Welding and cutting rods

[Hendrik]

Alright so I have decided to build my own thumb for my micro ex.
Been scouring scrapmetal places for suitable steel and and now need to think of the construction side of things.
All the welding I have done has been with GP rods or hard facing rods but apparently 7018 rods are the go for this type of job, however I have heard that they are a pain to get started and if they stick they are very hard to un-stick. There is a newer version of the 7018 called the 7018ac which is apparently a lot better to work with but are fairly rare.
Should a amateur welder go with 7018 or try and find 7018ac rods?
Or can I get away with GP rods?
Another thing I cam e across whilst finding out info about rods is that there are cutting rods out there, what is the go with them? Do you need a special welder or will a little welder work with them?
I have a full size angle grinder that is hanging out to do some serious work but if there is an easier way to slice through steel I am all for it.
Anyway if there are any people who like to dress in heavy leathers out there I would be most grateful in some tips on how to make the project work.

 

[Canadian_digger]

Try the 7018 rod, you will like it. That is the rod I used when I first learnt how to weld.

 

[willie59]

I'd go with the 7018. I'm not aware of a newer 7018ac, doesn't mean there not out there though. The 7018 low hydrogen rod is ideal for strong structural welding applications, like your thumb build. Yes, the rods do stick, probably more than the 6013 or 7014. But the more you work with the 7018, you'll get the knack of working with them. The best advice I can give you on the 7018 is getting the rod ready for start up. A fresh rod isn't too bad as the end is clean and the flux on the tip is tapered. You can start it up by quickly "dragging" the rod across the steel. Try doing this on some scrap metal to get the feel. Eventually, you'll be able to start up without dragging. But once you've burned some of the rod, and stop, the flux on the end of the rod is insulating the core of the rod making start up difficult, that's where people experience the "sticking", because they peck peck peck at the end of the rod until...stick! The best way to deal with this is give the end of a burned 7018 a quick smack right on the end of the rod on the piece of steel being worked on. This smack knocks away the flux right at the tip of the rod exposing the core. Now your ready to start up using the dragging method, or by just sticking it in as you become more experienced with the 7018. As for cutting steel, the old cutting torch is probably still the quickest way if you don't have a plasma cutter.
Had to edit and add one more thing. Even an experienced welder will occasionally "stick" a 7018. Don't panic! Don't try going back and forth trying to get the rod loose! Just unclamp the stuck rod from the rod holder. Then reach down and, with gloves on, grab the rod and dislodge it. Put it back in the stinger and give it another go.

 

[RandyS]

I've never been able to confirm this but some old geezer who hangs around my shop all the time claims that the 7018AC is designed for AC Welding. They can be hard to find and do seem a do a little better on AC machines.
I absolutely love 7018's, been using them so long I probably couldn't weld with anything else

 

[DPete]

A friend of mine built his own thumb, he made a model out of cardboard first to try the hinge points as I remember they bent the ram some way and had to get another. Good luck, 7018 is good to work with, it does'nt splatter. I like 1/8"

 

[willie59]

Another thing we forgot to mention here; the 7018 is designed to be a DC reverse polarity rod.

 

[td25c]

Sounds like a good project Hendrik.I would use 3/4 inch thick steel for the thumb on the mini- ex.I do allmost all my welding on DC current.The 7018 is a good rod,tap it smartly on the steel to start the arc,then keep it close to the weld pool when running the bead.The 6010 or 6011 also work good,They have good penetrating qualitys and good strength.Most pipe line's use 6010's & 6011's.I would use a standard cutting torch or plasma cutter to cut the steel to shape.Use the grinder clean up and bevel the edges.I built a thumb for my excavator years ago,I'll send some pictures if it will help.

 

[Hendrik]

Cheers guys, I'll give the low hydrogen rods a go.
Yes the 7018ac is designed for ac operation
http://www.tractorsupply.com/webapp...19|61720|53252?listingPage=true&Special=false
My info on the hard start 7018 came from here http://www.steamengine.com.au/misc/welding/index.html
This has a few good tips http://www.weldingtipsandtricks.com/stick-welding.html
I like that idea of the file as I have had the flux break off the rod when using the tap tap method
This is what I was referring to in regards to a cutting rod http://www.welding.com.au/df163-58/austarc-cg/

This is going to be just a very basic set up, no hydraulic ram.
However most manual thumbs have two working positions, one at 90 degrees and another at ~110/120 degrees. Is there any real advantage to having this as I was planning on 90 degrees but would be able to get more with a longer supporting arm.
Also given the size I will be making it so that it is taken off the machine when not in use rather than having a stored position on the arm.
Ooooh yeah BTW, did you know that Kobelco make welding rods, might the thing to use on a Kobelco ex
http://www.nationalwelding.com.au/electrodes1.htm

 

[willie59]

If you want to file the rods, that's up to you. After burning tons of 50 pound boxes of rods hanging stuctural iron I'm just used to smacking the end of the rod to prep for re-start. Didn't have time for a file. The cutting rod you refer to looks like a typical carbon rod or "gouger". It's typically used for removing welds. It can be used for cutting, but it's not nearly as efficient as the old acetylene/oxy torch for cutting steel in a precise line.

 

[Hendrik]

Sounds like a good project Hendrik.I would use 3/4 inch thick steel for the thumb on the mini- ex.I do allmost all my welding on DC current.The 7018 is a good rod,tap it smartly on the steel to start the arc,then keep it close to the weld pool when running the bead.The 6010 or 6011 also work good,They have good penetrating qualitys and good strength.Most pipe line's use 6010's & 6011's.I would use a standard cutting torch or plasma cutter to cut the steel to shape.Use the grinder clean up and bevel the edges.I built a thumb for my excavator years ago,I'll send some pictures if it will help.

Problem is I only have little 240v but from what I understand the 7018 will work with both ac and dcrp, as stated in the old school welding link I posted earlier. The 8 in the electrode code refers to the type of current the rod will accept.
The thing is that I am trying to keep the weight down as much as possible and only have a small space (about 75mm across the arm) to work in. I would ideally like to get some plate and then weld the lugs to it and then weld the whole assembly to the arm which would give more strength but add weight. Problem being I can't weld across the arm, so have to rely on welds down the side, to this end I would want to use the best rod I can and the 7018 is stronger than the 6011. I have 6013 rods which are classified as GP rods and thumb manufacturers stipulate that 7018 must be used when attaching their thumb to a machine.
However I will get out tomorrow and look for more material and if I can source a good quality small I beam I will be able to cut it to suit. This was my original plan, take an I beam and cut it in half and then cut the sides to fit on the machine and then cut two holes for the thumb and support link.
Here is another good tip for storing rods http://www.woodworkforums.com/archive/index.php/t-34235.html

 

[td25c]

I use a carbon rod in my "air arc" .I agree with Atcoequip,the air arc carbon rod works great for removing welds & undercutting for a new weld.Use a oxy-acetylene torch for cutting.I have never herd of "filing" a welding rod.Give that 7018 a good smack to start it,and keep the arc short.Or use a 6010 or 6011 rod.They start better and you can run a longer arc.

 

[flyboy912]

Every tool has it's purpose, and the sorriest job in the world is the home handyman, he needs every tool in the store. The welder is the luckiest. There are a few basics, welder, torch, grinder, a few hand tools and you are ALMOST in business. Away from the shop, a pipefitters tri-legged stand with chain vise is really handy. Right on the 7018. No rust though, and keep it tight into the weld. Also no moisture on the rod. If the can is open for long, heat at 300 degrees for an hour, minimum. Rod oven is necessary for shop use. Serious work, 7018 DC, 7018AC will be fine. 6010 is DC, 6011 is AC. For best weld run the rod as hot as you can handle it. Penetration and good weld chemistry is the result. 7018 is better because it is just tougher. 6010 and 6011 cracks easily unless done well. (30 year Boilermaker)

 

[Hendrik]

If you want to file the rods, that's up to you. After burning tons of 50 pound boxes of rods hanging stuctural iron I'm just used to smacking the end of the rod to prep for re-start. Didn't have time for a file. The cutting rod you refer to looks like a typical carbon rod or "gouger". It's typically used for removing welds. It can be used for cutting, but it's not nearly as efficient as the old acetylene/oxy torch for cutting steel in a precise line.

I agree that a gas axe is the way to go but I don't have one due to the cost of bottle rental.
I also agree that with experience the tap method is the most efficient for 're-setting' a rod but it does take a bit of skill.

 

[Hendrik]

Penetration and good weld chemistry is the result. 7018 is better because it is just tougher. 6010 and 6011 cracks easily unless done well. (30 year Boilermaker)

My main concern is the welds on the ex arm, as they may well take some shock loads.
Thanks for the tips, I'll be doing some practice runs with a 7018 before going into the serious stuff.

 

[td25c]

Every tool has it's purpose, and the sorriest job in the world is the home handyman, he needs every tool in the store. The welder is the luckiest. There are a few basics, welder, torch, grinder, a few hand tools and you are ALMOST in business. Away from the shop, a pipefitters tri-legged stand with chain vise is really handy. Right on the 7018. No rust though, and keep it tight into the weld. Also no moisture on the rod. If the can is open for long, heat at 300 degrees for an hour, minimum. Rod oven is necessary for shop use. Serious work, 7018 DC, 7018AC will be fine. 6010 is DC, 6011 is AC. For best weld run the rod as hot as you can handle it. Penetration and good weld chemistry is the result. 7018 is better because it is just tougher. 6010 and 6011 cracks easily unless done well. (30 year Boilermaker)

If the 6010 and 6011 crack easily,We would not use them on pipe lines or boilers.They are the favord rod for this type of work.I use 6010 and 6011 on DC and get good results.

 

[Hendrik]

If the 6010 and 6011 crack easily,We would not use them on pipe lines or boilers.They are the favord rod for this type of work.I use 6010 and 6011 on DC and get good results.

From my limited understanding the 7018 is better at absorbing shock loads, which is an issue on an ex, particularly low down on the arm. This is not an issue on a pipe, unless you back the D10 into it
Sure I would love to use 6011 rods but I have to use the best rod for the job but still be able to use it with my limited skills andequipment.

 

[flyboy912]

I made that comment because pipe and boiler tubing are not the same thing as welding on heavy stuff. Try using 7018 and 6010 on dogs, weld on one side only then knock them off with a hammer and see the difference. Also for tacking, the 7018 is "tougher".
Cert's on ASTM Boiler and Pressure Vessel Code #9, Navy, Coast Guard, Pipe G6, forgot others.

 

[Komatsu 150]

Way back before we had a torch I bought some cutting rods. They were not what are sold for gouging today. They worked but pretty rough cut and smoky. Actually you can take any rod and run it at 50% or so higher amperage than spec. and it will cut about as well as the purpose made ones. But they will up burn at an amazing rate and get very hot. The cutting rods lasted a little longer. Still, if you have some old or free rod it will work.

 

[swampdog]

Problem is I only have little 240v but from what I understand the 7018 will work with both ac and dcrp, as stated in the old school welding link I posted earlier. The 8 in the electrode code refers to the type of current the rod will accept.

Are you saying that you do not have a DC welder? If so, you may need the 7018ac, if the ac means that they are made for AC welding. If you want to make life easier, go and buy a DC welder. I doubt that you will ever regret spending a little more for a decent welder.

One of the first things my welding instructor told the class many years ago was to never buy a welder that only welds on AC. I took his advice. Buy a DC welder (it also can weld AC if one ever wants to) and forget about AC.

Most of the cheap welders (300 or 400 dollars) are AC only. You can buy a good basic Miller or other name brand DC welder for well under one thousand dollars and have something that will allow you to do good work.

Another piece of advice, if you can afford it buy a good welding helmet - something like an Optrel self darkening helmet. Again, you get what you pay for. A good helmet is especially important for MIG welding where the weld is not as bright and the work often is of a finer nature. A good helmet lets you see what you are doing and will make a world of difference.

 

[Knucklehead]

Get a good pair of gloves,and just before you go to strike your arc, reach down(with gloved hand) and break the flux off the end. I learned that from my godfather who Retired,but still welds everyday. This is really helpful when you are tacking things together.

When you think you are ready,tack everything together and dry fit. Also don't weld on one side at a time. Spread your heat around so that it don't pull or warp. Some of the more experienced hands can elaborate more on whats the best way to go about it. I just know that I have seen alot of people spend alot of money getting things straightened out because of this.

Good luck and don't forget to post the pics