# what's the diff between MAPP / Acetelene and propane with O2



## upTheHill (Feb 13, 2013)

I have bought a small Oxy/MAPP system from Lowes, and like it, and want to do more welding / brazing.
I'd like bigger tanks that last a little longer / cheaper to use.  and was wondering what the difference is between using an O2/MAPP vs O2/acetylene and O2/Propane

TIA, Dave


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## DMS (Feb 13, 2013)

Price, temperature, safety. Temperatures go from highest to lowest

acetylene > MAPP > propane

price goes

MAPP > acetylene > propane

Though, that may vary a bit.

Interesting piece of info, the stuff that you are buying is likely not MAPP, but a MAPP substitute (I think it's propane mixed with propylene). The one plant that manufactured the real stuff closed down last year IIRC. You can still find the old stock around, but it's expensive. The substitute seems to work fine, not sure what the temp difference is.

Acetylene freaks me out honestly. We used it in school, but I don't think I would ever want it in my house unless my shop was in a separate building.

If you are doing brazing, propane is probably the cheapest/easiest to get (refills are available at the local grocery). It's hot enough for most things.

Here is a page with flame temps for various gasses

http://www.engineeringtoolbox.com/flame-temperatures-gases-d_422.html


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## upTheHill (Feb 13, 2013)

looking at the web page, there isnt much difference in temp between propane & mapp. and i saw that the lone mapp wupplier shut it down.  I'll look into working with an o2/propane mix and see how that works


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## Ray C (Feb 13, 2013)

What do you want to accomplish? Welding, heating or cutting?

The differences are the pressures (which highly impact welding ability) and byproducts of combustion (which can contaminate whatever you're working on). 

I once switched to polypropylene instead of Acy because of a shortage. It's hotter than OA but you can't weld with it for love or money because it's 20PSI higher at the tip.  Using anything with Oxygen near aluminum has it's fair share of side effects.


Ray

EDIT: I guess, the point to be made is that each process is best at certain applications. Figure-out what you'll be doing most then, use the process best suited to that application -which is (for the most part) a cook-book decision.


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## upTheHill (Feb 13, 2013)

it will be for welding /brazing. steel, brass and aluminum. 
no cutting at all, nothing really thick either. maybe 1/4" steel at the thickest.


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## Ray C (Feb 13, 2013)

You're in a tough spot I think and hope someone with more industry experience will help out here.

Aluminum...  I don't think anyone will disagree too much that TIG is the way to go for small to medium aluminum jobs.  I don't believe it can be done with OA (but not quite sure).  It can be done with a MIG unit if it has high frequency capability. For small things with MIG, folks use an adapter gun that has a small spool on it. You need gas with MIG/Aluminum but can use flux core for steel (don't know about Stainless).  I'm told however, that MIG aluminum is really for larger pieces.

Small pieces of steel is easily handled with TIG.  It's all I use for small steel and even big pieces up to 3/4" (with proper beveling) if there's not a whole lot of welding to do.  If I have many pieces of big stuff to work on, Arc/Stick is the way to go.

Brass?  I know it can be done with TIG -and very efficiently too.  It's also great on Stainless.  I don't know about other methods for brass and I personally have never TIG'd brass.  I've done lots of Stainless and it comes out beautiful but you need to watch the heat input.  I use a secondary pulse function on stainless.

Brazing...  I'm terrible at it but on the rare occasions I need it, I run propane and oxygen through the OA torches. -Uses the same connector fittings.  You'll get nowhere with propane alone.

TIG is a little costly and takes some practice.  I had a good handle on Arc welding.   I was taught (long time ago) how to OA weld -but didn't do too much.  I picked-up TIG in a few days and was making trustworthy welds after the 1st week.  They continue to get better looking.  TIG is probably the most expensive because of the gas (Argon and/or Argon+Helium for aluminum and steel does fine with pure Argon).  There's an initial set of expenses for shielding cups, electrodes (use the lanthalated -and forget ceriated), bottle regulators etc. Once you buy all the packs of what you need, it lasts a long time.   I rent/buy the larger bottles of Argon (300 cuft) a refill cost $65 and it's good for about 30-60 hours of actual weld time (varies on required flow rate).  10% helium mix really makes aluminum look beautiful and increases heat w/o eating-up the electrodes.  I use it sparingly because helium shot-up in price lately to about $200/bottle.  -Used to cost 75!   TIG has a bit of a learning curve and takes a while to get proficient but I think it's extremely verstatile, outstanding for precision work and decent for low-production medium jobs.  The strength of welds is outstanding.

If you think you'll be doing mainly precision type work, I think TIG is king.  Even good for medium jobs of heavier stuff but it is a little slower process like OA welding.   If I were a gunsmith like you, TIG!  For brazing, you need a gas setup.  Propane/Oxy is cheap and you can BBQ while you're at it. 

Check this out.  Half tempted to get one as a standby unit for my 205Amp unit.  I have the second unit.

http://www.everlastgenerators.com/PowerPro-164-380-pd.html

http://www.everlastgenerators.com/PowerPro-205-379-pd.html

They also have a 256Amp unit...  It's overkill unless you go with a water cooled torch.  I rarely go over 160 Amps and can do it all day long with an air cooled torch.  Above 180Amps, things get hot -real hot!  You need water cooled stuff.  BTW:  Aluminum requires the highest amperage as it dissipates heat as fast as you can apply it.

Ray




upTheHill said:


> it will be for welding /brazing. steel, brass and aluminum.
> no cutting at all, nothing really thick either. maybe 1/4" steel at the thickest.


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## DMS (Feb 14, 2013)

You can't weld aluminum with oxy-fuel, but you can braze it with one of the zinc alloys designed for the purpose. It works pretty well actually. You don't even need oxygen, it works fine with an air-propane torch.

For sticking two lumps of metal together quickly, nothing beats MIG, but you can do a lot with brazing/soldering with a torch. It's great for joining two dis-similar metals together, and some things just can't be welded effectively.


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## paulweldit (Feb 14, 2013)

Ray C said:


> You're in a tough spot I think and hope someone with more industry experience will help out here.
> 
> Aluminum... I don't think anyone will disagree too much that TIG is the way to go for small to medium aluminum jobs. I don't believe it can be done with OA (but not quite sure). It can be done with a MIG unit if it has high frequency capability. For small things with MIG, folks use an adapter gun that has a small spool on it. You need gas with MIG/Aluminum but can use flux core for steel (don't know about Stainless). I'm told however, that MIG aluminum is really for larger pieces.
> 
> ...




I have been welding Aluminum successfully with acetylene/oxygen for well over 30 years. I am a metal shaper and when I say successfully, that means well enough to hammer, planish, bend and shape the areas where the pieces are joined. Many Aluminum bodied cars were and have been built with Acetylene/oxygen welding process as well as much of the early Aircraft chromolly( the Bell Helicopters you saw flying in Mash TV series) and the steel frames used in British Race Cars.


Welding Aluminum with a mig does not require a High freak unit. Only to items required are straight Argon gas, correct polarity and a plastic liner for the torch. I have had the best luck with the Drag welding technique and it is more for structural items IMHO. It does produce strong welds and somewhat more brittle but TIG or Oxy/Acetylene are cosmeticaly better and stronger by far. I have owned my TIG ( 500 amp ) since 1970 and I have never used any gas but straight Argon on Magnesium, Manganese, Copper, Brass, Aluminum, Stainless, Chromoly and Mild steel. Straight Co2 does produce the strongest weld and deepest penatration with a MIG but splatter is increased and appearance is reduuced slightly. Co2 will also produce a stronger weld (increased penatration) when used with Gas-less Wire.


Natural Gas( preferred) or Propane with Oxygen produces cleaner weld/Braze/Solder joint for non-ferrious metals such as copper, brass, Gold and silver.


I can't say much in a postive way about Mapp Gas or Propylene since I have mainly used it for heating and what little cutting I did was not desirable in my mind, however the proper tip and practice might change my opinion. I do know when used with my pattern torch, it required much slower speed and nowhere near the appearance of Acetylene. 



                                     Paul N.


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## AlanR (Feb 14, 2013)

paulweldit said:


> I have been welding Aluminum successfully with acetylene/oxygen for well over 30 years. I am a metal shaper and when I say successfully, that means well enough to hammer, planish, bend and shape the areas where the pieces are joined.



I'd like to hear more about your techniques for oxy/acetylene welding of aluminum. I knew that it was extensively used for aircraft in the past and I've seen it done. For me the biggest issue is supporting the material as welding temps and the heat conduction of aluminum can often lead to collapse of the material.


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## bushwacker (Feb 15, 2013)

02-14-13, 01:36 AM
DMS You can't weld aluminum with oxy-fuel.  

You can my friend, and it's the only way that it could be done many years ago.

  There are a few wrinkles to it admittedly though.  I haven't done any for many years, but I had occasion at that time to weld a lorry alloy body that had a crack in it for it's anual test.  We only had oxy/acetelene but had alloy welding filler rods and flux.  It has to be scruppiously clean. and I cut a vee in it with a diamond shaped chisel and then welded it straight away.  I had to do it in around 10" runs.  A tig plant is the way to go if you one or access to one and yes it has to have high frequency.  If you are unlucky when using oxy/acetelene it drops into a big hole all around it, the temperature inside being so much hotter than the outside, and you can't see whats happening really.​


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## DMS (Feb 15, 2013)

I stand corrected on welding aluminum with oxy/acetylene :tiphat:


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## bushwacker (Feb 15, 2013)

I stand corrected on welding aluminum with oxy/acetylene :tiphat: 


No problem at all.  I this year got my BS4872 certification & welder approval, and haven't even picked up a torch since doing it.  That was 2 years of my time at night school aswell, but still I've got my little bit of paper to say I can do it.  I don't suppose that it's a bad thing for a 60 year old.


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## Brandon (Feb 21, 2013)

I second Alan's request for more information on welding Aluminum with acetylene/oxygen. What filler rod do you use? I'm guessing aluminum? Do you create fillets before welding and fill, or butt weld? What type and size of torch tip are you using? 
Thank you in advance.
Hay Bushwacker... I race in Leicester... Leicester New York that is...


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