Welding Tips and Tricks

Hi,

I have just bought a second hand welding/cutting kit.

It is a BOC Diamond 2 shank, in a box with various welding tips and a cutting head and a few cutting nozzles.

The nozzles are labled ASFN0-3 and ANF6-12 3/64. From reading various web pages I gather that the letters are for different heads and the numbers are thicknesses that can be cut and nozzle sizes.

From what I gather, this is a lightweight shank as the nuts on the shank connection hose are smaller than the nuts on the regulator end. I would like to know if the all the equipment is interchangeable? i.e. the thread sizes and fittings are the same for all the torches and fittings. Or have I just opened up a can of worms!?

Hey mate,

Welcome along. A picture would help, if possible. What country are you in? Being BOC I'm guessing not the Us.

Mick

My apologies, picture attached. I'm in the UK.
Also the cutter doesn't have an oxygen control knob either? I assume this has to be done on the shank?

I'm just wondering really, is this kit any good?

Mike

Hi Mike

Welcome along also

There should be a red and blue knob on that unit. It's probably fairly old, but if it is serviceable, it should work fine.

Red is Acetylene and Blue is Oxygen. You normally light up on Acetylene, add oxygen to give you a blue flame, then press the cutting trigger and adjust oxygen to give you the desired / correct cutting flame

The lever on top of the cutting torch adjusts the oxygen for cutting. You need to read up on regulator pressures. Oxygen pressure is set much higher for cutting than for most oxy/acetylene welding jobs

Hope this helps

Ranger

Hi Ranger, thanks for the reply, I have a idea on how to use it, but am a bit confused about the different nozzles, leightweight, heavy duty, type 4, type 5 etc.

I have no idea if the kit I have bought is obsolete regarding parts, hose attachments and the like. Or are they all pretty standard fittings sizes and nozzles.

All the other cutting heads I have seen have two oxygen knobs and the trigger, I assume being a lightweight one that it doesn't need the second knob.

Mike

Mike welcome to the forum.
You don't say what size tanks you have.
This will tell you how thick you can safely cut.

Hi Mike,

I got the tanks today, a 9l oxygen and 5l acet.

I was having a play with the cutting head today, but couldn't seem to get a good cutting flame.
The following guide http://www.exeter.ac.uk/media/universit ... _39396.pdf on page 27 stated gas pressures 2 bar oxygen and 0.15 bar acet for an AFN 3/64 nozzle, which is the one I have.

With 0.12 bar of acet, I got a flame not much bigger than a lighter on full, so I cranked it up to about 0.4 and it was better. I turned the oxygen on and established a neutral flame, but as soon as i pressed the trigger, the flame went BRIGHT white nearly blinded me! I then turned the oxygen up with the trigger pressed and got a nice cutting flame, but as soon as I let go of the trigger it goes pop and the flame goes out???

Cutter Acetylene gauges Oxygen gauge What gas pressures should I have with an AFN 3/64 nozzle?

Regards Mike

400kpa for oxygen
And 100kpa for acetaline
Then just adj your flow at the torch to suit your cut.
Clean tips well!!! A dirty tip will pop and stop alot if dirty

So 4 bar oxygen and 1 bar acetylene?
I hadn't set the acetylene up that high as I wasn't sure if it was safe to.

I'll give it a go over tomorrow evening, fingers crossed!

1 bar is not much pressure, it's something like 14.6psi I think

I agree, its not a lot of pressure but a lot I have read say 2-3 psi for ascet and 10-20psi for oxy. So seemed like quite a big jump.

Increasing the acet to 1 bar was the only thing I could think that would make any difference, but not really knowing how to set it up I thought I better check first!

Didn't get a chance to try it today so will try on Sunday if I have any time.

Don't know metric system
My Linde W-200 likes 2-3 PSI acet and 30 PSI oxy for cutting also mine has two oxy valves one to set a/c flame and one to open all the way for full oxy on the torch cutting head.

Welding I set both on 3-4 psi with welding tip in place.

I don't know the metric system, but ,never exceed 15 lbs. pressure on the secondary stage of the regulator, because acetylene is unstable above the 15 lbs.and could detonate. also,always keep the acetylene bottle in an upright position. If used in the horizontal position, you could get acetone in your hose or torch.


good luck on your torch outfit..................................................................ron

P.S.,air and oxygen fittings are right hand threads and all acetylene fittings have left hand threads. And lastly,either soap test all joints,or do a leakdown test. and open oxegen bottles all the way,and acetylene bottle aprox. 1/4 of the way open.................................................................................................ron.

Capable bit of kit, I have used a similar setup. I'm pretty sure the first tip Asfn is for thin sheet, the Afn6-12 denotes material thickness in mm 3/64 is cutting orifice. For that tip your setting 3-4 psi on accetalyne and about 35psi on Oxy. To set oxygen cut pressure, open knob fully, press cut lever set on regulator whilst flowing. To light up open accetalyne knob, ignite adjust flame till the black sooty smoke is just going away then open oxygen and set till you get nice sharp cones on your preheat flame. Travel speed and practice will give you a nice dross free cut. You can cut up to 50mm with an afn 1/16.
Make sure you have some flash back arestors in your lines and drain out your regulators on shut down, be safe! Good luck

Don't turn your acet above 1 bar. You'll not the regulator has a red line just above that. It's important.

I've never done anything short of heavy demolition that required more than .5 bar. 3 bar Is plenty of cutting oxygen for a clean tip of almost any size, unless you're cutting above, say, 20mm (tip size will affect how much pressure you need to cut a given thickness, as well as how thick a piece you can or should cut.) The higher O2 pressure should solve your popping problem. At low pressures, the mix difference between "lever down" and "lever up" are significant. Dial it in with the lever down, then release it and get much more O2 flow through the pre-heat , and "pop", you're out.

Steve S

What you have there is a BOC Murex DH Lightweight shank and cutting attachment or copy of. It is still a current model and all spares and accessories are readily available. ASFN 03 nozzle is for sheet metal up to 3mm. AFN 3/64 is for plate 6-20mm. Set acetylene at 4psi (0.3 bar) and oxygen at 40-50 psi (3 bar). Hope this helps.
Ps DO NOT use without flashback arrestors.