hi    Buy a Sievert  kit,  torch , hoses,regulator and an assortment of burners sizes to suit your needs ,and run off your propane cylinder,reasonably economical and gives a good hot flame,with plenty of gas in reserve for those bigger jobs. Small canisters have no capacity for the medium and large jobs. Brazing needs more heat than silver soldering and there is no choice other than propane.When silver soldering to get the best results,the work and the flux needs to reach the soldering temperature quickly so use  a decent sized burner. 

For something simple, a Bernzomatic torch head with a yellow MAPP cylinder is excellent.  Far superior to all those cheap & not-so-cheerful butane torches that the DIY shops sell. 

Edited By Niloch on 05/07/2010 21:21:04

Hello everyone,

I know I am kind of resurrecting an old thread here, sorry in advance if that's the wrong approach.

I recently got the Bullfinch Brazing torch, and I would appreciate your input with a problem I am having:

I am trying to braze some 8mm threaded bar to a section of 30x30x3mm mild steel

The steel is drilled 8mm and the threaded bar is sitting in hole. The steel is set on, and partially surrounded with fire bricks, but I am struggling badly to reach a temperature where the brass brazing rod runs into the joint.

Is the steel section too big for this torch?

Or would it be a flux issue? (I ordered brass brazing flux, but the company sent me silver solder flux-I am temporarily using this)

The steel gets red hot easily enough, but the rod doesn't melt (or at least certainly doesn't flow) by touching the steel – only when the flame is directly applied to it.

Would appreciate your thought,

Thanks,

Á D

Thanks for the quick reply.

Do you have any experience brass brazing with propane only? I am wondering if the Sievert would give better results, or would an oxy- or air-gas torch be needed for that size of steel?

Thanks

Hi AD,

The Bullfinch should handle that work with no problems, provided the work is clean, you use the right flux (?) and you can 'contain' the heat (I use a simple hearth inside).

This is a similar sized part (3mm laser cut steel – base being about 35mm square) and the only problem I had (at first) was not allowing any gap for the Sifbronze to flow into. Second attempt worked fine – just a problem of my technique, not the torch.

Here is the finished part – not perfect perhaps but very strong. If you look in my 'Brazing' photo folder, you will see some larger items I brazed with the Bullfinch. Only when trying to join the very large plate to its base (it's about 180 x 120 x 100mm) did it struggle with the Sifbronze – and I had to use silver solder to complete it. These days, I would have just added some more heat from one of my other (disposable) propane.butane mix torches (as the metal radiant area was quite large) – and shielded it better.

.

The Bullfinch 404 is not a replacement for Oxy/A but works very well for small ferrous fabrications. There are many users of Sievert torches here (I have a similar (non-Sievert) torch myself) and they are certainly good where I want large volumes of heat (e.g. for boiler work). However, the Bullfinch is very good for the work I use it for – and Sifbronze is at least an order of magnitude cheaper than silver solder (which I still use of course for non-ferrous brazing).

So I'd suggest you practice with Sifbronze and the right flux – making sure that the work is correctly shielded and the filler can flow into a slight gap in the parts (similar to silver soldering really).

Have a look here – I use the 1.6mm rod by the way (£26.85 for 1kg ! ). They also do the correct Sifbronze Flux – 500gm for £13.75 (inc VAT) which will last you some time.

Sifbronze No 1

Regards,

IanT

I have had a Bullfinch torch for close to 50 years now, only once have I had a fault the auto ignition failed and the company fixed it and charged only return postage ! As far as the job in hand is concerned it should handle it comfortably but as already said you will need to make up a hearth, however beware some "fire bricks" are designed to absorb heat not reflect it, e.g. the ones from storage heaters, so make sure you have the correct bricks or other material.

Almost all my work is silver solder but for brazing you can use Borax, old fashioned yes but it was used pretty exclusively until better fluxes were developed.