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Oxy/LPG equipment

PostPosted: Sun May 12, 2019 1:29 pm
by AJS
Hi Gents/Ladies

A quick question to the knowledgeable here regarding Oxy gear. I've 25 years propane soft soldering experience, but looking to step up my game with a 4" build I'm planning. I was hoping to use Oxy/LPG for the hard soldering to keep the cost of gas down, but finding used gear is difficult (or I'm looking in the wrong places). Plenty of Oxy/Acetylene. I was wondering if Oxy/Acetylene equipment can be used with LPG? From my research, it appears the regulators for acetylene and LPG have different pressure ratings, so I expect than a LPG rated reg would be needed. Is this the only difference, or do I need different hoses, flashback arrestors, etc.......

Cheers
AJS

Re: Oxy/LPG equipment

PostPosted: Sun May 12, 2019 2:30 pm
by hillzabilly
You could make a call to a few hire places,ifn you can maybe another option to buying gear you wil rarely use.cheers hillzabilly :handgestures-thumbupleft:

Re: Oxy/LPG equipment

PostPosted: Sun May 12, 2019 2:51 pm
by AJS
Hey Hillz

At $101 a day, I reckon its cheaper to buy used, then if it isn't used for a while, sell and get 80-90% of money back.

Re: Oxy/LPG equipment

PostPosted: Sun May 12, 2019 3:49 pm
by Cadmoon
Why not buy a maap gas torch off you just want to braze? They're more than hot enough and if you're only doing a fairly small amount of brazing it's much less outlay that a proper oxy acetylene set up.

Re: Oxy/LPG equipment

PostPosted: Sun May 12, 2019 8:15 pm
by scythe
Ok so...
Using oxy/acetylene gear with oxy/LPG is very dangerous.
It will explode in your hand (I've seen it happen the the guy standing next to me)

Now having said that the main bits you need to change out are the mixer (i believe the BOC "H" type do both), regulator, and tips.
The rest of it is compatable.
Hoses, flash backs, handpiece and blow pipe are ok between the 2.

Google the different tips and you will see what i mean.
It is mainly to do with how the flame develops at the tip.

The oxy/LPG "welding" tips have a counterbore compared to oxy/acetlyene welding tips.
Heating tips are also very different.

Re: Oxy/LPG equipment

PostPosted: Sun May 12, 2019 9:27 pm
by AJS
Thank you Scythe

That was the informed info I was looking for. I have called 3 different suppliers and didn't get a definitive answer. No one could tell me why there was a difference. After your 1st hand explanation, I won't be trying to cobble a rig together. If I'm not looking at cutting, but just brazing or welding thicker gauge material, would Acetylene or LPG be a better option?

Cheers
AJS

Re: Oxy/LPG equipment

PostPosted: Mon May 13, 2019 8:29 am
by scythe
Oxy/LPG will do all you need for still work.
I like LPG because it does not create the soot that acetylene does, is easier to find and re-fill.
Oxy lpg will get you to 2800°C,
Oxy acetlyene will get, you an extra 300°C, to 3100°C.
Which is not really required when all brazing rods melt under 900°C.

Re: Oxy/LPG equipment

PostPosted: Mon May 13, 2019 11:39 am
by Ravvin
The only issue I have found with oxy/LPG over oxy/acetylene it the way the oxy/LPG blows the molten metal around.
I bought an oxy/LPG set to use for heating and brazing jobs on a truck restoration. I had 2 large fuel tanks with a row of pits and pinholes where a support strut trapped moisture and I used bronze filler rod to fill and level them. What I found was that once I heated the area and applied the filler rod, the flame pressure blew the molten metal all over the place if I had to reheat an area to keep the filler fluid.
It may be different when doing joints, as you heat the area enough to melt the filler rod, then apply the rod to the join while heating down where you want the metal to flow. Capillary action draws it into the join, so you never actually apply the flame to the molten metal. I just remember oxy/acetylene torches being a much gentler flame.
When I bought the kit, consisting of the 2 regulators, hoses, flash-back preventers, mixer handle, and cutting/brazing/heating tips, it was the same price as the oxy/acetylene kit.
The reason I went with oxy/LPG is that we have a couple of local companies selling welding oxygen, argon and argoshield cylinders with no yearly rental. As long as you take the cylinder back to them for replacement/refilling. The exchange price is actually lower than what you pay at the local BOC place, and you save the $200 a year per cylinder rental.
Of course, about 6 months after I bought the oxy/LPG kit, they started stocking acetylene cylinders under the same scheme.