Gas welding basics?

[Stuggi]

Anyone have any good sources on how to weld with oxy/acetylene or could someone perhaps give me a few hints? I'm used to stick and MIG welding, but I've never tried TIG or oxy/acetylene, which I would think require a bit different technique... I've done some soldering, if that helps

 

[piman]

Hello Stuggi,

simple basics are nozzle size relative to metal thickness, pressures for the different nozzle sizes. When I started, I got a little plastic card from BOC which gave pressures for nozzle sizes. You will probably find it on their web site.
Of course the best way to learn is to have it demonstrated but I would think that you will also find web sites with video clips that you can view?

What type and thickness of material are you expecting to weld?

Alec

 

[Stuggi]

Well, really all sorts actually, but car bodywork mostly. I've got a similar card from my nozzle-supplier, came with the kit I bought (handle and cutting/welding/heating nozzles in a handy metal box ).
I haven't found any sites with any nice videos for some odd reason...

As soon as I get my bottles from the gas supplier I'm gonna get some filler rods and start practicing, and hopefully by then I'll have some more direct questions to ask.

 

[piman]

Hello Stuggi,

if car body work then (BOC Saffire) No 1 and No 2 and occasional no 3 for heavier chassis section. 1\16" diameter rods will do fine. I presume you know about getting a neutral flame?
Plenty of tack welds to hold the items together. Start at the right of the seam and move leftward with the flame at about 45 degrees pointing along the seam, add the filler rod as you go. Actually with a tight butt weld you can join with no filler, just melting the two parts together. This is handy for patch repairs as it minimises any grinding the panel flush.

Alec

 

[Stuggi]

Sadly I live in Finland, so BOC nozzles are a bit hard to come by. The ones I've got have mm numbers stamped into them, like 0,5-1mm and so on, and not any numbers.

 

[piman]

Hello Stuggi,

I'm sorry, I didn't spot the location. You should be able to find the nozzle size versus gas pressures and also nozzle size for metal thickness tables on the internet.
Basically, too large a nozzle just burns holes and too small won't get a weld pool going.
Gas pressures are quite low also but my pressure are in pounds per square inch so probably won't equate to your gauges.

Alec

 

[Stuggi]

As I said earlier I have this sheet that comes with my nozzle set, with what nozzle to use with what at what setting, so I hope I'll be alright. I still haven't got my bottles, so I can't try anything out, but hopefully it won't prove out to be an extreme challenge.

 

[dstealth]

Hello Stuggi,

if car body work then (BOC Saffire) No 1 and No 2 and occasional no 3 for heavier chassis section.

Why would you gas weld car bodywork? You usually either use MIG which is common practice or sometimes occasionally TIG. Cannot begin to think why you would use oxy/acet.

Chris.

 

[piman]

Hello Chris,

oxy\acetylene is very good for car bodywork. It's main drawback is cost and distortion in certain circumstances. MIG is not very good for part panel replacement, better suited to the hidden chassis areas etc. Also gas doesn't fry the car electronic components if you forget to disconnect them :-)

Alec

 

[dstealth]

I didn't think anybody really used it anmore.

The car restoration business I used to work for only used MIG, no matter what part of the car. Given the right conditions, you can be very neat with a MIG welder and produce excellent results ie. the weld to is free of contaminants such as oil/dirt/rust etc, lots of light on the job, the right settings on the welder itself etc. I wouldn't touch a car unless I had these conditions exactly right. Pidgeon s**t welds aren't my style.

However, I'm just starting to get into TIG welding - see my post in the TIG part of the forum. I'm finding it really difficult and it eats those disposable bottles of argon gas - I thought the co2/argon mix ones went fast on my MIG! Any helpful hints would obviously be appreciated. I'm trying to learn off the advice/info on the Miller site atm.

Chris.

 

[Stuggi]

The reason I want to learn gas welding is that you can do all sorts of neat tricks with it, like lead loading and brazing. I'm probably not going to use it much for panel replacement, since I have a Migatronic Automig 273 for that.

 

[piman]

Hello Chris,

I have been, and still use oxy\acetylene for car repairs (hobby basis) as when I started there weren't any MIGs available. The weld from oxy is softer than mig and often less 'bulky' so less grinding and easier planishing.
Of course oxy has many uses in a workshop and it is this versatility that has kept me from buying a MIG machine. As I said, it is not a cheap option but it is effective.

If you did it professionally I'm sure you didn't use a 'hobby' MIG machine?

I also have a small TIG set but have never used it for car repairing.

Stuggi,
as I said versatile, I've also used it to repair radiators, i.e. soft soldering.

Alec

 

[Pete Williams]

Oxy-acetylene welding aluminium & making a tank

I'm into motorcycle drag racing and have been since 1964. As a spin-off I've learned to ally weld using gas and have made many motorcycle and some car petrol tanks in aluminium, also fairings etc. I'm 71 and retired now (from working) but still drag-racing. I put an instructional video together for the DIYer so you may find it of some interest. It is not a commercial advert. Hope you find it of some use. Cheers, Pete. Here's the link:- http://youtu.be/rw5lYMmxSB0

 

[Mr shiney]

Pete, you are a craftsman. Great video, thanks!

 

[outofthefire]

Why would you gas weld car bodywork? You usually either use MIG which is common practice or sometimes occasionally TIG. Cannot begin to think why you would use oxy/acet.

Chris.

With mig and tig to a degree your adding metal to the joint. With gas you just gently play the gas flame down the joint and fuse the two pieces together without the need for filler. I find it the most satisfying type of welding I do.

 

[Wendelspanswick]

I started off gas welding just before migs were becoming common, biggest drawbacks I found with gas for car repairs was slowness and how easy it was to set a car on fire!
Benefits were you only needed gas goggles so easier in confined spaces like wheel arches and the ability to burn off rust and underseal as you went (see point above with regard to burning off underseal!)

 

[pedrobedro]

All my car welding was done with oxy acetylene for about 20 years before mig became a viable economic option. It is easier to weld thinner sections and also heat and shape panels as you go along.

 

[HughF]

I started using O/A before I had my mig and in fact did most of the work on my 2cv body using it. It is a wonderful process in the correct application.

If you want to lead load - learn with regular propane flame, it is much softer and you won't damage the tinning with it quite so easily.

If you want to braze or silver solder stuff (really handy process to learn btw.) then forget acetylene, it is overkill and expensive. Regular oxy/propane or oxy/mapp is a great way to go.

We still have acetylene on the farm, only for when the old man wants to do a spot of gas welding (usually when I'm away from home and something breaks!), everything else is stick or tig. For cutting we use oxy/propane.

 

[octo0072000]

don't know about welding with this but good for cutting
petrogen oxy petrol quite impressive video

ive oxy/acet for years and mig oxy is nicer than mig quieter neater on car panels loads of other benefits as well like heating rusted nuts etc a no 3 nozzle can be got into a very small tight spaces better than propane but that's my opinions

http://www.youtube.com/watch?v=YWAnv3r0CSw&html5=1

lots of videos on you tube on oxy/acet welding

http://www.youtube.com/watch?v=mQbu1y7Gluw&html5=1

 

[zardoz]

Hello Chris,

oxy\acetylene is very good for car bodywork. It's main drawback is cost and distortion in certain circumstances. MIG is not very good for part panel replacement, better suited to the hidden chassis areas etc. Also gas doesn't fry the car electronic components if you forget to disconnect them :-)

Alec

Agreed. I always found oxy ace a lot easier for thin auto panel repair than MIG. As long as you keep a bucket of water and rags near by and a spotty young assistant to apply said damp rags to metal to keep it relatively cool. Just make sure you remove all carpets and anything that might melt, from anywhere near being welded.

Ahh the good old days