# fillet braze



## tidi (Jan 11, 2008)

what are the down sides of a fillet brazed steel frame as opposed to TIG weld? i have the opportunity to get a de rosa with fillet brazing but don't know much about it.


----------



## Touch0Gray (May 29, 2003)

none that I know of.....sure is better looking if it's done well


----------



## DaveT (Feb 12, 2004)

tidi said:


> what are the down sides of a fillet brazed steel frame as opposed to TIG weld? i have the opportunity to get a de rosa with fillet brazing but don't know much about it.


If there were two bikes, identical in all ways except one was TIG welded, the other was fillet brazed, the TIG'd bike would weigh very marginally less. Nothing else. [Editorializing] The Fillet brazed bike would be much more beautiful of course. [/Editorializing]


----------



## moschika (Feb 1, 2004)

tidi said:


> what are the down sides of a fillet brazed steel frame as opposed to TIG weld? i have the opportunity to get a de rosa with fillet brazing but don't know much about it.


you'll regret not choosing the fillet braze, if you get the tig, but not the other way around. btw, never heard of a fillet brazed de rosa. pics?


----------



## holy cromoly (Nov 9, 2008)

From my experience, I have never detected a performance difference.

If given the choice, I would go for fillet braze anyday.


----------



## terry b (Jan 29, 2004)

The major downside to fillet brazing is that once you see it, you'll never want anything else again.


----------



## holy cromoly (Nov 9, 2008)

terry b said:


> The major downside to fillet brazing is that once you see it, you'll never want anything else again.


It's true. After looking at a fillet brazed frame, TIG frames are going to look like toothpaste joins. Single pass TIG aluminum frames being the most toothpasteof them all (looking at my Nashbar TIG frame as I typed that).


----------



## Touch0Gray (May 29, 2003)

I like this thread!


----------



## Peter P. (Dec 30, 2006)

I never heard of a fillet brazed DeRosa. Are you sure it's not TIG welded?

A plus to fillet brazing is, if a tube ever had to be replaced, it's easier to heat and separate the tubes because there's not lug to disconnect from. But that benefit is really for builders, not consumers.

On plus for consumers is fillet brazed frames are easier to clean because there are fewer nooks and crannies. I have a fillet brazed Bilenky Signature Clubsman. No problems.


----------



## misterdangerpants (Oct 23, 2008)

Good thread over on MTBR about TIG versus Brazing.

Specifically, here's something from Ted Wojcik:

*Welding disciplines*

Very few frames fly apart from using either technique. So which technique the builder uses should be based on the skill he/she has command of to build a sound frame. When I started joining tubing it was on British motorcycle frames in the 60's. TIG was reserved for aircraft, aluminum and I first came across it on Rickman motorcycle frames. After talking with a number of racing M/C frame makers, I became aware of the advantages of TIG welding. Speed, light weight, (brass is heavy), and if done correctly, the joint can be almost homogeneous. You won't see many structural Chro-mo aircraft tubes brazed together Before bicycle tube makers made air-hardening steels available, fillet brazing (bronze welding) temperatures took the tubes above the critical temperature that cause grain growth and it would anneal the tube to make it dead soft. Then Tom Ritchey introduced short butted, heat treated tubing intended to be ideal for TIG welding and small fillet brazing done by those with a high degree of heat control. High quality TIG equipment is expensive and requires a skill to join the very thin gauge tubes that not everyone is going to acquire. There seems to be some builders claiming that there is advantages to heavy gauge, bomb proof (?) tubing that is fillet brazed. Remember that a frame works like a spring in many cases and that is why I would choose one of the "super steels" in a very light gauge to make a frame of the highest strengths and to provide a ride that is lively and exciting. There are not a lot of builders TIG welding tubes of .6mm or thinner. That skill level comes after years of practice and many frames.


----------



## deadlegs2 (Oct 3, 2009)

fillet brazed steel? Someone show an example


----------



## DaveG (Feb 4, 2004)

*have one*



deadlegs2 said:


> fillet brazed steel? Someone show an example


My Coppi Genius using fillet brazing for the two head tube connections (lugs elsewhere). It certainly looks better than a weld, although the brass probably adds weight over welding or even lugs. Here is a picture of the frame before I built it up (with Centaur)


----------



## deadlegs2 (Oct 3, 2009)

Thanks.. I knew TIG was the rage a few years back but I didn't notice filleted steel.


----------



## misterdangerpants (Oct 23, 2008)

deadlegs2 said:


> fillet brazed steel? Someone show an example


A few examples from a recent thread (bottom brackets) on MTBR:

View attachment 182982


View attachment 182983


View attachment 182984


View attachment 182985


----------



## Touch0Gray (May 29, 2003)

sweet, I love the way he/she filled in the sharp angles on the lugs......it makes the lines so smooth and fluid


----------



## Mel Erickson (Feb 3, 2004)

Not dissing filet brazed joints in any way but after a frame is painted can anyone tell the difference between tig welded joints that have been ground and filet brazed joints by just looking at them?


----------



## Scooper (Mar 4, 2007)

deadlegs2 said:


> fillet brazed steel? Someone show an example


Here's a fillet brazed head tube by David Kirk:










Here are examples of head tube/top tube joints (top to bottom) lugged, TIG welded, fillet brazed:


----------



## Touch0Gray (May 29, 2003)

Dave does incredible work from what I have seen. Tig is industrial....fillet brazing is an art form.


----------



## laffeaux (Dec 12, 2001)

Mel Erickson said:


> Not dissing filet brazed joints in any way but after a frame is painted can anyone tell the difference between tig welded joints that have been ground and filet brazed joints by just looking at them?


Fillet brazing is used on steel tubes.

Grinding down TIG welded aluminum frames gives a similar appearance to a fillet joint. However, I'm not sure that it's possible to fillet braze aluminum tubes.

For TIG welded steel, filling down the weld bead may leave very little material left in the joint. So yes, it's pretty easy to a TIG joint from one that is fillet brazed.

The only real downside of the fillet brazing is the cost. It requires more work for the builder since the miters need to be perfect, so the cost of a frame is more. But it does look nice.


----------



## davidka (Dec 12, 2001)

FIllet brazing used to be marginally stronger than tig because here was less loss of heat treatment in the steel due to lower heat of brazing. That's over now, most top-end steels have some type of air hardening property (ala Reynolds 853) that allow them to gain strength in the weld zone. 

It sure does look good.


----------



## terry b (Jan 29, 2004)

These are what sold me.


----------



## george kraushaar (Jan 15, 2007)

I remember the old Lambert/Viking frames which were built by Yamaha had fillet brazed steel frames. The older frames were lugged.

I still like the look and art of a finely made lugged frame best, although I really can't tell any performance difference. My current bikes are tig welded steel.


----------



## caterham (Nov 7, 2005)

fillet brazed cinelli nuovo supercorsa


----------



## Pancho's Balls (Aug 15, 2009)

Those rear stays are most likely silver brazed.


----------



## Touch0Gray (May 29, 2003)

Pancho's Balls said:


> Those rear stays are most likely silver brazed.


wondering how you could tell? I do notice that the "line" is much finer, and I do know that silver would be a lower temp and easier to control possibly..?

The large and small tubes would present a bit more of a challenge as the two would not heat at the same rate. I love fillet brazing.......it's kinda what I do for a living on a much smaller scale.


----------



## Pancho's Balls (Aug 15, 2009)

Seat stays are typically silver brazed.


----------



## Mel Erickson (Feb 3, 2004)

Many frame makers grind down their fillet joints and some will grind tig welded joints. Material left is about the same in all cases. I'm just wondering if anyone could tell the difference after paint? I doubt it. I'm speaking of steel frames only.


----------



## laffeaux (Dec 12, 2001)

Mel Erickson said:


> Many frame makers grind down their fillet joints and some will grind tig welded joints. Material left is about the same in all cases. I'm just wondering if anyone could tell the difference after paint? I doubt it. I'm speaking of steel frames only.


Yes, it's very easy to tell a fillet joint from a TIGed one even under paint. A fillet joint has significantly more material. Look at the pictures in this thread. There's no way to file a TIG steel weld and add material to it to achieve this look.


----------



## Scooper (Mar 4, 2007)

laffeaux said:


> Yes, it's very easy to tell a fillet joint from a TIGed one even under paint. A fillet joint has significantly more material. Look at the pictures in this thread. There's no way to file a TIG steel weld and add material to it to achieve this look.


I agree; the smooth, large radius joints inherent in fillet brazing are very different in appearance from TIG welded joints. While I appreciate the appearance of a well executed TIG welded joint with small, even "dimes", to my eye it can't compete aesthetically with a well executed fillet brazed joint.

Here's a fillet brazed BB shell on an early seventies production Schwinn Super Sport. For additional strength Schwinn also brazed steel sleeves into the interior of its frame tubes at the joints.


----------



## caterham (Nov 7, 2005)

Pancho's Balls said:


> Those rear stays are most likely silver brazed.


 the toptube to seatube join is fillet brazed....sorry if my intent wasn't clear in the pic- it's the only close up photo i had of the seatcluster and imo,should have been obvious


----------

