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Up Topic Welding Industry / General Welding Discussion / Gouging with propane?
- - By weldstudent (**) Date 10-26-2012 03:09
Hi all, i have been using a propane torch this last week to scarf off old welds on 3" and 5" plate, the welds im scarfing are 1/2" fillets. I finally convinced my boss to get me a scarfing tip after three days of using a cutting tip. Now to the issue. I dont seem to be getting any preheat out of the tip. Some times i need to hold in one spot for around five minutes before i get a cherry i can work with.
The tip is a #2 on a Victor torch. Propane is set to 10-15 PSI, and Oxygen is at 40 PSI. The tip is one of the round ones, no flat on the back and the Oxygen jet hole is centered around six preheat holes. Hope this is enough info.

Thanks for any help.
Parent - By DaveBoyer (*****) Date 10-26-2012 06:41
You could use another really big welding/brazing tip or a large cutting tip in another torch [both torches at the same time] to get the start point up to temperature sooner.

At the auto & truck frame plant We used oxy propane on a line tracer to cut plate, at times heavy plate. To get the start point up to temperature sooner, the preheat from a hand cutting torch was directed at the same place as the machine torch.
Parent - - By Oneatatime (**) Date 10-26-2012 06:43
Are you using a propane tip? Or a Acetylene tip?
Double check the part # to see if u got the correct tip......
Parent - - By Superflux (****) Date 10-26-2012 07:41 Edited 10-26-2012 07:45
Yes, I believe natural gas and propane tips are a 2 piece configuration with a buncha little tiny recessed holes. At least that's the way they were constructed back in the day when I last used them. 1970's...
I just reread your post and if there are only 6 holes, sounds to me like you have (an Acetylene) the wrong tip for your gas.
FWIW, I've never seen a scarfing/gouging tip for this gas.
Best brain storm your supplier.
Parent - By Superflux (****) Date 10-26-2012 08:36
Oxy-fuel gas scarfing is very labor intensive. Given the choice, Acetylene is much better. Natural gas just does not produce the BTUs in my opinion to be efficient, not in this day and age.
Either way, I sure would look into Air Carbon Arc Gouging. WAY faster.
Parent - - By welderbrent (*****) Date 10-26-2012 13:34
I agree with the other posts here, I believe you have the wrong tip for the fuel gas being used.  Propane, Propylene, MAPP, Natural Gas, all use different tips than a standard Oxygen/Acetylene torch set up. 

If I remember correctly, all burn slightly cooler than Acet.  But not enough to really be all that different if you have the correct tip.  I am inclined to second Superflux, don't believe I have seen a true scarfing tip for the other fuels.  Doesn't mean they aren't available, just may be harder to find. 

Hopefully you are using Propylene or another such variation of Propane.  They run better for torches.

While it is great to know how to scarf, air-arc and even grinding is usually faster.  The only time scarfing is an advantage is if the equipment is right there, the fastest thing available, and the operator really knows what they are doing.  Most people end up gouging/scarfing into the parent metal too deep even when just 'washing' the weld without adding extra cutting pressure oxygen.  Then you have a complete repair to make.  Depending upon the code and application that is not a good thing.  It is also a potential problem to have that much heat concentrated on one area long enough to wash the welds.  There it depends on the base material as well as operator skill to not get the area too hot while pre-heating to get the metal to flow.

Have a Great Day,  Brent
Parent - By ctacker (****) Date 10-27-2012 03:24 Edited 10-27-2012 20:59
I have a scarfing tip for LPG gas. I'll see if I can round it up and snap a picture this weekend. they come bent and round, not bent and flat as you would see in an Acetylene tip. the oxygen hole is a little different also. it starts small and when it leaves the end of the tip it looks like a #7 tip and just  gives enough oxygen to blow the weld away but not gouge too deep in the base metal.

Edit: I added 2 photo's, its been awhile since I have seen it, It is a little flat on the sides, and the hole is about 3/16 inch round. I think they bend it to get the oxygen flow to spread when it leaves the tip so it's not able to stream and make a cut.
- - By weldstudent (**) Date 10-26-2012 15:32
I am using propylene, not propane, my mistake. I did check the tip and it is for propylene and natural gas. The plate is going to be used for ballast in a locomotive so the welds im removing need to be flush to slightly below base. i wanted to air arc the welds but i was told to use the torch. I think im being punished, just dont know what i did.

Also, i have heard that when making a cut you can turn off the fuel and cut with just the oxygen jet. I did it, didnt mean to, i snuffed the flame out and was able to go about another six inches before it guit cutting.

Thanks again.
Parent - By G.S.Crisi (****) Date 10-26-2012 17:18 Edited 10-26-2012 17:21
Superflux is right. The problem is not the tip you're using, but the gas. No hydrocarbon gas, whether propane, propylene, natural gas, LPG or butane has the combustion heat acetylene has.
Many years ago, I'd say 50 or more, there was an attempt to replace acetylene with LPG in cutting and welding torches. Soon after, everybody went back to acetylene because LPG could actually cut and weld, but spending a considerable longer time.
Superflux is also right in recommending carbon arc for gouging. The result is far better considering time and quality.
Giovanni S. Crisi
Sao Paulo - Brazil
Parent - - By Blaster (***) Date 10-27-2012 05:07
Hi Levi

Are you working the flame up?  If you are trying to adjust it like an acetylene tip (turn up fuel and then add oxygen, one time) you will get little heat.

I recommend you adjust the flame like normal, then add more fuel, then more oxygen, and repeat this working up process until the flame is roaring pretty good.

With a little practice you will get where you can light the torch, with the tip touching a piece of iron and leaned over to one side, with the gas turned up pretty good, without blowing the flame out when adding oxygen.  This will save some time over working the flame up in steps.
Parent - - By weldstudent (**) Date 11-04-2012 17:00
Hi Boss.
I really haven’t used acetylene since I left the shop, we have one acetylene cart here. Its used mainly for welding. I light my propylene torch by rolling the tip onto the flame and adding my oxygen. Im starting to think my problem is the thickness of the material. I’m working outside in the cold and the rain and I think that mother nature is fighting with me. I got to use a tank of liquefied petroleum gas last week and it burns hotter so I do not have to wait nearly as long.
Parent - By DaveBoyer (*****) Date 11-05-2012 06:42
I don't have the numbers right here in front of Me, but I believe You SHOULD be able to get a higher overall heat output [more BTUs] as well as a higher flame temperature from propylene than from LPG.

Sounds to Me like You are using too small a tip [#2] for the material thickness. Check this link:

http://victortechnologies.com/IM_Uploads/DocLib_5218_Victor%20Professional%20Cutting%20Tips.pdf

Look about 1/2 way down the page, You will see the GTB and 318MP propylene tips, the model # will be in yellow print for propylene.

It looks like You should be using a #4 GTB tip or a #4 or #6 318MP tip for the thickness material You are working with.

Note that the pressures given are for 25' of 1/4" hose for tips through #5. Longer hoses require higher pressure to give the same flow.
Parent - By DaveBoyer (*****) Date 10-28-2012 04:21
Another potentially useful tip [pardon the pun]:

You could use much higher fuel gas pressure than the 10-15 PSI allowed with acetylene on all of the alternative fuel gasses, and You MAY HAVE TO to get enough preheat.

If You are using an acetylene regulator, You can ONLY GET 15 PSI, but with an alternative fuel regulator You can crank it up much higher, usually to 50-60 PSI.
Up Topic Welding Industry / General Welding Discussion / Gouging with propane?

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