Brazing, etc. with a 1/2" Porter burner

J

Jason Fry

Joined
Jun 5, 2008
Messages
3,224
If you ever think about building a forge, get the Michael Porter book about burner building. It's available on Amazon. I just got the book about a month ago, read parts of it half a dozen times, and then built the 3/4" burner. Fired it up this weekend, seemed to work well in my limited experience.

Last night I bought the fittings to build the 1/2" burner that Porter recommends for brazing. I've never brazed before, but have read a little. Anybody have experience brazing with a burner like this? What can you tell me about it?

What have you brazed in your knife shop? I'm thinking at least of threaded ends for stick tangs, and some external parts on my forge body. What else?

What else could you use the burner for? Definitely drawing back the spines of knives, I'd assume. What else?
 
Yes, I used the 1/2" burner (Michael Porter style from his book) to braze large fender washers to the burner collars. The original purpose of the burners (I built two) was for my two burner freon tank forge. I don't weld nor knew how to braze but realized the burners would suffice for that task as well.

I used 3" fender washers as the flange with the burner collar and a 1.5" black pipe as the collar. I learned that much mass is a tremendous heat sink. The burner is more than capable of generating the heat, however my body could not get close enough... Just too hot! So... I took several blocks of ISFB, stacked them to form a corner, propped up the material, used a single 1/2" burner to get the mass hot and used (yes, I had to buy another toy!) a little brazing torch that connects to those little MAPP and Oxygen bottles to get the joint hot enough to effect the braze. In hindsight, I should have paid a welder. Regardless, that was four years ago and have not had any issues with the brazed joints.

How I used it is at one end of the spectrum... Smaller items with much less mass would be much better. One thing I learned is that if one waits till about 30 minutes after sundown to light up the burner and run the pressure up above 30 PSI, it will scare the dog walkers! Of course that was in my driveway in a HOA subdivision!
 
Jason not with a forge burner, but with oxy acetylene I've silver brazed the
bolsters on the last 16 knives I've made-- and I can assure you I will never
look back. I figure its going to take me a couple of years just to use up the
scrap from integral milled frames. The cool thing is no visible joint anywhere
and you never have to worry about a bolster coming off from heat. The frames
also seem to remain "dead flat". Now I can make like 4 bolstered knives with the
same amount of 416ss it used to take to make one. Oh yeah, and I don't have
to mill the frame out except for the reliefs.
Ken.
 
Last edited:
Brazing and hard silver soldering ( silver brazing) are very useful. However, a 1/2" burner is probably a poor tool for the job. A Prestolite torch or and A/O torch is a far better heat source.
 
Well, I got the 1/2" burner running with a temporary flare. Once I got it warmed up and to more than about 4 PSI, it was running rich. Couldn't open up the choke any more, so I have a few more mods to make to see if I can make it pull more air. I also have a small tool rest that's screwed together, so I tried to braze the joint. Got it hot enough to melt the flux and soften the rod, but couldn't get the rod to really melt or flow. Didn't try it on smaller parts, and not quite happy with the flare or choke yet.
 
In brazing, the entire joint and both metal needs to be at the flow point....usually around 1200-1500F.
 
You must log in or register to reply here.
Back
Top