I tried working it out once and there were so many noughts involved it did not matter.
I have a vague memory of around 10,000 times the volume of gas per £ in BOC bottles opposed to the little disposables.
Try to get an account with anybody but BOC if you can, a load less hassle and usually cheaper.
It costs £12.91 per little bottle multiply that by 83 = £1071.53. So in a Y size bottle there is £1071.53 worth of little bottle gas - crazy.
The boc volkzone offer is £62 for the first year rental plus a full bottle. £32 rental for the next year and £74 for the third and subsequent years. I'm tied in for 3 years. So 63+32+74 = £169.
So if I go for the boc deal and end up only ever using one Y bottle full of gas to weld my mk1 golf then I have saved (1071.53 - 169) = £902.53.
see if you can find an independent supplier, BOC used to have almost a monopoly over gas supply, they act as though they still do. Go in yellow pages and see what you can find, google energas and industrial gases.
Chunko'.
Ive gone for the volkzone offer and sent back my account paperwork last tuesday so now just waiting to hear what I need to do about getting the gas I guess..
you almost defiantly won't use a whole Y to restore a golf, I used less than half an X to replace the sills and rear floor in a land rover discovery, thats with other jobs in between too, though I don't you mig for much other than cars, mostly used oxy acetylene for making stuff, (I know I know, more expensive, slower, and more distortion) heh tig now anyway