Re-drying E7018

Some time ago I purchased a 50# box of E7018 Hobart electrodes. I'm not a professional welder, nor do I have occasion to do that much welding, which
means that I had an open box of low hydrogen exposed to atmospheric humidity for quite some time, like a year.
I'm in the midst of building a custom steel fence on the front of my residence property and some of the welding will be done with low hydrogen. At the local welding supply I mentioned in passing the story about the opened rods and asked if low hydrogen rods actually "got old," like I'd heard for ever. They indicated that they did indeed degrade, such so that they couldn't even be reconditioned in an oven.
When I got home I called Hobart and spoke with a technician who said that once low hydrogen was exposed to the atmosphere, it immediately started *irreversibly* degrading, and that, yes, re-drying them in an oven didn't help. I said that that would seem to indicate that a chemical reaction had taken place (with what I thought was rather inert inorganic material (rutile, for instance)) and he, sorta handwavingly (if that's a word) said, yeah.
To confuse and confound the question, I found a document on the Web from Lincoln Electric that indicated that Lincoln E7018 could indeed be reclaimed by drying in an oven (http://www.jflf.org/pdfs/papers/fabguide.pdf , p. 7). So...what IS the story on storing an open quanity of 7018 for protracted periods, in out of the weather (my garage, for instance), but nonetheless exposed to Southern-style humidity.
Thanks, Alan
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The Lincoln "Stick Electrode Product Catalog" http://content.lincolnelectric.com/pdfs/products/literature/c210.pdf page 46
has this to say <start quote> Re-drying Low Hydrogen Electrodes Re-drying, when done correctly, restores the electrodes’ ability to deposit quality welds. Proper re-drying temperature depends upon the electrode type and its condition.
One hour at the listed final temperature is satisfactory. DO NOT dry electrodes at higher temperatures. Several hours at lower temperatures is not equivalent to using the specified requirements.
Electrodes of the E8018 and higher strength classifications should be given no more than three 1-hour re-dries in the 700° - 800°F (370° - 430°C) range. This minimizes the possibility of oxidation of alloys in the coating resulting in lower than normal tensile or impact properties.
Any low hydrogen electrode should be discarded if excessive redrying causes the coating to become fragile and flake or break off while welding, or if there is a noticeable difference in handling or arc characteristics, such as insufficient arc force.
Electrodes to be re-dried should be removed from the can and spread out in the oven because each electrode must reach the drying temperature.
Electrodes which have come in direct contact with water or which have been exposed to high humidity 180° - 220°F for one hour, then 650° - 750°F for one hour.
<End quote>
That temp schedule is not achievable in a standard rod oven, hence the comments you get from the various sources.
Should you use it? If this was a critical application, toss the rod. If it is not a critical application, you can use your judgment about drying the rod per the schedule, then deal with "if there is a noticeable difference in handling or arc characteristics, such as insufficient arc force". In most cases, the problems with lousy rod far outweigh the cost of the rod, not to mention the cost of materials and the time to weld.
Alan Andrews wrote:

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Roy, would a gas fired barbeque oven work for this application, if it could achieve 650-700F (as mine can, IIRC).
i
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A decent double burner BBQ should get up to the proper temp. Regulating it for an hour might be dicey. Lincoln was rather specific on the temps and times. I have a type K thermocouple thermometer that reads accurately at that temp, most folks would not have something suitable.
Another issue is that the air in the BBQ is likely to be fairly high in moisture but no more so than any other gas fired oven.
Ignoramus14119 wrote:

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How about a timer controlled - counter oven - a convection oven or the like. e.g. smaller than a microwave. Has temp control, nice trays, long enough, and has a timer. Nicer than building one or buying one - pick one up at a driveway sale!!!
I got moms after she passed and we had one so the older but nicer one went to the shop. Nice convection oven.
Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com /
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Thanks much. I think it's safe to say that my application falls into the "non-critical" category. What with the expense of low hydrogen nowadays, though, one needs to have a really good reason for throwing away undamaged stick electrodes.
Thanks again, Alan

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Alan Andrews wrote:

Alan, stop a bit and think about what you are asking. You are building a fence! The welds you need on your fence need be little more than decent tacks. Unless you are incorporating a heavy gate, there is little stress on a fence at any time. You have no need of the ultimate failing strength of 70000 pounds that you get from perfectly maintained 7018 rods.
I once acquired quite a bit (~100 pounds) of old 7018 rod. It was open, dumped into a large cardboard box, and would have never been suitable for a certified weld. Yet I welded with it, making dozens of useful items. Were they as strong as they would have been if I'd bought new rod each time and kept it in an oven? No. Were they plenty strong enough? Absolutely.
You have already gotten conflicting opinions from Hobart and Lincoln, why would anything posted on a newsgroup carry any more weight than those?
I would stop worrying and weld up your fence with your rod.
there .. that was worth at LEAST what you paid for it!
Grant Erwin
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I agree.
Unless we are talking about rods that have been soaked or have been exposed to wet atmosphere for a very long time and/or bear evidence of deterioration due to heavy rust or white powder deposits on the coating. Most/many low hydrogen rods have lime and other hygroscopic materials in the coating and will attract moisture and if severe it can make them unpleasant to weld and with poor quality results.
Low hydrogen rods (and SA Lincoln welders) were developed to limit hydrogen embitterment (WW11 Liberty ships) which is mostly a problem of high duty cycle loading and is similar to fatigue. It often manifests itself by underbead cracking and is sometimes the problem when people point to a crack beside a weld and comment that the weld was stronger than the parent metal. AFAIK, most plain steel is only good for ~45k tensile and normal rods like xx10, xx11, xx13, xx14 are not low hydrogen but still make lots of satisfactory and serviceable welds.
Unless this is a code fence built with high tensile steel you are unlikely to have any problems even if you do not dry your rods at all, but a simple drying for ~1hr in a kitchen range @ 350-450 (spread then out on the wire rack) is unlikely to do any harm and will probably improve their performance. Only dry them as you need them as repeated drying is not desirable. The place where it is most important to use new rods from a sealed container is when welding pressure pipe or high strength steels subject to high loads and cycles and where failure will have consequences. I would be very careful of the condition of rods used for welding anything critical and particularly trailer hitches or suspensions for on road use.
If it is not possible to keep you rods in a warm dryer, it is worthwhile to keep them in containers that limit the contact with air, and to open new boxes when doing critical work.
Just my .02, YMMV
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"...or white powder deposits on the coating."
Funny you should mention that. They DO have a white powdery residue on them. That's bad, I take it?

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A light powdery residue is not too alarming (as long as you are not trying to be code compliant) but major white fuzz is not good. Any rod where the flux cracks or falls off is completely worthless.
Alan Andrews wrote:

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The exact chemistry of rod coatings is a bit beyond my knowledge but I have noticed that rods that have been exposed to a lot of humidity often have a white powdery residue that can often be wiped off with a glove. I suspect it is from some coating substance that is leaching out due to moisture or humidity. I have successfully used old rods that I have re-dried in a kitchen range and while some did have a small amount of white residue, it was not excessive and they were not used in critical applications.
I would suggest you dry some rods and do some test pieces to check for weldability and porosity. Make a smallish weld on thick plate and break it by bending with a long lever, this can often show porosity on the failure line. For your fence job I would not be too concerned as long as the rods burn OK and show no surface porosity. You can use good joint design and a little more weld to add some allowance for reduced strength.
IMHE most failures of general fabwork are due to poor prep work, rusty steel, poor joint design or just plain lack of operator skill. Most bad rods make welds that look bad both as they are made and in post weld appearance. Bad rods will exhibit coatings that bubble above the arc as they are heated or do not burn off evenly and exhibit excessive fingernailing or chunks of coating popping off as the rod is burned. It sometimes acts like a bad case of arc blow. Bad rods are often very sticky and the flux will fall off as the rod is bent to free the sticky end. they can also cause excessive spatter. All these symptoms can have other causes and most can also be found with new rods.
We all end up doing much of our general non-critical work with rods that have not been stored to the standards required by critical work. I prefer to buy rods in boxes that are sub packaged in 5 or10 lb sealed boxes and open a new box when doing critical work. when I need to buy a big can of rods I can often get my supplier to repackage the rods in smaller sealed plastic bags with a blast of dry inert gas before sealing. It is always easier to keep rods dry than to attempt to re-dry them.
Good luck, YMMV
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What Ernie says about old 7018 is simple. Pick a single rod at random. Bend it until the coating falls off the bend. If the metal underneath is corroded, the rod is too old to use for code work. If it isn't, it can be restored to code quality by reheating.
I had lots of old non-code-ever-again 7018 which had coating falling off, white powder everywhere, all the things people say make it useless. I welded it all up, every bit. Lots of times the coating would sort of disintegrate and I'd get a funky spot in a weld, so what? I'd sand it a little and paint it and it was all a whole LOT cheaper than buying new rod.
Grant
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On Mon, 24 Mar 2008 04:49:42 GMT, Grant Erwin

Same here.
Gunner
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British perspective, where there's
- theoretical knowledge from welding engineers working with petrochemical refineries, oil-rigs and the like
but
- in fab. shops and site welding people will use Rutiles (6013's) however ridiculous, absurd, slow and uneconomic it is (no-one ever ever ever uses cellulosic (6010, 6011) or Basic (7016, 7018) for general welding)
Experience from the experienced is that indeed Basics (7018's) are hygroscopic - they suck up moisture - and will max out at about the moisture level of Rutiles (6013's) or maybe a little bit higher. That is NOTHING if you are welding a fence from mild steel.
From my limited experience:
- properly from-day-one dried and rod-ovened 7018's burn with a clean transparent arc and you see big clean blobs of metal transferring across the arc to the workpiece (I've only seen this once).
- rods which are not kept like this have a dirtier misty arc and I am told if I look again I will see they spark and spit more. But they weld just fine and then there's the sledge-hammer test, which is the big bad final arbiter - which says all is well.
I know that 7016 half-rods kept in my boiler-suit pocket for days produce sound welds
In the US, humidity in summer East of the Mississippi River is very high - know from experience you can keep a cigar in your shirt pocket and it's just fine to smoke. Does this cause problems for 7018's? I've never seen a 7018 with the white powder on the surface which some mention.
Rich Smith
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Put them on a gas barbecue grill if you have one -- that will get a lot hotter than your kitchen oven, and will eliminate the wife factor...
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IIRC the major gas given off by burning propane is water vapor.........
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On Sun, 23 Mar 2008 13:39:28 -0500, "Alan Andrews"

I was involved in a huge nameless fabrication activity. Some of my duties involved sampling Low Hy electrodes for moisture content. There was a limit depending on the strength of filler material. There was a limit to the exposure time and then you had to return the filler material to be held, disposed of, or reconditioned @ >300 F as others have mentioned. That being said, after the electrodes were reconditioned a number of times, you could "rebake" the electrodes by increasing the temperature to >800 F and then held for a set time to "drive" off the moisture.
The Hobart tech knows the "small operator" does not have access to a welding laboratory, mechanical and/or chem laboratory to perform full procedure testing as we had access to (money for us was no object), so its better (cheaper, easier, by thousands of dollars.) to sell you another can of unopened electrodes(+ Hobart makes money).
We were required to open 10 lb cans of Low HY electrode and test them for moisture. Since the material was moisture sensitive we were required to dispose of any of the remainder from the cans. We used to stick them on a pallet and occasionally, workers would stop by and ask if we had any electrodes that they could have for "country jobs" (home use, fence building?).
So, you have two types of welding, critical or non-critical. For example, if your fence was likely to fall on someone walking by (or like the attachment welds for that crane in NY), then yes it would be considered critical. If your fence was just a visual embarassment to your wife, family or others and if it fell over would not injure anyone, than that would be considered non critical.
So, run a bead, grind it half way down, if you see any porosity or other defects, then you probably wouldn't want to use that electrode, if not, its probably still good to use for non-structural, non-critical welding applications. Switch to E6011 or E6010 and be done with it.
--
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The rule I have worked by is that unless the rod was soaking in water, (which will break down the binders in the flux), you can usually bring the rod back to usefulness.
However,the first test to see if the rod can be salvaged is easy. Take a sample rod, or a few, and bend it in a tight "U" shape until the flux breaks off. If thew wire inside is rusted, trash it. If the wire is OK, then roast it.
Lincoln has the PDF about roasting in an oven for a long period.
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