Anyone ever gas weld without flame arrestors?

[Sebculb]

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!

 

[PILOON]

I've owned torches for some30 years and never had 'flame arresters' and probably nobody in your area does either since none are to be found.
Oh, yes I've had occasional POPS or POOFS but that's never bothered me or my welds.
Happy welding!

 

[Sebculb]

Thanks! Ha ha somehow I put this thread up twice

 

[WranglerX]

SOME torch handles have built in flame arrestors in body where hoses connect, think later model Victor brand is one of them.... A lot of people seem to think they are not necessary, but I do have them on my torch set and it give me a little bit more piece of mind....

 

[workinonit]

I've never used them either. Didn't even know they existed. I doubt that I start now.

 

[etpm]

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!

When I learned to gas weld 52 years ago our oxy-acetylene torch set up did not have flame arrestors and I didn't start using them until about 20 years ago. BTW, have you ever brazed cast iron?
Eric

 

[Sebculb]

When I learned to gas weld 52 years ago our oxy-acetylene torch set up did not have flame arrestors and I didn't start using them until about 20 years ago. BTW, have you ever brazed cast iron?
Eric

Eric,

No, hardly ever brazed anything before...

But I've done a LOT of stick welding, on cast iron sometimes. Preheating with propane toeches, weird off label ghetto rig fixes with lead and tin solder, advice and guidance from people who know, I'll be able to figure something out I'm sure.

Thanks!

 

[etpm]

Eric,

No, hardly ever brazed anything before...

But I've done a LOT of stick welding, on cast iron sometimes. Preheating with propane toeches, weird off label ghetto rig fixes with lead and tin solder, advice and guidance from people who know, I'll be able to figure something out I'm sure.

Thanks!

Well, here is some advice from someone who has brazed plenty of cast iron. First of all you need to get the whole part pretty damn hot to avoid cracking. Cast iron does not usually warp if heated and cooled slowly. Done fast, heating and cooling, leads to cracking, which is what cast iron usually does instead of warping. So if you're gonna braze a cast iron part your best bet is to build some sort of heat retaining structure around your part and then get the part quite hot before brazing. I use a ceramic "wool" , which is some sort of ceramic fiber that is compacted into sheets about 1.5 inches thick, to form a heat shield around the part to be headed or welded. This ceramic stuff is used for making kilns and similar things needing good heat insulation. I then use a weed burner torch or a rosebud torch to get the part very hot. Then, using plenty of flux to coat the surfaces be brazed, I "wet" all the surfaces to be brazed with the brazing rod. Once wetted the braze filler material can be added easily. If I am TIG brazing I don't worry about wetting the surfaces. Same for welding. After all that said I would be surprised if your equipment had any cast parts that are highly stressed. Often forged parts look like cast parts. Forged parts generally tolerate brazing and welding better than cast parts. But the methods outlined above should also be used for forged parts.
Eric

 

[Sebculb]

Cool, thanks! I'll incorporate all that information into whatever plan I come up with.

What I'm hearing more than anything is I'd better *make sure* I have enough brazing rod on hand so I don't have to run to the store while the thing is hot.

Thanks again!

 

[etpm]

Cool, thanks! I'll incorporate all that information into whatever plan I come up with.

What I'm hearing more than anything is I'd better *make sure* I have enough brazing rod on hand so I don't have to run to the store while the thing is hot.

Thanks again!

You will need to vee out the crack too. Sometimes, if you can get to both sides of the part, it is best to vee out most of the crack from one side but leave enough material to locate the pieces together. Then fill the vee with brazing rod. After the part has cooled enough to handle then turn it over, vee out the rest of the crack, and finish brazing. Remember, to avoid cracking you must pre-heat the work and then let it cool slowly. Having it take hours to cool is best.
Eric