how to braze a rat trap?

I would clean the zinc(galvanization) off the areas to be brazed with a little muriatic acid and then clean up with some 220 sandpaper. If you leave the zinc, you will be breathing zinc oxide fumes(volumes of white stuff) and that is worse than 2nd hand tobacco smoke by a factor of 100. I speak from 1st hand experience.....coughed and gagged all night.

Larry

Well I braze using a _Little Torch_ that jewelers use for making my wire sculptures and the like.

I use MAPP with oxygen. Also, I use the smallest rod Harris makes, 1/16 "

5% silver solder _Stay-Silv 5_(available at local welding supply). This brazing material doesn't need any flux.

Larry

Noooo! It makes brazing a beautiful operation. Like pretinned wire. I suppose it might be a worry with oxy-fuel torches where it's easy to overheat stuff, but that's why you don't overheat the damn thing! LOL Zinc boils at a temp a little over what most brazing rod melts so zinc fumes will be no worry. Especially on a small job like this.

Phil, to braze you need a torch and some brazing rod... a small propane torch will barely cut it, $30 at the hardware store, plus a $.69 flux- coated brazing rod. Some firebrick to back up and reflect heat on the work helps tremendously.

Get stuff in position, point torch at the joint, when it's hot (around orange heat), fill in with the brazing rod. For stuff like this where the work is about the same dimensions as the rod, you'll want to heat up the brazing rod along with the work. With a propane torch, hottest point is the tip of the bright inner cone. Keep that on the work.

Tim

-- "That's for the courts to decide." - Homer Simpson Website @

"Tim Williams" snipped-for-privacy@charter.net

wrt galvinized steel

I would clean the zinc(galvanization) off the areas to be brazed...

Tim

Why not worry about ingesting fumes, just because of zinc's boiling point? Don't understand you. FM

A couple of points that are relevant in this case: The tiny amounts of zinc on wire such as this should not be a problem, if you're using galvanized wire. Just do it outdoors and don't get too close. Although I'm very wary of breathing zinc fumes myself (I've caught the "flu" a couple of times, and it isn't pleasant. I wear a disposable 3M fume mask now), I did it for many years without knowing better, just working out of doors and avoiding those white fumes. Until I got into doing larger pieces with an O/A torch, I never encountered fume fever than I know of.

Secondly, this is a job that's manageable with an ordinary propane torch, even if you use plain bronze brazing rod. I've made camping grills this way in the long-ago past, using nothing more than an ordinary Bernz-O-Matic propane torch, bronze (it's really brass) brazing rod, and laundry-type borax for flux. On those small wires, there's no problem getting enough heat and a high-enough temperature into the joint. Just keep it clean, mix a little borax with water or alcohol to make it stick, and brush it liberally into the joint. Once it melts and turns glassy, start trying to melt the rod into the joint. It may flow before it glows much at all, depending on the rod you're using. For good measure, I preheat a couple of inches of rod and dip it into the borax to coat it first. Commercial fluxes are better but borax will work on plain steel, in a pinch.

The one problem with brazing wires like this is that the wire is usually hard-drawn and brazing will anneal it. It will go from being moderately hard to dead-soft near the joint. This is a disadvantage in making grills this way, over resistance welding, which is the way they do it commercially. Quick, intense resistance welds don't cost you much hardness in the wire.

So I made them from a slightly larger gage to compensate. I'm still using one of those grills, more than 25 years later.

Ed Huntress

Bingo. Even when melting small blobs of bronze in the basement(!) and sometimes coming back with that "super-fresh-air" smell stuck in my nose, I've never had it yet... Maybe it's 'cuz I'm addicted to milk... :-o

Use music wire, heat the whole thing to orange heat (just below melting point of the braze.. at least, the stuff I find at Ace says 1650°F or so), then quench in salt water. Temper in the oven, 500°F for 1/2 hour, now no rat is gonna never gnaw its way outa yer trap. :-P

(If you don't believe me that you can braze + harden carbon steel like this, I've done small brazed toolbits before. Works fine. :)

Tim

-- "That's for the courts to decide." - Homer Simpson Website @

Yes, and that's an insightful discovery that you made on your own. In industry, bronze (brass) brazing is sometimes chosen over silver brazing for just that reason. There are a lot of furnace-braze-and-quench simultaneous processes in use, or there used to be.

Ed Huntress