What can you tell me about gas welding?

[VAN with a PLAN]

I am interested in setting myself up with some gas welding gear but I think I may have underestimated the costs involved. I am trying to get an idea of the likely ongoing cost of consumables such as rods and gas. I understand that I will need to hire both cylinders. Can anyone give me an idea of the cost of setting myself up with a pair of cylinders and what the ongoing rental and refill costs would be? I don't want huge cylinders but nor do I want tiny ones that will only last a couple of days!

Any advice from those more knowledgeable in this area would be greatly appreciated.

[tandemsandy]

If you're thinking about doing vehicle bodywork with gas welding, then I'd suggest it's not a good idea. The amount of heat input to the surrounding metal is much greater with gas than with the various forms of arc welding, because it takes much longer to bring the metal to melting point, then has a much larger weld pool. TIG has the minimal heat input, then stick (MMA) & MIG. Gas welding will cause massive amounts of heat distortion in the surrounding metal, making all the panels go wonky.

Gas welding has a place, but to be honest the only benefit I can think of for the process is it doesn't need an electric power supply, so handy in the middle of a field!

That was meant to be a constructive input, rather than just negative!

Rob (ex-welder, Rolls-Royce aerospace)

[HarryMann]

Times have changed and you can buy or hire much smaller 10 litre size bottles of oxygen and acetylene (£37 this one)

http://www.ebay.co.uk/itm/Full-Refillab ... 19d7d07d51


Do your reserach on eBay, or some of the new gas suppliers (BOC used to impose their own rules and take you prisoner on rentals and refills charges)

One area where gas is useful is a bit of brazing, say recently I brazed all the cracks *and there were many) in a US Smallcar Subaru/T25 exhaust manifold. Sometimes for flowing a bit of braze into places that MIG just can't get, let's face it, theres nowt quite as small as a N0.1 or 2 gas jet, MIG has great difficulty getting into tight corners.

But it is true, distortion is a constant problem, and with brazing metal has to be quite clean, although a good flux can work miracles. There are ways to minimise heat distortion (cooling putties etc), but it's always a fact that the surrounding metal will heat up a lot while getting the weld pool going...

I have a large set I rarely use (mainly for heat correcting shapes) and a small turbo set for brazing... I must get one of those 10 litre oxygen bottles.

Took me about 2 years on and off to get good enough and comfortable enough to be happy with MIG, but its a brilliant system when everything is right... with much less peripheral damage and distortion.

I also use gas for very big thick jobs, like gates (20 jet) but most would use stick for that today. The main use today is freeing bolts and seized nuts as well as aiding metal forming (e.g. joggling, adjusting, removing forming stresses etc). Also for heating up when toughening or annealing post-welds,

or solutionising duralumin...

[mm289]

Hey VwaP,

I'm sure Mike will be along soon to comment as he is our resident expert (see Sunnivanagon and Kevthe Revagon threads) and he will have a view on Rob's comments.

For myself i have looked at gas welding (oxy/acetylene) as if you are trying to do body repairs with minimal rework it seems to be far superior to Mig and Tig especially if you weld without much filler rod. Trouble is acetylene is a highly volatile substance and as such has a cost overhead associated.

From my research the easiest way to do "hobby" O/A is with something like a BOC PortaPac (google it) but by the time you have bought the torch, flashback arrestors, tanks etc it ain't cheap. Full cyclinder hire is even more cost innefective unless you are using it a lot.

Then you have the HSE implications which i won't bore you with, but your household insurance won't cover you if it goes wrong and there are some reasonably stringent HSE requirements about storing/declaring Acetylene.

Worth doing some research aroudn the HSE stuff as well as the costs.

I would love to go down that road but at this point in time it just isn't cost effective and that is why most of us stick with MIG/TIG which will do most of what we need although not quite as well as gas (IMHO)

Cheers,

MM

[HarryMann]

Yes H&S boyos do not like people that have OA at home...

Yes Acetylene is a concentrated source hydrocarbon fuel and pure oxygen when it gets near hydrocarbon (e.g. grease/oil) tends to set it orft..

[VAN with a PLAN]

Ok! well thanks to all who have posted already

I have a couple of small MIG machines and am reasonably adept at using them, although no metalmick8y (I love following his threads).

I am hoping to get into a spot of coachbuilding - I have been trying to find a suitable chassis for a while now and have located and Austin Seven chassis that has been used as a tractor and then left to rot.

While I would love to have a TIG set, having one capable of welding ally is prohibitively expensive. Gas welders can, with much skill, weld ally, and a gas set would also let me anneal alumininum sheet prior to working it, heat and bend heavier bars and plates for brackets etc. Heat up stubborn fixings, braze, cut etc. etc. there is an inherent flexibility with a decent gas set that the other systems cannot match. Plus the welds, and welded panels are generally easier to work and dress afterwards when compared to MIG.

HarryMann - Thanks for that link, 10lt is probably an ideal size but I cannot seem to find the equivalent acetylene. I know that BOC will rent me a similar size but I cannot find any info costs etc. I am concerned that the portapac style disposables are too small and expensive for any concentrated bouts of enthusiasm!

I had not considered the insurance aspect, the storage and use of the cylinders would be a fair distance from anyone's house (10m +). This needs further investigation...

[HarryMann]

I am concerned that the portapac style disposables are too small and expensive for any concentrated bouts of enthusiasm!

Well, the turbo sets are, the Oxygen is over £20 for a litre bottle and runs out 4 times faster than the MAPP fuel gas (that plumbers use without oxygen)

Try these for small acetylene bottle

Barnet Welding
Unit 14B
Tollgate Farm
Colney Heath
St Albans
AL4 0NY

http://www.Barnet-Welding.co.uk" onclick="window.open(this.href);return false;

Office : 01727 568 017
Mobile : 07865 923 625

Mailto:info@Barnet-Welding.co.uk

[Plasticman]

well Rob I couldnt disagree with you more , in body work , mig has its place ,but gas is preferable for lots of the intricate work , you cannot do with mig what i can with gas, ok maybe you dont want to . but say if the op wants to work with ally sheet then you need gas if your bodying, mig and tig are hopeless for this for many reasons.
I would need a book sized space to detail all the pros and cons that i can think of and still miss many.
as a guide a large H size acetylene last me about 4 years.and oxy Large about 2 years and i do a lot more than on here , burning eats it so thats left out of this for now,
gauges , buy 2 stage as they offer finer control more stability, nicer , s/hand often but you need to be wary of the source, so buy new, i rebuild the O2 and acety gauges but not all can or are qualified to,
hoses ,get the lightest you can and for a gun ,then a nice old boc saffire 3 would be nice, seen a few sets on the bay going for about £50 which is fine and parts for the gun are available ,you also MUST buy flashback arrestors that fit to the outlet of the gauges as well as the small poppers in the ends of the hoses, initiual cost is high, , boc the dearest well there is a dearer but leave them out, energas are good, shop around for rental,
oh a big oxy £20, big acety £100
porta packs are great and I could do a major job on a van and not empty a set.
acety is very safe in itself , but the cyclinders dont like getting hit hard nor dropped well kn ocked over as it can cause internal combustion, do a web search
O2 is safe as well ,just dont get any greasee/oil on the bullnose into the cyc top, EVER.
in 40yrs with oxy/A i have never seen one go up.never had a problem.
oh and rods for steel are very cheap, brazing rods expensive, braze flux cheap
mm

[mm289]

Wondered how long it would take for you to chip in, bit slow off the mark eh?



MM

[VAN with a PLAN]

Many thanks for your replies.

HarryMann, I couldn't see anything on acetylene on the Barnet site - I will give them a call.

Mike, This is why I don't want anything too large - it's extremely unlikely I could use up these gasses as quickly as you and I don't need years worth of supplies! I will also need to transport them occasionally (short distances < 5miles).
I have been offered a Saffire 3 torch on long-term loan so glad to see you recommending it.

It's interesting to see you suggesting the portapac size are not consumed too quickly, perhaps this is the way to sart and then progress to larger cylinders if I find the need?

I shall keep shopping around

[Plasticman]

will get some accurate costing for you tomoz providing i remember and get time
mm

[Plasticman]

boc..
large O2 £98/year,,,,,,,,,,,,,,,,,£21 refill +vat
large acety £129/year............£101 refill+vat
so about £470 filled collected inc vat:lol:
porta pack
both cycl £60/year each+vat
refill
O2.........£11+vat
acety......£38+vat
about £205 collected,inc vat
will have energas later today
mm

[VAN with a PLAN]

Great stuff Mike - thanks a lot for all the info, very useful.

Today the nice old bloke who had offered to lend me his Saffire 3 torches has said he would give them to me if I do follow through with setting myself up with gas. Which was nice!!

[Plasticman]

yes and you can get a nice gas axe end for the saph as well very usefull
mm

[HarryMann]

Never cut with oxy-acetylen, watched my dad a few times, have loads of nozzles and torches for it, but it always frightened the bejeezus out of me as a lad when he put the extra oxygen feed on