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flag madmonky
Posted: Nov 27, 2015 at 16:00 Quote
That's awesome, how do you find brazing for strength?
flag dump
Posted: Nov 27, 2015 at 16:03 Quote
That looks really clean! What are you using for your pivot? I also assume you calculated the seat tube length correctly for your dropper Smile
flag shirk-007
O+
Posted: Nov 27, 2015 at 16:31 Quote
madmonky wrote:
That's awesome, how do you find brazing for strength?

A properly brazed joint will be stronger than the tubes used to build the bike.
flag happy-gilmore
Posted: Nov 27, 2015 at 18:44 Quote
simon477 wrote:
Got this 6 inch trail bike together for a test ride before powder coat.
photo

nice work, the geometry looks good
flag simon477
Posted: Nov 27, 2015 at 18:52 Quote
dump wrote:
That looks really clean! What are you using for your pivot? I also assume you calculated the seat tube length correctly for your dropper Smile
I machined a piece of tube to take 32x12mm bearings then used a 12 mm bolt for an axle.
Yep got the seat tube the right height to start with.
flag simon477
Posted: Nov 27, 2015 at 18:55 Quote
shirk-007 wrote:
madmonky wrote:
That's awesome, how do you find brazing for strength?

A properly brazed joint will be stronger than the tubes used to build the bike.
Agreed, I've done a lot of testing with a big hammer and bending with big bars and the joints seem amazingly strong! I'd let someone else ride rampage with a brazed frame.. done right
flag phutphutend
Posted: Nov 28, 2015 at 13:02 Quote
Any help with stopping distorted seat tubes?

I sometimes find my seat tube has distorted at the braze to the top tube. The is obviously caused by fixing the distorted heated shape into position as the braze cools. I've tried tacking each of the four points individually then letting cool between each, but this doesn't always work. The mitres are cut on a hole saw and tight. I'm brazing to the thick butted portion of the seat tube.

Any help please? What's the magic I'm missing?
flag simon477
Posted: Nov 28, 2015 at 13:15 Quote
phutphutend wrote:
Any help with stopping distorted seat tubes?

I sometimes find my seat tube has distorted at the braze to the top tube. The is obviously caused by fixing the distorted heated shape into position as the braze cools. I've tried tacking each of the four points individually then letting cool between each, but this doesn't always work. The mitres are cut on a hole saw and tight. I'm brazing to the thick butted portion of the seat tube.

Any help please? What's the magic I'm missing?
I've had the same issues! I ended up machining a solid steel rod to slide in there when welding, stopped any distortion, works a treat!
flag phutphutend
Posted: Nov 28, 2015 at 13:22 Quote
simon477 wrote:
phutphutend wrote:
Any help with stopping distorted seat tubes?

I sometimes find my seat tube has distorted at the braze to the top tube. The is obviously caused by fixing the distorted heated shape into position as the braze cools. I've tried tacking each of the four points individually then letting cool between each, but this doesn't always work. The mitres are cut on a hole saw and tight. I'm brazing to the thick butted portion of the seat tube.

Any help please? What's the magic I'm missing?
I've had the same issues! I ended up machining a solid steel rod to slide in there when welding, stopped any distortion, works a treat!

Did you leave it in just for tacking? Sticking a big heat sink in there isn't going to help with getting the braze to stick?
flag simon477
Posted: Nov 28, 2015 at 14:34 Quote
phutphutend wrote:
simon477 wrote:
phutphutend wrote:
Any help with stopping distorted seat tubes?

I sometimes find my seat tube has distorted at the braze to the top tube. The is obviously caused by fixing the distorted heated shape into position as the braze cools. I've tried tacking each of the four points individually then letting cool between each, but this doesn't always work. The mitres are cut on a hole saw and tight. I'm brazing to the thick butted portion of the seat tube.

Any help please? What's the magic I'm missing?
I've had the same issues! I ended up machining a solid steel rod to slide in there when welding, stopped any distortion, works a treat!

Did you leave it in just for tacking? Sticking a big heat sink in there isn't going to help with getting the braze to stick?
Yep left it in the whole time, i spent a long time getting the whole area up to temp, the braze seemed to go well. Once cooled the rod tapped out surprisingly well and everything was straight.
flag madm3chanic
Posted: Nov 28, 2015 at 16:14 Quote
phutphutend wrote:
Any help with stopping distorted seat tubes?

I sometimes find my seat tube has distorted at the braze to the top tube. The is obviously caused by fixing the distorted heated shape into position as the braze cools. I've tried tacking each of the four points individually then letting cool between each, but this doesn't always work. The mitres are cut on a hole saw and tight. I'm brazing to the thick butted portion of the seat tube.

Any help please? What's the magic I'm missing?

i made a thing with two long taper cones with a 12mm allthread section going up the guts of them. i cut a piece of heave walled water pipe into three long pieces and put them against the tapers and jam it down the seat tube. crank the allthread and the cones pull in and squash the pipe outward. always worked for me Smile

cept once i welded one of the pipe sections to the inside of a really thin walled seat tube, had to pry it off with a long screwdriver and kinda bent it and slightly distorted the seat tube wall. funny in hindsight...
flag prophet413
Posted: Nov 29, 2015 at 20:55 Quote
Anybody here ever order from solid bikes?
flag madm3chanic
Posted: Nov 29, 2015 at 22:19 Quote
yep, the're good. the 30.9mm seat post insert thingies they sell dont really work tho.
flag prophet413
Posted: Nov 30, 2015 at 6:10 Quote
Great, went to order and got sketched out for some reason

 


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