Fillet brazed and Bi-laminate bikes = Sexy

[pdonk]

If you have hours to waste and want to see many Ritcheys check out

https://ritchey.vintagebicycledatabase.com/listing.php

I will also always point out how nice the seat cluster looks on a dekerf.

[cadence90]

Originally Posted by David Kirk

A bit of a different take on fillets - Gothic Webbed fillets for NAHBS 2017.

dave

Holy smoked salmon from wherever the best salmon are caught.Wow, beautiful.

Dave, is this a one-off only?

The brass "webs" are as strong as the tubes, correct? How do you form them?

I am curious as to why you choose to go with a simple uni-crown fork on this frame? You wanted something simply curved at the crown, etc.?

Very nice work.
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[Kobe]

Originally Posted by Gsinill

What an awesome color combo.
Do you know what color/paint code was used for the frame?

Thanks, the powder coater was not able to do my first choice, thankfully. As soon as I took it out of the box I thought it came out exactly as I wanted it.

The code is Misty Midnight P-4239B.
https://www.prismaticpowders.com/col...FUpZhgodudECLg

[David Kirk]

Originally Posted by cadence90

Holy smoked salmon from wherever the best salmon are caught.Wow, beautiful.

Dave, is this a one-off only?

The brass "webs" are as strong as the tubes, correct? How do you form them?

I am curious as to why you choose to go with a simple uni-crown fork on this frame? You wanted something simply curved at the crown, etc.?

Very nice work.
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Thank you.

So far it is a one-off but I have some on order that will be built in the next 6-7 months.

Forming them is tricky and if one knows what to look for, and looks very closely, there are clues to how it's done in the photos. It's up to folks to figure it out.

Fork - Some of the worst riding forks ever made are unicrown forks and while the look would match well I just couldn't do it. So I selected this simple curvy crown that in internal (crown goes into the blades instead of the other way round) so it would have a all-of-one-piece seamless look under paint.

dave

[cadence90]

Originally Posted by David Kirk

Thank you.

So far it is a one-off but I have some on order that will be built in the next 6-7 months.

Forming them is tricky and if one knows what to look for, and looks very closely, there are clues to how it's done in the photos. It's up to folks to figure it out.

Fork - Some of the worst riding forks ever made are unicrown forks and while the look would match well I just couldn't do it. So I selected this simple curvy crown that in internal (crown goes into the blades instead of the other way round) so it would have a all-of-one-piece seamless look under paint.

dave

OK, thanks. I'll Poirot the brass-web photos more closely...but I doubt I'll find any clue...I am not a frame-builder.

Now I understand; I didn't think you would produce a basic, standard uni-crown fork for such a lovely frame.
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Is the arrow pointing at a clue? An architectural/structural element found on Gothic arches, etc.?

[David Kirk]

Originally Posted by cadence90

OK, thanks. I'll Poirot the brass-web photos more closely...but I doubt I'll find any clue...I am not a frame-builder.

Now I understand; I didn't think you would produce a basic, standard uni-crown fork for such a lovely frame.
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Is the arrow pointing at a clue? An architectural/structural element found on Gothic arches, etc.?

Maybe....maybe not.

dave

[v531xc]

Originally Posted by YoKev

Really leaning towards Chapman (a northeast based builder is important to me). Giddyup

would totally recommend working with Brian. I love the bike he built me, and here's a couple photos of it:

[fiamme red]

I've always liked fillet-brazed Mosers like this one: http://www.ebay.com/itm/Moser-leader...a/122724442982.

[uno-speedo]

My 1982 Salsa Scoboni. Number 7.

[moobikes]

Awesome Salsa.
“ Scoboni” isn’t a model name, is it?

[MikeD]

Originally Posted by David Kirk

I don't say this to try to change your mind nor to say you are wrong. If you don't get turned on by fillets I more than respect that.



I suppose the reason I write is to comment on the word "spackled"........it may come as no surprise that I would not chose that term for top shelf fillets. The laying of a tight fillet is every bit as neat and fastidious as laying tig beads and is quite the opposite of what some might think......that a lot of brass is schmeared on with little care and then filed down to look good. A skilled fillet guy will lay the brass in such a way that shaping and polishing the joints takes nothing more than emery cloth and a short period of time.



Fillets are heavier than tig beads but the amount heavier is often a surprise. Typically the brass used to make the fillets contributes about 2 oz of weight to the frame compared to tig welded construction. Most people find that surprising and expect it to be much more.



As a 'form follows function' guy I think you might appreciate the fact that more often than not a well built fillet frame will have better fatigue resistance than a tigged bike and the ultimate strength can also be higher depending on the tubes used. The thing is that laying of fillets only bring the tubes up to about 1800° F which is much lower than the typical 3500° F used in tig construction. The key difference here is that the heat needed for fillets is low enough that the molecular structure of the tubes isn't altered so the tubes don't lose vital strength during the process. On the other hand tig welding gets the material much hotter and this very often compromises the strength of the tubes and lowers its fatigue resistance. This is why we so seldom see a fillet joint, or the adjacent tube, fail and why it's much more common to see a solid tig joint hold up very well only to have the tube next to it (in the heat affected zone) fail.



Combine this with the fact that the typically larger size of a fillet joint is better at distributing the loads compared to a tig joint and I personally see fillets as being the ultimate 'form follows function' way to hook together steel tubes.



The real downside of fillets is that they are time consuming to make. Tig welding is much faster and then the joint is done, it's done. With fillets it takes longer to lay the fillet, and then the flux needs to be removed, and then typically they are polished to get that classic fillet look. This all take time and in that way tig welding has a real advantage over fillets - and this is of course why the industry moved from fillets (and lugs) toward tig welding. Welding saves time and time is money and that is important.



In the end all three of the popular ways to join steel tubes can make a very nice bike and of course if the tubes are the same the bikes will ride just the same. That said the properties aren't always as they seem and there are hidden advantages/disadvantages for each way of hooking tubes together. Like everything there is compromise and the buyer gets to choose which compromise is best for them.



Thanks for reading - as usual I got wordy and I apologize for that. Have a great weekend.



dave

Brazed fillets look great and I'm by no means disparaging them, but isn't the braze material weaker than the weld rod used to make a tig weld (which is as strong as the tubing)? This means that the brazed fillet would need to have a larger throat thickness than an equivalent tig weld would to achieve equivalent strength. I've seen some pretty small brazed fillets. That concerns me when I see stems and forks with tidy fillets.

Also, isn't there tubing that's specifically made for welding, having thicker butts, which make up for loss of strength in the heat affected zone?

[v531xc]

Originally Posted by uno-speedo

My 1982 Salsa Scoboni. Number 7.

That's cool! would love to see more photos of this. The top tube/seat tube junction looks a lot different from the couple I've seen (#4 and #5) where the top tube pierced the seat tube.

[fiamme red]

I was really impressed when I first saw a Casati (a fellow club member had bought one from R&A). I loved the smooth fillet brazing, the internal cable routing, and paint job.

Contrary to what the eBay seller writes, this one is fillet-brazed, not TIG-welded.

https://www.ebay.com/itm/53x54-CASAT...-/302566790351

[cadence90]

Originally Posted by fiamme red

I was really impressed when I first saw a Casati (a fellow club member had bought one from R&A). I loved the smooth fillet brazing, the internal cable routing, and paint job.

Contrary to what the eBay seller writes, this one is fillet-brazed, not TIG-welded.

Very clean. I love Casatis, and really respect how they have transitioned into the current era without losing their soul. Unfortunately I rarely if ever see decent used ones for sale in my size. Fillet-brazed in 58.5 TT....
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[Ciavete]

Gothic

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