Locate BOC in Sydney.
Does anyone know of a source of small quantities of silver solder (say SBA 245) in Sydney (preferrably inner). Otherwise does anyone know of a method of brazing mild steel that doesn't require oxy/acetylene, otherwise does anyone know of a way that a hobbyist can procure an oxy/acetylene set? (they seem to me to be only available to the trade).
(I have been able to source 1/4 kg packets of SBA 245 at $600/packet )
Locate BOC in Sydney.
The More I Learn The Less I Seem To Know
have you a stick welder- or access to?
If so you can get hold of a twin arc holder. this- as the name implies is a simple device which holds two carbon rods and connects to the welding transformer so that an arc can be produced. I have used one for years- you can weld- using oxy acet technique, or braze, silver solder or spot weld. It is far hotter than acetylene- so care and indirect heating technique is essential (lead can just vapourize- nasty!). In my humble one- it's better than oxy acetylene for most jobs, and dead cheap. have also used a single carbon for spot brazing of thin- 20- 22 g steel sheet. The more concentrated heat source produces less warpage. The problem is eye/ skin damage from the intense radiation- A correct- full face mask and gloves essential.
Intriguing, I do in fact have a stick welder, and had been wondering about whether it could be pressed into service for this application.
Two things however, I'm not sure my stick welding skills are up to it, is it tricky to do?, and (here we go again sigh...) where the heck do you get the carbon rods from? (assuming I can get a twin arc holder).
Well I've finally done it. It's cost me approximately the cost of two of the items I was repairing, but at least I've learnt something.
I bit the bullet and bought some 45% silver solder from BOC. I had to buy far more than I'm likely to ever need, but, at least now I know I can do it if the need arises.
In the end it was still a lot more difficult to do than I had hoped due to the fact that one side of the break has a lot of mass and the heat tended to run away from the joint, but time and lot's of flux seems to have done the trick.
Thanks to all that contributed information.
Sorry I'm late with a answer but you can buy single sticks of 2% 5% 15% 35% & 45% from either a plumbing or air conditioning/refigeration supplier.
However if you just wanted to braze 2 pieces of steel or repair a crack you can use comcoat rods which are availble at hardware stores like bunnings.
Having done the job, I know this is all too late, but just in case you find yourself with more to do one day, here are a couple of tips I have accumulated, mostly from others, but verified in practice.
The difference in heat mass can be accommodated (with practice, obviously!) by judicious use of the torch, concentrating the heat on the heavier part (but I guess you know this already), or by somehow clamping insulating material to the lighter part, thereby reducing the leak-away heat loss. If possible, look at burying the parts in ordinary sand (except for the area to be joined, of course), or surrounding them with refractory material if you can get hold of some. A second person wielding a larger, low heat torch (propane, or similar) in appropriate locations will also help greatly in containing heat loss.
Regards, Ian Kirby.
Thanks OzHeat and Ian, tips are still very welcome because I, for one, will still be using these techniques in the future, and I am sure others will as well. Even though I have completed the 'one off' job, it showed me that the technique will be very useful in other areas as well. This thread then becomes a very useful resource indeed.
Subsequent experiments with the yellow tip rod I purchased from the Hardware store seem to indicate that it is fine to use for many purposes providing you use the right flux. Whether it remains so over time, well, only time will tell. The SBA 45 is much easier to use but very much more expensive, so even though I now have a largish quantity of it I think I will reserve it for the more 'exotic' jobs.
Sorry I have just seen this thread so am probably much too late to be of any help. Most engineering suppliers sell individual sticks or certainly used to. Most if not all regrigeration parts suppliers also used to sell it by the stick. I am not sure about the type number you mentioned as we used to just call it blue tip. Back in my apprentiship days we had light and dark blue tip. The refrig blokes mostly use brown tip which I believe is also known as phos copper. That is not suitable for use on steel.
I've used MAPP gas (comes in yellow gas bottles) to braze steel with bronze. If you can find someone who stocks it they also should have small packs of silver solder and fluxed bronze rods. I've also seen sets advertised online with MAPP and oxygen bottles for increased heat.
I even used MAPP to melt down some bronze brazing rod for an experiment in lost wax casting.
+1 on MAPP gas , I bought myself a Burnzomatic torch kit from Mitre10, it came with the std Blue bottle of gas for lower temperature work and I bought a bottle of the yellow gas, (hotter) as well.
It has been one of the best tool investments I have made, highly recommend to anyone.