Hi,
I guess this is as good of place to post my questions since I see there is a "hotrodder "here.

I'm a long time rodder, builder, toolmaker, engineer and a few others.

I have a Lincoln 175 that is ok I guess. Not the old Miller that I learned TIG on many years ago and doen't have the very latest adjustability that I'm thinking I need now.

So here goes:
back on post 3 hotrodder shows some excellent photos of welds and the one that really interests me shows the 'butt crack.'

I do a lot of fuel tank repair and a few new tanks for the streetrod and racers. Almost all of my aluminum welding is done on 14 ga or less, usuallly .050 and .040 5052.

I have a tank in for repair that has probably the best welds I've ever seen. They look the same inside and outside. I don't see how it could have been machine welded as there are various turns that would have prevented it. It almost looks gas welded except for the TIG like beads. It is .050 and I think it is 5052 judging by the hardness and stiffness of the material. Near the welds it is considerably softer however.

I don't know how it would have been possible to use a backing in this tank. I have been able to look at every weld and they are flawless inside and out. This tank is at least 15 years old and was anodized. I had them strip it so it is clean now.

I had to cut a sizable section out of this so I tried some practice welds.
When I weld this stuff no matter how hard I try I still get the butt crack or closed butt crack. At very best I can get a full weld on the inside but you can clearly see a dark line down the middle of it. To date I haven't had any problems with the welds cracking even on some really old stuff I did back in my shop work days. You can clearly see the oxide layer on the inside weld.


I have a good double flow regulator so I can back purge. This doesn't seem to help much except for stainless.

I have a number of stainless wire brushes that are used just for aluminum. I also have some stainless wool. It is supposed to be 304 but I can't verify it. I can't say it is bad or good either. I have brushed and immediately began welding, I've stopped and brushed again, I've even gone so far as to brush the filler rods. I still get the same thing. Outside welds are ok, it's just the inside that doesn't pass muster. I also have some de-oxidized copper sheet that i use for backing occasionally. It works when I can use it.

Being old school I have a hard time converting to the auto dark lens. I still habitually flip the helmut up. I still on occasion use the old flip down helmut. I normally use a #8 shade for this welding. Interesting enough I see better welds with the old lens. It definitely is a different color. I use several reading glasses for help with my eyesight. the welds appear magnified so I can control the puddle better.

For this I use both green and red 1/16 tungstens with new gas lens and ceramic, no real difference. I balled both and tried both pointed. I see some difference but the balled green seems better. At least the welds look better.

I got fresh 1/16 5356 rod as the tank will be re-anodized. I have also gone over the welder for gas leaks from the regulator to the electrode. Nothing. I have grounded directly to the tank, no difference. The pedal works very well. I set the welder at about 60 amps and I have plenty of range with the pedal.

I think I have some technic problem that maybe you guys can help with. Any suggestions???

thanks

 

Hotrodder!!

Great post, (GOT TO IT from the Practicing thread I started theat you commented on) best AL info to date. I cut/pasted several of your commentaries out to put in my How to archive to reference as I learn.

I also will try to get the book you referenced.
(So where do you live? I should pay your fare to come up and tutor this ole fart to tig aluminum)

Many thanks,

Tim

 

Hotrodder,

I ordered the Lincoln hand book today and look forward to studying it.
In post #21 you mentioned using zirconiated tungsten "rounded", can you elaborate on the grinding proceedure you recommend for the Dynasty 200dx and the recomended size for 1/8" plate?

I have been making progress on my AL beads, still feel inadequate in just what to do with the settings as to Balance and freq. I have been using between 60-70 balance and 180 freq with the peak amps set at 130. I am welding on a coupons that are aprox 2 x6"

Thanks for the great photos that clarify a lot what many have been saying.

Tim

 

Grind your tungsten to a sharp point. I like to use 2% ceriated, and 3/32" in size. The setting i use on a dynasty when welding Al (used to do it in production) AC freq at 180Hz, pulse freq at 170pps. 80% peak, 60% background, 60% balance. Amperage up all the way and controlled by peddle.

 

Go1lum,


Thanks for the quick reply!

I will give those settings a try, I tried to get some Ceriated, but the LWS didn't have any at the time. (I fiddled around with the pulsing a little bit, but was a little confused (even after reading the manual) It would be great to have a "Dynasty" pro to watch and practice with. (I plan on doing some advertising) here on Craigs list to see if I can hire a little teaching or trade for some other work I am qualified to do.

T

 

Tim,
Never used a Dynasty but from what i've heard they were really designed around the use of a sharp tungsten or sharp with a small flat at the tip- don't know, but they may have trouble starting a rounded tip.

Zirconiated tungsten 'rounds' off naturally with transformer based machines. Typically requires striking an arc briefly with the balance around 55 - 60% EN (toward the upper amperage for a given tungsten size) with inverters after grinding to a short, around 1D, truncated point.

For the most part tungsten prep is personal preference, have a look at this thread. Different preps influence arc shape and stability but unless you're running automotated kit weld quality is down to the operator

For 1/8 material a 3/32 tungsten regardless of prep. Balance and frequency settings effect things a little but i usually use a 1/16 tungsten upto around 80 - 90A AC, 3/32 above this and about the only time i use an 1/8 tungsten on a 200A machine is if i'm running the welder wide open (or close to it) on 'dirty' (metallurgically speaking) castings requiring more EP time

I'd recommend leaving the pulse off for now- once you're pretty/very consistent you'll be in a better position to evaluate the results small changes to pulse parameters make. If/while you're still chasing solid consistancy pulse is more likely to confuse/slow down your learning curve imo

Balance and frequency... best thing is to experiment. Run some beads on an offcut starting with the balance at 70%EN. Take it up to 90% in 5% increments noting the effect on both the weld puddle and the finished bead. Too much EN results in a sluggish puddle initially and a sluggish puddle with 'bits' in it if taken further. Then do the same dropping the EN down to 55%. Below 65% you'll probably notice no improvement in the puddle but the tungsten will start to have a tougher time. Sweet spot on my v205 is between 68 and 74% EN depending on frequency and amperage unless pre weld cleaning is a bit OCD like. Once you've narrowed down the range that gives the best results do it again at different AC frequencies.

Don't drive yourself mad with the different settings though. They don't 'make or break' weld quality, just allow an experienced user to tailor the arc for the job at hand making some jobs easier/many jobs faster

About a year too late (missed Bentwings post) but that tank sounds to me like it was origionally welded with oxy fuel

 

wgw
your dog is eating too much meat , not enough dry food...see h ow the bead looks a little cold?:drinkup:

 

Thought id show this pic. We met him on a plane last summer in Miami on a seminar down at AWS! LOL

 

Hotrodder,

Thanks for the tips, I will start a log of the Balance/freq settings and some "identical" bead layouts to get familiar with the machine. I will pickup some ceriated 3/32 (when I see some in LWS's)

Thanks for pointing out the date on Bentwings post! In my past life I had quite a few "Cub" AL tanks repaired where they had cracked and seems they were somewhat never ending. the best ones I had seen (built new) were set up with what appeared to be a Flanged edge with either both pieces flanged or one with the material having a radius in conjunction with the seam that spread the shock/vibration away from the joint. I can see where consistancy in the bead form would make big differences in AL weldment (when exposed to shock stressing or movement)

I have a long ways to go, but determined to get there. Thanks for your imput. (I hope to be able to be alittle more consistant with my practice-photo-posting in the future.

Enjoy the weekend!

Tim

 

BAWAHAHAHAHAHAHAH !!! :laugh:

Oh Man ! I starting looking at the first few photo's and IMMEDIATELY thought to myself, "If Metal could be pornographic, this would be it." Ha, ha..., LOW and BEHOLD !! All those FANTASTIC photos of WELDS and RON JEREMY (AKA: "The Hedgehog") TOO !!

What an awesome thread !

Hah, hah.... :laugh: Love it.

/Jman...