The WELDING thread

[SabreKai]

Duty cycle relates to the heat generated in the machine at various levels of power. You can run it at full power settings for more than the duty cycle but the machine will over heat, possibly burn out. The machine will pull what ever current its set for for as long as you pull the trigger.

Sabre

[disturbia]

SGJ has asked me to help out a bit on this thread. I am not a welder but am the Safety Manager for an Engineering company so I have a different perspective on this. In the course of my job I have to deal with numerous injuries (the fabrication bay has a high percentage of overall workshop injuries). When welding, as with any job, safety should be of the highest concern. Especially to us doomers. Getting medical treatment in a post PO world may not be easy, so prevention is better than cure, right?

I've already posted some tips from injuries I have seen recently. Today I'll present a couple of topics for your perusal -

1) Weld flash
Weld flash is by far the number one issue and can be a major injury. I have had guys off work for a week with both eyes bandaged up. Also keep in mind that weld flash may not be evident immediately. Mild cases may not begin to affect you until a few hours later. You know you have it when it feels like your eyes are full of sand and your eyes are so bloodshot, it looks like you’ve just pulled a few cones.  This is generally caused by not having your visor down when striking the arc. It is the initial flash that does the damage, although looking at an arc unprotected for a long period of time will also cause it. Mig and Tig guns have the advantage of a trigger mechanism so you are able to setup your job and get your gun into position before lowering your visor and commencing work. Most stick welders do not have this luxury - the rod is live when it is in the handpiece. So that means as soon as it touches your job (assuming you have the earth clamp set right) an arc will be struck. It is difficult for learners to get their handpiece into position ready to weld with the visor down. If you’re using a shade 11 or 12 lens, you won't be able to see a thing until the arc is struck. As the rod is around 8-10 inches long a small vibration or trembling in your hand will be magnified significantly at the end of the rod. I have found that when learning it is preferable to cut the rod about half way. This minimises the any movement at the end of the rod and ensures greater accuracy. Practice makes perfect. If your new, use a test piece first until you are comfortable.

2) Rayburn
Another issue is rayburn. Some types of welding are more prone to this occurring than others. I have seen guys emerge from the PTA (Plasma Transfer Arc) bay after welding stainless steel  for a couple of hours looking like they had spent a day at the beach with no sun lotion on. If you’re going to be spending a lot of time at a welder I would advise, in addition to all the clothing Jim has already mentioned, to wear a hood (balaclava) under your visor and maybe put on a dose of SPF 30+. You don’t need a direct line of sight to the arc to cause rayburn. The UV rays will reflect off walls and the roof.

3) Electric shock
Another big problem in untrained welders. We had quite a spate of shocks at one point. Various causes from faulty machines to people doing the wrong thing. So some tips-
-DO NOT hold the earth clamp with bare hands when you are welding. Keep in mind that, when welding, from the rod or wire through your job to the earth clamp is a high powered electrical circuit. You will be zapped. It won’t be pleasant.
-If you are buying a welder, ensure it has a VRD or Voltage Reduction Device. This won’t stop you getting zapped but will greatly reduce the possibility of a serious shock.
-DO NOT operate a welder standing in water. You’d think that would be just common sense but you’d be surprised how many people don’t take notice of their surroundings when doing a job.

So, hopefully that helps out any newbies. I’ll post more on the subject later and remember – “If it’s not safe, don’t do it that way”.

[jock]

I speak from experience, your point on weldflash or arc eye is a good one. I managed to do this to myself once while mounting a tag onto a motorcycle swing arm. Was a real fiddly job in a tight space which I had screwed up a couple of times. Out of sheer frustration I didn't use the mask on the 3rd attempt (thinking wrongly that a mere inch long weld wouldn't do any harm)

Not particularly painful but was left with an afterimage on my right eye that lasted days (similar to the effect you get if you look directly at the sun).

[Six Gun Jim]

Quick question - If a 30a outlet is enough to power one of these things, does that mean you would need at least a 7200W (240V*30A) inverter to power one of these things? If you set this thing for 150 or 200 amps, is the duty cycle reduced such that it only draws 30 amps at the outlet? What would you consider to be a minimal acceptable power level at the socket that would be required to perform the bulk of the welding jobs found around the doomstead?

A welder is basically inducing a short circuit and thus draws a surge load like a compressor kicking on (start load), it tends to try and trip a breaker when you strike the arc. But, the magnetic breaker also gets weak after MANY such cycles, a 30 especially so. However a 30 will last a very long time, many strikes, at standard 100 amp range. Most are already 50 amp service anyway, and I recommend 50 only because it lasts longer and gives you less trouble. For the bulk of your welding 100-140 amps is all you'll ever need unless you plan to run an Air-Arc which we'll get to later. Duty cycle is simply a measure of minutes welding per ten minute period, 60% (for example) is 6 minutes per 10 minute period. Duty cycle will not effect amp load or draw down, if it will trip the breaker it will do so immediately or usually not at all (far from the cycle limit in other words). I have repeatedly hit 30 AMP breakers with 140 and they hold fine. The ideal setup is 3 15 AMP slow blow fuses in a series, they have no magnetic component and therefore last nearly forever. That is a shop setup mostly but not expensive really to do IF you can wire it in. 

[Six Gun Jim]

Disturbia special and many thanks, I have a lot to cover and I don't want anybody hurt so what you're doing is excellent.

One more safety issue I thought of today, TANKS. The cutting and welding of ANY vessel with ANY chemical or petroleum component inside it or formerly inside it is ASKING FOR DEATH.  Vapor in a tank will explode at low concentrations depending on the substance and vaporize you and the vessel together. There are inert gas flooding procedures to follow and I will NOT cover them directly, although I may couch some of the info as a suggested practice. I weld fuel tanks, I follow careful procedures and I would recommend NOT doing so unless you have one on one face to face instruction of great depth. One mistake.......and you'll not make another. No welding near gasoline, diesel fuel, aerosol cans, flammable liquids/substances, cutting torch bottles or BATTERIES. Batteries contain hydrogen gas and will ignite and explode like a fuel air bomb. DO NOT forget this, many people have been killed by exploding batteries.


Now onward with the info. We will begin tonight with preparing to weld now that we have our gear on and machine set up.


Preparing metal.......sucks.  You can grind, chip, scale, sand, blast, steam, degrease chemically, tumble....oh the excitement, NOT. This is the phase most people skimp on and that ensures your welds will be less than stellar. Don't listen to people who say that "X welder and X rod will burn right through that!" Bullshit, it will burn it and in doing so use heat from the puddle that you need to flatten and dig your weld in. Depending on what the crap is on the metal it may also leave "inclusions" in the weld. Lets define that, this is important.

Inclusion: Any of several usually undesirable impurities found in a weld joint, including air bubbles, slag, and other particulate matter.

For GOOD welds we want zero inclusions, while that is not always possible you can try. Paint, mill scale, grease, oil, galvanizing, bluing, anything visible and especially rust we want gone. I use three things primarily to clean with. For grease and oil or any petroleum compound it gets a brake clean hose bomb. Liberally hit it with the brake clean and wipe it down with a rag. Once the liquid part of the brake cleaner is evaporated you can hit it with fire from a torch and get all that junk burn off the metal. 3M is cheap and does well, any brand will work and keep it off your hands! 

   

For rust, torch slag, light paint, mill scale and any hardened junk I like a 4 1/2" angle grinder with either a 24 grit common stone wheel or a Pearl type flap disc sanding wheel. You can also use (last photo) a regular 24/36/60 grit sanding pad on a back up disc. This is aggressive, takes metal away quickly and leaves you a very nice shiny steel surface.

 

common stone wheel AKA 4 1/2" grinding wheel Type 27 with a 24 grit.



Flap wheel. Basically a bunch of small pieces of sandpaper glued to a disc. they don't load up badly and they really cut well, don't last as long as a Type 27. They are sweet on sheet metal and paint.
 




Standard red disc sanding pad.



And back up disc to attach it to a grinder.



A needle scaler, this is an optional tool if you have an air compressor. This thing flat KICKS ASS! It's basically an air hammer that hits a set of steel needles and rebounds in a fast motion. Whatever you touch with the needles gets hit hard, like a sand blaster effect. They scale weld slag, torch slag, paint, mill scale, rust pits, mud, rock, sand, and ANYTHING you can get the needles on. They are the best rock and mud remover made and a lifesaver for chipping welds. Rocjk and mud can be a bitch, don't grind or sand worth a damn. The scaler eats it like nothing. 



Close up of the needles.

[Six Gun Jim]

Just for fun this is me 2-09-10 working on a coring barrel for a drill rig. The nice office lady agreed to enter the dirtball zone and photo my scroungy ass.  I am putting new teeth on it and wear buttons as well as building up the tooth pockets. This device cuts into solid rock when a rig spins it into the ground under a great deal of pressure. It also had cracked (last picture) and required a four pass weld joint 1" thick and ten inches long to repair it. 

this is an example machine and not ours, it is using an auger, the barrel goes where you see the auger. The auger drills dirt and the barrel cores rock, that is the only difference.






The tooth build up.



The 4 pass repair of 1" plate.

[houseoftang]

I suppose, given the caution about welding near flammable/explosive stuff, that when you're done cleaning with the brake cleaner, you move the can away from where you're about to light it up with a torch or start welding?  Kind of a dumb question I guess but sometimes those are the ones most worth asking.  Isn't brake cleaner mostly denatured alcohol, if memory serves?

Is there a brand of needle scaler that's pretty good?  Are the needles replaceable, as they'd get worn down I'd think?

[Six Gun Jim]

The brake clean will touch off and that is a good question actually. It falls under NO AEROSOL cans of any type anywhere near your area. NONE, ZERO, they will almost all be a disaster. I have seen them go and it's not a good thing if you're close to one.

Ingersoll Rand or Chicago Pneumatic are "good" ones but even a cheapo scaler is enough. They don't screw up very often. The needles are replaceable but honestly, a set lasts the life of the internal hammer parts. By the time they are done so is the anvil and the housing. I think mine probably has at least 80-100 actual hammering hours on it and it is still fine top to bottom. 80 running hours is a LOT of hours, probably more than most people would ever need one in a lifetime. Mine is an Ingersoll but I've used cheap ones and they work just fine.   

[Daewoo2]

I have a welding question since you are answering them

I have a little lincoln Ranger (225 amp) that I barely use (has 12.5 hours on it).  I want a mig welder to go with it.  Am I better off looking for a dedicated MIG machine or are there mig feeders that will work with that ranger???

[Six Gun Jim]

The Lincoln's can use the LN-25 suitcase and SOME suitcase to engine drive rigs are very versatile and run well. I have very little time with Lincoln's but tons of suitcase time with Miller rigs because we used them for heavy flux core repair on CAT scraper bowls. I will say this, all of them run .045 flux core well, not all run the .035 and .023 solid wire well. So for small stuff and precision work they aren't always so great but on plate work and heavy welding they are excellent. The setup is really pretty easy and convenient other than the suitcase with a full roll is a little heavy to move and you need a nice long gas hose if you run solid wire. Also, some of the rigs WOULD run .035 okay, just not a for sure thing. Whatever you do I would not buy a Lincoln MIG except the LN-25 suitcase. They are never as smooth as a Miller and the parts suck to locate for a lot of their feeders.   

[Daewoo2]

The Lincoln's can use the LN-25 suitcase and SOME suitcase to engine drive rigs are very versatile and run well. I have very little time with Lincoln's but tons of suitcase time with Miller rigs because we used them for heavy flux core repair on CAT scraper bowls. I will say this, all of them run .045 flux core well, not all run the .035 and .023 solid wire well. So for small stuff and precision work they aren't always so great but on plate work and heavy welding they are excellent. The setup is really pretty easy and convenient other than the suitcase with a full roll is a little heavy to move and you need a nice long gas hose if you run solid wire. Also, some of the rigs WOULD run .035 okay, just not a for sure thing. Whatever you do I would not buy a Lincoln MIG except the LN-25 suitcase. They are never as smooth as a Miller and the parts suck to locate for a lot of their feeders.   

Thanks, Jim.  I think I will go ahead and look for a dedicated unit since it sounds like it would be a little more versatile.  I need something I can crank down for precision work.  I bought that little lincoln welder for work, mostly because it was on sale, then about 2 days later got a GREAT deal on a new miller trailblazer so I ended up buying that for work and then keeping the little lincoln for home.  I have some stuff coming up that I am going to need some new equipment for and I was hoping I could repurpose that little lincoln.  It does not sound like that is going to work out, though.
Any recommendations as far as what I should be looking for??

[Six Gun Jim]

I am heavily biased towards Miller products because the parts are available and they stand behind them but...ESAB is good too. In a Miller that you'd like to run .023 and .035 only, that will do .25 plate and down.......the 180 (love the new 180's) or the 212. If you can find a used 200 classic GET IT! That was the best ever. The 250's are great, no problem there, but they aren't on offer anymore either. All the new Miller MIG set up's with the auto set I despise. The set is usually okay, but more digital crap to go bad. You know how that is, over complexity kills a good thing. In a an ESAB the 203 or 253 would do you well, ESAB stands by their stuff too and parts are nice and available.   

[disturbia]

We run a Miller Deltaweld Mig in the fitting area, but pretty much run exclusively with Lincolnweld machines (water cooled) for fabrication

[Daewoo2]

What I am going to be doing is primarily 3/16, 1/4 and 5/16 square tube, grate, angle, and channel, and a LOT of it.  I want something that will do it WELL  How big do I need to go for that???

[Six Gun Jim]

3 phase or single?