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  #21  
Old 10-21-2013, 04:09 PM
David Gardiner David Gardiner is offline
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Frank you should open the valve a couple of turns, it's so the pressure at the gauge will go up and down as you turn the valve on the guage. The flow will not effect it.

I always use a slightly carburizing flame for welding aluminium, if you weld ally with a neutral flame it can easily adjust itself to an oxidizing flame, which you don't want.

The flame should never hiss loudly. I show most of the setting up process on my youtube footage.

David
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Last edited by David Gardiner; 10-21-2013 at 04:20 PM.
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  #22  
Old 10-22-2013, 01:32 PM
Tom Walter Tom Walter is offline
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David -- As you describe works fine with my large Victor Journeyman torch when welding 12g steel. I bought that torch in '74, but when I go to weld with the Meco it was just too much airflow, and would blow molten aluminum all over the place. The regulators with such a low flow, never appear to move the off the needles.

Oxygen Bottle. Big Valve (top of the bottle) should be all the way open to seat that upper packing. Yes, open slowly.

Acetylene bottle. Just open 1/3rd or so. You want to be able to shut is off quickly in an emergency.

Safety tips, from State of Virginia (page 26 has details on opening the oxygen valve fully, but a good safety review)

http://www.dmme.virginia.gov/DMM/PDF...eandsafety.pdf

I've had my regulators rebuilt, and with my big old 40 yeas old Victor Journey they work nicely. With the Meco.... boy it was confusing to set pressure and not be able to weld.

Just passing this along to anyone else struggling with OA welding aluminum.
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  #23  
Old 10-22-2013, 02:11 PM
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Frank.de.Kleuver Frank.de.Kleuver is offline
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Hi Tom,

I'm also working with the Meco. At what pressure do you set de regulators? Or do I misinterpret you're story?

Grt

Frank
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  #24  
Old 10-22-2013, 02:29 PM
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Frank.de.Kleuver Frank.de.Kleuver is offline
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Sorry Tom, I didn't read it right.

Do I understand correctly that you don't touch the knobs on the Meco and set the flame with the regulators?

You wrote : "Oh the flame is 1/8" away from the tip? Just flick the torch up and down (pointing with the flame in the same direction) and the flame will be on the torch.". I'm a bit slow today. Could you rephrase this?

I'm battling with the settings on the Meco for some time now. Some great welding days some not so good.

Thanks for your help so far.

Frank
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  #25  
Old 10-22-2013, 04:10 PM
Tom Walter Tom Walter is offline
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Frank,

I do apologize as I had not commented that after the initial pressure setting, all adjustment is done with the Meco knobs.

I've added this to my write up from the previous post:
Quote:
EDIT 10/23/2013: Now that I have a nice flame, I use the screw knobs in the Meco to adjust the flame. I do not touch the regulators, only the Meco knobs. If I need to refill my cup of coffee, I just shut down the torch, Screw the Meco knobs closed. Enjoy an espresso, then open the Meco knob about 3 turns on the acetylene, light torch -- no black wispy's. Then bring up the oxygen will three full screws. Look at the flame, adjust back to where I want. Cone is about 2 to 2.5x the width of the aluminum I'm welding. END OF EDIT
What is so interesting is setting my torch this method, when I look back at the gauges they do not seem to have moved off their pegs. I suspect both Oxygen and Acetylene are at 1 to 2 psi on both pressure regulators (otherwise I'd have no gas flowing, so the low pressure gauges are just not registering).

Richard pointed out you want just a little more acetylene. Slightly rich is good for aluminum welding.

With my small Meco tip, often the flame will sit about 1/8" inch away from the body of the tip. If I hold the lighted torch pointed away from me, and flick the torch body away from me, into the flame... that flame jumps back to the end of the tip. That is something I've never experienced with my larger Victor Journeyman, but baffled me a little with the Meco. I just accept it does that.

One of the biggest helps for me was to get some good reading glasses. 2X power. I couldn't see the weld puddle. Yes, I bought those expensive welding goggles, and could finally figure out what I was looking at. The 2X reading (actually inserts I put into my welding goggles) help me see the details on the puddle.

Make it as easy on yourself as possible for practice. 3003 H14 0.050". Shear a pane into 2" wide strips. If you have a brake, bend up a 0.100" lip on both sides. Make up a bunch of them. Now scrub (stainless steel brush) both edges. Wipe with alcohol (91%). Flux both sides. Just start welding. Notice I didn't say to use rod. With both lips up and meeting each other you have a lot of material to practice with. Tack about 1" in from the sides on both sides. Now just start welding. If the two sides open up like puckered lips.... just jump an inch further down and keep going. Once you have a pretty nice bead... just keep practicing and enjoy the flow.

You'll notice the flux gets watery just about the time to start welding. If you stop and wait for that the happen.... it's too late. Just the moment it seems to get watery is when you start welding.

Clean and scrubbed. Oxide starts forming the minute shiny aluminum is exposed to the atmosphere.

My airplane fuselage is all 4130. I'm pretty good at welding 4130, but realize some days I'm just not into the zone for what ever reason, and best not to weld that day! Welding aluminum is fun, but on those days when nothing seems to go correctly.... good day to bicycle riding and get out of the shop.

I hope this does help. Yes, I should get new regulators for low pressure welding, but like the ones I have. Just the Meco flow rate with a #1 tip isn't moving enough to get my gauges to move off the pegs. If I screw in the regulators to 2psi.... that flame blows aluminum out of the puddle. Oh that was so frustrating until I learned why.

Also is you have some stiff copper wire... knot it up and little and use that for cleaning your tip. They sell the wire here for hanging up paintings (you string it between too hooks on the back of the frame). You should have something like it, but just wanted to point out it wasn't plain copper wire.

Welding shops sell some "tip cleaners" but they are small files, and remove too much material. Soon your #1 tip is the same as a #3 tip. Not good.

Read through this, let me know if you have any questions.
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  #26  
Old 10-22-2013, 04:33 PM
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Many thanks Tom,

I'll take the time to let it sink in. This weekend I'll be practicing.

Jeff Moss uses a rather large tip (5) with 3 psi so the flame doesn't blow that hard (no Meco though).

Grt

Frank
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  #27  
Old 10-22-2013, 06:51 PM
Tom Walter Tom Walter is offline
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Lots of practice.

Flipped though my notes: With 3003-H14 0.050" butt welds.
My Meco #3 tip (0.042" orifice) was used. Pressure should be 3 psi Oxygen and 3 PSI Acetylene, but as I described previous my regulators do not seem to indicate under 5psi.

I find myself often using a #2 tip, but a friend pointed out that my shop is preheated in August. 120F in the shade. Correct 50C. I do tend to weld while wearing shorts and a T-shirt, hence enjoy OA.

Photo is my son concentrating on his weld. Learn to make a nice flange weld (use a bigger tip), then start on a butt weld adding a little rod (spool is handy). Yes, the gas valve is a handy shut off tool. Great to have the sparky (silver box sitting above the valve) to light the torch with just a tap. Lift, light, tack, repeat. Very fast to tack weld using that.

Recommended article (it deals with steel, but still good reading):
http://www.airbum.com/articles/ArticleZenWelding.html

P1000430.jpg
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Last edited by Tom Walter; 10-22-2013 at 06:56 PM.
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  #28  
Old 10-23-2013, 12:37 AM
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Priceless picture and briljant article. Ihve somethng to study on for the next couple of days. Many thanks for that.

Nice concentration on your boy his face.

Is the ali laying on a piece of steel?

Grt

Frank
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  #29  
Old 10-23-2013, 07:33 AM
Tom Walter Tom Walter is offline
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Frank - you are more than welcome.

It was interesting to note how different my son's method is, yet he can produce great welds.

There is a an aluminum "diving board" attached to the wooden work bench. Helps prevents catching the work bench on fire! Thing to remember is anything under the alloy sheet is a heat sink. All the sudden it seems like you have a nice weld bead going, and viola... the aluminum splits wide open. Well you ran off the edge of the heat sink. It caught me off guard, until I realized what happened.

Once you have flange welds going nicely, then move on to butt welds as shown in the photo. Then hang a piece of aluminum off from the edge, then weld with nothing behind it. Just the two pieces in free air.
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  #30  
Old 10-23-2013, 02:08 PM
David Gardiner David Gardiner is offline
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Quote:
Originally Posted by Frank.de.Kleuver View Post

Jeff Moss uses a rather large tip (5) with 3 psi so the flame doesn't blow that hard (no Meco though).

Grt

Frank
That's the same set up as I use. If you use a small torch and tip you will have nothing but problems, the tip will get hot and the flame will become smaller, causing more problems and slow welding. Flux inclusion is probable. Use a decent size torch and a no. 5 tip and your weld will flow, you have to learn to weld at the speed dictated by the flame.

The metal hardly needs cleaning prior to welding using this set up.
David
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Last edited by David Gardiner; 10-23-2013 at 02:12 PM.
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