Anyone ever gas weld without flame arrestors?

[Sebculb]

It's not much to look at but here's my new bathroom sink cabinet. Took the picture at night. Easy little project to learn how to weld with the torch. Took 10 times longer than a stick welder would've.

Gonna cover the outside with furniture plywood and molding, make cabinet doors, etc. Figure out some way to pour a little countertop around the sink.

 

[Sebculb]

Next I've got this cast iron stovetop that I'll use to get practice brazing. Years ago I tried to weld it with 6013, but that was before I knew anything about cast iron and could hardly put down a bead

 

[CalG]

Hey everyone,

So I gotta fix a piece of backhoe, thick cast iron. Decided to bronze braze it cuz I don't wanna heat it up with 5/8" thick by 8" long of nickel stick weld. Worried the thing'll warp like a potato chip if I do that.

Bought oxy acetylene kit off Facebook. Good deal in good shape according to everyone that's seen it. I dunno nuffin about it (yet, I learn quick though).

The kit doesn't have flame arrestors on it. It's obvious they'd been using it without them. Been looking all over but none of the welding stores or workshops here in SW Costa Rica have or use them. I'm talking big fancy commercial workshops too. Most haven't even heard of them. They say "less thinking, more working, keep it moving".

Anyone on here ever work without them? Everywhere on the internet in English says they are necessary. But I don't want to wait a week to even turn my new toy on while they ship from praxair in the capital.

I know it's not recommended. But who here has done it? Is flashback going up the hose a vague possibility or a real hazard?

Thanks!

gosh, I've never fitted arrestors to my gas set up. Silly me.... I suppose.

 

[MutantGenepool]

Just make sure you turn the acetylene off first.

 

[rScotty]

There's really no limit to what you can do with a torch, alternately welding, cutting, brazing.... and all the while using the flame to stress relieve the metal.

It helps to have a selection of tips. You can make your own tips by either drilling them out, or peening the sides at the end to close down the orfice. Peen with a small drill bit butt stuck into the hole in the end of the tip to maintain a nice orfice shape.

For small welding, I have a tip with an extension that I have counter-drilled and then hard-soldered a piece of tiny copper tubing into the end. The copper tubing came from an old and old oil pressure gauge sending line. This makes a nice welding flame about the size of a grain of wheat. I run it at 5 psi acet. and about 8 psi oxy. It's still as hot temperture-wise as a larger flame, just less total quantity of heat. I use it for welding things where the bead is small enough that I have to wear magnifying glasses to do the work. Other than being small, it works the same as large.

Down in Central America I used the small tip for welding to build up old firing pins and broken triggers and bolts on the .22 rifles that are so common there.

 

[rScotty]

Next I've got this cast iron stovetop that I'll use to get practice brazing. Years ago I tried to weld it with 6013, but that was before I knew anything about cast iron and could hardly put down a bead

I've done a lot of that kind of work. V it back with any kind of grinder until you get to good metal. Then lay it flat, preheat while fluxing that V really well - but don't burn the flux - and increase the heat along the V so that it is hot enough to melt the brass into the V. Remember, you don't melt the brass with the flame..., at least not very much. Mostly you want the iron hot enough so that it is doing the melting of the brass. It's a balancing act between hot metal and the flame. Done right, that stove top will be as good as new. Done wrong, just do it over.....

If you can find one, get a towel-sized fireproof cloth - we used to use woven asbestos fabric from old foundary gloves - to put over any brazed piece to slow down the cooling. It will be stronger and warp less.
rScotty

 

[Sebculb]

There's really no limit to what you can do with a torch, alternately welding, cutting, brazing.... and all the while using the flame to stress relieve the metal.

It helps to have a selection of tips. You can make your own tips by either drilling them out, or peening the sides at the end to close down the orfice. Peen with a small drill bit butt stuck into the hole in the end of the tip to maintain a nice orfice shape.

For small welding, I have a tip with an extension that I have counter-drilled and then hard-soldered a piece of tiny copper tubing into the end. The copper tubing came from an old and old oil pressure gauge sending line. This makes a nice welding flame about the size of a grain of wheat. I run it at 5 psi acet. and about 8 psi oxy. It's still as hot temperture-wise as a larger flame, just less total quantity of heat. I use it for welding things where the bead is small enough that I have to wear magnifying glasses to do the work. Other than being small, it works the same as large.

Down in Central America I used the small tip for welding to build up old firing pins and broken triggers and bolts on the .22 rifles that are so common there. View attachment 715882

So where were you in Central America and for how long? Doing what? Just curious...

 

[Sebculb]

So here is my second attempt at brazing anything. Just a couple pieces of 1/4" bar put together in a straight line and then ground down. Clamped it up to do a "bend and break" test, and when I put enough of my weight on it it was clear that the bar was going to start bending all up before the bronze broke I thought "hey this is a good piece of metal maybe I can use it for something useful someday" and stopped trying to bend it. So I dunno if that means the bend and break test was aborted or it passed with flying colors. Regardless I'm relatively confident it will be strong enough to hold my hub together.

 

[Sebculb]

So on another note, I ran into one of the machinists from the shop around the corner today at the hardware store. Actually the first dude I showed it to asking for advice a couple weeks ago when I started analyzing what the heck I'm gonna do about this.

Told him I was thinking of brazing it with bronze instead of stick welding it with nickel cuz I'm worried 5/8" thick of weld bead by 8" long would generate way too much heat and warp the thing. He said it's the other way around, because for the bronze to flow and stick well the whole vicinity of the patch has to be heated red hot if not orange.

Sooo, what's correct? Conventional wisdom is that brazing doesn't require heating the base metal as much as welding. I think my machinist friend's viewpoint is incorrect cuz we all know that under that welding stick the metal is white hot. And, for what it's worth, when I stick welded a stabilizer foot that had broken in half the other day it twisted and warped all over the place. That didn't bother me cuz the foot isn't a precision piece. But the hub is.

I think my machinist buddy is like an "on the job training" kinda guy who specializes more in cutting metal with lathes and mills rather than weird types of welding. I know he's a wizard in other aspects so don't want to discard what he says but I'm hoping he's wrong here.

What do y'alls think?

 

[Sebculb]

So here are the first and third things I ever tried brazing. First is the cracked stovetop, and third is a leg on the same stove that the bolt had rusted out.

The stove top seemed simple enough, but after I ground it flat one of the cracks appeared to have a little porosity. That's probably actually embedded slag from some 6013 about eight years ago when I was just starting to weld and couldn't put a bead down and had no idea of the intricacies of cast iron. Anyways I noticed something wasn't working right and left it alone for several years.

The foot was like a horizontal bead inside an angle. Ugly but I think it's solid.

Still trying to get used to burning the brazing rod and have it flow where it's supposed to go. Can sorta poke it along with the rod that's not melted.

Getting reeeal close to starting to hack up my hub and stuff ha ha. After one little welding project and about a half hour of brazing I think I'm ready to fix real problems with a torch?? Sounds almost foolhardy just typing it.