see how long you can hold the workpiece right at the liquid point of the flux.

You'll see why after you try it.
- Garro.

PS - yep, it's a hell of a way to make a living…...

looking at your effort I suggest you read this again.
he's right.

both times.

[steve garro]

don't be afraid of heating, but be gentle. brazing is like stroking a cat.

Or woman you've had an argument with.

Dude……

\m/ \m/

- Garro.

[Doug Fattic]

Today Yuriy practiced brass brazing by melting a straight line on a tube. I changed the tip from a Victor TEN-2 to a TEN-1. This really helped because at 1st his reaction time was a bit slow creating a too wide and messy melting pattern. Furthermore his off flame direction created a heated side path that attracted brass away from a straight line. When he started using the smaller tip, it gave him more time to better understand and adjust to the circumstances on the tube and his confidence level went up. Once a person starts to feel some sense of being in control, their practice can become more focused. As a teacher I am very aware of the negative effects of frustration when a student isn’t catching on. Nothing kills motivation like a bad attitude from poor results. After about three 10cm lines his compact on/off motion got snappier (which stopped the side path flow and his melt became more consistent) and his repositioning became more precise (so he wasn’t melting brass off into space or too far in front of the puddle). His line got straight with a consistent width. We tried a TEN-0 tip but that was too small to work effectively on the materials he was practicing with. Eventually we started to run out of oxygen so I went back to making a sample frame so he could copy the steps with drawings and video in Russian. This is the reason I love my oxygen concentrator at my home shop. There is an endless supply of air to convert into almost pure oxygen. I don’t have to stop at inconvenient times to lug some heavy tank to the welding supply store where I have to pay money for a full one. The start up cost of a concentrator can be less than buying a decent sized tank and regulator too. But I digress.

The best students can learn with almost any kind of equipment and the very worst aren’t going to catch on no matter what they use but those in the middle of the bell curve (particularly the lower middle) really benefit with the right equipment (and expert instruction) – which is the right brass and flux using a light torch and hoses. I’m repeating again the obvious but the difference between being successful and not is very little. Small details matter. Framebuilding forum posts are not likely to come from those that don’t succeed so online advice is most likely to come from the most talented that can make anything work.

[Jonathan]

All I've got to add is if you slip someone who knows what they are doing $100 to look over your shoulder for an hour or two you will probably save 2-3x that in gas and practice materials over the next few months.

[Mike Mcdermid]

These problems are often very simple and quick to fix

Head on over to the lincoln or miller website :-)

[devlin]

was a bit slow creating a too wide and messy melting pattern. Furthermore his off flame direction created a heated side path that attracted brass away from a straight line.

This is exactly what I was getting on the flat. The metal beyond the puddle was getting hot as well and drag the bronze across. You can see the flare. Is this a matter of working out a the right angle for each scenario? As I was going along I could see when it was getting too cold and when I was dwelling too long with the flame.

I did what Garro suggested with the flux. I'm using the Cycle Design flux and it seems to bead up rather than stay as a continuous glaze. Is that normal? Too hot, too cold? With the silver flux you seem to have so much more margin compared to the bronze flux. After doing the bronze practice and going back to the silver for some fittings on a frame I'm repairing the silver seemed easy.

I looked at oxy concentrators here in Australia. For a refurbed one the best I could find was nearly $1k. Even a good one on eBay recently went for $750 and I just didn't have the cash for it at the time. I've asked a couple of the suppliers in the US and they were reluctant to ship it out. So Bottle for me and I'm only paying $65 for 3 months plus the fill. It's going to take me a while to get through it.

Keith Marshall from Kumo gave me some of his valuable time a couple weeks ago but we didn't get a chance to do any brazing. There was a whole heap of other stuff I was able to learn from him at the time though and it made such a difference to the way I looked at the whole frame building game. ie. if I wasn't hooked before I certainly was after the chat. Unfortunately he is a 2 hour plane flight away. The other closest builder is Dazza. I've asked him in the past about learning from him and he was hesitant to go there. Maybe a couple hours one day he might be ok with. He is only 30 mins away so maybe I'll call him and see what he says. Other than that I have to do it in isolation. I've procrastinated up till now because of that but if I want to build, even if means I'm only part time then I have to get in and get my hands dirty.

Thanks again for the advice.