Welding STICKY

[turbo54]

Originally posted by twinturbostang
Actually, I have a question also.  When doing MIG welding, how do you cover up the tack welds, making it look like a nice continuous weld?  I recently did a project, and tacked the metal in a few places.  Then came back and welded it up, but as I was going over the tacks, the weld built up in those locations.  It's not so pretty like that.

Sounds to me like you're making really big heavy tacks with a lot of buildup...

I'd suggest you turn up the juice to get more penetration and less buildup.  Try making a smaller tack.  That way when you go to do your full weld, it looks more continuous, and you won't lose your "rythym" as you pass the tacks.

[turbo54]

Originally posted by twinturbostang
And when making tacks with TIG... it sounds like you can do a weld bead, stop, then move to the next, etc.  So you could tack it easily, and come back and finish weld it and it would look great.  That sound right?  I like the look of the "stacked nickels" that you can really get with a TIG machine.  I'm assuming that's controlled by how you move, dab, move, dab, etc.

When tacking steel/stainless with TIG, I don't use any filler rod.  Its important to note here however that if you don't have excellent fit-up (the two parts MUST be physically touching for this to work!).

That being the case, you get no buildup whatsoever, and when you go back to make the actual full weld, you can continue right across the tack area completely unaffected by it.

Now, in the case where your fit-up isn't so great, and you have to use filler to join up the parts, you just have to be careful not to use so much rod that it build up.  If it does, you'll have to work around it later.

My technique (when passing over an already welded area), is generally to keep the arc going, but extremely weak (so as not to actually make a puddle), simply as a light source so I can see enough to start a new puddle in the next place to weld...  I don't have an auto-dark hood (none of them have the large lens, which I very much prefer!)

[twinturbostang]

Originally posted by turbo54
Sounds to me like you're making really big heavy tacks with a lot of buildup...

I'd suggest you turn up the juice to get more penetration and less buildup.  Try making a smaller tack.  That way when you go to do your full weld, it looks more continuous, and you won't lose your "rythym" as you pass the tacks.

Yeah, you're probably right.  I did try it with the heat up, but was getting real bad pop-pop-pop spatter.  Maybe I need to go somewhere in the middle.

This was my first real welding "project" though.  I'm just starting out.  So it looks like crap.  I have pictures, but don't really want to post them!    Unless you think it would be worth the education to show what I was doing wrong!

[Dangerous Dan]

I would not weld aluminum that needs to be strong with dc , with out the cleaning action of ac the oxide layer is not removed and althought it will not melt , it can become mixed in the puddle ,which will lead to cracks .

[turbo54]

I beg to differ Dan...

I have done doube V groove welds on 1/2" thick aluminum coupons...

When tensile tested, success is had if the base aluminum, not the weld, breaks.

You must have the aluminum ultra clean though!  Don't forget there is still enough argon for cleaning.

[Dangerous Dan]

Originally posted by turbo54
I beg to differ Dan...

I have done doube V groove welds on 1/2" thick aluminum coupons...

When tensile tested, success is had if the base aluminum, not the weld, breaks.

You must have the aluminum ultra clean though!  Don't forget there is still enough argon for cleaning.

I'm not gonna agree or disagree , as i have not tried this because becuase i have a high freq tig welder , I just know why  this should'nt work in theary . I'm just about hook my tig up at my  new house , and may give it a try for shits and giggles .

[tkelly27]

what happens to aluminum if you don't use the helium? I am learning to TIG at my school and would like to try this with a good machine because its probably going to be the only way I can afford it (either a 3g or a cheap a$$ used TIG), and the school does not have helium gas running to the machines. Anyone have any info on mig? I've got the miller "power pack" series of books but they don't always answer the how come like someone who has already done it.

[Dangerous Dan]

I use straight argon to do aluminum and steel with tig , and 75/25 for steel and straight argon for aluminum with mig .
Heluim /argon mix and staright helium only come in giant bottles , around here which i don't need , so the only avaible thing in mid size bottle which i own is argon , c02 and 75/25 .

[Dangerous Dan]

Aslo Argon is a fast freeze gas , and using it staright for mig on anything other than aluminum and silcon bronze makes it tough to get a good looking weld ,  when using heluim for tig  the consuption rate goes up because its lighter than air and will want to rise away for the weld necistating the use of high flow rate , argon is heavier than air and flow rates can be kept  lower .

[Dangerous Dan]

when ever looking at tig welders , Take into acount feature's .
If your only gonna be welding at table and want to do aluminum ,a high freq. with pedal is a good bet .
If your gonna be doing alot of outa position welding on mostly steel ,scratch start or lift arc is more ideal so you don't have to be on the pedal to weld in weaird positions ,  Lift arc is a little harder to get used to but is a better option imo.
A square wave machine ins't really nescary unless doing aluminum and even you don't need  it for basic shit .
If you wanna scimp on tig machine and already have  a decent mig welder, go with dc machine  to do steel, and get spool gun in future to do aluminum is you so desire .

[oil pan 4]

Steel, aluminum and stainless. Any one weld Titanium other than me?

[turbo54]

Yes, I weld Titanium, Cobalt, Magnesium and many other exotics...  I just thought it was beyond the scope of a mustang fabrication welding thread...

However, in the next couple days when I get a little more time (weekend busier than I thought!), I'll post up!

[73Runabout]

I have a miller syncwave 250dx. What filler should i use to weld my 4130 moly cage to the mild steel 6x6x.125 floor plates? thanks

Tony

[oil pan 4]

Titanium isn't even considered an exotic any more, it has become to comon for that I guess.
I have thought about magnesium but have not realy looked into it.

[ziptie007]

 Thanx

[xr8tt]

Use a sanding type disc on your angle grinder...Not cutting or grinding disc...

[T.J. 87-GT]

Originally posted by 73Runabout
I have a miller syncwave 250dx. What filler should i use to weld my 4130 moly cage to the mild steel 6x6x.125 floor plates? thanks

Tony

Go here http://www.tigdepot.com it mostly pertains to 4130 welding.
Also click the links there as well for tech and stuff.
 
T.J.

[mkoebra95]

Talk about any welding topic...

[Junkman]

Ok so I thought I would add some info this is taken from the welder's hand book:

Aluminum Alloys

Alloy #-- Tensile stregth --    Weldable

1100   --  15,000psi  -                 Yes
3003   --  26,000       -                Yes
3105  --   23,000       -                Yes
5005   --  26,000       -                Yes
5052    -- 41,000       -                Yes
5086     -- 47,000      -                 Yes
2024     -- 61,000      -                 No
6061     -- 42,000      -                 Yes
7075     -- 65,000/75,000 -          No

[twinturbostang]

Any info on anodizing aluminum welded parts?  I heard that some types of filler rod turn black when anodized.

[Junkman]

http://www.focuser.com/atm/anodize/anodize.html

[Ballistic]

You'll find that stainless can actually be "sweated" together (if fit up is good), which is to say you don't even need filler metal. Just strike your arc, hold until a weld puddle spans across the seam, and move the torch across the seam. While this is really easy, there is no strength... You must add filler metal to get penetration, and get good metallurgy and strength.

I disagree.  

While it is certainly possible to create a poor weld by merely melting the surfce of the base metal together, I've made many quality welds in stainless using autogenous GTAW.  It is necessary to purge the backside of the part being welded.

[Ballistic]

Oh, uh. . .

Autogenous is welding with no filler metal by melting the base metal to form a bond.

Sweating is a term used with brazing/soldering where the filler metal is drawn into a close fitting joint via capillary action.

And, GTAW is Gas Tungsten Arc Welding AKA TIG welding.

[T.J. 87-GT]

I agree with Ballistic. I have even TIG'ed alum with no filler. Get the fit nice and it "keyholes" nice nice. I have TIG'ed stainless as well with no filler and the weld was strong.
  T.J.
http://www.tjsperformance.com

[artic]

if you can weld with filler then do it, i've welded ss tubing without filler too, but if your plan on polishing it for a finished look then use filler otherwise you usally end up with a "dip" also filler will help control the heat in any situation to help with burn through and penetration

as for aluminum, i agree cleanliness is a must, but often overlooked and the cause for the balling on the end of the rod is a dirty rod, the rod gets a oxide on it too, and the melting point of the oxide is higher so the inside melts before ther outside, the best thing to do is to use clean gloves, have specific TIG gloves so you don't get oil on them, also take a scotchbrite pad and clean the rod off.

something else not mentioned yet, ONLY ONLY use a SS brush to clean AL and SS, use seperate brushes, if you use a steel brush or a brush that was used on steel it can and will leave contanimates behind on aluminum.

as stated before you can use 2% thoriated on aluminum with a point on AL but a balled pure(green) will work better, if the ball is too big then grind to a point and reball for a smaller ball. the pure can become contaminated useing AC and may have to be snapped off to get back to clean tungsten. as for balling a copper plate works best but a clean think AL piece can work in a pinch, to ball the tip turn the amerage all the way up on dc(i can't remeber straight or reverse i have it marked on the welder if some one can help me) and peg the pettle until a ball forms.

as far a sharpening 2% use a clean grinding wheel that is used just for resharpening. always grind with the point facing the wheel so material is being taken from the tip and moved to the rear to avoid a bur on the tip. the taper should be 2-3 times the diameter of the tungsten. if you use a wheel that has been used for steel or other metals you can contaminate the tungsen, if you grind it sideways it can cause strange arc charateristics.

as far as the other mixed tungstens on most machines they aren't any better, but the newer inverter machines with arc controls i understand that zirconiums are used. The new inverter machines are a whole nother ballgame btw.