[Dr_Snapid]

Has anyone on the forum had any experience brazing.

Steel or ally

I have bought some of these to try for ally http://www.toolking.com.au/products/ULTRA-BOND-aluminium-repair-rods.html

Not sure what rods to get to try brazing steel.

To begin i just want to learn to braze and dunno if i should try a butane torch (<$100 and self lighting), MAPP gas kit (<$200 and self lighting) or LPG torch for my existing bbq cylinder (<$200, prefered option but not self lighting)

I am thinking butane is out... not sure the torches are big enough. I want to be able to deal with 3mm ally and 2mm steel.

[honks]

Depends on what your trying to braze, how thick the material is and how neat you want it. I'm a plumber and mapp gas is fairly slow at getting the heat into 3/4" copper pipe and also heats a large area unlike an oxy set where you have a fine tip which can concentrate on one set area so i think you would struggle with getting a decent join on steel also I'm not 100% sure but I remember a mates dad telling me that lpg is no good on steel I'm not sure why but he was a panel beater so I think he had tried it.

[Shansh]

^^^ oxy acetylene is the go mate, MAPP gas & butane wont get enough heat into the material quick enough for what you are wanting to do unless its really thin material. Like honk says MAPP is only good for smaller diameter copper pipe,thin material. Back in the day when I was doing lots of copper work we didnt bother fucking around with butane/MAPP, etc, if you can afford it go straight for the oxy/acteylene, you also have to option of the gas axe then too

[Dr_Snapid]

Oxy Acetylene is a bit dearer to set up though

Just to be clear... you guys think 3mm ally and 2mm steel is thick, or thin? I dunno what you mean by thin...

[stockman]

I have boxes of those rods. Will work with Mapp gas, but you will waste a shit load heating up the metal.
As Shansh said, oxy is the go.

[Shansh]

Dr_Snapid wrote:

Oxy Acetylene is a bit dearer to set up though

Just to be clear... you guys think 3mm ally and 2mm steel is thick, or thin? I dunno what you mean by thin...

mate those are thick if you are using MAPP, etc but they will be no dramas with an oxy set, like I said if you can afford it go that way, it is a bit pricey to set up but well worth it IMO

[Dr_Snapid]

stockman wrote:

I have boxes of those rods. Will work with Mapp gas, but you will waste a shit load heating up the metal.
As Shansh said, oxy is the go.

What sort of stuff do you do with these rods, stockman?

[Dr_Snapid]

Anyone use oxy/lpg here?

[Fatzook]

Dr_Snapid wrote:

Anyone use oxy/lpg here?

I've used it for pre-heating jobs for weld prep, and I've seen it used for cutting ( not very clean result), but I've never used it for Brazing.

The small amount of Brazing I have done was with oxy/ acet.

[honks]

As I said in my earlier post I am 90% sure that oxy - lpg is no good for steel apparentley it doesn't braze properly i was told by my mate dad who was a panel beater unfortunately he is no longer alive other wise i would get a definate answer for you I'm not sure on alloy it might be ok. We used to use oxy lpg for copper and it was great as a 9kg lgp would outlast 2 'D' size acetylene and the heat difference wasn't that much different ( lpg is supposed to be a slightly colder flame that acetylene ). I hope some of this info can help would hate to see you fork out a heap of cash on a set up that wont work for what you want.

[ball]

Dr_Snapid wrote:

Anyone use oxy/lpg here?

I have quite a few customers that use LPG now.

The only thing they say you can't do with LPG is fusion weld steel. Everything else is ok. LPG is a bit colder flame.

The guys that repair the railway tracks use LPG to cut the rail before they weld the joins together.

[Dr_Snapid]

honks wrote:

I hope some of this info can help would hate to see you fork out a heap of cash on a set up that wont work for what you want.

My thoughts exactly, i thank you guys for your opinions on this.

[bigrig91]

Just remember when brazing that the solder follows the heat so you always point the oxy/map gas where u want the solder to go. Clean both surfaces well and i dont know if u use flux on steel or ally but u do with copper and steel to copper welds. The key to brazing is controling the heat.

Have fun. Cheers

[JrZook]

#1 cleanliness followed by

bigrig91 wrote:

The key to brazing is controling the heat.

Have fun. Cheers

[Shansh]

JrZook wrote:

#1 cleanliness followed by

bigrig91 wrote:

The key to brazing is controling the heat.

Have fun. Cheers

x eleventy gajillion

[Dr_Snapid]

Well I borrowed a small LPG torch and had a crack. Felt just like soldering only bigger. I felt a bit un-co and clumsy actually because of the size of the torch but i'm sure, just like soldering, it comes with practice....

Ok no laughing!

Attachment:

2012-07-03 17.24.09.jpg

Attachment:

2012-07-03 17.24.17.jpg

Here's where I bent it back and forth till it broke, the joint never let go, it tore the ally around it.

Attachment:

2012-07-03 17.25.38.jpg

I also did a second joint, a butt joint with pipe onto the flat bar, and i knew it hadnt worked. Looked like a solder dry joint to me. And sure enough, with enough abuse, the joint let go and I could see it had not penetrated the aluminium. So I am glad that at least my soldering experience has helped me recognise a bad joint when i see it.

So anyway it was a bit of an experiment but very helpful in deciding whether to go out and buy some gear. I am thinking that without bottled oxygen there is not enough of a sharp flame - heat is very spread out with atmospheric oxygen. So I think oxy/lpg is the go if I can afford it...

[stockman]

Did you get the stainless steel wire brushes to give the surfaces a good clean.

Dr_Snapid wrote:

stockman wrote:

I have boxes of those rods. Will work with Mapp gas, but you will waste a shit load heating up the metal.
As Shansh said, oxy is the go.

What sort of stuff do you do with these rods, stockman?

Bought them to do repairs to Aluminium bicycle frames. Like anything, it's 99% prep.
I tried with the mapp gas once and it was rubbish. Oxy is so much easier and 100 time quicker.
I use to tig the cracks, but then the crack would reappear on either side of the weld, never had one crack again after using the rods though.
A (aluminium) frame builder once told me this was from lack of heat treatment after the repair but I wasn't listening as Steel Is Real

[Dr_Snapid]

Actually no stainless steel brush. I used a scouring pad. It isnt stainless steel but shouldnt contaminate... i dont know what it is made from, its the type used by spray painters. not kitchen type.

I really should get a brush

[shakes]

Dr_Snapid wrote:

Well I borrowed a small LPG torch and had a crack. Felt just like soldering only bigger. I felt a bit un-co and clumsy actually because of the size of the torch but i'm sure, just like soldering, it comes with practice....

Ok no laughing!

Here's where I bent it back and forth till it broke, the joint never let go, it tore the ally around it.

I also did a second joint, a butt joint with pipe onto the flat bar, and i knew it hadnt worked. Looked like a solder dry joint to me. And sure enough, with enough abuse, the joint let go and I could see it had not penetrated the aluminium. So I am glad that at least my soldering experience has helped me recognise a bad joint when i see it.

So anyway it was a bit of an experiment but very helpful in deciding whether to go out and buy some gear. I am thinking that without bottled oxygen there is not enough of a sharp flame - heat is very spread out with atmospheric oxygen. So I think oxy/lpg is the go if I can afford it...

I prefer oxy/acet (Plumber)

I find to get the same heat as I like with oxy/lpg the flame is too fierce and you lose alot of fine control, as well as the flame will 'blow' the solder out of where it's meant to be.

For testing cut the joint on a 45* angle across it, and try to see where you have wicked the solder into the join.

[ainzy]

Ive done plenty of work with both oxy/lpg and oxy/acet hands down winner is oxy/lpg for brazing big stuff eg. Very large cast bearing housings lathe beds large gear boxs and so forth... But for fine stuff like around a mill or two thickness spend the extra and get the acet... Acet will also allow you to fusion weld car panels.... And i have always used bakers soldering fluid and probably always will it makes life easy

[rustyzook]

i go for the oxy/acet when ever i can (refrigeration) i some times use the mapp/oxy they work well but empty quickly plumbers and refrigeration shops sell them. and then mapp last as its shitty for anything over 5/8

i can help with copper brass and stainless brazing. main thing is keep it clean and DON'T overheat your joint as it will weaken it

[Dr_Snapid]

My understanding is that Aluminium doesnt really glow before it's been overheated. Any tricks for knowing when your temp is ok?

ATM I just have to keep testing the brazing rod on the surface to see when it melts.... But it means taking the flame away from the joint over and over otherwise the flame ments the rod directly and that doesnt work at all...

[Fatzook]

Dr_Snapid wrote:

My understanding is that Aluminium doesnt really glow before it's been overheated. Any tricks for knowing when your temp is ok?

No, it doesn't glow at all. The hardest parts about welding ( or in this case, brazing) ally, is that you have to look for a molten pool that is almost the same colour as the surrounding material.

You will burn some holes, and lay down some cold 'welds', but you'll get a feel for it with practice.

[Dr_Snapid]

Well when brazing you should not melt the metals being joined at all. Only the joining metal should melt, and youshould go only hot enough to acheive this and no higher.

So basically i'm just testing as I go but hoped there was a better way to know when the base metal parts are hot enough to melt the joiner.

[JrZook]

Shouldn't the flux you are using be a good indicator of the brazing temp? Isn't the activation temperature of the flux very close to the melting point of the rods when it starts to bubble/boil?

[Dr_Snapid]

Fluxless rods JrZook

[rustyzook]

flux is really only needed for dissimilar metals, or dirty joints, with what i do anyway i hardly ever use flux, also clean the flux off when your done, as it can eat into the softer of the two metals

[appsie]

bees dont need flux

[rustyzook]

dude i dont work there anymore im back in the real world of work lol bees can go to hell and they can die! them bastards hurt!

[jonno_racing]

stockman wrote:

Did you get the stainless steel wire brushes to give the surfaces a good clean.

Dr_Snapid wrote:

stockman wrote:

I have boxes of those rods. Will work with Mapp gas, but you will waste a shit load heating up the metal.
As Shansh said, oxy is the go.

What sort of stuff do you do with these rods, stockman?

Bought them to do repairs to Aluminium bicycle frames. Like anything, it's 99% prep.
I tried with the mapp gas once and it was rubbish. Oxy is so much easier and 100 time quicker.
I use to tig the cracks, but then the crack would reappear on either side of the weld, never had one crack again after using the rods though.
A (aluminium) frame builder once told me this was from lack of heat treatment after the repair but I wasn't listening as Steel Is Real

i use the same stuff for rc work.. temperamental stuff!! but works well with map IF the material is small enough, in genral i hate working with ally, but get very little choice when it comes down to rc stuff!