OA frustration ...

[JayWelchy]

Well I am at that point .. need to take a step back. I have been practicing my new OA setup for the last few days .. got a total of around 6 hrs OA time, not much at all. Dont expect to pick it up quickly, but at this point I dont have a clue and its wearing on me bigtime.

So far, using 4psi on both O an A, a #1 tip and the "neutral" flame, I just cant find a happy medium. On thick steel ( 1/8" or so, #5 tip) I can sorta get a puddle sorta around where I think it should be. Adding filler wire is a challenge unto itself .. seems I want to put it in the flame, or I just miss the puddle and end up soldering the wire to some spot away from where I want it. No biggie, as that is just coordination which I will get. On the thick stuff, I can see the puddle, and slightly manipulate it. But barely. And I am barbaqueing the surrounding metal...I think. Read charcoal below.

The next issue, again inexperience bigtime, is that as I am trying to keep heat on or around a puddle, everywhere around the puddle is sizzling away .. like its boiling or just plain burning the metal all around. Not burning through, just the surface. Horribly worse on .035 Chromo. It looks really gnarly when it cools. Oh, and its like a milli-second after I add filler that it Pops! ... even if the torch is far away from the work. Bummed.

And further, when I am done making my mess, the finished steel, looks like charcoal... on the outside AND on the inside (tubing). Its like I am getting it all too hot?? Burning the "skin" layer?

Man, I just dont know, but it has me in the dumps a bit as I have this gorgeous piece of artwork of a fuselage that I DO NOT want to destroy with my failed attempts. Funny, I am pretty stable and secure about my abilities to learn, but I am a bit concerned at this point :-\

I can Mig weld, I understand the process and the temps. Ive read more info on OA and watched lots O' vids.

Let me say I knew it would be a slow learning process .. but I just cant grasp that I cant figure out what I am doing wrong. Might take a break from all of this for awhile till I can move forward.

Anyhoo, any comments good or bad are all I am hoping for from this thread.

Jason

 

[oahupilot]

I have a meco midget torch and it made a big difference in my welding of oa. It was just easier for me to use the small torch on .035. Also I found the er70s-6 to be a more favorable welding rod. I like to to preheat the weld area cherry red before I start the weld pool, that way the required added heat is less for total fusion of the weld joint.

 

[Pttim]

Seems to me your tip is too large, which could be why your popping as you dont have enough pressure to support the large tip. Try moving to a 0 or double 00 tip. I run my aceytlyne around 6 psi and the oxy around 10 although the pressure doesnt really matter as long as you have enough to support the flow requirement of the tip size. The cleaner your tubing is the cleaner the weld will be, heat it up and wire brush then weld. It really is a balancing act, just keep practicing on scrap tubing.

Tim

 

[Tom H]

Jason,
Be sure your flame is neutral, maybe slightly rich. You should see a slight fuzziness of the inner blue cone. If it is real sharp looking, you are probably too oxidizing (too much oxygen or too little acetylene). An oxidizing flame will burn the metal and throw sparks. The flame is hot, but damaging.

On the other hand, if the flame is too rich (carbonizing), the puddle will be calm, but appears to have a film over it. This will add more carbon to the metal, and you don't want that.

Be on the lookout for your flame changing its mix. Could be the regulators are not holding their settings.

Next, do you have enough flame? Is the tip the right size for the job at hand? If you find yourself pushing the tip too close to the metal to get it to melt, then tip is too small. If I don't get the metal to start getting shiny in, say, 4-5 seconds, I question if the tip is too small. Of course, complex fit-ups may have a lot of metal in the joint to heat, so allow for that.

I have found torch popping to be caused by getting the tip too close, causing heat backup into torch tip, causing a mini-explosion, or the gas flow is not high enough through the torch tip, allowing the flame to travel back into the torch tip, causing the popping. In this case, either open the torch adjustment valves some more, or increase the supply pressure a bit, or maybe both.


Hope this helps.

Tom Hubbuch

 

[n3480h1]

Good advice above. If it looks like charcoal, you are oxidizing - run the gas a little richer (at the torch handle knobs). I noticed that as my torch tip heated up it seemed to change the mixture a little and it would pop, so now I adjust after the tip starts getting hotter. I used a 0 tip exclusively on a Victor full size torch and really didn't have a lot of trouble, even on the cluster welds - but I am extremely patient.

On the thick plate-to-thin tube welds, bias the heat to the thicker metal. There's a pic in my gallery showing one of the .125 seat belt tabs welded to .035 tube, and I heavily biased heat to the plate to get one of the better welds on my airframe.

We hear about preheating the weld area. But I also preheat the stick before attempting to fill, not to dripping, but pretty warm. Once the puddle is started, look for a very slight undercut at the front of it. You should be filling and driving the puddle then. I have good success with a 1/4" to 1/3" circular motion at the torch tip, to keep the heat spread out a bit and to help control the form of the bead. I am not a professional by any means, but I do persist. Then my son comes over and lays a perfectly straight bead that looks like a stack of dimes evenly spread out.

Tom

 

[racegunz]

One of the best tips I ever got was to cut a peice of filler rod with the torch, it should not throw sparks, if it does it's set too hot and will oxidize the weld area.
a good torch set will also make the job SOOO much easier, or maybe I should put it the other way, a cheap or malfunctioning torch and regulator set makes it frustrating. And to repeat some of the good advice above a #1 tip is too big for the tubing we are welding a 0 or 00 is the proper size unless you welding the tubing to .125 or thicker base metal.

 

[Schmleff]

When you say *psi, do you measure this with the valve open or closed? It should be open. On my torch with a 0 tip, to get 4psi with the valve open on the acetylene, it reads about 10psi when nothing is flowing.

That being said, be careful not to exceed the max pressure of the acetylene.

 

[JayWelchy]

Thank you all for the support ... I think my #1 tip is too large, and now that I think of it, I did start with a neutral flame but as it got heated it always got very "sharp", or out of adjustment. Sounds like too hot. And the regulators ... I would set to 4 psi at the guage on Acet, and estimate 4-5 on Oxy on the gauge as the first "tick" on the oxy gauge is 10. This is only at the guages with the torch closed up. I did take a peek right before I had a mental breakdown, er, before I was done for the night, and noticed the pressures with the torch open and lit were around 2-3 Acet, and maybe 2 on Oxy. Hmm.

Another thing that I know better about doing, was once I started a weld, than let it cool, then went right back time after time .. without cleaning the metal! My bad ..

I will regroup and keep on pluggin along. Practice, practice. I can do this.

My torch set is a Lincoln, actually made by Harris. Doubt it is anything to write home about, but at the point I think its the operator



Thanks again guys for the words,


Jason

 

[soneraifred]

Jason:
Try running your regulator pressures a little higher. On my single-stage Smith set, I always run the oxygen between 10 and 15 psi, and the acetylene around 7-8 psi. Remember the pressure that is seen at the tip is controlled by the valves on the torch body. And also remember that those same valves can be used to change the strength of the flame over a failrly broad range.

It might also help to get an experienced OA welder to look over your shoulder. Do you have an EAA chapter in your area that perhaps has an experienced guy available?

 

[JayWelchy]

Thx Fred,

I do have chapter 292 just 20 minutes away. They hold meetings on the second saturday of each month, and I work every saturday ... soooo .. havent been in much contact with them.

I will keep a better eye on the pressures and try that out.

Jason

 

[JayWelchy]

Got some more welding done .. also oredered a #0 and #00 to add to the tool box.

Had a ton more luck today ... like night and day.

Set gas at 4-5 with torch lit, and Oxy right at 9-10. Also used a rich setting and and seemed to have a whole lot more control. Had some successful welds, joints, etc. Even managed to get a super thin piece of sheet metal welded to a much thicker piece of tubing. Looks decent, not awesome. Using scrap, so didnt bother measuring thickness. But it stayed togethor, no holes, and I cant twist them apart .. woohoo ;D

Probably going to keep cutting/trussing out the fuse as far as possible with it on the bench, and keep gas welding scrap as much as time allows.

I did a destruction test on a 90 degree joint of 2 .035 square 4130 and I couldnt twist them apart at all. Then I crushed the joint all around with the usual suspect .. hammer. Still stayed togethor with no tears or cracks. Then stood the piece on end, and swiped it with the hammer which then it sheared off.

Spirits are up again, I appreciate the good words from the veterans in here.

Jason

 

[n3480h1]

You are making real progress, Jason. From where you are right now, things get easier - and the welds get even better. Seems your journey towards being a good aviation welder is very normal and typical. I remember well the frustration of trying to get it right, as well as the relief and joy of major progress.

If I don't weld for a couple weeks, I still have to set up some scrap and run a few lines of weld, to get back into the mindset that produces a good weld.

Good job, Jason!

Tom

 

[maddogbrown]

Jason,

Glad you are testing some parts to destruction, but the words sheared off seems less than good. The metal around the joint should be the parts that finally tear after a lot of deforming (not the weld).

Can't see from here but a pic would be nice.

When you can beat a 90 almost (sort of) straight and all that is left in the bend is the weld you will know that you are there...

Just can't give you kudos from the words you are using, hope this helps,,,

Mike

 

[JayWelchy]

Thanks Tom .. It is more difficult than I anticipated, so my mind set going in was "I got this" .. Ha!! Nope .. going to have to take it seriously and learn the right way.

Mike, I agree .. verbiage is important without pics.

So, 5/8" .035 thinwall square tubing standing vertical on workbench. A second 5/8" .035 square tubing OA welded to it in the horizintal .. on the side, NOT on top making a "T".

AFTER de-forming all 4 sides of the weld with the hammer, with no visible cracks or breaks, I stood it back up vertical on bench and swiped straight down with the hammer on the horizontal which caused the pieces to separate. The Horizontal piece stayed attached at the bottom, but nevertheless they came apart. My opinion, I didnt get good penetration ... the weld stayed mostly with the horiz piece that came off. So at this point, I am brazing more than welding.

I am a perfectionist and the OA welds aren't as "pretty" as I would like

Good News: Today is sunday the 3rd and I am heading to EAA chapter 292 to meet up with their tube and cloth guy who I talked with last night. He is more than willing to help me get up to speed, and built an SII LT in the 80's.

Jason

 

[Idaho Spud]

Jason, Here are a couple of good books on welding if you don't already have.
Welders Handbook, by Richard Finch and EAA Aircraft Welding, by Poberezny&
Schmid. They both have a lot of helpful information in them.;the both of them
can be purchased through aircraft spruce anf they are reasonally priced.
I used the one from Richard Finch when I started O/A welding. I also did a lot
of praticing before I started welding aiecraft parts. My first project was a cart
for my O/A bottles and welding equipment. Hope this may be of some help.
Keep praticing it will eventually come together.
Jim C.

 

[JayWelchy]

Jim,

great info, thanks. I visited our local chapter EAA 292, and got some great insight on what I am doing and also some great advice followed by a demo.

Practice is what I need to do most, and I am using too much heat for the material. I need to develop a technique and go down in nozzle size to suit my comfort level.

Good group out there at 292 ... they are building 5 (!) DH-2's from WWI ... very, very cool stuff going on out there. Got to poke around a bit and look at 3 partial fuse's, one wing half nearing completion, and lots and lots of really well made parts.

Jason

 

[Chuck in Indiana]

Jason.. you need to learn to walk before you can run.
Get some flat stock, about .035 would be good. Get the right size tip for your torch. Different torches need different size tips. An 0 with a Smith is *not* the same as an 0 on a Victor, for instance. OK? Start by learning puddle control. Don't even try to add filler rod yet. Just start a puddle and learn the art of moving the puddle along with a very gentle circular movement of the torch. Notice that you can greatly affect the heat/size/depth of the puddle by the angle that you are holding the torch respective to the base metal.
Do this until you are comfortable with puddle control. It won't take long. I've taught quick learners the basics in under an hour.
Now.
This is the rubbing your head while patting your belly part. While you are moving the puddle with the circular movement that is almost second nature by now hold the filler rod in front of the puddle to keep it warm. Once it's warm, dip it in the puddle, and it will melt immediately and make the puddle a little larger. Keep the puddle moving, and dipping as necessary to make a uniform weld bead.
When you are comfortable with that.. and not before..start on tubing.
This is where your already learned skills are put to the test. The angle that you hold the torch to the workpiece will change from fairly oblique on the "flat" areas to 90 degrees in the crotch of a cluster.
This should get you started.. hope it helps. ;D

 

[JayWelchy]

Chuck,

yes it helps Thanks for the tips .. no pun intended.

I plan on just that .. walk first. I am not in a rush, and one major reason I am building this thing is to learn how they are built and learn how to properly build them. The Sonerai is cool enough, but there are so many aircraft that a guy could play with The hope is to successfully build the SII, meet and make some great friends, and learn some aviation building skills ... not to mention the "I built and fly that" sentence I hope to say!

Jason

 

[phzabriskie]

Good News: Today is sunday the 3rd and I am heading to EAA chapter 292 to meet up with their tube and cloth guy who I talked with last night. He is more than willing to help me get up to speed, and built an SII LT in the 80's.

Jason

Good news...I was going to say that you should drop in on your chapter any Saturday. Bet you even money they are sitting around one of the hangers with coffee and donuts like we are. Only the published calendar says 2nd Sat.
Thanks for voicing all of this experimenting.....I will be joining you soon.
-Pete

 

[JayWelchy]

Ok, update .. had some cash saved for material, and decided to get a victor jr. torch handle (small) and a new #00 tip, and some .045 wire .. spent some time playing around, got some tips from an old timer, and walla! We are up and welding, and even better I feel like I am in control, not the flame. After lots of dinkin' around during practice, I bit the bullet and welded up my rudder pedals. Turned out good, no burn through at all, and got penetration like I hoped. Spirits are up.

Jason