# Need help or advice brazing carbide



## Lons (15 Jul 2014)

I need a couple of thrust rods for my bandsaw and rather than pay the ridiculous price quoted decided to attempt to braze my own carbide tips on to steel rod.
big mistake #-o - I've never brazed before and couldn't do it. (Have an ark welder with brazing attachment).

Can anyone do it for me at a reasonable cost if I provide steel and tips? Or failing that, advice please. Thought I'd try here first before trawling aroung small engineering companies.

I've temporarily put in hardened tool steel rods which will last longer than the original mild steel but not a long term solution.

I need 2 in total or better still 4 to give 2 spares. I have plenty rod and 6 tips available. Rods are 65 approx upper and 50mm lower. 9.5 - 10mm (old 3/8") and tips I have are 12.5mm square and 3.5mm thick. The tip fixed to the rod in the pic was araldited on to see if it worked which it did perfectly for a couple of days before falling off :roll: 

cheers
Bob


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## Doug B (15 Jul 2014)

Have you thought of silver soldering them, whilst not as heat resistant as brazing I find it easier to carry out particularly on small components.


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## Lons (15 Jul 2014)

Doug B":3ci7r199 said:


> Have you thought of silver soldering them, whilst not as heat resistant as brazing I find it easier to carry out particularly on small components.



i've never tried silver soldering either Doug but looks as though its probably a better solution. Can I do that with a standard butane torch or do I need a higher temperature type?
I don't mind buying equipment if I need to as can always be used again, just hate forking out large amounts for small items that seem grossly overpriced  

cheers
Bob


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## Phil Pascoe (15 Jul 2014)

You probably can't, as the "heat sink" is too great although theoretically your torch is hot enough. Can't you stick them with JB Weld or similar - there's no particular stress on them?


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## marcros (15 Jul 2014)

are you really likely to get through that many tool steel rods that it is worth the hassle. Even if you used the bandsaw a lot you would still get years out of one wont you?


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## Lons (15 Jul 2014)

phil.p":w1d8rkcy said:


> You probably can't, as the "heat sink" is too great although theoretically your torch is hot enough. Can't you stick them with JB Weld or similar - there's no particular stress on them?



They stuck really well with araldite but I guess it couldn't take the heat. I'll look at JB Weld thanks.



> are you really likely to get through that many tool steel rods that it is worth the hassle. Even if you used the bandsaw a lot you would still get years out of one wont you



That's what I thought but the top one is marked already which suprised me (it's correctly set up). If it wears a groove like the mild steel I think it will overheat the blade.
When I used it with the tip it didn't mark it at all. The tip seems to be the answer if I can get it to stay put.

Just to put it into context: I can get 2 thrust rods off the internet for just over £60 delivered which seems a lot to me. However, startrite quoted £113 for the same stuff. :shock: one of the managers is involved now and he was shocked as well and promised to look into it when he gets back from China on Thursday so will be interested to see what he says.

Thanks for the advice guys, much appreciated.

Bob


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## Phil Pascoe (15 Jul 2014)

Just a thought - on my saw, the rear support doesn't touch until the saw is cutting. If yours are getting hot to the point that the heat affects epoxy, are they in contact all the time? If so, should they be?


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## Lons (15 Jul 2014)

phil.p":3971y6ap said:


> Just a thought - on my saw, the rear support doesn't touch until the saw is cutting. If yours are getting hot to the point that the heat affects epoxy, are they in contact all the time? If so, should they be?



No Phil, I've set it up as it should be so only contact whilst pressing against the blade during cutting. Ive ordered some JB Weld from ebay as it says it has a very high temp durability. so as I've plenty of rod and tips i can hedge my bets.

cheers
Bob


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## woodfarmer (15 Jul 2014)

Back in the sixties I did a spell brazing carbide tips onto the ends of hard rock mining drills. The steel needs to be absolutely clean. we used to "vapour" (water plus sand) blast them before brazing. I think a decent blow torch will do it.
Clean the steel and tip.
Using flux braze to the steel.
using more flux drop the tip onto the molten braze and heat the tip and steel until braze is flowing.
allow to air cool.

Hope that helps.


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## Lons (15 Jul 2014)

woodfarmer":3p2fdtjy said:


> Back in the sixties I did a spell brazing carbide tips onto the ends of hard rock mining drills. The steel needs to be absolutely clean. we used to "vapour" (water plus sand) blast them before brazing. I think a decent blow torch will do it.
> Clean the steel and tip.
> Using flux braze to the steel.
> using more flux drop the tip onto the molten braze and heat the tip and steel until braze is flowing.
> ...



Thanks woodfarmer

I'm going to have a go as I'm sure a bit of brazing / hard soldering experience will stand me in good stead.
Will stick some as well with JB Weld so if it all works will have enough rods to last several lifetimes. :lol:


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## Doug B (15 Jul 2014)

Lons":1i637vim said:


> Doug B":1i637vim said:
> 
> 
> > Have you thought of silver soldering them, whilst not as heat resistant as brazing I find it easier to carry out particularly on small components.
> ...



I just use my plumbing propane blow torch out of the van Bob, no special tools needed just flux & silver solder.


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## dickm (15 Jul 2014)

If you've only got a smallish plumbing torch, it's a great help to create a hearth on which to do the silver soldering. Mine is three fire bricks set up as a base and two sides and makes an enormous difference to heating stuff for hard soldering.


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## Lons (15 Jul 2014)

Doug B":2rbgpjxg said:


> I just use my plumbing propane blow torch out of the van Bob, no special tools needed just flux & silver solder.





> If you've only got a smallish plumbing torch, it's a great help to create a hearth on which to do the silver soldering. Mine is three fire bricks set up as a base and two sides and makes an enormous difference to heating stuff for hard soldering.



Thanks guys

I pulled my storage shed out this morning when I remembered I'd been given some torches years ago when my neighbour died. He used to build large scale locos so I guess he did a lot of brazing and hard soldering. There are a couple of large torches and one smaller which looks as if it will produce a lot of heat so just need to dig out the cylinder to see if any gas or exchange if not. (I'ts buried behind a store of timber  ).

The firebricks sounds a great idea and I have some as well as a few very dense bricks which came frome an old night store heater so sure I can fashion something.

I'm looking forward to trying it now  

Bob


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## Lons (31 Jul 2014)

To update for anyone interested.

Though I haven't tried any further brazing, I did stick tips on with JB Weld and so far it's working perfectly. Great stuff, thanks to those who suggested it.

Bob


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