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Discussion Starter · #1 ·
This is the next step in the build process for my custom frame from Mike Zanconato up in Worcester, Mass. First we chose lugs: http://forums.roadbikereview.com/showthread.php?t=46871

Tubes and lugs came in. The tubes are Dedacciai Zero (aka SAT 14.5). The steel importer is Joe Bringheli is Ohio: http://forums.roadbikereview.com/showthread.php?t=49006

Then he built a fork: http://forums.roadbikereview.com/showthread.php?t=49478

Then he mitered the tubes: http://forums.roadbikereview.com/showthread.php?t=60591

Now he is going to braze the tubes. In my first photo, the front cluster is pinned and fluxed and ready to be brazed. It's done in a jig whether the builder is using pins or tack brazing. Because the angles fit together so well, Zank said, he was able to pin it and it stayed aligned. If he has to bend the lugs on some unusual design, sometimes he must to tack it. Pins are finishing nails driven into small-diameter holes in the lugs and tubes.
 

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Discussion Starter · #2 ·
More flux

Seat cluster and BB shell with silver-brazing flux. Flux is basically an acid that cleans off the oxidation on the tube and allows the brazing material to wet the surface of the steel.
 

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Discussion Starter · #3 ·
After brazing

Just after brazing. You can see how when he increases to brazing temp (1100F-1200F) the flux becomes translucent and watery. He always feeds the silver braze from the down tube side or top tube side toward the seat tube. The spot of silver on the lower lug is brazing material that has encapsulated the pin.
 

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Discussion Starter · #4 ·
He soaks the flux off with hot water. You can see the pins and how the silver comes up around them. He will file down the pins with a small half-round file. The brazing has been sucked underneath the lug by capillary action. (The heat from the torch draws in the brazing material.) It leaves a clean line of silver around the lugs.
 

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Discussion Starter · #5 ·
A look at the front cluster after he has bead blasted it. (Bead blasting is like sand blasting with much softer material--some even use walnut shells). You can actually see the silver around the edges.
 

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Discussion Starter · #7 ·
More work on the seatstays

1. He has brass-brazed the caps to the tops of the tubes. Brass braze can get hotter (~1700F), so when they are eventually brazed to seat tube cluster with silver (at lower temps), the torch won’t remelt the caps.

2. he has trimmed the excess off with a grinding wheel and hand filed them.

3. The completed seat stays ready to be brazed to the seat cluster.

That's it for this round of photos. Next week, photos of the finished bike and the wheels.
 

· Downhill Juggernaut
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This is awesome, as I'm getting ready to try and build my first frame. The pics help me get a good idea of exactly what I've been reading about. Thanks for posting, and keep the pics coming!
 
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