I read here that 7018 must be kept dry to be effective. I do have a Phoenix dry rod oven off ebay.
I was at Home Depot this weekend, and read on a box of Lincoln 7018 that Lincoln recommends redrying before use at 650 - 750 deg F for an hour. I thought I read you could redry the stuff in a household oven. Mine won't go that high.
Is this temperature required, or will lower work for redrying the rod? If the rod is dry, is the flux less prone to flaking?
It is highly unlikely that you are welding critical material that requires E
7018 if you are buying rod from Home Depot. If you are welding low alloy steel over quarter inch thick it then becomes important. Just store your rod dry and you are fine for most applications. Once the electrode is damp the flux will flake off with simple handling. If it is that moist then the rod is often thrown away rather than salvaged. Welding codes often require heating in an oven before the electrode is used fresh out of the sealed container. Some shops I have worked in require that you do not take out more than one hour's worth at a time. Other shops just require fresh rod before and after lunch. My guess is that ninety percent of e 7018 is used in non critical applications. all that is needed is dry rod rather than fresh out of the oven. Randy
If you are welding to a code like AWS D1.1, unless the 7018 came out of a hermetically sealed container, you have to dry it before using it. The boxes at Home Depot are not hermetically sealed. The flux will absorb moisture from the atmosphere even though there is plastic wrap around the box. The moisture will result in increased probability of porosity, hydrogen embrittlement, etc. in the weld. If you aren't welding to code, it is up to you. It may or may not make a significant difference in the weld. I would consider it unwise to ignore the manufacturer's instructions welding anything to which liability might attach, like a trailer hitch. FWIW I have seen successful bend tests done on welds made with 7018 that came of non-hermetically sealed containers of dubious history.
Thanks for all the input. I think I'll leave 7018 alone, at least until I build a heat treating oven. If I have time, I'm going to give Watlow a call today. They have new pre-insulated heater panels with the heating elements close to the surface. It'll be interesting to see what they cost.
I keep my 7018 in an ammo can with a good seal. Got a little fancier and it now has a removable power connector and a 100W reptile aquarium heater bulb keeping things a nice 132 degrees when I plug the cord in, and very dry after I take it out. All in all I think it cost me less than twenty bucks.
Sometime back (maybe a year or more ago) I seem to remember some discussion on this newsgroup about using some of the silica (?) crystals that absorb moisture to help keep rods dry. Anybody tried this? Results?
I was dissatisfied with 6013 for inside corners on tubing frames, probably because I'm a novice. It was very difficult to get a good weld. I had much better luck, decent looking fillets, with 7018. However, you need to get rid of the flux hydration to eliminate flux flaking off and get the best performance.
For this project, I switched to 6011. It produces a much rougher bead, more splatter, and doesn't clean up as nice as 6013 or 7018, but appears to give lots of penetration and good welds. I'll probably stick with it, at least until I have a way to dehydrate 7018.
I believe you are thinking of 7014 when you are refering to "cheater's" or "farmer's" rod. Like many of the other rods, different companys'
7014 will run differently, and some will even make several types that can all be loosely defined as 7014. It's worth it to try several different brands to see what you like. It's also worth noting that the same rod in 3/32 may perform differently at 1/8 or 5/32 on the same machine, or the same rod can behave quite differently on different
machines. Personally, I find all the 70xx easier to run than any of the 60xx, on my machine, with my current skill level. Need I even say YMMV?
As for 7018 (low hydrogen, LoHi), if you have an AC-only buzzbox, it's worth getting the 7018AC over the straight 7018, it makes a quite noticable difference.
If you're thinking 7014, yeah, you gotta pay a little attention to it our you'll get the slag inclusions from hell. If you can run it a little uphill, it helps. Downhill is asking for problems.. That's a very useful rod in some situations, especially plugging a hole- you can turn it way down and still hold an arc.. Also, you can put a lot of steel down in a hour with it, even more with 7024, very high rate of deposition.
Don't be afraid to hold a short arc, if you're having trouble keeping it lit then turn it up a little, especially on thin stuff. That's where a lot of people go wrong on sheet; they turn the amperage down and then they have to hold a long arc, the heat spreads, they're travelling slow, they get a huge hole.. Hot, short arc, fast, unless the job requires otherwise, is best.
Well, far from being an expert, here's how I understand it:
7018 and 7024 are both the same strength rating (the 70xx) part. The difference is in the flux coating. 7018 is a low-hydrogen rod, that reduces porosity and embrittlement due to hydrogen, often from water, that is often found in the flux on other rods such as the xx10 and xx11 series. 7024 (and 7014) are high deposition rate electrodes that have extra metal in the flux.
You would typically use 7018 or 7018AC anywhere you are worried about a weld cracking under high stress, either from a fresh box or out of a rod oven, or preferably, both.
You would use 7024 or 7014 anywhere you want to put down a lot of metal in hurry, and are less worried about stress (such as where you know the piece will be lightly loaded or you have a lot more weld than needed to support the intended loads). They are a very easy rod to run.
Damp (from leaving out in the open in humid air) 7018 nullifies its advantage as a low-hydrogen rod, so that unless you dry it out again, you basically have a 7014 or 7024 equivalent (a relatively easy to run rod with no special properties).