Fillet Pro

[Dornbox]

I just built a 29er with Fillet Pro. I welded the BB cluster with my TIG, used LFB on the dropouts, and FP on everything else. I must say that I didn't use nearly as much as I though I would have. I consciously kept the majority of the fillet inside the tube and did very little exterior fillets. Prior to doing this, I bench tested a few joints with just the wicking pass as seen in Tim's top three photos. The joints were plenty strong enough to hang with prying, bashing, and general mutilation. In fact, I've done the same thing with 45% and had the same results. If you want a clean small fillet look, it's not that bad on the budget, and damn strong.

Just my 2¢!
Chris

[Freddy]

Thanks Chris,
"Fillet Pro" leaves more copper than 45 is all, and that solid copper deposit is where the joint integrity is.
The leader elements it the rod and the flux allows a more complete adherence.
What I like the most about a silver bearing bronze is how simple it is to create a nice sound inner fillet.
I can quote the engineer for the largest industrial brazing firm in this world that he doesn't understand what bike builders see in large outside fillets?
"Quote a sound fillet must be inside and out and all edges encapsulated in the alloy filler"
I am glad you tested things on your own and found that the product is everything I said it was.

Thanks Chris

[NBC]

hi all,

sorry to raise this post from the dead,

reading in to this, it's seeming that the benefits of the fillet pro over brass rod can outweigh the extra costs involved ?

i was thinking of a fillet brazed spirit frame,(spirit megatubes) however 0.5mm tubing sounds like it could be troublesome

does the lower temperature involved make a significant difference regards to long term durability of the frame ? or am i doomed to failure from the start ?

also without risking sounding dumb, do you use the system 48 flux with fillet pro rod ?

thanks

NBC

[e-RICHIE]

hi all,

sorry to raise this post from the dead,

reading in to this, it's seeming that the benefits of the fillet pro over brass rod can outweigh the extra costs involved ?

i was thinking of a fillet brazed spirit frame,(spirit megatubes) however 0.5mm tubing sounds like it could be troublesome

does the lower temperature involved make a significant difference regards to long term durability of the frame ? or am i doomed to failure from the start ?

also without risking sounding dumb, do you use the system 48 flux with fillet pro rod ?

thanks

NBC

Nathan - I use regular brass rod and the blue paste flux for all my lugless joints. It's the regular no-fuss material sold by The Gas-Flux Company in Ohio.

How many joints have you brazed (so far)? If i were you (and I'm not) I'd line up 20-30 miters and spend a few hours just brazing in order to get a sense of things. Maybe do it again the next day and the day after that. When all of the mechanics start resonating, you'll understand what I mean when I say that the integrity of a frame, its durability, is far more tethered to the skill of the brazer than it is what he used to join the pipes atmo. In other words, the filler doesn't matter as much as you do.

[NBC]

richard,

2 lugless frames, and some practice parts, and a few that didn't go so well ! definitely going to practice more before i begin on the really nice stuff !

point taken about the filler rod being an insignificant factor in durability,

is there a point where you'd feel a tube is just too thin to even think about using ?

thanks

nathan

[e-RICHIE]

richard,

2 lugless frames, and some practice parts, and a few that didn't go so well ! definitely going to practice more before i begin on the really nice stuff !

point taken about the filler rod being an insignificant factor in durability,

is there a point where you'd feel a tube is just too thin to even think about using ?

thanks

nathan

Yes - the point is now. With so little experience with a torch and metal, I would say you've met your match. My advice is to put the framebuilding on hold and become a brazer. See my comments above. Since you are going the self-taught route (a road I basically took to reinvent myself in the mid 1970s), get a load of pipe and filler, and develop a routine that allows you to perform a certain task repeatedly until you are simultaneously sick and bored with it yet also know it intimately. After that, move to another task etc etc. Then, braze the frame.

[Curt Goodrich]

I agree with Richard. Fillet pro will have a lower melting point and this will reduce the chance of heat damage. But ultimately it's the brazer's experience and skill that will determine the degree to which heat damage will occur. Given your lack of experience I'd wait a little while before using those tubes.

[hmbatrail]

I would strongly encourage you to NOT use Fillet Pro until you have your brazing chops down with brass. To get up the learning curve fillet brazing using silver will cost orders of magnitude more than just buying regular brass rod and going to town.

If you can comfortably lay a solid fillet with brass then shifting to silver is easy peasy. And will save you loads of money.

[Will Neide]

The Fillet Pro reacts and flows much differently than bronze. Much less heat, watch the flux, and really pay attention to when the silver melts. It moves fast! Tiny flame and great heat control. I really like brazing with fillet pro, but I only use it on stainless or attaching stainless to 4130 (financial reasons). I haven't played with system 48, and I stick to Fillet Pro with Stainless Light. Cycledesigns has a good write up on System 48 on their page.

[NBC]

more practice it is then !

most of my experience so far, and i know it's not very much at all, is with lugs

when you do practice fillet joins, do you file and sand the joints at all ? or are you practicing purely the laying down of the fillet ?

do you also cut all the joints open ? or just pick a few ?

thanks

nathan

[e-RICHIE]

more practice it is then !

most of my experience so far, and i know it's not very much at all, is with lugs

when you do practice fillet joins, do you file and sand the joints at all ? or are you practicing purely the laying down of the fillet ?

do you also cut all the joints open ? or just pick a few ?

thanks

nathan

Just line em up, braze em en masse (that's french...), and get a sense. If you must, saw them up. Or file them. But only if you must. I'd recommend not, and simply waiting until the light goes on. You'll be a more complete brazer if you take that chance. Failing all this, I'm sure there's YouTube you can watch, or someone else who can tell you how to do all this so that, by Saturday, you can braze that frame.

[NBC]

richard,

i'm certainly not going to rush in to a frame like that yet, i hate the idea of someone getting hurt, even if it's accidental, by a frame failure caused by being too eager and misjudging my ability

thanks

nathan

[e-RICHIE]

richard,

i'm certainly not going to rush in to a frame like that yet, i hate the idea of someone getting hurt, even if it's accidental, by a frame failure caused by being too eager and misjudging my ability

thanks

nathan

Oh yeah - that much I got. But I was trying to reoveremphasize again the importance of learning by practice. I wouldn't trust the advice of someone who's built 4-5 frames. His shoulder might be okay, and his encouragement, too. But if you want a fighting chance to understand this brazing and fab stuff, you have to do the work, and then do it again and again. Thanks.

[Eric Estlund]

A couple of thoughts, in no particular order:

- Your torch is about 6000 degrees, and about 4000 of those are above the melting point of bronze or silver filler (both of which melt within a mere couple hundred degrees of each other). If you are going to over cook it, you are going to overcook either. "Heat control" has as much to do with keeping everything cool enough as it does hot enough- you want to find that balance.

- Practice joints come in two flavors- joining practice and clean up/ shaping practice. Missteps at either could kill a frame, especially fillet undercut on a .5mm tube. Finish work is very important, but should be treated as a stand alone skill. Both will inform the other, but get the stuff to join first, then learn to make it pretty. Advanced skills will help you learn to shape the fillet on the torch end, but that comes AFTER learning the basic skills.

-Super light tubes save a very modest amount of weight when one looks at a complete bicycle. Build with some thicker stuff and know that you can still have a killer bike.

Personal anecdote- like Richard and Curt, I did this for someone else before I did it on my own. I'm not sure how a single operator would go about getting the numbers up, but it was vital in my own development. When Richard suggests knocking out 20 practice joints we need to realize that is just a drop in the proverbial bucket. I reviewed a few numbers from my production days, and in a year I was looking at:
- Used 50gallons of gas flux
- Lit my torch 43,000 times
- Brazed on 55,000/ 60,000 braze ons
- Used 29,500 ft (about a 5.5 miles) of brazing rod weighing approx. 190lbs
- Brazed around 1500 single bikes, 200 tandems and 1700 or so forks

I was only in industry for a couple of years, but that is a whole lot of experience I would never be able to replicate on my own. For new folks starting out I can only suggest putting your head down and committing to getting some volume practice pieces. I know that I still figure out new and better approaches every time I get into the shop. The "ah ha" moments are generally smaller, but they still happen regularly, and they happen because I am pushing and searching for them.

On a side note, I have never used fillet pro, so I have no specific feedback there.

Best of luck, and keep on pushing!

[e-RICHIE]

This should be a tee shirt or at least required reading for anyone visiting this forum atmo...

Personal anecdote- like Richard and Curt, I did this for someone else before I did it on my own. I'm not sure how a single operator would go about getting the numbers up, but it was vital in my own development. When Richard suggests knocking out 20 practice joints we need to realize that is just a drop in the proverbial bucket. I reviewed a few numbers from my production days, and in a year I was looking at:
- Used 50gallons of gas flux
- Lit my torch 43,000 times
- Brazed on 55,000/ 60,000 braze ons
- Used 29,500 ft (about a 5.5 miles) of brazing rod weighing approx. 190lbs
- Brazed around 1500 single bikes, 200 tandems and 1700 or so forks

I was only in industry for a couple of years, but that is a whole lot of experience I would never be able to replicate on my own. For new folks starting out I can only suggest putting your head down and committing to getting some volume practice pieces. <cut>

[edoz]

Man, I already knew how to braze pretty much and I went through 40ft of chromoly tubing before I bought my first tube set.

[EricKeller]

Man, I already knew how to braze pretty much and I went through 40ft of chromoly tubing before I bought my first tube set.

Not to pick on Nathan, but some days I think that we shouldn't answer any questions until someone shows us the results of their woodshedding. And for as little as I braze nowadays, I warm up on something I don't care much about before I braze on something I do care about.

I have had good luck with fillet pro, but I have never used it on main triangle joints. It's nice, but it's harder to deal with than LFB for me.