Basic items for a new O/A user

admin

Hello everyone,I have a new O/A set up...new to me that is. I intend to get practicing asap this weekend.I will have full cylinders tomorrow.What sizes of welding nozzles should I have for practice welds on say, 1/16" and 1/8 pieces of mild steel.Also what pressures should I be looking at for the fuel and the oxygen.Is there a link for the safety procedures for O/A on this site?I have a welding book on hold from the library as well...so that will help a wee bit.any help will be great.Thanks,SD
Reply:I was taught 2 lbs pressure for every tip #.  Probably 5 and 5  or 5 acet and 10 oxy to get you going.Have fun.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:On my setup pretty much all the tips run ~ 3 to 6 psi on both oxygen and acetylene. I think that's standard. Make sure you check the gages on the regulator with gas flowing, at the low setting the you will find that after you set the pressure it will drop very low when you open the valves on the torch.
Reply:be careful you dont overdraw your acetelyn, what size cylinder..Various GrindersVictor Journeyman torch200cf Acet. 250cf oxygenLincoln 175 plus/alpha2 gunLincoln v205t tigLincoln 350mpEsab 650 plasmaWhen you can get up in the morning, Its a good day.Live each day like its your last.
Reply:Thanks for the insights...I have a 75 cu ft for the acetylene and I think it is a 80 cu ft for the oxygen.I have noticed that the single stage acetylene regulator seems to stop at 3 psi even with the cylinder valve closed and both the lines and torch purged of acetylene?Do you think the gauge is NFG?I did buy the whole set used, however, the guy did weld two pieces of steel together as a test. It seemed good to me but hey...what do I know right?Let me know what you think.Night Night from the shed...back on Friday.
Reply:Variety of tips, proper O/A welding rods (RG45 and RG60), good glasses, fluxes if doing things other than mild steel.  It takes 2 hands to gas weld so you'll need clamps and magnets in the future.  There is nothing too unusual.Your gauge is out of calibration, no worries.  Just remember that it reads about 3psi higher than it should.
Reply:I forgot to mention, don't let the acetylene pressure get to 15 psi or above. It is unstable in gas state above 15 psi, that's why the acet cylinder contains acetone, this dissolves the acetylene and allows the tank to have much higher preassure.Not knowing what type/or age of your torch, I would check to see if you have flashback arrestors installed. You should at least have a set on the gas inlet's to the torch, ideally there would be a second set on the output of the regulators. This will prevent any gas backflow (acet to oxy or oxy to acet lines) and fire from entering the gas supply lines/regulators/cylinders. You especially need these when welding because of the low pressure's being used. While learning you will probably many times hear a loud pop, this is caused by the tip getting too hot or clogged and the gas exploding inside of it.
Reply:Hello everyone...Well,today I exchanged the two cylinders so I have full fuel and oxygen.I went to buy a flash back arrestor set and it was half the cost of a Victor torch with the arresters and one way valves built into the torch, so I bought a new torch. Now I know the history of the torch. The old one was an Omniweld. It is fine but now I have a better one I think.I bought a #2 welding nozzle, three dia's of RG45 rod, new welding goggles and new welding gloves. I will get a new 2" acetylene working pressure dial?I should be melting something tonight in the garage I hope.Question:When we use a RG45 filler rod in the weld pool, are we "welding" or are we "brazing"? I'm cornfused at this end.Cheers,SD ( I'll take my answer off the air at this time  )
Reply:You are welding.  Heating the base metal to the molten state and the filler mixes with the base.Real world weldin.  When I grow up I want to be a tig weldor.
Reply:Thanks David R for the answer.I bought some angle iron this weekend. I have to paint my cylinder cart as it looks rusty and un-professional.  I bought a universal cylinder key...a handy piece of kit that is.I would like to make a movable smallish welding and cutting table to do work on. Nothing too huge you understand. I might even tack weld the assembly up and take it to a local fab shop for them to lay the nice beads of mig weld. I want to use 1 1/2" X 3/16 angle iron for the frame and I think me welding all of this up with O/A will use a lot of my fuel gas. What does the community think?Cheers,SD
Reply:With a #2 alls you need is 1/16 rod.  3/32 is a little thick, but can be used.  With the size cylinders you have, a #2 is about as big as you can go.  You can run a #3 at the low side (4cfh I believe,but check your book on flow rates) 1 to 7 remember, otherwise youll suck the acetone up into your regulator and cause burn back (torch will pop like crazy).  Just dont want you to go through what I did when I was learning.  To start, Id just get you a hunk of 3/8 plate (2 foot square is plenty of room to learn on), use a workmate or sawhorses to prop it up on and get you some fire brick to put your coupons on.  Id practice square grooves first then move to t's, then laps, then round shapes.  If you get good doing it flat, then start trying to go vertical (I tacked a little hanger on my bench to do vertical and overhead stuff).  To be honost, I did one good vertical butt weld and called it a day with the torch and moved on to mig and other stuff.  Been in a class and as soon as a couple of projects are done and class is over, Im gonna dust the gas torch off and start practicing some more.  Good luck, its fun.Various GrindersVictor Journeyman torch200cf Acet. 250cf oxygenLincoln 175 plus/alpha2 gunLincoln v205t tigLincoln 350mpEsab 650 plasmaWhen you can get up in the morning, Its a good day.Live each day like its your last.
Reply:Originally Posted by Shed_Dwellerwhat pressures should I be looking at for the fuel and the oxygen.SD
Reply:Sorry, missed the post on the bench.  Well, Id say youll use up quite a bit of gas on the table.  That would be quite an undertaking for a first go.  I wouldnt go any thinner than 3/8 inch plate for the top, or you can do a grid pattern with angle and  clamp your work to it (if its too small).  if using angle iron go 1/4 inch.  Id practice for a bit like I said, and accumulate the metal you need for your table (figure out what you need, make a sketch with dimensions, and remember, this is a work table, so dont go too overboard).Various GrindersVictor Journeyman torch200cf Acet. 250cf oxygenLincoln 175 plus/alpha2 gunLincoln v205t tigLincoln 350mpEsab 650 plasmaWhen you can get up in the morning, Its a good day.Live each day like its your last.