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Hi Tim, Here, in full, is a posting from the Tool Talk Archives from 2002. The writer is Mark KW whose welding knowledge was enormous. He hasn't posted in several years now---much to Tool Talk's loss. Stan Mark KW writes:
Read the post on AC vs DC and saw the 6010 / 6011 debate show it's head.
For me, the 6010 has always been the "pipe rod" and personally I like the Lincoln 5P+. Smoothest running rod and well suited for low and high current applications. Flux slag nearly removes itself and they hold a super flat bead on horizontal joints. The debate seems to arise when doing repair work, something I do a lot of. When doing new fabrication, the steel is clean and does not require a lot of prep and you have less chance of porosity and slag inclusions. Working on broken things is not as easy. You have dirt, oil, rust and a host of other things to deal with in the weld joint. Try as you may, in most cases, you simply cannot get all the crap out of the joint. The main thing I get is items that had been fixed before but not done properly. Most of the weld failures I see are caused by any or all of the following: Slag inclusions, porosity, poor fusion and or lack of penetration. Some welds are good but the joint was improperly designed causing the failure but that's another story in itself. Slag inclusions are the hardest to deal with. In many cases you can't cut or grind enough of the metal away because of it's location or what not. Sometimes you have the option of carbon arc gouging the old weld out in order to remove the slag and get down to the base metal. When you can't clean a weld good is where the 6011 comes into play. The flux ingredients on these rods will do a lot of cleaning if used right. The 6010's do not have the same flux coating composition and will not clean as well as the 6011's. Running 6011 DCEP (reverse) polarity, you can use a combination of technique and amperage to do a lot of things. Low amperage has less cleaning power but will allow for bridging wide open roots far beyond what a 70 or higher series rod will. Running at higher amperages, you can gouge and clean a weld as well as get a good root pass in all at the same time. Granted I work on bigger machines, 100,000 pounds and up, so take this in the context of steel thicknesses. Normally I'll start out using the torch to remove as much of the old weld, slag and dirt as possible. Then grind clean whats left and go at it with a 1/8" 6011 around 130 to 140 amps for the cleaning root pass. Vertical up is the best if you can position the work to allow it, if not, overhead is second best choice. Gravity will help pull the slag and dirt out the weld so the more you can use it in your favor the better. Most times, I will always stay with a 1/8" rod unless I have stock over 1.5" thick in which case I'll start with a 5/32" or 3/16" 6011 running between 150 and 200 amps. The higher the amperage you can run without blowing through the better for cleaning. You will induce a lot of heat into the weld area which helps melt slag included in the old weld and also causes the flux to have a better blowing action to get the crud out of the root pass. Second pass in a wide V groove on 5/8" or thicker stock is also done with a 6011 set at a lower amperage, 90-110 for 1/8", 125-140 for 5/32" and 130-165 for 3/16" all depending on how much cleaning and penetration I want get on the sides of the weld. Using second pass stringers on either side of the root is also acceptable for this but you need to get a good wash into the root to make it work right. Follow-up filler passes are usually done with 7018, 8018, 9018, 10018, ect as required for the work and should be done when the root passes are still warm IE 400F or above to ensure good inner pass slag removal. Given that most people deal with 1/2" or thinner materials, running a single good hot root pass with a 6011 on AC or DC and following up with one or two 7018 cover passes will usually hold anything the base metal will take. BTW, I did try some of the 7018AC rods the other day on an old Lincoln AC buzz box and they do lay a nice bead however, they do lack penetration you can get on DC. Using 6010 for root passes on new fabrication is fully acceptable since you do need the full cleaning power. Penetration and weld bead specs for the 6010 and 6011 on new steel are about the same. When it comes to dealing with used equipment and broken welds, the 6011 has many advantages over the 6010. Not saying they won't work but in most cases you will find the 6011 will work a lot better for those weld you just can't clean good. 6013 is something I am not fond of. It'll do a nice weld on AC with the buzz boxes but is very easy to have problems with too. If you get 'em hot enough to get good penetration, you end up with a lot of spatter. If you turn them down enough to get a nice looking bead, you give up penetration and will also likely have a lot of slag inclusion if you lift the rod even a tiny bit. On DCEN, strait polarity, they will do OK but still have less than desired effects you can get from the 6011 or 6010. Someone suggested running the 6010 on DCEN but from what I have seen, this only gives a great risk of porosity and slag inclusion. 6011's will also run decent on buzz boxes too, just crank the amperage up and keep the arc tight. The tighter you hold the arc, the better the weld will be. If you can't feel the rod dragging on the stock without it sticking, you don't have enough amperage. Not looking to start a rod war here, just giving my input on things having gone around the block a time or ten. Mark KW
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