Esteemed group,

We are closing in on painting the boiler of A&WP 290. While I had planned on blasting the boiler, a contractor bid $6500 for dry ice and baking soda. The Museum's budget is not in a position to expend that amount. So it looks like needle guns.

What have others used for a serviceable boiler for coatings inside and outside of the barrel? I do not want to paint the boiler with something that may need to be removed in the future.

Thanks,

Dale Grice

Barbecue high heat paint.

I understand that the IRM Steam Department has used Apexior 1 by Dampney Co. for boiler interiors, and Dampney's Apexior 3 for tender water tank interiors for many years. I have been led to believe that these products were used "back in the day".

Brush strokes are clearly visible on the inside surfaces of some IRM boilers which were painted with Apexoir 1 perhaps 30 years ago - including boilers which have experienced numerous steam/cold cycles.

It appears that Dampney still sells Apexoir 1 and Apexoir 3. I did a web search of the word Apexior, and one of the first items go me to the Dampney web site page for Apexior products,
http://www.dampney.com/Products/Default ... ategory=16

If the link doesn't work, you can start from dampney.com, or try a web search for Apexior.

Regards,
Bob Milhaupt
IRM Steam Department Volunteer

IMHO, painting the interior of a boiler is pure futility, unless you are planning on maintaining it as a cold, static display. When a boiler gets steamed, the Apexior starts working loose, laying in flakes in the belly and water legs. You cannot coat the water legs of the firebox. Even at that, more cost effective and demonstrated, experienced based methods are available.

For a tender tank, blast to white metal and coat with Aquatapoxy.

http://cohesantmaterials.com/Products.aspx.

If you want to be ' old school ' prime with Rust Oleum and coat with Pitch Mastic, which is essentially roofing tar that sets-up in place like a heavy paint.

If the cold and static display is the plan, simply purge the dampness and oxygen out of the boiler using dry nitrogen. Close up the boiler. No moisture & no oxygen = no rust.

If you are planning on steaming the boiler;

1. Passivate the metal surface.
a. This cleans out all the loose mill scale, fabricating debris and metalworking lubricants.
b. This establishes a protective Magnetite Hydroxide film on the metal. This is resistant to rusting. It is only a few molecules thick, so it must be replenished, repaired and maintained by step # 2 below.

2. GET with and STAY WITH a Water Treatment Program.
a. You will be maintaining 1a. from above.
b. This requires Consistency, not One Shot, for a while... or If we happen to remember.
c. Absolutely Do Not let a boiler stand cold and wet more than a day or two.
d. Steam a boiler as soon as possible after filling with water.
e. Not following c. & d. above is Inviting Oxygen Pitting and Rusting.

3. Industrial water treatment programs are geared for;
a. Pre-treated, softened and de-aerated water.
b. Typical locomotive practice uses raw, mineral bearing saturated-with-dissolved-air ( 21 % oxygen ) water.
c. Locomotives need special consideration due to these conditions.
d. The use of Sodium Sulfite in cold feedwater for a locomotive ( or similar ) use is not only a waste of money and effort, it contributes toward carryover of water in the steam, corrosion of superheater tubes, and galvanic ( mixed metal ) corrosion.

4. There is a time and experience proven water treatment developed especially for use in steam locomotives and their special needs.

http://www.boilersaver.com

Demonstrated results and proven method are;
a. Boilers stay clean, Owners, Maintenance People and Inspectors love the results.
b. Fuel savings over 30% have been measured by eliminating hard water scale.
c. The protective film prevents oxygen and chloride ( salt ) pitting when treatment is used regularly and the protection is maintained.
d. Handling of caustics chemicals and dangerous sulfites is eliminated.
e. Daily water testing is eliminated. Engine and Shop personnel don't need to be Chemists.
f. Add the treatment when filling a boiler and tender.
g. Either listen to the sound of the engine exhaust and whistle to determine the need for blowdown or for a scientific control method, Check the Electrical Conductivity of the boiler water by using a $ 30 pocket sized conductivity meter.
h. Blow down either when the steam exhaust sounds ' wet ' or when the Conductivity / Total Dissolved Solids reaches the control point, typically 2,500 ppm to start.
i. Established users, whose boilers are clean and conditioned, work their TDS up to 7,500. This enables big savings in water, fuel and treatment, along with top notch engine performance.
j. The cost is $ 1.25 per thousand gallons of soft water. Hard water treatment is roughly double that.

Hi Dale - Apexior is indeed the state of the art for internal. As in all paint applications, surface prep is paramount to longevity. Exterior is less critical, anything that can withstand the heat and shed water will do fine.

Water treatment - well, the best experience I have had is instituting a testing program and treating to the test results specifically. The quality of what you put in the tank will vary, and what's left in the boiler will vary much quicker. One size does not fit all in my experience. Did you ask about treatment? Best wishes.

dave

Hi Dale:
As Bob (and others) have pointed out, Apexior No.1 provides long term protection on the water side of boilers for decades, IF applied promptly over a freshly sandblasted surface. I have used it on every "tube job" that I have done with equaly excellent results. I wouldn't, however, expect it to work over a needle scaled surface.
The locomotive to which Bob refers was coated with Apexior in the early 1970s'.
On the exterior of boilers, I have used everything from red lead (the real McCoy!) and Rustoleum 7769 and all sorts of HighTemp Aluminium paints with good short term (5-7 years) results when applied over a needle scaled and wire brushed surface. I had the boiler on the locomotive we are working on at this time sandblasted inside and outside, and on this one I used Sherwin-Williams "Silver-Bright B59S2" on the outside.
One thing to keep in mind is that years ago we were doing external inspection (removing jacket and insulation) more frequently than under the revised 49CFR Part 230, so if you figure that your jacket and insulation are going to be on for the full 15 years, it is probably a good idea to spare no expense with the protection of either side of the boiler.
I think the estimate you got was reasonable.
The issue of waterside protection of tenders has already been mentioned, so at risk of thread drift, I'll comment that I have found no coating that works unless it is applied over a sandblasted surface. We have been putting on three coats of Rustoleum 9100 series epoxy with the activator designed for water immersion service for past 10 years or so.
Finally, I would note that I would not recommend any water treatment system for which there is no daily test. Without daily testing (and recording those tests) I don't see how it would be possible to track whether or not the proper amount of chemical has been added and number of blowdowns required.
I have the daily water analysis sheets (and inspection reports) for our locomotives for the past 25 years. I would be pleased to show them to any of you who might be interested in learning about the water treatment that we have been using and the results that have been achieved. Further, I invite any of you to drop by the Valley shop in January when we do our annual inspections, and take a look for yourself at the condition of our boilers.
J.David
PS: I have no stock in (or have received any payment from) Dampney, Rustoleum, Sherwin-Williams or any company making or marketing sulfite water treatment.
JDC

Dale,

Surface prep is paramount. If one only needle guns this process must be followed up with the use of a rust neutralizer. Otherwise the rust will continue to grow at a reduced rate below the surface.
The BEST exterior boiler coating is Dampney (parent company of apexior) Thermalox 260 http://www.dampney.com/Upload/Downloads/Downloads57.pdf . It can be applied directly to either ambient or hot surfaces. However, the vessel must be blast for the same reason stated above. And, it is futile to apply it over a rust converter.

Last year I quite successfully blasted the boiler of an "in service" locomotive in the process of replacing jacketing and lagging. This was done using recycled glass media (approved for open air use by the EPA, it produces only nuisance dust) while taking great care to "seal" the running gear with 6mil plastic sheeting and several roles of duct tape....sealing around saddle and waistsheets, running sheets down to the ground form side to side. Total tab being about $1,000 plus labor.

Does the museum still have the large sandblast pot? Could easily be done "in house" with a little bit of care and attention to the detail of the setup.

Cheers, Jason

Mr. Hogger,

Apexior has been around since the steam era, heavily utilized historically by railroads having been developed for locomotive boiler use. I have seen boilers that were originally coated with the product and locomotives in service today. NEVER have I seen Apexior peel off of the barrel interior.

Simply put, if the failure of this product has been witnessed it is due to improper application/surface prep. As you were stating about the interiors of tender tanks, the boiler must be brought to a "white metal" finish prior to application. 2-3 coats recommended....

In regards to boiler chemical, feel free to search out my narratives regarding LSB 4000. The results I and others have witnessed/experienced with both LSB and Apexior are irrefutable, the are simply the result of proper application/utilization. For boilers that are not regularly in service(or not in service for extended periods of service days) cannonball water treatment is VERY well tailored.

One must keep in mind that despite their claims, commercial boiler chemical companies are not fully versed in putting together treatment programs. Lastly, anti-foam is a vital component(the correct type of antifoam, for "open system" boilers. Only one is available in this country that is thoroughly suited for locomotive service) that is part of a regular regiment.... Not a fix when foaming occurs.

Cheers, Jason

I agree with the high-temp paint recommendations for exterior surfaces. The glass bead blast (after protecting the running gear) will give you a much cleaner and more rust-free surface than needle-gun alone.

Needle guns inevitably deposit air-tool oil on the surface. They're great for removing heavy scale and crud. The best job uses abrasive blast afterwards for a white metal surface.

Wirebrush tools in a angle grinder smooth the surface, but cannot get rust out of the pitted areas.

Regular industrial primer (not rated for high temp) cooks and turns into loose crumbles the first time the boiler is steamed. It's a bit of a mess to clean off afterwards. But it's much better than no corrosion protection at all for very-long-term cold storage.

- Doug Debs

Mr. Debs,

I agree with that of which you speak and wish to add a few points to your post and clarify one of mine.

While glass "bead" blasting may well be ultimately effective, I was referring to recycled glass media which is available in the same grit sizes as standard blast media(such as 20/40) http://www.newageblastmedia.com .

The "white metal" finish is important for several reasons. First, for proper adherence to the surface. Most importantly though, the process removes all of the rust from the grain of the metal. No other readily practicable method can effectively do this. It must be kept in mind that the surface of the steel is relatively open. As rust occurs, it "roots" into the surface....needle scaling and wire wheeling only wipes the surface clean and does not provide the finish required for proper adhesion.

If one is going to go through the trouble of correctly preparing the surface for the purpose of preserving and protecting a component of the artifact.... Why not use a coating system that would not need to be replaced with a properly suited one should it ever re-enter service?

Cheers, Jason