I have been researching baking soda blasting for a while now and have seen photos of some of the end results some have been quite interesting. My question is has anyone had any experiences with using it and what are the pro's and con's?

Thank you for your time
Daniel

I work in insurance claims restoration as a manager and can tell you that we have used baking soda blasting numerous times over the past couple years. The pros are that it is fast, thorough, schedulable, doesn't tie up crews for days on end, provides excellent results compared to sanding by hand, and is cost efficient for large jobs. The cons are that it is expensive for small applications, equipment rental logistics can be a headache due to availability and cost, there is extensive clean up involved, it requires training, the media is expensive, and when used indoors you need ventilation and containment set up. You may also want to look into dry ice blasting for more delicate surfaces. It requires no clean up afterward and is good outdoors. Make sure to research it first. Hope this helps.

Have had dry ice blasting performed in a wastewater evaporator. They have a tendency to scale up worse than any reasonable boiler operation would. Also, water treatment cannot be used, as it would defeat the purpose, to concentrate and eventually dry the waste solids, high in calcium, sulfates and silica.

Have had excellent results where the scale could be physically reached.

On the others side of the coin, if you have a boiler that is in operating condition, scale can be prevented or cleaned-up in operation. This can be done without attacking, thinning or degrading the base metal. Wheel barrow loads of crud have been washed out of boilers, without resorting to the use of acids or strong, dangerous chemicals.

Likewise, scale and rusting can be prevented from accumulating in the first place. This is the wisest approach to a recently reconditioned boiler.

Aside from boiler applications, what are the pros and cons of baking soda, dry ice and another type called "abrasive sponge"? Has anyone here used these methods for blasting of rolling stock-- paint and rust removal? There must be a better (easier-cheaper) way than the old tried and true method of abrasive grit (sand or "Black Beauty").

Howard P.

I can't think of a cheaper way of blasting a piece of rail equipment other than with sand or Black Beauty with air supplied by the main reservoir of the locomotive that pulled the car out to the sandblasting location.

A pallet of Black Beauty, some diesel fuel and thats about all the costs involved.

Been there, done that, etc. Many times, in fact. Yes, quick and cheap. And then the stuff has to be shoveled up and disposed of. Maybe there's a better way?

Howard P.

Externalities. When people fail to consider the true costs of a project, leaving others holding the bag. Nuclear power is full of them.

The "tow it out and blast it" inflicts externalities like:
- Wear and tear on a historic locomotive. Compressor rental is cheap.
- Toxic cleanup. That old paint, now powdered and in the wind, is full of lead and heavy metals for pigments.
- Lead and heavy-metal poisoning for on-site crew and visitors.
- Silicosis risk if you use a silica sand.
- Damage to blasted car from grit and rust bits getting absolutely everywhere.
- Damage to compressor locomotive from grit getting absolutely everywhere.

There's nothing quite as unsexy as cracking open a malfunctioning airbrake part and finding not only is there blast media inside it - but the brasses are now scored. Been there seen it. And there you are, lapping an irreplaceable part down to near condemning limit just to get the scoring out.

I did some research on the subject a few years ago for a project at work. The main thing about baking soda blasting is it will not remove much in the way of corrosion because baking soda is relatively "soft". OTOH this is a benefit for blasting of some materials, such as aluminum. It's used for paint removal from aircraft (fixed wing and rotary) for this reason as it won't damage the aluminum. It's also usually used in a wet process which results in a dust-free blasting process. This also prevents heat build-up (which can cause warpage) when blasting thin materials like sheet metal. With the wet process, there's no residual blasting media to be cleaned up, and when blasting steel, the baking soda leaves something of an anti-corrosion coating which prevents the metal from quickly flash-rusting before you can get a coat of primer on it.

So, depending on what you what you're trying to accomplish, it can be a superior process compared to conventional sand blasting.

Are boiler interiors ever chemically cleaned for inspection / repair? Mixing up a large quantity of compounds similar to those in the consumer product "C-L-R" comes to mind but I'm not sure if it can damage the steel.

Steve

Have tried both dry ice and sponge blasting on passenger/head end car interiors (the latter performed by contractor). Neither is completely effective if the paint is well-adhered to a stiff substrate (works better on aluminum that flexes in the blast stream than steel that does not, for example). Also would not recommend dry ice blasting during hot and humid weather: it makes a nice artificial fog so you can't see what you're doing. Looked into soda blasting but concluded it was not abrasive enough for railroad paint applications (works great at auto body shops, though). Would like to try water blasting on the car exteriors (like Juniata Terminal does) but haven't been able to find a rentable rig or mobile contractor in our area.

Where damage to the substrate from blasting would be a problem (e.g., on stainless steel) there are some good chemical strippers that might suffice in place of abrasive blasting if you have patience and follow the directions (regarding recoating and "cooking" time) closely.

Steve, you answered your own question.
Shock chemical treatments are always bad-except when you really want to kill or destroy something, like in a swimming pool or cooling tower.
Much better, smarter and easier on the hardware to have a consistent and effective maintenance program. However, I'm seeing that up-to-date knowledge in the realm of boiler water chemistry is an extremely rare thing in this chooch hobby / biz. old wives tales, half-understanding half voodoo and inconsistency is more prevalent.
My profession is power plant water treatment and my new calling is to help improve that.

On CNR 6167, we used recycled glass (green blast) for sandblasting the boiler jacket, and soda around the running gear. We taped up the bearings and journals as best as we could to keep as much dirt out. Of course, when we went to move the locomotive, we had to pull all the driving box cellers out, which gave us the opportunity to clean out any sand that did make its way into the cellars.

Apparently we used 20,000 lbs of "Greenblast" and 1,000 lbs of soda.

Further more, I've been told how the group up in Capreol tried to use CO2 blasting, on the tender, and it just couldn't cut through all the old paint and rust and they ended up using regular sand.