Brazing troubles

[G]

The last crash on my 675 snapped off both arms on the front fairing bracket.

It seems to be made of some light alloy; not sure what, but doubt it will weld with my arc welder.

So I decided to try Brazing it. Never done brazing before.
I've got me one of these which claims to be suitable for brazing and a selection of different coated rods from B&Q.

From what I've read I basically need to heat the item up, then pull the heat back a bit and push the rod onto the materials to be joined.
However, so far I've not managed to actually get the rod to melt.

Last night I tried with a couple of one penny pieces and got one to the point it was glowing orange, but the rod still wasn't melting.
Any suggestions?

The torch has a 'swirl pattern', but this means there's not a distinctive traditional flame so that I can place the items at the obviously hottest bit. Seems to work better holding the torch quite close - is this right?

[MarJay]

G,

My understanding of braizing comes from University. When I was there, they explained and demonstrated braizing to me.

Basically, it requires a paste which I think contains copper and tin iirc. They referred it as "Braize" or "Braizing paste".

You put the paste on both surfaces to be braized, then marry the two together. Once this is done, you touch the flame on the paste. The paste then flashes/ignites, and the bond is made. This bond is then stronger than the steel which it connects together.

So, I think you need some braizing paste, if your defenition of braizing matches mine!
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Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[MarJay]

https://en.wikipedia.org/wiki/Brazing

The American Welding Society prefers "Braize Welding" for what you're trying to do G... According to wikipedia anyway!

Also, Wikipedia says bronze brazing won't work on Aluminium.
____________________
British beauty: Triumph Street Triple R; Loony stroker: KR1S; Track fun: GSXR750 L1; Commuter Missile: GSX-S1000F; Cheap project: CBR900RR FireBlade
Remember kids, bikes aren't like lego. You can't easily take a part from one bike and then fit it to another.

[G]

That is indeed what I'm trying to do. I'm pretty sure it's some alloy, not aluminium, though may have some in it of course.

[hmmmnz]

i dont think your going to manage to actully braize the alloy, i think your going to have to weld it with some sort of tig welder or get some special welding rods for your arc welder
____________________
the humans are dead
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Wiring Diagrams BIDNIP it bitches

[Bezzer]

The only way you'll do it yourself with just a heat torch is with "Lumiweld" or other similar rods made for alloy.
If the bracket is light then it's obviously an aluminium alloy, you don't use pure aluminium, when people talk of Aluminium welding they're really talking about alloy.
____________________
I used to be indecisive but now I'm not quite so sure.

[Ichy]

You can braze any two metals together, I used to use it a lot to attach aluminium plates to steel bodies. Brazing is basically a sort of glue so it doesn't need any specific rod or flux. Its very similar to soldering except your using brass instead of lead so if you've done any plumbing you already know what to do.

As Marjay said you need some flux but you don't always need to coat the metal, just warm up the rod and dip into the flux.

For what your doing you need a thinnish rod, 1-2mm, you can use bigger but it needs more heat. Arc brazing can be a bit aggressive especially on thin material. A blow torch might be better, the type used for plumbing with an end that gives a very pointed tip, in fact, in some cases you can get away with soldering the bracket.

[G]

I have been using a blow torch (see the link in my first post for what I've been using). I bought rods that were right next to the torches and are made by the same company.
The torch doesn't have a pointed tip to the flame, but claims to be more suited to brazing than the ones that are designed for plumbing thanks to a hotter flame.

The rods are coated, so should I still have to use flux? I did get some flux in case I had to.


I did wonder about sticking the rod into my Arc welder, but in the end decided it was best not to. Could I still use the Arc welder with this alloy? Would it conduct electricity well enough?

[Ichy]

Sorry being too lazy to follow the link and read the post properly I assumed you were using a carbon arc setup since you mentioned the welder.




Anyway, there's definitely something not right if the rods not melting on two pennies. The temperature should be up to about 450 degrees which your torch should be capable of although the output of the others on the site in your link are almost a 1000w higher. What material is the rod and can you melt the it by just holding it in the flame? The flux won't have any effect on this since its only there to prevent oxides from forming, stops the molten material from balling up.

I've always used oxyacetylene torches with quite a pointed flame and I've always kept the heat on the part because it draws the filler through the material.

You need to make sure the rods you have brought are ok for the material your bonding. Copper and brass is ok for steel, copper etc but won't work on aluminium, you'll need an aluminium filler rod for that. Any sign of magnesium and you've got more problems.

Think you'll have the same problem with the arc welder unless you get aluminium filler rods.

[G]

I got one of each of the ones they had, which I'm pretty sure were designed to work with this torch, but the two I've tried so far won't even melt in the flame from the torch.

Using my IR thermometer it's shown the surface of something I was heating up to be about 550 degrees when it had cooled down slightly - seemed to have trouble above that.

Screwfix didn't have any torches, so I had to get it from B&Q and this was the only model they did.

[stinkwheel]

Allen Millyard of V12 Kawasaki Z2600 fame uses lumiweld to join the bandsawed crankcases on his inline five, KH250 based 2-strokes.

Low temperature aluminium solder. Got to be worth a try.

Are they circular in cross section? If so, have you considered drilling them and sweating a slug in?
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
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[G]

They are some fancy ergonomic shape or something .

I did consider trying to drill some very fine holes and stick a couple of pins through, but I think better would be just to slap a bigger bit of metal on underneath.

[stinkwheel]

Bit of flatbar, a vice and a lumphammer? (aka a 'bracket kit').
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Ichy]

I've got some two pack adhesive that you can have, use it to refit broken studs and fixings on cars where we can't get a welder in. Its called power mix, made by www.vip-gmbh.com. look under
products,
adhesives,
2 part products,
then scroll down to 2 part Urethan adhesive.

It does mention plastics but the spec sheet also mentions metal. I have the mixing nozzle but not the application gun, I use my fingers to push the plungers down.

[G]

Now this is a bit embarrassing

I actually tried the aluminium rods I've got and they, err, do seem to work! I had been saving them as I only had two.

Doesn't explain why the others ones don't when I'm sure they 'should'.

Cheers for the offer ichy, got a few other adhesives I can try as well so should be ok one way or another.

Should these aluminium rods be fluxed? They don't seem to have any outer coating from what I can tell.

[hmmmnz]

its not really nessasary, the flux just cleans the area up so it bonds easier, but if they are working with out flux then sweet, mabee a quick sand to clean up the area would be enough
____________________
the humans are dead
I kick arse for the lord
Wiring Diagrams BIDNIP it bitches

[Ichy]

Should have some type of flux to remove oxides and contaminates.

Problem is to braze aluminium you need a flux with alkaline chlorides or fluorides and lithium salts, maybe the one you brought will be ok?

Some rods are flux cored, not flux coated so give them a try, it will be obvious if there isn't any.

[Bezzer]

Lumiweld rods and probably yours as well don't have/need a flux, but you need a stainless steel wire brush which you use to agitate the liquid rod into the area you're using it. Don't know why so don't ask but that's how they "work" for some reason.
____________________
I used to be indecisive but now I'm not quite so sure.

[Bezzer]

Here you go -

[Ichy]

G, remember aluminium doesn't glow when it gets hot, watch the temperature or the bracket will melt before you know it especially since the melting temp of the filler rod is close to the melting point of aluminium.

[G]

Hmmm, I was hoping to not have to 'clean up' the joint at all as far as abrasion is concerned - the parts still match pretty well where they cracked.

The flux I've got doesn't mention what it has in it, just that it doesn't have lead.

These are the rods I've got (also got two others listed under 'brazing rods' on the left:
https://www.bernzomatic.com/bernzomatic/consumer/jhtml/detail.jhtml?prodId=BernzoProd100064


Cheers for the thoughts all .

[Bendy]

Superglue it and wrap it in gaffa.

[Ichy]

AL3 are flux cored. Out of interest how much did they cost?

[ZRX61]

mildly entertaining thread... LMFAO!

[hmmmnz]