|01-08-2010 06:48 PM|
|oldred||And what I am trying to point out is what is recommended by the all the manufacturers, such as that link to Victor which is one of if not the leader in torch/cutting gear, plus trade schools and every welding text you are likely to find. In all my years of doing this I don't think I have ever heard such a thing as one simple setting from an experienced welder, I mean good gosh man it is just basic and common torch skill! That one particular setting like that may be a decent number to use if the operator was limited to one such choice but as that chart (and many others) clearly shows any one setting would have to be a compromise in most situations so why limit yourself? Like I said if it works for you do it that way but for most people there is simply no reason to limit their tools to such a simplistic compromise when tuning the darn thing for optimum results is so simple, anyone using that chart will find it very easy and will quickly find they can do it by "feel" in just a very short time and the chart is really not something always needed as a reference. The chart is a handy way to get started but just as other techniques will need to be learned so does adjusting the regulators, it is just part of it and saying that one specific pressure setting is best for everything makes little sense because every situation is different. Actually a few lbs of Oxygen pressure makes a big difference in how well a torch will cut and I just can't imagine trying to use one without being able to tune it to whatever is best for what I am cutting, like I said that is just part of it. I guess if a person can not develop the skill for what is the right setting and don't want to bother with using a chart then maybe that simplistic approach is better than nothing.|
|01-08-2010 04:46 PM|
|01-08-2010 04:07 PM|
You might get away with 40 PSI on a machine torch and large hoses but I find that 50 to 55 works a lot better when cutting by hand with the usual equipment most of the guys here are going to have, however if you are super steady you may be able to do it, most people will not be able to. Besides that's way bigger than anything likely to be found for what anyone here will be using. 40 PSI is way too much pressure for 1/2" or less and for automotive work like what we normally talk about here 25 lbs is plenty with a, for example, Victor no. 1 tip or slightly higher with a smaller tip, it in fact will give a better cut than the higher pressures on these thin materials in addition to saving Oxygen. Again there simply is no one Oxygen setting for all around use but if that's the way you do it and it works for you then by all means keep doing it that way. For you guys learning to do this try using a tip chart for the particular brand of tip/torch you will be using or simply adjust the Oxygen down to the lowest PSI that gives a clean cut for you. Some of the smaller rigs with the 1/4" hoses may need a slightly higher pressure setting than the bigger torches with larger hose but the difference will be slight.
Here is a handy chart I have used as an example before and it works quite well, 40 PSI certainly is used as are many other pressure settings.
These are just good starting points however and good cutting skills will determine what variations are required when using different tip sizes than the chart shows. Very few people would have an exact optimum tip size for for every thickness of metal likely to be encountered so as an example then the chart shows 1/2" plate at 30/35 PSI with a no. 0 tip but using a no.1 is just fine at about 25 to 30 PSI, a no. 2 will also give a good cut on 1/2" with about 25 PSI on the same plate thickness but that would be about the largest practical size to use on plate of that thickness. Certainly larger or even smaller tips could be made to work but anything out of that range starts to push practical limits, same principle applies to thicker/thinner metal. This is why there is no one setting for everything and telling someone who is just learning that there is will be getting them off to a bad start. Generally adjusting the Oxygen pressure before starting a cut is just part of the process and after you do it a while it becomes quite simple to look at the size of the tip and the thickness being cut and set the pressure according to the task at hand. A "one pressure for everything setting" may work ok for some things, make a poor cut for some and simply waste Oxygen on others so why not just learn to do it right? Nothing to it really and it simply becomes second nature to know how much pressure will work best for what after a person does this for just a little while.
|01-08-2010 01:00 PM|
I've never had a problem cutting plate up to or more than 6" with OXY set at 40 PSI and Acetylene at 7 PSI,i just do a bit of preheating with the torch before i make the cut and they've come out clean cuts..which personaly i do the little pre-heat on anything or any size i cut with a OXY/Acetylene torch,it makes a cleaner cut.
The summer of 2008 up in Morgantown W.V. i was on the new coal burner they were building,biggest boilers in the USA,i was regularly the one cutting the cope out on the beams because the steel was fabbed in china and nothing fit right,and the beams were anything from 1/2" to 8",using a #3 tip on the thicker iron.
The only time i've ever had to set it higher is if we added a hundred feet or more to the hose to get up high somewhere or somewhere where the torch cart couldn't go.
I've never seen it a problem as waisting OXY at 40 PSI with anything 1/4" up,anything thinner i use a Plasma Arc or a 6" Metabo or Dewault with a cutting wheel.
Use the right size tip according to the size steel you're cutting and the tip won't let it waiste OXY with it set at 40 PSI
I do agree that anyone using an OXY/Acetylene torch to cut 1/8" or less will get away with less pressure settings,but i'd never use it for that for the fact it will warp anything that small or smaller even with a .00 tip making it a mess to straighten out.
|01-08-2010 09:20 AM|
|oldred||These "one size fits all" suggestions for Oxy/fuel settings is simply ridiculous and the Oxygen pressure needs to be set for the task at hand, are you saying you cut 1/4" plate with 40 PSI Oxygen? How about 1/8" plate? What about 6" plate even with a large tip? Sure 40 PSI CAN work in a lot of situations but there are a heck of a lot more where a lot less pressure, or more pressure, would work a lot better. Using 40 PSI on thin plate is going to waste a lot of Oxygen and with the right (small tip) it is going to make a poor cut! Fellas there IS NOT ANY ONE SETTING FOR OXYGEN! Even Acetylene sometimes needs more than 7 PSI although for the vast majority of jobs that setting would be fine, try using a no. 6 (Victor) tip to cut 6" plate with only 7 PSI on the fuel gauge, might work if you have 1/2" hose! Learn to set the Oxygen pressure to whatever works properly for what is being done and I would think that for what most of the guys here would be using a torch for 40 PSI Oxygen is simply way too high, even if it works ok you would be wasting a lot of it on thin plate.|
|01-07-2010 06:24 PM|
WOW..talk about bringing a thread back from the dead!..lol
But i've never seen this one,mostly because i am not here much in the past 2 years or so because i have been into the 4x4'n,Jeeps and Early Bronco "FAD" lately..lol
I have to agree with krazyone 100%,not because i am also an International Ironworker and been in the trade for 30+ years,but i've also ALWAYS been told Oxy-40 PSI,Acetylene-7 PSI...and the oxy valve wide open..and the Acetylene valve 1/2 way.
This is also and has always been the practice of Pipefitters,Boilermakers,Millwrights and Specialty Welders companys and any Fab shops i've ever worked around the country and Apprenticeship classes.
The reason i have been told is that the Acetylene valve is not designed for "wide open"....the acetone in the bottle used to dissolve Acetylene when refilled can get to the seal if the valve is wide open and
cracking the valve wide open can cause the Acetylene to be even more unstable as it already is because of the high pressure being exerted through the gauges....whether this is true or not?..i don't know,but i tend to use those practices because we go through "thorough" safety classes and STRICT safety rule standards in the BIG industrial plants and jobsites before we are even allowed to work there and this is what myself and millions of craft hands have been and still taught.
One thing i didn't notice in this thread ,maybe it was brought up because i mostly "breezed" through all the posts...
NEVER..i mean NEVER! use oil or grease ANYWHERE on a torch setup..gauges,torch,hoses,fittings....NOWHERE...it will ignite the Acetylene/Oxy like as if you put a flame to it,its not a Question of "IF" it will happen..it is a fact of "IT WILL HAPPEN".
Fire Arresters,or also called "Flash Arresters" are a standard on a torch setup and a MUST on any job i work anymore,they must be placed at the exit side of the regulators/gauges,not at the torch end.
|01-03-2010 05:16 PM|
|krazeyone||might as well put in my 2 cents! i am an ironworker and use oxy/acl torches on a daily basis. i was taught in apprentice class that oxy tank gets opened all the way. acl tank gets opened half way. 40 lbs at the oxy, and 7 lbs at the fuel. i think that the most important thing is to prevent an accident in the first place! whenever i use the torches at work they are at least 25 ft away. when i use the torches at my house i put them outside the garage door. always blow the slag away from the bottles! keep a fire extinguisher next to your work! even a bucket of water to put cut scrap pieces into. torches have to be one of the most usefull tools in the shop, but if they have leaky hoses, leaky regulators they can be a real big hazzard. alot of people buy those japan torch kits with the 15 ft hose that comes with them, buy another section of hose, be safe! buy a few plastic hand spring clamps and some fireproof tarps if you do cutting in the garage and need to protect windows and stuff you don't want slag on. it's all just common sence!!!!!! anyway my 2 cents!|
|01-29-2009 06:49 AM|
The demo I saw the guy had 8 plates stacked together for a total of 4", as I said I was told about the video of the larger stack but I never saw that.
It's supposed to be on the web, let's see if we can find it,
Well that didn't take long!
How about TWENTY rusty plates?
Not a video but quite interesting anyway.
Ok, I just discovered that the video I was told about is found on the site at the link above.
|01-28-2009 10:03 PM|
The 10-12 plates were stacked for the cut?
|01-28-2009 08:17 PM|
|oldred||The one time I saw it demonstrated the fella had eight 1/2" rusty plates stacked on top of each other and that darn thing went right through them like it was one solid piece of clean steel! Pretty impressive itself but I have heard of a video where the same demo was done using something like 10 or 12 rusty plates of about the same thickness, I have sure seen the times when something like that would have been really handy. Since I have retired I keep seeing all these wonderful toys coming out and I can't help but wonder what the next 40 or so years will bring.|
|01-28-2009 05:36 PM|
|wedgehead63||Red, I have seen it used, but have never gathered up the testicular fortitude to try it! It is actually making a comeback. Something about fire and gasoline seems scary to me! I've always said that a welder is just one step above cavemen. I tell my students we are basically knuckle draggers, get used to it! FIRE GOOD!!! LOL|
|01-28-2009 04:07 PM|
|oldred||Wedge, have you used Oxy/gasoline? I have never had the opportunity to try this setup but from what I have read it does seem quite fascinating.|
|01-28-2009 03:05 PM|
I might as well chime in on the arguement. Not that it makes me the authority on the subject, but I do teach welding and fabrication for a living, and I am a Certified Welder, Welding Inspector, and Certified Welding Educator through the American Welding Society. I teach per Harris Calorific's instruction of 1/2 turn acetylene and full open oxygen. 5-7 PSI for fuel, never to exceed 15 PSI 20-40 PSI oxygen, never to exceed 1/2 wide open of gauge. As previously stated, I teach the oxygen regulator is a double seat design. I have never encountered a double seat fuel regulator. As for gasses, I use acetylene and a fuel blend sold by CHEMTANE (propane blend) It is capable of 6000F. It cuts extremely well and very fast. It WILL NOT weld, but for cutting, I have never used better. It is safe at full tank pressure, not that you would ever need to. It lasts longer and is much safer. I was a die hard acetylene man and I still use it, but the CHEMTANE is awesome. Try it, you will like it. My
|01-28-2009 02:51 PM|
|oldred||I agree that there is no performance gains in opening more than 1/2 turn and I actually never even thought about that one way or the other. That is not a manufacturer manual I have but rather a welding supply catalog from back around 1998 or '97. As I said from the beginning this has been discussed for as far back as I can remember and that's why I said several times in this thread that it is a matter of opinion and for everyone to be their own judge. One thing is for sure whether or not one takes the position of opening the valve all the way or only 1/2 turn the overwhelming advice is to go only with the 1/2 turn, so overwhelming in fact that I have found next to nothing to the contrary even though I took the time to search.|
|01-28-2009 02:18 PM|
To the best of my knowledge, no valve manufacturer makes a double seat low pressure valve. Keep in mind, it takes very little leakage to sound like a hole in the boat.
If you feel more comfortable opening it all the way, I say go nuts! There is no gains as far as performance of the tool to be had by 1/2 turn or 12 turns.
As far as leaks in the stem and bonnet, if there is one, the supply house should be notified and the valve should be replaced.
The curiosity is killing me. what manufacturer manual do you have that shows a double seat? I would be interested into looking at one.
Thanks for your input on this Oldred.
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