Whats the difference between propane and propylene?

Jake

The Wikipedia article on Oxy-fuel welding and cutting has a bit about propylene.
http://en.wikipedia.org/wiki/Oxy-fuel_welding_and_cutting#Propylene
Are there any differences between torches and tips for propylene and propane?

The company I work for went to propylele a few years ago, all you need to change is the cutting tip . A acetylene tip has 6 holes for the gas, a propylene tip has 8 hole for the gas . You can continue to use the same gauges, tourch head, ansd every thing else, you presure will need to be set around 6 to 8 psi .

Kip

the static build-up in those plastic bags is going to give a very BIG surprise someday!!

Rob, by far the easiest way is to get a much smaller tank than 1000 gal. I use 5# tanks of propane on my portable rig, (known as turbo tanks), and every thing from 20# to 100# tanks around the shop. If you have the ace. regulator with the male left hand thread, it will screw right into most propane tanks. If not, you need an adapter. The hose MOST DEFINITELY must be changed to type t oxy-fuel cutting hose. The torch is modified only by replacing the tip, with a propane tip. I highly recomend using two peice tips, as Jay said they are far easier to clean. Like the others who replied, I keep an ace. set for other uses, but do heavy heating and cutting with propane only. You can hook up the 1000 gal tank, but it is a job for a gasfitter. John Christiansen

John-
Many thanks for your input. I really would like to change over to propane after my present tank of MAPP runs out. I do like your suggestion about using a small tank, just for simplicity and portability.
Thanks again.
Rob

Rob,
One additional caveat about your 1000 gal tank is that you can install a fitting on the bottom-feed side (it currently has a capped check-valve looking at you) that allows you to refill your own portable tanks.
Your 1000 gal tank will have two ports, one on each end. One is for filling the tank; the other is for emptying the tank. You want the one for emptying the tank, since you need fluid when refilling portable bottles.
Your propane company can make up these fittings & hose for you. When my distributer refused me this option, I found a company that would and fired the other.
It takes me 3-5 minutes to fill a 20# bottle.
Ron

If I read this right I can get set up with an economical way to cut and heat steel for bending with an oxy-propane set up? Currently I do not have any oxy-fuel equipment. Since I can weld with my stick welder and mig when I get one all I need is cut and heat for bending. The local/regional welding place did not seem too keen on selling me a propane setup. I guess I need to go in with a shopping list. Here is what I have in mind:

20# grill type propane tank from local gas station.
From the welding supply place
Oxy tank rental S or K size (154 vs 249 CUft)
Oxy-acetylene torch rig.
Upgrade to "T" grade hose
get propane cutting and rose bud tips

In the future if I want to get in to acetylene welding I will have to purchase a new regulator.

you only need 14 lbs. with the propane and a mapp propylene or propane tip it will be about 1200 degrees colder than acetylene

14 psig for the propane may not be sufficient for cutting the heaviest plate, but for most stuff it would probably do. Propane does have a higher stoichiometric requirement fo roxygen than acetylene so expect that it will take more oxygen - perhaps 10-15% more than acetylene.

The adiabatic flame temps of acetylene and propane are ~6000F and ~5100F, respectively.

Rich

at present we are consuming Diesel for burners in production and cooking of Biscuits. Now could we utilise propane gas in burners by change of pipe fittings.what are the ingredients of propane gas . whether propane gas is natural g as. please clarify the questions.thanks.

I can't clarify your question, only you can do that. I can, however, tell you that propane has one ingredient - propane, (C3H8). Propane is a naturally occuring compound present in natural gas and petroleum, and is in the series of all the alkanes; methane, ethane, propane, butane,pentane, hexane, etc. Propane is present in natural gas before refining, but is removed along with other contaminants, to leave nearly prure methane for consumer use as "natural gas." Propane, as delivered in the compressed liquid state (LPG), may also contain some butane, pentane or other alkanes.

Propane can be used for heating billets, but fuel oil has a greater number of Btu's per pound than propane and would, therefore, be more economical, I would think. It is also easier to control the furnace atmosphere, i.e. oxidizing to reducing, with an oil burner than it is with a propane burner.

HEATING VALUES OF FUEL GASES:

PROPYLENE ACET PROPANE NAT GAS
NEUTRAL FLAME TEMP 5295 5589 4600 4500
BTU, PRIMARY FLAME 438 507 255 11
BTU, SEC FLAME 1962 963 2243 989
TOTAL BTU 2400 1460 2498 1000
BTU HEAT VALUE/LB 21,600 21,500 21,600 23,600

THESE NUMBERS FOR PROPYLENE ARE WITH OXYGEN. BUT LOOK AT THE SAVINGS COST VERSUS ACETYLENE, 5 TO 1 RATION, STABLE OVER 15 LBS, UPTO 135 LBS... NEED MORE HEAT...... TURN IT UP. NEED GRADE T HOSES, NEED SINGLE OR TWO PIECE TIPS FPR PROPYLENE. A ACET REGULATOR HAS THE SAME SEALS AND SEATS AS A PROPYLENE REGULATOR.

Doesn't really matter unless your a chemistry nerd, but it's methylacetylene propadiene (MAPP). Not polypropadiene. Polypropadiene would be, if I remember my o-chem, a highly unstable liquid.

Jason
I just read the running comments on the Mapp gas vs. Propane. I have been using Mapp for making glass beads. Today, I got a larger container (7 lb) instead of the one lb. tank. It says it's Chem pane. I can't find that anywhere on the internet and hope it will work for me. Propane leaves the glass dirty and I don't want to go with an oxygen mixture. It is in a silver MAPP can. I also need the added heat of the Mapp Gas.
Thanks for any info you can give me.

Janet Blain
jannie_g_99@yahoo.com

Janet-
My guess is that using any of these gasses without oxygen mix will put deposits on your glass. I think what happens here is that without the addition of additional oxygen (in addition to the ambient oxygen, of course) these gasses will not completely burn and the unburned carbon will be deposited on your work. I could certainly be wrong, so if others more knowledgeable on this site contradict me, I would certainly follow their advice. I finally went to using propane (ala small barbecue tanks until I get my act together to hard pipe propane from my main tank). With Oxygen it is hot enough for my needs (cutting, heating, brazing), economical. I do all my welding with TiG or MiG
Rob

I just read all of the comments and would like to thank you all for the information. but just to recap am I to understand that I can use Propane in stead of oxy/acy for a fraction of the cost? I use a #40 rosebud to remove carbide that has been brazed onto steel cutting tools. I then recycle both the m2 and the carbide. please Clarify?

Brad

Brad,

You can use propane and oxygen in place of oxy/acetylene for most everything except welding, and save a considerable amount on the fuel gas cost.  You will use sllightly more oxygen with the propane than with the acetylene.  You will need to buy special tips for your torch, but they're not expensive.

upthread someone said propane was an alkene....propane is an alkane ( no double bonds )

alkane = no double bonds ( methane, ethane, propane, butane, pentane, etc )

alkene = double bond ( propene aka propylene )

alkyne = triple bond ( acetylene )

I believe that Chemtane is a compound gas sold by the Airgas chain of welding supply stores throughout the US. For the purposes that most of us here would use Chemtane, I think simple propane would be a less expensive and perfectly adequate fuel gas.

Chemtane, propylene, Mapp or propane are definitely not substitutes for acetylene for welding - no other gas really is. Only acetylene/oxygen will produce the proper atmosphere in/around the weld puddle to allow clean fusion of the parent and filler metals.

If you are planning to convert from O/A to Oxy/Propane for heating and cutting you will need to obtain grade T hose to replace the grade R that is customarily used with O/A, you will need the 2-piece propane cutting tips for your torch and you will want to obtain a propane regulator to replace the acetylene regulator so you can take advantage of the higher pressures available when using propane instead of acetylene.

Rich

Yes, you can weld with propane, but you won't nearly the same quality of weld that you would with acetylene. Propane doesn't develop as clean a weld puddle and the results are usually disappointing for all but the best welders.

You can weld using old wire coat hangers instead of proper gas welding rod for filler material, too. Again, the material is not designed for the purpose and the welds will be sub-standard. For fixing your lawnmower handle it may not matter but for welds that must pass inspection it certainly does.

I guess it depends on the circumstances and the end results you need.

Rich