Brazing

[wronghand]

Just an add on about strength and heat treating. The old boys who made race cars in the 50s and 60s brazed tube chassis cars together. They all held together just fine. Take a look at the Lotus series from back then. Amazing looking chassis and they were all brazed or brass welded together.

Brazing is almost gone here too. I do make a couple hundred "foot clamp jaws" a year tho for the diamond drilling industry. They are a 3" diameter puck with 8 carbide jaws (about 1" long by 1/2" wide by 1/4" tall) brazed into machined slots with nickel silver rod. I really enjoy doing it.

And when I get a new apprentice in he/she is pretty amazed at the process. They don't even teach it at the welding school here anymore!! A real shame...

[strube1369]

And if that ain't enough, here is more info: http://www.gsegmedia.com/Book/book/index.htm

[justgas]

Brazing Silver brazing

brazing covers a few types and many ways to braze.I have done most and have been a certified silver brazer for more than 10 years and love it. I use a gasluxer model 69 that uses a liquid flux that is mixed withe the acetelyene and also do most parts on a turn table fixture as all my silver brazed joints have to have a 1/8" radius almost all parts also have a silver solder ring in a groove on the joining part. 99% of the parts I do are for Navey ships that is the reson for the radius on the joint. it is mor an art as most welding is either you have it or your work harder to get the hang of it. when silver brazing a prepared joing the silver solder ring melts and appears at the top of the joint that is the time to back off on the heat befor adding more filler to make the 1/8" radius.if one holds the heat for 10 to 30 secounds to long the silver solder will drop out of the part and then you have a junk part.

[glockdoc]

Thanx, I can alway use a few good ideas. So far I have just been making Blackburn designs which work ok but welding aluminum has been a challenge. Is the Harris #17 nickel-silver you're using the basic 50N stuff?

[KB Fabrications]

KB Fabrications
Do you have any pics of the bike racks you're making? I've been working on a few made from 6061 and wouldn't mind trying some out of 4130. Are you using LFB or silver?

I don't have any pictures but I couild take a couple and post for you early this week. We make anywhere from 16 to 24 rear racks every week so when this weeks production begins I'll be sure to hold one back for pictures. These are actually pretty slick and not as heavy as you might think. They also fold up flat so if you travel with your bike it is an added bonus.

I use a combination of brass and Harris #17 nickel silver. Some joints get brass while others get the nickel silver.

[glockdoc]

KB Fabrications
Do you have any pics of the bike racks you're making? I've been working on a few made from 6061 and wouldn't mind trying some out of 4130. Are you using LFB or silver?

[Tanner]

to see beautiful brazed frames, check out Peyto Cycles at http://www.peytocycles.com/

[KB Fabrications]

Brazing bike tubing.

Do you know if they braze structural parts as well?

Does post heat treatment still have to occur? I am not as concerned for the saddle bags as for the frame?

Cheers,

Steve

Absolutely. The term in the bike industry is known as "fillet brazing" and traditionalists will braze every joint on the frame. Then the idea is to hand finish the joint so that it appears that the tubes flow into each other. It can make for a beautiful frame.

As far as heat treatment, we never did. I don't believe it is required but I could be wrong.

[KB Fabrications]

KB Fabricatoins

A few quick questions.Does the flux have much afect on the flame temperature,and does the flux leave much of a residue to clean off compaired to other flux methods.Does it leave any residue on the torch tip.
I am seriously cosidering this flame flux for my shop.Is the initial set up very expensive?It looks pretty simple.

If the flux does have any affect on the temp I can't tell. You adjust the torch controls like normal for a neutral flame and braze away. As far as the residual flux, it is almost non-existant compared to traditional paste flux. It is easily removed with a quick wipedown or sandblast. The same goes for the torch tip and it just need to be wiped periodically as well as using a tip cleaner like you normally would.

I bought my unit a little over three years ago and shipped to the door with a gallon of flux I think it was just over $400. BTW, the liquid flux lasts a long time. I would strongly recommend getting the 4 quantity, single gallon case as they charge you a $20 hazmat transport fee whether you buy 1 gallon or the case of 4 so the larger quantity is a much better value.

FWIW, I think you will be blown away by this process and the ease at which you can braze without the traditional use of a thick coat of paste flux that you can only remove with a good hot water soak or a stick of dynamite.

[Steved]

Brazing bike tubing.

Do you know if they braze structural parts as well?

Does post heat treatment still have to occur? I am not as concerned for the saddle bags as for the frame?

Cheers,

Steve

[burninbriar]

KB Fabricatoins

A few quick questions.Does the flux have much afect on the flame temperature,and does the flux leave much of a residue to clean off compaired to other flux methods.Does it leave any residue on the torch tip.
I am seriously cosidering this flame flux for my shop.Is the initial set up very expensive?It looks pretty simple.

[KB Fabrications]

Wow:I've done quite a bit of brazeing in my time but I have never heard of flux in the flame.I have a hundred questions so I guess I'll be doing some reading on those links also.Brazing has all but disapeared in my neck of the woods.Welding supply stores where I kive don't cary bare rods or flux of any kind.All I can get locally is coated rods either blue or white.Its a sad state.I could go on & on but to make it short without getting to far from the subject I have to order on line almst every thing I use.

Sad to say but for the mainstream it seems that brazing IS going the way of the doh-doh. To bad because it is a very cool process that is not the easiest to master. Only a few industries still using it regulary like bicycles, medical equipment and some sheet metal fabricators. I learned while welding bicycles and used to braze some steel and stainless fittings for different applications (between welding frames). I do braze a fair amount as one of my contracts is with a local bike mfg'r to make their pannier racks for their bikes. They are made out of 4130 tubing in .313" x .035", .25" x .035", and .375" x.083" and all the joints get brazed. I use the Gasfluxer and bare brass rod as well as some bare nickel silver.

[burninbriar]

Wow:I've done quite a bit of brazeing in my time but I have never heard of flux in the flame.I have a hundred questions so I guess I'll be doing some reading on those links also.Brazeing has all but disapeared in my neck of the woods.Welding supply stores where I kive don't cary bare rods or flux of any kind.All I can get locally is coated rods either blue or white.Its a sad state.I could go on & on but to make it short without getting to far from the subject I have to order on line almst every thing I use.

[Steved]

Thanks for your help guys!

Lots to read now.

BTW, nice cart set up. Something tells me that you braze quite a bit! I don't think that I will get that hard-core into brazing though....

[KB Fabrications]

Hi there.

How about this for a simple question?

I know that brazing is good for various jobs but to tell you the truth, I have no idea how to do it.

I can Tig, stick and OA but have never brazed. Rather embarrasing.

Any suggestions? Is it hard? What do you do?

Hi Steved
Great question. Brazing is great for certain applications and if you can weld with O/A then you should certainly be able to braze. Using your O/A setup you would need to get some type of paste flux for your particular application (brazing steel, stainless, aluminum) which usually corresponds with a particular filler metal (brass, bronze, silver, nickel silver). I use a Gasfluxer (flux is in the flame) most of the time and only break out the past flux for certain things. A couple of links are in order that will give you a lot of great info.

http://www.gasflux.com/

http://www.tinmantech.com/index.html

Here is a cart I recently made for my brazing set up. It is a model 69 Gasfluxer with a Meco Midget torch and lightweight hose set up. I also incorporated a Weldit Gassaver with a pilot light into the cart.

I hope this has been somewhat helpful. I'm sure others will chime in.