Welding Tips and Tricks

I am attempting to weld together a small fuel tank for a Sthil weed trimmer that the fuel tank is now obsolete on. The trimmer runs great but the tank has long since deteriorated to the point that it is all cracked up. I cut out some aluminum plate and I welded it together but the welds look bad. I tried what Jody said (aluminum drill) And I thought I was doing pretty good BUT when I got down to welding the tank, well... not so good.

Anyway my question is, Can I go over the weld beads with the TIG torch and PRETTY them up or should I grind the welds down and just start over? The welds seem to be ok structurally just from a visual inspection but just don't look good.

I'm using a Miller Sync Wave 180SD with a 3/32" 1.5% lanthenated tungsten and air cooled torch and 1/16" 4043 wire

And NO I haven't put fuel in it (in case you were wondering)

Thanks in Advance
James

There are others on here much more experienced than me, but my suggestion is if you want to go over the welds, clean with stainless steel brush, acetone, then grind it all the contamination, acetone, brush, acetone one last time. Yes that might be overboard but you clean everything extremely well, wipe down you're filler, and make sure your using enough shielding gas.

You'll get better penetration if you put fuel in the tank! JUST KIDDING.....Thought that addition was funny...You know why we knew there wasn't fuel in it? Cuz your able to write the post...Lol....made me kinda laugh anyways. But yeah you can go over it. Cleaning it isn't a bad idea at all...I mean anytime I weld I try to do everything in my power to better my chances at getting it right if not the first time...the second at least. I bet if you have the ability a picture would lead to a better diagnosis of what really went wrong....These are a good bunch of people...Even if it looks bad no one is gonna make fun of u for it...Trust me on that. But the knowledge they can give is a great tool that's just as important in my opinion as some of my favorite tools. That's exactly what we have here and important/practical tool!

There are too many variables that can give you problems welding...It's better to put your "best foot forward". So that you can effect the variables you can before you even get started.

What is the model number of trimmer. Work part time for Stihl dealer we have warehouse full of old trimmers that are not worth fixing. We give customers 5 bucks or so on new stuff if they leave old one over years accumulated lot of old ones. I might have parts or know of place to get them.

On side note most old 2 cycle stuff gets junked because of seals or crankcase air leaks. Proper way to test is seal motor up and pull 1 bar of vacuum see if it holds then pressure test to 1 bar. If it doesn't hold you will have erratic idle or motor leans out when running full throttle. Also depending on carb most have check valves on low side and highside jets as the rubber gets old doesn't seal and causes running issues. Lot of hack 2 cycle repair shops think a carb kit will fix all carb issues it doesn't. They might get it to run but it runs crappy. I junk a lot of stuff out cause of air leaks. Lot of the older trimmers leak where the case splits by crank. In order to repair gotta remove cyl and split case and labor wise at shop can buy new one just in labor price. However if doing it yourself might be worth it if you like to play with this stuff. If it's a FS 36 or FS 44 throw it away. These where built by ryobi for stihl.

Thanks for your input. I loaded a photo. I am thinking that it has to do with my position when I am welding and also my vision. I wear glasses BUT I take them off to weld. Problem is that I have to get in close to see clearly. I am not using any cheaters in my hood. BTW its a Miller Auto darkening. I welded this together on a base plate on a drill press in a sitting position. I always see Jody welding in a standing position. I guess its what he is used to. I have not had much experience welding TIG with a foot pedal while standing. I need to weld together a table (I have the plate) and learn it I guess. The TIG finger takes a little getting used to. My fingers are small and it fits kind a loose.


James

James,
In all reality, there should be nothing wrong with those welds as long as it passes a pressure test. If you would like to make them look "better" I would sand one weld down at a time until you are almost through the weld and go over it again. If you don't sand it, it will build up causing it to look bad. Another option is to pulse the pedal. You might not get that stack of dimes look but it will look ok. Just some thoughts.
-Jonathan

Hey,

The technique you are referring to is called "washing" and is a handy skill to master. However as some one said, the high spots will still be high and the low spots low.

If you are trying to practic feeding, get some good heavy rock music going in your shop, (ac/DC is good) and dab the filler in time with the bass drum beats. Helps learn timing.

Mick

If it don't leak, don't fix it, unless it bothers you every time you look at it.

You are right. If it holds, don't mess with it. But, its for a friend of mine and I just wanted it to look good... not JODY GOOD but better than what you see. I have some highs and lows but I believe I have enough material to "wash" the bead and even it out. I need more consistency in the appearance.

I will try it on one weld and let you see the results.

There are sections that are a little rough but nothing that says don't let anyone see it. The bottom left looks especially good. Question; were you dabbing or using the laywire technique?
-Jonathan

After seeing the pic, and not sure if the settings available on your welder, I'd say less cleaning action, lower amperage, higher frequency, and have your tungsten sharpened to a truncated tip.

If you use a flap wheel or anything like that putt a little wax on it to keep it from loading up with aluminum. Then if you want to try running a bead again clean with every method you have available and and have another try.

bent flanges using 3xxx series make better tanks and appearance

appears like squrae cut edges and a 6xxx series ,makes for tough welding,

like Superioirwelding says "nothing wrong with those welds as long as it passes a pressure test"

Superiorwelding wrote:There are sections that are a little rough but nothing that says don't let anyone see it. The bottom left looks especially good. Question; were you dabbing or using the laywire technique?
-Jonathan

Dabbing

dsmabe wrote:After seeing the pic, and not sure if the settings available on your welder, I'd say less cleaning action, lower amperage, higher frequency, and have your tungsten sharpened to a truncated tip.

If you use a flap wheel or anything like that putt a little wax on it to keep it from loading up with aluminum. Then if you want to try running a bead again clean with every method you have available and and have another try.

I'm using a Miller SyncroWave 180SD transformer. All I have is On Off, Polarity, TIG/Stick, Amps, and a foot pedal. 1.5% Lanthenated tungsten sharpened, with a #7 cup and gas lens air cooled torch

I ran it hot enough to get it to melt and not so hot to trip the 50A breaker... not sure about the Amp setting.

If I remove any material at all, I will use a carbide burr on a die grinder then clean.

I kinda like the "washing idea" At least I would feel better In case I had any inclusions I would know about them. I haven't cut the hole in it for the filler neck so I'm not sure about the penetration.

Not sure what you gonna use for cap but make sure you vent it. Stihl caps have vent to allow air into tank as fuel is used up but keeps gas and vapors in. With out vent unit will run for awhile then vacuum lock won't be able to suck fuel out of tank so it will lean out and die.

dirtmidget33 wrote:Not sure what you gonna use for cap but make sure you vent it. Stihl caps have vent to allow air into tank as fuel is used up but keeps gas and vapors in. With out vent unit will run for awhile then vacuum lock won't be able to suck fuel out of tank so it will lean out and die.

I got that all figured out. The cap I will be using is solid. I already have purchased a 3 hole stopper/fuel line/vent setup from an ECHO unit. Should work like a champ!

Ok I finished it. I did not wash the welds. I just wanted to get the tank done and hear the thing "pop an fire". Bottom line is that it holds fuel. And the unit runs great. I don't weld all the time and it shows but I enjoy doing it. BTW the unit sits flat on the ground and holds a ton of fuel. The other end is a brush cutter... my friend will use this for clearing fence lines.

Looks great J

Pete