Singlespeed & Fixed Gear - torching off braze-ons

hi folks,

so my buddy is about to rent a plumber's torch to do some work in his kitchen. i'm thinking i can use that torch to take off the cable guides and stops on my miyata 912 conversion. but i don't know ***** about this.

any tips?

will the heat ruin steel steel tubes?

muchas gracias,
a

....will the heat ruin steel steel tubes?

muchas gracias,
a


Short answer: Yes. especialy if you dont know what your doing.

Yes you can use a plumbers torch to heat the brass and pluck off the brazed cable guides.

If you are careful you will not alter the steel in any way.
a few tips:
the MAX possible temperature of a propane/air torch is 3700 F, this is after a while...

the MAX possible temperature of a mapp gas/air torch is 4700 F aka "supertorch"

your tubeset is probably comparable to reynolds 531 which has a workable limit of 2000 F some tubesets are as low as 1300 F. after which the properties of the tubes will change from heat.

brass brazing rod melts at about 1300 F, which is why on super high end bikes silver is used. Having stripped down a comparable miyata I'm postive it's put together with brass.

step 1: get some gel furniture stripper and strip off the paint in the area.

step 2: get some vicegrips and clamp onto the little bugger.

step 3: put on your welding goggles or buy/borrow some with a level of 4-5 (don't skimp)

step 4: heat up the joint with the propane torch or mapp torch, move the flame all around the joint, until the metal starts to get dark blood red -dark cherry red. (not glowing at all) this is about 1000 F. at this point a light tug or the weight of the vice grips should pull it right off. don't worry you're not going to take a chunk of tube with it.

step 5: let the joint cool down. and let the residual brass solidify. 15 min

step 6: file off the excess brass, and finish with emery cloth.

boooyah!

let us know how it goes and post pics!

good luck

Careful with the filing off, removing half the thickness of your tube with an errant slip of the file will do more damage than the heat.

While you still have the brass hot hit it with a steel wire brush, this will remove 90% of the brass and stuff the brush a bit but they're cheaper than tubes the emery should take care of the rest.

Another tip whilst heating focus the tip of the torch on the part your removing and the brass limiting the heat on the tube the smallest area you can.

Yes before and after pics please.

How much different is the process for an AL frame? If you click the MTB link in my sig you can see the frame that I am interested in doing this as well. What I really want to do is remove all of the stops including the 3 cable stops on the top tube and plcs single cable stops back on the top tube for the rear brake. I have a friend who is a welder but I wasn't sure about damage to the AL.

I'd suggest grinding them off and forgeting about the torch, but that just me.

don't clamp on to the braze-on with the vicegrips until you're ready to pull it off.
the vicegrips will act as a heatsink, which means it will take longer for the brass to reach temperature, increasing your chances of damaging the tube.

I'd suggest grinding them off and forgeting about the torch, but that just me.

Seconded.

i torched the braze on's off my 77 raleigh record with a hand held propane torch. i just let it heat up for a minute or two and then popped 'em off with a pair of pliers. really easy. in one case on the top tube, a small bit of the frame came with it. little bit of bondo and powdercoating and you cant tell... but be careful. i did it on an older steel frame... not sure how thick your steel is or if its chro-mo... proceede with caution.

Seconded.

Sounds like a better option to me too. Rent a cutting wheel and *zing* they're off!

Yes you can use a plumbers torch to heat the brass and pluck off the brazed cable guides.

If you are careful you will not alter the steel in any way.
a few tips:
the MAX possible temperature of a propane/air torch is 3700 F, this is after a while...

the MAX possible temperature of a mapp gas/air torch is 4700 F aka "supertorch"

your tubeset is probably comparable to reynolds 531 which has a workable limit of 2000 F some tubesets are as low as 1300 F. after which the properties of the tubes will change from heat.

brass brazing rod melts at about 1300 F, which is why on super high end bikes silver is used. Having stripped down a comparable miyata I'm postive it's put together with brass.

step 1: get some gel furniture stripper and strip off the paint in the area.

step 2: get some vicegrips and clamp onto the little bugger.

step 3: put on your welding goggles or buy/borrow some with a level of 4-5 (don't skimp)

step 4: heat up the joint with the propane torch or mapp torch, move the flame all around the joint, until the metal starts to get dark blood red -dark cherry red. (not glowing at all) this is about 1000 F. at this point a light tug or the weight of the vice grips should pull it right off. don't worry you're not going to take a chunk of tube with it.

step 5: let the joint cool down. and let the residual brass solidify. 15 min

step 6: file off the excess brass, and finish with emery cloth.

boooyah!

let us know how it goes and post pics!

good luck

Excellent post! Thanks. I'll file it away for when I have a torch and a new frame.

I used the hacksaw/file approach on my conversion. It worked just fine, but took quite a while.

ehem..... dremel

I'd suggest grinding them off and forgeting about the torch, but that just me.

I agree. I just used a grinding wheel on my bike and it came out great.

I just ground off my shifter bosses last night. Used a grinding wheel for the round bit, and the ratherr gnasty file with large teeth for the square bit. Took all of 10 minutes.

I'd suggest grinding them off and forgeting about the torch, but that just me.

Thirded.

Oxy scares me. It's soooooooo easy to burn holes in thin walled tubing. Soooooooo easy. But THEN you get to try and cover up the hole with a patch and make it WAY worse and ruin your whole #)($*&%^ frame.

I had a frame bead blasted before I heated the brazons. This allows you to see the braze flow and just pluck it off as soon as it does.