Water treatment for iron boiler?

[k4kfh]

Hi again,

As some may have seen, I recently finished building the Popular Mechanics boiler, which is a combination of a copper water-tube coil and a chunk of black iron pipe as the reservoir/steam dome. All the fittings are brass.

I have been using distilled water (local water is extremely hard) with the boiler thus far, but I'm curious if this is all I should do. Since it is iron, it is of course prone to rusting, and when I drain it there is a slight rusty brown tinge to the water.

Should I be using some kind of water treatment? Or is it not worth it for a boiler of this size, and I should just keep an eye on any rust and do a hydrostatic test every so often?

[BClemens]

Marty Knox; you gave us some great advice recently in answer to these questions so maybe you will reiterate? The 'new place' is on a well and we are certain that it will need 'treatment' too... It has been tested as safe for humans - but probably not safe for our locomotive to 'drink'.
BC

[Fred_V]

k4k, are you really talking about "IRON" pipe or regular steel water pipe which is often referred to as iron pipe. I don't think iron sewer pipe is designed for any kind of pressure.

[pat1027]

If you order black iron pipe what you will get is steel pipe with a coating on it. I do a white vinegar wash once a year with a camera inspection to make sure the interior is clean. I also store the boiler dry. The first steel boiler failed in 12 years due to build up on the firebox sheets accelerating corrosion. With the second boiler getting an annual wash and visual inspection the second boiler is 12 years+ with no notable corrosion. Some people do a wash with CLR and pressure wash the inside. The goal is the same to prevent build up on the sheets. I don't have any experience with distilled water.

[reubenT]

I use LSB4000 locomotive boiler water treatment, contains an oxygen scavenger to protect the boiler from rust. And distilled water is the best to use, rain water next best. It takes an extremely small amount to do the job. I think the treatment used for water stoves works too, cheaper but maybe not quite as good.

[Marty_Knox]

If it really is iron, wouldn't be too worried about it. But as Pat said, these days the chances are it is actually steel.
As for water treatment, I wrote about water treatment in the Sept./Oct. Live Steam magazine.
Marshall Black's article on water treatment was reprinted in the same issue.

[Glenn Brooks]

One other thing to consider, is limit the physical aeration of water you put into the tender or boiler. For example, dumping water from a raised water tower, or squirting water from a garden hose nozzle into the tender, will greatly oxygenate the water- in the same way that fast flowing mountain streams, rushing over bolders and obstructions aerates water - exposing your heated internal surfaces to a fresh over abundance of oxygen - casing rust to eat away away your internal boiler surfaces. I rode the Folsom Valley RR this fall. They are rebuilding their second boiler for Cricket in two years because of this phenomena. Even with the constant use of water treatment.

Glenn
.

[k4kfh]

Thank you all for the advice! I guess my boiler is steel, not iron (it is quite literally hardware-store "black iron" pipe) so it sounds like distilled water and some kind of treatment is necessary. It's a very small boiler so it's not an issue to use distilled water.

Should I just put some vinegar or CLR in the fill hole and slosh it around? Or heat it up? Or do I need to disassemble it sufficiently so I can get a brush or a sponge in there and actually scrub?

Also, as far as water treatment, how does normal household boiler treatment stack up? I can get that easier than special live steam stuff. I can also get kettle descaler from the local supermarket, but I assume that's different stuff.

[Harold_V]

I know precious little about the operation of boilers, but I have some experience with running a (small, continuous feed) ball mill. That experience should translate in to something useful for anyone who operates a boiler and is concerned about rusting.

Because the discharge from the ball mill had to have a pH of greater than 9.5, I used lime along with the ore I was crushing, which yielded the desired results. I had little choice, as the pH of the feed for my agitation tank had to be no lower than 9.5, otherwise I risked producing hydrocyanic acid, commonly known as the gas used in gas chambers. I used cyanide to recover both gold and silver.

So long as I didn't rinse out the ball mill when it was allowed to sit idle, there was never any formation of rust, in spite of the fact that the interior, which was wet, was sparkling clean from being operated, and the balls used were made of steel. So then, you can safely assume that if you use a product to raise the pH, you will automatically limit rust formation.

H

[jamesjgould]

Lime scaling is a huge problem in our boilers. It can be controlled by "pickling" the boiler often enough to keep it from forming. Distilled vinegar, CLR, or my favorite "Limeaway" are the simplest to use. Correctly treated water is always the best to use, reducing entrained oxygen is the goal. I have seen the interior of steel boilers that have used rain water for many years that are still in great shape with just a good flushing and drying between runs. Lime in any form is probably the last thing you want to use in your boiler because heat will cause it to plate out on hot surfaces. I would defer to Marty Knox on any of this because he is really the expert about boiler feeding and use.

[jamesjgould]

I should add to my post that any acid treatment must be neutralized with a base to prevent acid corrosion. I use
Tri-Sodium-Phosphate (TSP) as a flush. That's commercial dish washing powder available everywhere.

[Harold_V]

I didn't imply the use of lime, as I realize its consequences. For me, it was the perfect solution for the extraction of values, as my solutions were not heated.

I did imply altering the pH, which can be accomplished by other means that wouldn't result in residue deposition. I suspect boiler treatments do just that---raise the pH.

H