What welding questions do you all have?

[PlasmaOnTheBrain]

Hello everyone,
I am at a loss as to how to contribute to this forum being a welder that wants to be a machinist... All I know of machining is what I read online and absorb at work. I can count on one hand the number of times I've gotten to run a machine...
I do however weld on a daily basis with all of the common processes, and have spent much time and effort to learn as much as I can about the how and why of making metals melt the way you want them too.
So does anyone have any burning questions about welding or even a general curiosity about something that you'd like to ask?
I have a few pictures I'll post up... can't tonight, out of time...

Quick bit of advice on MIG and Flux Core welding; Mind your Contact Tip to Work distance/ electrode extension. This is how far away the contact tip is from the plate your welding. With wire welding, more electrode extension means more of the amps go into heating the wire by resistance before it meets the plate/arc. What happens is that the wire heats up before it reaches the point of melting and arcing. For solid wire that means less volts at the arc which means a smaller arc that will pop and stutter. Keeping the contact tip as close to the weld as you can will help, an 1/8 to a 1/4 depending on the thickness and amperage. Flux core wires, either self shielded or dual shielded (requires additional shielding gas) have a specific distance that they work best at. Read the instructions or ask the manufacturer. Some self shielded wires NEED about 3/4 to 2 inches of wire stick out to run right, usually with some sort of guide. This is because they use the resistance heating to bring the flux elements in the core up to temp before they hit the arc/puddle.
Thank you all, gotta run, Ask Away. :welding:
-Clif

 

[Ray C]

So here's a question... How do I keep the plasma torch from cleaning-out my wallet? The unit is in good shape. I've tried air dryers (dessicant type) and tried changing pressures etc. Still, the darn tips don't last long and when the inside electrode goes bad, it gets expensive.

Any general tips and what are good pressure and amp settings for various types of metals and thicknesses. BTW, it's a 50 Amp everlast unit.


Ray

EDIT: BTW, thanks for reaching-out and offering to help.

 

[xalky]

Theres almost nothing on the everlast site about settings for thier plasma cutters but i did find this link which is for a hypertherm http://www.everlastgenerators.com/forums/showthread.php/3382-Speeds-amp-Feeds?highlight=chart .

You should be using some sort of cut guide that attaches to the torch head to keep you spaced away from the material. The piercing causes lots of blowback which will clog up your nozzles in a hurry. The chinese plasma cutters work but unfortunately the engineering behind the cut science of these cutters is severely lacking. Hypertherm is the king in that area. The good news is that the consumables can be had cheap on ebay, so stock up...LOL. You can also buy the spacer guides on ebay. Far cheaper than getting those items from everlast.

 

[PlasmaOnTheBrain]

It really depends on what and how much your cutting, and how you expect the cut to turn out. Is it a cut to sever 2 parts for milling/grinding/welding without much regard for finish or is it a near finished cut on a part that you'd rather not work on much further? Expanded metal can be mean to the torch parts with all of the restarts and paint/coatings can do nasty things.
For piercing, hold the torch a little further away from the part and tilt it off of 90 by as far as you can and have a good cut... the tilt is a feel and/or necessity thing. If your say cutting out a 3 inch round circle out of a 2 foot square, you can tilt the torch a significant amount on the start of the pierce and keep the metal from splashing back, without messing up the finished cut. If your trying to cut a straight line on thin sheet metal, too much tilt will gouge the metal more than your cut.
As for power and gas settings, I never go by specific numbers for power, its a case by case thing for the most part. In general I run the unit as low as I can and still get a good clean cut. start on the low end of the dial and if it doesn't work crank it up until it does. The part should fall away without effort or assistance and very little slag on the bottom of the cut. Check the units instructions for gas pressure, that can change from unit to unit. I have the numbers of 40 to 80 PSI for most common plasma units... more for bigger.
I have heard of much bigger units using mixed gases from high pressure tanks for specific cases and uses. For cutting stainless I've heard of people using nitrogen to keep the cuts clean and shiny compared to shop air on stainless. Argon and helium for reactive metals like titanium or zirconium to keep them very bright and shiny, and they don't hurt stainless either. Kinda pricey to run argon through the plasma but if you need the cut to be that shiny...... :nuts: Most of those cases involved automated setups and mass production cutting.
At one job I ran an ESAB every day to pop holes in pipes for sprinkler fittings. I may have had to change tips once or twice in 6+ months and I don't remember having to change the electrode... Tip cleaners for torches work on the plasma holes if they get a little spattered.
Now at work we have a miller... seems like every time I need it the tips shot. I don't need it much Mainly when somethings gone wrong and its made out of stainless or aluminum... and the cutoff wheel on a grinder isn't gonna fit or is too dicey. :angry:
My thermal dynamic at home barley gets used... but I've done some abusive things to it and have only had to change it out once or twice...
The biggest plasma I've seen was an ESAB... thing was the size of a 400 am mig/flux core welder. If I remember right the thing would cut 1 inch steel without breaking a sweat(sort of...). It could sever some silly thickness, 3 inches or so maybe? Can't remember the amps but it was well over 100 and nearly the size of not being a manual torch anymore... I never had the occasion to use the thing, and those that had said that the tips and electrode barely held on... Like one slip up while your cutting and *poof* time to change the tip:banghead: very very tricky machine and hardly ever used.

Plasma's can be really awesome or out right painful to use and maintain, I have never figured out why... Look into getting diffrent tips or if your up to it making or modifying your own. Copy the original idea but make it thicker or wider hole what ever is needed to make the thing run better. Try it out on some used tips and electrodes. Guides and standoffs are always a good idea if they can apply to what your cutting on, and don't be scared to make them your self if you have the time. Pipe/bar stock works better than square stock because the metal from the cut builds up against a flat piece of stock and jams up the tip. The rounded area on pipe/bar stock gives the splash some where to go instead of the tip and the smooth surface your trying to follow...
I hope my rambilings are of some use, I'm off to get beer and food

 

[Ray C]

Much thanks. You kinda confirmed what I was thinking... It's a case-by-case situation. I had some cuts go smoothly and other struggled and I used 2 tips inside of 20" of material. -That's painful.

BTW: most of what I do are severance cuts that do not need to be beautiful. Sometimes things are just too big or heavy to get inside the bandsaw so, chopping them down to size first makes life easier.

One more question if you don't mind... For arc welding rods, which brands do you stick with? I had been using primarly Lincoln in various flavors. I liked the Excalibur 7018 a lot. Years ago, I tried some Forney and the slag on the 7018 was impossible to get off. I recently read that Forney modified their formulation and also started packaging them in nice plastic containers. I bought some 6011, 6013 and 7018 and just an hour ago, did some test welds on some shop drops of 1/2" thick angle iron. One side, I did a root with 6011 and finished with 7018 and the other was straight 6013. The slag issue seems to be fixed as it popped right off in one caterpiller piece. It's a lot less expensive than the Lincoln and when I need it, it's usually 10-15 pounds at a crack so it's a good savings...

So, I guess the question is, is there a good reason to always stick with a single brand and if so, what are your preferred brands? BTW: I only do basic welding and am self-taught. I can do welding in all positions and actually prefer vertical. Someone I know was a certified pipe welder (he was chief engineer on transport ships) and now that he's retired and working part time at a marina, he throws his welding jobs my way. -So I can't be doing half bad...

Here's a piece I did those test welds. I was standing and holding with one hand outstretched just to see how it would come out. One side is 6011/7018 and the other is straight 6013. This 6011 dug in like none other I've used before and had to cut back amps. One mighty solid root pass! The piece was beveled 45 degrees on all 4 sides -two pieces separated 1/8" before joining. If I honker in, I can get a pretty tight and even bead... This was just a silly test to see if I could do it

Ray

 

[valleyboy101]

Hi Clif,

Thanks for the offer of advise from a pro. I've been stick welding for over 20 years with my Miller Thunderbolt 225 AC/DC, but need to be able to weld aluminum as well as thinner metal than I can now handle. The largest project that I a have in mind is an aluminum cabin on my 26' US Navy whaleboat. It would involve a fair amount of overhead welding. However I would also like to be able to weld ~ 1/16 steel. I am considering a Miller diversion TIG - link attached. However I am kind of lost between MIG and a spool gun for aluminum and TIG. It is a fair sized investment - if I had quite a bit more money i'd have a MIG, TIG and stick but I think that I can only afford 2 of the 3.
Any suggestions?
http://www.millerwelds.com/products/tig/product.php?model=M00337

Thanks,
Michael

 

[Ray C]

Michael,

I'm not pro but I do a good bit of TIG and I'll say this... Doing small jobs, like a few inches here and there -maybe even 10" at a crack is OK, but when you need to lay down a line 20... 30" long, it's no picnic. The arm and hand gets pretty tight and cramped. FWIW: I'm thinking mig-gun in your case.

Ray

Hi Clif,

Thanks for the offer of advise from a pro. I've been stick welding for over 20 years with my Miller Thunderbolt 225 AC/DC, but need to be able to weld aluminum as well as thinner metal than I can now handle. The largest project that I a have in mind is an aluminum cabin on my 26' US Navy whaleboat. It would involve a fair amount of overhead welding. However I would also like to be able to weld ~ 1/16 steel. I am considering a Miller diversion TIG - link attached. However I am kind of lost between MIG and a spool gun for aluminum and TIG. It is a fair sized investment - if I had quite a bit more money i'd have a MIG, TIG and stick but I think that I can only afford 2 of the 3.
Any suggestions?
http://www.millerwelds.com/products/tig/product.php?model=M00337

Thanks,
Michael

 

[PlasmaOnTheBrain]

valleyboy101:
MIG on aluminum can be kinda tricky... The starts will be frozen cold, half way through the weld the heat will be perfect, and from that half forward it'll be too hot. adjusting so its hot off the start will make it WAY too hot by the end, setting it cold for the end will make it cold UNTIL the end. The best way to counter this is to learn to go slow at the start then haul A$$ by the end... If your going to go that route, get more machine than you think you need. If you plan on welding 1/8th" aluminum, get a machine that says it can weld 1/4". (might be a little much but you get the idea...) If you get a machine that says 1/8th max and you try and weld 1/8th all day then you'll be running into the duty cycle ever few min and it will get very annoying.
TIG will cover most of your bases, but again, get the most that you can afford. Its a little less critical to overrate with TIG vs MIG. TIG can be slow and a pain in the arse out of position, but with practice itll get you the results your after. Generally... TIG can do damn near anything IF you have enough power... MIG can do specific things fast with more ease... but with more likelyhood of defects if your not careful... If you have the funds for a TIG and a MIG.... spend it on a Bigger TIG unit.

Ray C:
I'm spoiled when it comes to stick. I barely have to use it but when I do its usually Lincoln, or something much more expensive... Last stick job I did was a build up on a duplex stainless impeller, with washington alloys 2209-16... Other than that its whatever the boss has in the rod oven, which is mainly Lincoln's. The only times I really have to stick is when the "enjimaneer" designed something with NO room at all to shove a TIG or MIG lead into the joint, or I have to work on some nasty oil filled cast iron. We have a lot of random alloys and brands stashed at work from before my time. Reasons to stay with one brand or another; If it runs good for you and hasn't failed you, why change? I came to love the excaliburs from welding school where they gave us some no name 7018 to burn pounds upon pounds of... and one day I got my hands on an excalibur and was amazed that I didnt have to fight it to the death to get the slag free... Sold from that point on

Gotta go guys... Hope this helps.

 

[Uglydog]

the darn tips don't last long and when the inside electrode goes bad, it gets expensive.

That's the primary reason I haven't gone plasma (yet).
I know others who cut replacement expense by finding consumables rated for larger machine.
The increased cost of the initial purchase was more than saved in replacement costs.
It's an option you might try, if it will fit your torch.

Daryl
MN