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dan s
03-05-2008, 02:15 AM
Yesterday i finally stopped by my local gas distributor and picked up a tank of C25. I have been using flux core wire since i picked up my welder (black Friday impulse buy :) ).

One thing is for sure I'm never going back to flux core unless i need to weld outside.

the following are my newbie (less than 6 hours of stick time) attempts at MIG welding.

My beads still aren't the most consistent.

http://img169.imageshack.us/img169/9824/28153876hi0.jpg

A perpendicular cut through the bead to check penetration.

http://img504.imageshack.us/img504/8710/40177306gz0.jpg

This butt joint was 1/8" bar no bevel or gap (my welder is only 110v), i still have an issue with little pin sized gaps.

http://img182.imageshack.us/img182/2519/51437542lo9.jpg


Is there a simple formula to calculate bevel and gap, for a given ipm/amps?

Davek0974
03-05-2008, 04:11 AM
Looks good, check out here...

http://www.mig-welding.co.uk/

lots of help and calculators there.

Dave

Your Old Dog
03-05-2008, 05:42 AM
One thing is for sure I'm never going back to flux core unless i need to weld outside.

I was told I'd never go back to fluxcore after trying gas and they were right. Someone here told me that. I guess the fluxcore still works outside in gale-force winds :D I never weld outside.

torker
03-05-2008, 07:18 AM
Your weld...not bad. Try to steady it up so you avoid the "sawteeth" on the edges.
Destructive (bending) testing would show a fracture along that area.
With a light welder...don't walk it from side to side (weave)as much...that'll avoid the saw teeth issue.
The "T" joint...in the position shown is a horizontal weld. Don't weave in this position.
Run nice straight beads. You want a wider fillet...do multi pass welds..
If you want a 100% weld your bevel must come to a point. You will also want good preheat...especially for a light machine.
"Rule of Thumb... Fillet size (for that "T" joint) should equal half of the base metal thickness.
If you want I could post some pics of a heavy multi pass weld on a T joint.
Keep at it!
Russ

dan s
03-05-2008, 11:00 AM
Torker,

The pics would be interesting to see...

Do any texts exist that cover the different set-ups?

All the books i have checked out of the local library (and university) are either child simplistic, or studies on ways of minimizing costs in a production environment.

I haven't been able to find anything that talks about bevel, root gap size, bead laying etc, in any kind of systematic way.

these two videos are pretty interesting.
http://www.youtube.com/watch?v=7AZXG5WVw6E
http://www.youtube.com/watch?v=HL2H79cgDuo

oldtiffie
03-05-2008, 11:24 AM
Torker,

The pics would be interesting to see...

Do any texts exist that cover the different set-ups?

All the books i have checked out of the local library (and university) are either child simplistic, or studies on ways of minimizing costs in a production environment.

I haven't been able to find anything that talks about bevel, root gap size, bead laying etc, in any kind of systematic way.

these two videos are pretty interesting.
http://www.youtube.com/watch?v=7AZXG5WVw6E
http://www.youtube.com/watch?v=HL2H79cgDuo

Thanks Dan.

That's good work that would do for most folks.

To see it better, sand/grind/polish some of those faces in your pics and acid-etch them (almost any "acid" will do) and you will see the changes in colour and boundaries that will tell you how it went. The "miss" or "inclusions" at the roots will do for most jobs.

Torker is pretty well the subject matter expert here and really knows his stuff and really goes out of his way to help - which he is very good at.

A lot of reading, a lot of practice, more reading, more practice etc.

Anyway, some of these links should help.

http://www.thefabricator.com/ArcWelding/ArcWelding_Article.cfm?ID=1083

http://www.millerwelds.com/education/bookspamphlets.html

http://www.millerwelds.com/pdf/mig_handbook.pdf

http://www.mig-welding.co.uk/tutorial.htm

macona
03-05-2008, 02:39 PM
Dont weave at all. Unless you have a tractor with a weaving feature. Most people can not do it with enough repeatably to do it consistently.

http://www.weldreality.com

boslab
03-05-2008, 04:55 PM
the right hand flank showed a bit of undercut, watch the amps, you dont realy need to weave more than the width of the weld unless your trying to plug a big gap, then that wouldent realy be a good idea. on the whole a brilliant first effort, mine looked like seagull **** splatered on a windsheild according to my instructor!
keep at it [you can try running a chalk along the weld it does help, reflects uv etc and gives you some reference point in an otherwise dark world]
regards
mark

Alistair Hosie
03-05-2008, 05:05 PM
That's a gold star for your first attempt . I tend to not see the workpiece or the nozzle. I have an automatic helmet should I adjust it more so as I can see better what I am doing that's definitely my problem any advice welcome.Alistair

torker
03-05-2008, 05:18 PM
Weaving is entirely acceptable in most industries...in the flat, verticle and overhead positions.....never in horizontal.

dan s
03-05-2008, 05:27 PM
Alister,

what setting do you have your shield set at?




That's a gold star for your first attempt . I tend to not see the workpiece or the nozzle. I have an automatic helmet should I adjust it more so as I can see better what I am doing that's definitely my problem any advice welcome.Alistair

tattoomike68
03-05-2008, 06:41 PM
[QUOTE=dan s]

My beads still aren't the most consistent.

http://img169.imageshack.us/img169/9824/28153876hi0.jpg

QUOTE]

That looks good to me,for a 110vac welder thats fine. I have seen my friends drive up on new Harly Davisons with welds that make that look the very best weld on the bike.

I know if any of you old guys are crippled up and have a tough time welding all bent over but, an old wheelchair lift with a 4' X 4' plate steel welded to it makes a dandy little welding table.

Welding table hight sure can help you get comfortable and weld real nice.

lazlo
03-05-2008, 06:43 PM
I tend to not see the workpiece or the nozzle. I have an automatic helmet should I adjust it more so as I can see better what I am doing

Most auto-darkening helmets have three settings: shade on the outside, and sensitivity and delay on the inside. For MIG and TIG most people like a shade of 10. I've got the sensitivity and delay on my helmet turned down to ~ 2 out of 10, but it differs from helmet to helmet. The best way to set those is to watch someone else weld.

As far as weaving, I weave on MIG, especially to cover a wide butt joint like that. On pulsed MIG, my brief experience was that you pretty much have to weave, it's laying down so much bead...

But I've never been able to do the textbook orbital weave on TIG and get a satisfactory result. My instructor, who is known as one of the best TIG welders in Central Texas, taught me to do straight drag on TIG, which I find gives the most consistent bead (for me anyway).

Edit: here's one of mine -- 10 gage mild steel, ER70-S6:

http://i164.photobucket.com/albums/u15/rtgeorge_album/MIGWelds.jpg

CCWKen
03-05-2008, 11:09 PM
Yes sir, that's some dandy looking welds for a beginner.

Well Laz, I'm glad you qualified your statement that your teacher is One of the Best in Central Texas. :D

If you do your welding on a bench, you are very fortunate. In real life, you're lucky to have a rope to hang onto with one hand or a creeper to lay on. :o

torker
03-05-2008, 11:14 PM
Oh boy...here you go.. Sorry about the pics. A long hard day then the gawdamm batteries start dying on my camera. Need a corded camera.
Some are out of focus as the camera won't focus right with dying batteries...so shoot me!
BTW//Laz...lookin good! Did you know...before you make any more passes over a bead like that...you should take a real sharp little pick and scrape those silica deposits off that weld (the little glassy brown spots.) The weld could fracture because of them.
Here's a crappy pic of a mig weld T joint. Welder set as the gurl had it...wide open w/.030 mickey wire.

http://img.photobucket.com/albums/v210/torker/DSC00007-3.jpg
Here's the first pass on a T joint with the heavy machine. This is dual shield .045 T wire...27 volts/ 290 ipm. Not a good setup for 1/8" stock...lol!
http://img.photobucket.com/albums/v210/torker/DSC00006-3.jpg
Second pass..
http://img.photobucket.com/albums/v210/torker/DSC00008-1.jpg
Third pass...thing is VERY hot now!
http://img.photobucket.com/albums/v210/torker/DSC00009-1.jpg

torker
03-05-2008, 11:27 PM
A real crappy pic... This is a verticle weld... 28 volts/305ipm...uphill on 3/16" steel...really hard to hang onto...halfway up it's almost burning right through
http://img.photobucket.com/albums/v210/torker/DSC00014.jpg
Here's verticle stringers on the same thing..
http://img.photobucket.com/albums/v210/torker/DSC00016.jpg
You want a weave...here's one..3/4" wide and 1/2" deep...one pass
http://img.photobucket.com/albums/v210/torker/DSC00015.jpg
Shouldn't show you this one but I'd like to see someone do this on this little piece of steel...This is called a triangle weave...it's big...about 1" wide and 3/4" deep all done in one pass uphill...notice it's still just a tad warm...lol!
You start this in the corner...bring bead out 3/4"...go across the front...then go into the side and head into the corner again. Keep repeating it in a triangular motion. It was crazy to do this on such a small piece of steel but that's all I had in the scrap bucket.
http://img.photobucket.com/albums/v210/torker/DSC00020.jpg
All these welds were run in very hot.

JRouche
03-05-2008, 11:40 PM
Very nice!! I dont know beans about welding but sure enough Dan, you will find some great weldors here. Russ being one of the tops in my book.

My only contribution is slow down. Many newer guys tend to rush through the bead (not even saying you did), maybe for fear of burning through.

I say burn through!! Burn through many welds so you can see where the break point is. Then you will see it is higher than you may have expected.

Analogy.. Learning to drive a car fast, really fast on a closed circuit. You can learn where the break off point is and become familiar with the car. Doing it on a closed circuit helps cause you are trying to do it (loose control) in a safe environment. Once you have felt the car and have a decent idea of its capabilities, to failure, you know how to keep it out of that zone.

Similar with welding (for me). Learn your machine and its heat range. Purposely burn through some test pieces so you get a feel for the heat.

Penetration is key to a good weld as much as control. You will get a feel for the penetrating ability of your machine with some proper burn outs..

Again, I am not a weldor, just my two cents worth of wire :) JRouche

torker
03-06-2008, 12:29 AM
Dan...geez..I wasn't thinking...turn your heat up and the wire down a bit...that'll help flatten that bead out. 45* gun angle in and maybe 15* back...straight down the middle of the groove...no wigglin.
BTW...you pushing or pulling that?
Russ

dan s
03-06-2008, 01:00 AM
BTW...you pushing or pulling that?

I have been using the pull method trying to maximize penetration.

I think part of my issue is that i'm not moving fast enough. so tonight i was playing with feed rate.

Right when i thought i had it down i ran out of wire (factory supplied partial role .023"). :rolleyes:

Tomorrow i will be picking up to things, another role or wire, and a 28" x 23" x 1/2" section of plate that will be the top of my role away welding table.

torker
03-06-2008, 01:08 AM
Dan...pulling is the prefered method of wire welding(on plate etc.). Only problem for a noob is it's hard to get used to seeing where you are going. Easy to see where you've been...
That also explains the "High in the Middle" weld. Pulled welds tend to be higher than a pushed weld.
So...this means you need to really watch your travel speed and your steadiness. You make a boo boo on a pulled weld..it will show up more than a pushed one.
Be careful you don't get the gun angle too far down as you pull. A "flat" gun angle will also increase bead size.