Evaporust Life Expectancy

dgale · Post by **dgale** » Fri Apr 11, 2014 12:42 am

Well, according to Evaporust, a gallon should treat 300lbs of steel…not sure how they really come to that figure, as weight seems like an arbitrary way to assess life expectancy of this stuff…surface area is what counts, not mass. Anyway, I made some PVC tubes and filled them with a gallon of Evaporust and put a 10E way tube in each one…they were pretty rusty but nothing too bad (i.e. no pitting etc. - just good batch of surface rust). I pulled them out after a handful of days, which was probably longer than necessary but life got away from me. They came out nice and clean and the Evaporust was looking pretty dark but I went ahead and put a second pair of tubes in similar condition in there and reused the Evaporust. Left them in for about 5 days and pulled them out this evening and the tubes were maybe halfway clean…not nearly as nice as the first pair. So I have to assume I hit the life expectancy of the this gallon after about 1.5 pairs of 10E tubes. I then lured the spent Evaporust back into the original gallon jug…not sure what to do with it (?) THe label says "in most cases" it's safe to pour out on the ground…not sure how good I feel about that…I think I'll set it in the crate of stuff I'm accumulating for our next local "toxic disposal day", where they take old paint, oil, solvents, etc. free and properly dispose of them.

Anyway, that's my experience - off to buy a second gallon tomorrow and redo the 2nd pair of tubes and see how they come out this time. Curious what longevity others have seen with this stuff? All and all I paid something like $22 for a gallon at HF, which was well worth the saved elbow grease so far, so no complaints but I somehow expected a bit more life out of it.

JPG · Post by **JPG** » Fri Apr 11, 2014 2:41 am

dgale wrote:Well, according to Evaporust, a gallon should treat 300lbs of steel…not sure how they really come to that figure, as weight seems like an arbitrary way to assess life expectancy of this stuff…surface area is what counts, not mass. Anyway, I made some PVC tubes and filled them with a gallon of Evaporust and put a 10E way tube in each one…they were pretty rusty but nothing too bad (i.e. no pitting etc. - just good batch of surface rust). I pulled them out after a handful of days, which was probably longer than necessary but life got away from me. They came out nice and clean and the Evaporust was looking pretty dark but I went ahead and put a second pair of tubes in similar condition in there and reused the Evaporust. Left them in for about 5 days and pulled them out this evening and the tubes were maybe halfway clean…not nearly as nice as the first pair. So I have to assume I hit the life expectancy of the this gallon after about 1.5 pairs of 10E tubes. I then lured the spent Evaporust back into the original gallon jug…not sure what to do with it (?) THe label says "in most cases" it's safe to pour out on the ground…not sure how good I feel about that…I think I'll set it in the crate of stuff I'm accumulating for our next local "toxic disposal day", where they take old paint, oil, solvents, etc. free and properly dispose of them.

Anyway, that's my experience - off to buy a second gallon tomorrow and redo the 2nd pair of tubes and see how they come out this time. Curious what longevity others have seen with this stuff? All and all I paid something like $22 for a gallon at HF, which was well worth the saved elbow grease so far, so no complaints but I somehow expected a bit more life out of it.

Do not leave it in there so long. Over night should be adequate unless severely rusted.

I think leaving steel submerged in it depletes it.

heathicus · Post by **heathicus** » Fri Apr 11, 2014 10:01 am

If it's just light surface rust, over night may even be longer than needed. A couple hours may be all that's needed.

dgale · Post by **dgale** » Fri Apr 11, 2014 12:46 pm

Thanks for the tips - I knew I left them in there much longer than necessary...wasn't by choice but just the reality that I put them in there and the rest of life took over and 5 days had passed before I remembered to go deal with them...it hadn't occurred to me that continued immersion would further use up the Evaporust - I guess I just figured it would eat up the rust and then just sit there and wait for me. I wouldn't describe what I had as "light" surface rust...more like moderate to heavy surface rust but still it sounds like overnight would be adequate (?)

Another Evaporust question - I assume this stuff has no effect on painted surfaces, so how do folks deal with a rusty part that is still partially painted?

terrydowning · Post by **terrydowning** » Fri Apr 11, 2014 1:39 pm

Evaporust and other chelation based rust converters (Krud Kutter) will convert rust under plating, japaning, and paint if it is accessible by the liquid. The result is that the surface treatment will lose its bond to the metal below and lift. If there is no rust accessible no real worries (Prolonged exposure unknown by me, paints with iron oxide pigments not known by me either)

Generally these are not paint removers but if the metal under the paint is rusted the conversion effect will still happen if the liquid contacts it.

Most of the Japaning on an old number 6 plane of mine was lost to Krud Kutter, not because it attacked the paint, but because the metal underneath was rusted and the japaning lost its bond. There were flakes of japaning in the bottom of the container.

dgale · Post by **dgale** » Fri Apr 11, 2014 6:05 pm

terrydowning wrote:Evaporust and other chelation based rust converters (Krud Kutter) will convert rust under plating, japaning, and paint if it is accessible by the liquid. The result is that the surface treatment will lose its bond to the metal below and lift. If there is no rust accessible no real worries (Prolonged exposure unknown by me, paints with iron oxide pigments not known by me either)

Generally these are not paint removers but if the metal under the paint is rusted the conversion effect will still happen if the liquid contacts it.

Most of the Japaning on an old number 6 plane of mine was lost to Krud Kutter, not because it attacked the paint, but because the metal underneath was rusted and the japaning lost its bond. There were flakes of japaning in the bottom of the container.

Okay, that makes sense - thanks. What effect does this stuff have on cast iron?

terrydowning · Post by **terrydowning** » Fri Apr 11, 2014 6:56 pm

Converts the rust to the black stuff that wipes and wire brushes off easily just like the steel. It does a great job on Cast Iron.

rlkeeney · Post by **rlkeeney** » Sat Apr 12, 2014 5:00 am

I asked Evaporust about testing the pH and they said any pH meter will do. They sen me this link.

I may get one of these or similar I have other uses for it.

fitzhugh · Post by **fitzhugh** » Sat Apr 12, 2014 7:14 am

I'm an absolute novice so take this with that in mind, but I had such luck with electrolysis on the rusty parts, including the lower tubes, that I'll chime in with a suggestion to consider it if you have not been. You may week know reasons I don't to use evaporust instead, but if not...
I nailed some scrap lumber into a 6' by 1' rectangle, nailed on some 8" feet in the corners, and draped a tarp over it. I also added a plastic dropcloth that was on sale for 90 cents at Ace. The washing soda was $5 at ace, or $3.25 at Walmart. The car battery charger was already around. Oh, and I used a piece of old bed frame for the sacrificial anode. I used naval jelly a few times on old hand planes and it was a messy toxic hassle. This is messy but easy and the mess is safe and simple to handle and the results sound like what you saw on your first tube with evaporust.
Again, I can't claim much experience but I can say it was cheaper, easier and much more effective than I would have thought.