Welding Tips and Tricks

Was reading this post on storing 7018's

http://forum.weldingtipsandtricks.com/v ... =4&t=11507

Instead of hijacking it over rod ovens, I started this one.

Have been getting ready for my first 3 & 4 G structural test. Bought a new can of 7018s, and what a difference. No snuff outs, easier starts, and just better all around beads. I am in North Mississippi were its freaking humid, and my shop is not climate controlled. Also, I have taken on a stair case job, and plan on doing more commercial work soon as I pass cert. I am considering getting a 10lb oven. I have seen several of similar design on the interweb. They were about $200. If they work, and you want to get serious about weld cert and do small commercial work, I would think its worth it.

Do any of you home gamers use a rod over, and which one?

Thanks,

I use a Keen KT-50 (50lb oven) that has a thermostat so it doesn't run all the time - max draw of 150 watts.
($75 used if I remember right)

My 15 lb oven just draws a constant 100 watts - so I don't use that one hardly at all.

Plus I dislike it anyway - has a "rod elevator" to lift them up.
I prefer the large one where I just flip the lid and reach in.

Thanks MinnesotaDave. That was one of the models I was looking at. Keen KT-50. I see 2 used ones on FleaBay for 175. See some smaller units. They are not proportionally cheaper. One question I have is that the Keen 10lb & 50lb say 275F temp.Thought you had to get them up to 550F.

Search craigslist, surplus actions, etc for "autoclave." Medical is fine if the price is right. Tight seal, controlled venting, and accurate temperature.

Steve

bosulli wrote:Thanks MinnesotaDave. That was one of the models I was looking at. Keen KT-50. I see 2 used ones on FleaBay for 175. See some smaller units. They are not proportionally cheaper. One question I have is that the Keen 10lb & 50lb say 275F temp.Thought you had to get them up to 550F.

Storage temp is lower than the re-bake temp.
275 is in the correct range for storage.

So @ 275 dungerees they will maintain Lo-Hy properties. Since the Keen oven in question only goes to 275, what does one do, if the rods are left out for a while? Since H2O turns to gas at 212, it seems that if the rods are kept at 275 for a long while, all the moisture would evaporate, and your back in business. Does the logic follow that you only need the 550 oven if you want to dry out the rods in short order, say 4 hours???

If you keep them above 212 deg they won't have the chance to absorb moisture. So they won't need to be dried out.

bosulli wrote:So @ 275 dungerees they will maintain Lo-Hy properties. Since the Keen oven in question only goes to 275, what does one do, if the rods are left out for a while? Since H2O turns to gas at 212, it seems that if the rods are kept at 275 for a long while, all the moisture would evaporate, and your back in business. Does the logic follow that you only need the 550 oven if you want to dry out the rods in short order, say 4 hours???

It unfortunately does not work that way. They don't absorb water like a sponge, there is a chemical bonding from what I've read on the subject (from the rod manufacturers and long boring scientific papers on the subject).

As a result it takes a lot of energy to break the bond - some papers specifically note that long periods at lower temps is not equivalent to the high temps specified to do the job.

I don't have the proper background to be more technical than that I'm afraid.

bosulli wrote:So @ 275 dungerees they will maintain Lo-Hy properties. Since the Keen oven in question only goes to 275, what does one do, if the rods are left out for a while? Since H2O turns to gas at 212, it seems that if the rods are kept at 275 for a long while, all the moisture would evaporate, and your back in business. Does the logic follow that you only need the 550 oven if you want to dry out the rods in short order, say 4 hours???

I'll back Dave's comment. The 550* bake-out isn't about removing water. It's about removing the effect water had on the rod. I'm not sure if any codes allow the use of baked-out rod, as there's a point where moisture has facilitated oxidation (rust) that can't be baked out, and you can't see that until it's extreme enough to show on the exposed rod tip. It's perfectly suitable for restoring some lo-hy properties for non-critical use, though. A wife might frown, but your kitchen oven can do this.

Steve

I have some 3/32 that got left out and you can see rust in the flux. From the iron powder in the mix. But if you don't let them get contaminated then you don't have to get them up to bake out temps. Some codes allow for one bake out. But some only give you 2 hrs out of the oven before they get tossed.