welding term

By pipewelder_1999 (****)

Date 10-16-2007 16:44

In Oxyfuel Welding, that is called "backhand" welding. "Behind" the tunsten in relationship to the direction of the travel is what I would imagine.

By js55

Date 10-16-2007 16:51

The technique you are talking about, if I understand correctly, is common with machine and auto GTAW. In those applications its called cold wire feed. It can be done from the front or back of the puddle.
Add a current to the wire for I2R heating and its called hot wire GTAW, but you still add the wire to the puddle.

By piperdolan (*)

Date 10-16-2007 17:50 Edited 10-16-2007 17:52

I looked up "backhand welding" in A3.0, In my case the torch is facing the direction of travel but the filler wire is just being added in the tail end of the weld puddle. I am doing this to get the same effect for the backhand technique, but need to preheat or premelt the base metal before adding the filler wire.I find this to work a little better than adding the filler to the leading edge of the puddle.

By 357max

Date 10-18-2007 13:54

In backhand OAW vertical w/downhill travel or any other position, the torch flame is pointed back at the molten weld pool and filler wire is added towards the leading edge of the pool. This torch angle differs from the pointed forward in the direction of travel. Used for small diameter steel city gas lines. For greater speed a 1 1/8 - 1 1/2 times acetylene flame (carburizing).
Backhand has been used in GTAW anodized aluminum; again pointing the tungsten back towards the weld pool and welding away from the pool. This provides penetration below the anodizing.

By chall

Date 10-16-2007 17:04

I've seen it added through the root on one side of the pipe to the other; and the guy called it "backfeeding".

By js55

Date 10-16-2007 17:51

Charles,
Ive done that a couple times on circumferentials when a vertical pipe was against a wall, or in a corner, and I couldn't get my fat head around to the back. I gapped it wide and fed the wire through the pipe from my side to get a full pen GTAW root (gets tougher as the pipe diameter increases). I never thought of it as having a name.
I've done it on o-lets too when they had extreme hi-low. Just hook the wire a little smaller than the o-let ID, stick it in there and feed sideways. Or feed it from the inside entering the ID a couple of inches or so in front of the arc. You get really good penetration.

By ssbn727 (*****)

Date 10-17-2007 17:01

For those jobs, I used a mirror. ;)

Respectfully,
Henry

By js55

Date 10-17-2007 17:47

I would try and avoid mirrors as much as possible. As you well know you gotta think different than what you see because its backwards. I've done it, and aside from the fact that I just wasn't very good at it, I just plain didn't like it, and would avoid if possible. Sometimes its just too much trouble to find a place to put it and make it stay, aside from a little duct tape. Especially when your tiggin with two hands, or there's nobody available to hold it. Or all you have is an inspection mirror that is just too small to find the place to put your head and see. Etc.
Of course, for boilermakers a decent mirror is standard equipment. As a pipefighter it was just not my forte'. A preferrable state of affairs IMO. In fact, the lack of a mirror is a good excuse to argue for that gravy weld in jack stands.
In jack stands, on the ground, in the shade, too small to crawl in, and too big to build a dune buggy out of. Perfect.

By ssbn727 (*****)

Date 10-18-2007 03:40

Hi Jeff!

You mean to tell me you never used the magnetic base with the swiveling arms that held the mirror in the slotted piece of sheetmetal that held it in the position one desired? Granted sometimes even this tool did'nt always work and one had to sometimes improvise with two mirrors or use the "EB" duct tape in some really tight situations but for the most part, the magnetic base mirror with the swiveling arms usually was all that was necessary to complete or repair the job at hand.

I was also very fortunate to be trained by some of the best in the world
up in "Rotten" Groton, CT!!!

Yes! They actually had "mirror" welding training sets of courses, and we were qualified to NAVSEA/NAVSHIPS standards all the way from structural SMAW to unlimited pipe GTAW with all alloys. ;)

People did show you a bucket load of respect in those days because of the difficulty to access some of the jobs but, there were always a few who challenged your abilities until they would get in there themselves and experience the conditions for themselves. :) :) :) Only then would they change their tunes so to speak, and turn around to shower you with envy... Those were the good old days of free beer, and sometimes free money after work on a daily basis. ;) Being very abandextrious with a strong southpaw influence did'nt hurt either. ;)

Respectfully,
Henry

By Tommyjoking (****)

Date 10-18-2007 08:16 Edited 10-18-2007 08:46

LOL those little mag bases with hydraulic arms work great for mirror holders ...you just got to rig a clamp at the end (the nice ones machinists use for indicators). to me the biggest thing you can do welding with a mirror is practice the joint in your head and hands....."I am going this way/direction" once you make your self believe that..... welding in the mirror is no biggie. Another thing is the idea that with SMAW your usually burning that rod down toward yourself instead of away....but thats easier to get a grip on then the direction thing. Zcat posted some pics where being experinced with mirrors would be a lifesaver technique http://www.aws.org/cgi-bin/mwf/topic_show.pl?tid=13320 I think its something every field welder should get proficient at ...ya never know when you will be faced with a 4" pipe 3" off a wall.

Unlimited pipe GTAW Henry? that sounds like a long day...never had one and I hope I never have too.

By js55

Date 10-18-2007 13:24

:>) Never was that sophisticated. Never really needed to. I can see a real need for boilerbreakers and old salts, but for pipe fighters it just doesn't pop up that much. Power houses can after all, and do, acquire more space than a submarine.
Trust me, when a pipefighter is using a mirror, he ain't happy with a design engineer.

By ZCat

Date 10-18-2007 14:22

anytime I had something that tight I would wait till nobody was looking and zip it up downhill! :-)

By pipewelder_1999 (****)

Date 10-18-2007 14:43

ULLMAN DEVICES, MODEL K-2 with base

By ssbn727 (*****)

Date 10-18-2007 16:58

That's the one Gerald! ;) Btw, as my memory serves me correct, Gerald was also in "The silent Service" too so, he's one of the few in here that really knows what it's like to weld with a mirror or two inside a Submarine, and how useful it is to have one when working in a power plant. ;)

All of the rest here - I'm sorry but without being in there, and with all due respect, you're all clueless as to what has to be done just in preparation, to getting ready to strike the arc. ;) :) :) Gerald Knows as does Marty and a few others but, I do'nt remember all of us that do... For that I apologize!!!

Respectfully,
Henry

By js55

Date 10-18-2007 17:22

Preparation stuff. Thats the biggest reason why when offered the opportunity to move into the fab shops I moved.
I wouldn't replace the experience for nuthin, but what I wanted to do was weld.
1, 2, 3, 4, 5 welds a day in the field, sometimes more, sometimes less. 10, 20, 30 welds a day in the shop. I just wanted to weld.

By ssbn727 (*****)

Date 10-21-2007 23:13

Believe me you Jeff, we did more than twenty welds a night ourselves on average ;)

It was the challenge that kept us involved and when we needed to "Bail some wire or burn some rod" they meaning EB, let us do that also but when the repair tickets started to stack up, well we had to do what we had to do. :) :) :)

Respectfully,
Henry

By Shane Feder (****)

Date 10-22-2007 12:21

Henry,
I have mentioned before that I have crawled around in some crappy boilers and that was both before and after I became a CWI.Whenever I couldn't find inspection work I would jump back on the tools, generally as a pipefitter and not as a pipewelder. Pipewelding was my specialty but I found it was too hard to be inspecting guys welds on one job and then welding alongside them on the next.
Had been off the tools for about 4 years and I agreed to go on a 2 week boiler shutdown as a tubewelder. First job was a door opening (can't remember the technical term) with 12 horizontal butt welds 2" above the concrete floor. To say I was standing on my head was an understatement. Being embedded in concrete meant I couldn't spread the tubes with a wooden wedge, so it was weld them "as is". The sigh of relief when they all passed RT was huge.
Next day we had to do a welder qual on high chrome tubing where your wire was fed through the pipe from the other side by a second welder due to access problems where we were going to be welding.I had never done this before and I completely stuffed up the bottom. My off sider (who didn't know I was a CWI) said thats OK, we will just rotate the test piece 90 degrees. He got a bit of a shock when I told him we definitely would not be rotating the pipe and why.
I'm too old and fat to ever go crawling around in boilers again but I can look back on some good and not so good memories,
Regards,
Shane

By ssbn727 (*****)

Date 10-24-2007 07:21

Amen to that Shane ;););)

The Lead shielding compartments in the reactor rooms were no piece of cakes either!!! Niether were those battery lead shielding compartments either;) (the grammar police should like this one:))

The worst was in the engine room for repairs even though most folks tended to look to the COC/CIC which simply meant: Combat Operations Center by EB or Combat Information Center by the USN... Of course there were more repairs in the COC than any of the other compartments but, the dooosie were always in the engine room - PERIOD!!! Always a pleasure Shane to share - talking about the good and bad times;)
BTW, those pics ya sent me were spot on concerning the sparkle folks ;)

Respectfully,
Henry