Most of our uses of Corroseal so far have been on steel parts of wood cars. As the wood then needs to be primed anyway we would end up putting primer on top of the metal parts as well before painting.

The manufacturer claims that it functions as both rust converter and primer at once, and we've seen nothing to disprove that. It's dried/cured appearance is a smooth, firm surface, just like a coat of oil-base paint. We've had no issues with peeling paint, save for spots that were rusted through completely, and should have been cleaned and filled first (this was our error, not a fault of the product).

When coating our tender tank's interior the contractor applied their topcoat directly on top of it, without an additional intermediate layer. Upon reviewing my notes, I don't seem to have written down exactly what they used for a topcoat, but I will ask and find out.

Ah, unmasking the lettering. First, don't wait for the paint to cure completely, you need to unmask as soon as you are done painting the top color. Now this is a bit nerve-wraking, as you don't want to mar the fresh surface. It's been a while-- a long while! but as I recall, you do need a razor blade in hand. I recall using just a single-edge blade, although an exacto knife might be just as good, if not better. The first edge is always the hardest, and with removing masking it is always best to pull it over the edge so the making tape is cutting the paint for you (hmm, this is hard to explain, might be best to have a painter show you, but you pull the tape off at 90 degrees to the edge your are unmasking. And you keep a close eye on what is going on so you don't peel off the fresh paint.
It actually goes pretty fast, the masking material we used was really nice stuff, it came from a sign company. I remember that we had to do a little adaption as their font, although very close to the original WP font, had one or two letters that weren't quite the same, but we could "read" the original lettering through the original paint before we started sanding. The curve of the orange on the 805A was taken off one of the other F units (where you could still see the slight ridge of the original paint underneath the North Platte repaint on that unit as there curve didn't follow the original curve) as by the time I got to painting the 805A, its nose had been completely stripped. Someone found the factory masking for the wing, which made that part easier--that and photographic comparisons such as where the white stripe went through the nose louvers--all detective work. The 2001 took a lot of detective work for the tiger stripes. We were helped by one photo that showed where the crews had put the deck light cover on upside-down, so we could establish exactly where the stripe crossed that area. With that, and where it crossed the class lights and handrails established the angles for the stripes.

David -

That was a nice piece of luck! I once had a tour of the inside of the Cincinnati Union Terminal station head house and in one of the offices, the docent explained that they weren't sure what the original paint was on the walls. Then they moved a heavy wood storage cabinet and the wall behind it was decorated with the original paint and design which they then were able to replicate. Sometimes you just have to get lucky!

Les

Couple comments....

Rust converter: I’ve used both Corroseal and Ospho. Both work about the same - phosphoric acid and some kind of polymer sealer. Get all the loose rust off as best you can. A needle scaler would work in the nooks and crannies you can’t get to otherwise. Remove all the dust and crumbs with compressed air and tack cloths before you use this stuff. I’ve painted with sealer/primer + top coat over it with no problems (with automotive finishes).

Masking: My favorite is the low-tack masking that you can get from sign shops. For lettering, heralds, etc, I send vector PDF files and they us a CNC cutter same as for the vinyl appliqués except they’ll put on a backing sheet to make everything much easier to position. Depending what is peeled off the backing, the final mask is either positive or negative - whichever meets your process. Burnish the edges before you paint over the mask to prevent bleeding under the mask. Dental picks make great tools to snag the edges of the masking to peel it off either the backing or the car. Remove the mask before the paint starts to kick or you run the risk of either having ragged paint edges or semi-permanently adhering the mask edge to the car. Cutting the mask off with a razor blade is not something you want to do as you run the risk of cutting down to the metal and trust me, you will. Do experiment and practice this first with scraps of masking and rattle cans so you know what to expect.

Dental Picks!! YES! I should have thought of that. But you still sometimes need a razor blade to cut the paint film if you wait too long. Yes, the trick is to cut the paint film top color, but not go through the bottom (lettering ) color. One nice thing about trains is they are so large the it will be very rare for anyone to be that close to your painting edges to notice any small "oopsies" that would stand out on an automotive application.
I really don't recall any problems with the sign company made masking; it was really nice to use as you could tape it on the engine on its top edge and reposition until it was where you wanted it, then lift the sheet and take off the protective paper and ease it onto the surface.
What I do remember being tricky was the large WP logo decals on the sides of 2001. The trick to those was to tape it where you wanted it (from the top) then lift it up and soap the surface well and while it was still wet with soap, start pealing the protective paper off and squeegee the decal onto the surface, working the soapy water off as you went. Voila, no bubbles!! I know, it doesn't seem right, you'd think the soap would be an issue, but the decals are still there 20 years later! The first one I did, we didn't use the soap & water and we had little bubbles everywhere.

By the Way, those dents in the pilot on 805A still bother me. They were there when we got the unit, and I tried to knock them out with the few tools we had (and without unbolting them), but that metal is THICK and it just wouldn't budge with what I had on hand. I suspect taking them off and using a press would be the way to go about it. The guys there were wanting the engine finished for the big "Circle the Wagons" unveiling, and they didn't think it was important enough for me to spend any more time on it, so there they still are.
When I was posting about the painting process, I realized all the photos I've seen of the REAL railroad shops doing it, there is more than one person in the booth spraying. I didn't have that luxury, but looking back, it would sure make the job go easier, once the team gets used to working together. It is a ballet of sorts.

Yes, that is why I recommended the primer - the stuff has high solids and sands great (fast) with no clogging and you can go after it in hours. The primer is sealed by the paint and is not designed to resist weather. Safely tucked under good paint, it can last a very long time. Depends on the exposure. Yes, as long as thoroughly sanded which is the difference between it and some of the IMRON "wash and paint" products.

A lot of good advice here. Especially concerning safety and breathing equipment all urethane's contain isocyanate's so fresh air mask should be worn at all times along with other protective equipment.. I worked in industrial coatings for 30 years now and I've also sold New York City subway anti-graffiti paint for 30 years. Fortunately we've never had anyone become ill using these products. I don't know what Imron is going for these days but I imagine it's quite expensive. When doing equipment outdoors the preferred coating system is two coats of the moisture cured aluminum pigmented permanent rust sealer which is surface tolerant in other words it'll seal the rust. The topcoat is a polyester two component finish coat that is an anti-graffiti coating. This system was developed for bridges where sandblasting was prohibited by law due to lead paint hazards. The topcoat AG 111 was specifically designed for the New York City subway system in the late 70s. This system is a documented service life of over 15 years outdoors with less than 5% corrosion. If you would it take two coats of epoxy primer a couple of codes Imron it would do approximately 500 to 1000 hours of salt spray compared to 14,000 hours salt spray with the three coat polyurethane system. The Illinois railroad museum is doing a car like this now.

[attachment=1]railroad roof.JPG[/attachment] This car was sandblasted prior to priming

Pat - Can the AG-111 topcoat be custom color matched? Most RR colors are very specific and definitely not off the shelf colors except for maybe black and white.

When it comes time for painting our crane, your stuff is in the mix for consideration for the main black body color. So the next question is.... Is it compatible with other coatings since I’ll need a very specific color for lettering?

Anyone here have firsthand experience with the modern generation of polysiloxane topcoatings? Seems to me those would be ideal for many 'preservation' applications.

Jayrod They can mix specific colors if you provide a swatch for starters. I will get more information about more specific colors for your applications. AG 111 is available in a clearcoat to go over existing paints. You can use any type of paint over the Mastercoat permanent rust sealer primer surfacer.You can letter over the AG 111 but it should be done the following day no later than six days to ensure your lettering paints adhesion I will post more information in the coming week about colors.Thank you for your patience stay ,safe stay healthy.

I hear the desire for a quality paint like IMRON. My own target when painting is "I never want to paint this thing again" :)

And I gather you're saying Imron because it's pretty much the household name in advanced paints.

The original famous Imron was an aromatic urethane and it's been largely surpassed. However Dow has morphed Imron into a brand name for a bunch of stuff.

But the upshot is you should be looking at a bunch of products from a variety of crafts.

VOC is a big issue

And a reason to look widely is government regulation on VOCs. Removing VOCs forces quality compromises in paint. And with VOC rules, they went after the "low hanging fruit" very aggressively, and left other areas nearly alone.

Take autopaint. It's the #2 type of paint application after architectural paint, and more worrisome, auto body shops aren't in industrial parks but nestled in neighborhoods often within 500' of homes. So VOC's have been regulated down to almost nothing. This has forced autopaint into waterborne formulas that simply don't behave like normal paint, and require exceptional skill, care and hygiene to apply successfully.

By contrast, marine paint is relatively untouched by the regulations, since it's a very small niche. There's another bonus in marine paint. You can't put a ship in a paint booth. And you often have to paint "haze gray while underway" where it's impossible to cordon off a huge section of the ship for overspray control. So they make marine paints dual-formulated either for spray, or for brush/roller application.

Marine and some of the other niche paints are allowed 720 grams/litre of VOC... but then, VOCs typically weigh about 900 grams/litre, so they're basically allowing most of the paint to be solvent.

The dangerous part is overspray

Paint is made out of three major parts: the solids, the liquid resin which turns solid when it cures, and the solvents which will evaporate. Of course we know the solvents are stinky and have their health impacts. The solids are where the lead used to be, but that's largely been cleaned up.

You'd think the resin couldn't be too dangerous because it remains on the wall, but 2-part paints are special -- they take an A and B part resin, which chemically transforms into C - a solid. Only C has to be non-toxic. A and B have no such restrictions.

And on these 2-part paints, the B-parts are made of either BPA or di-isocyanate, which do severe damage to your immune system. Skin is a reasonably good barrier (though you shouldn't make a habit out of "testing" that). However, the danger is when it coats the lungs, which it will do when you inhale the extremely fine mist of overspray.

That is why you need ideally SCBA or supplied air; however a very good particulate filter will do. The goal isn't to react/reduce the fumes, it's to keep the atomized resin out of your airway.

You must also keep a very large cordoned area - you can't have people inside the building (if you have one) and for hundreds of feet around the spray area.

And this is the advantage to brushable formulas. The very dangerous resin stays on the brush or roller (unless you are very fervent). So the safety gear required is simply gloves and long sleeve shirts, and don't touch your face. Certainly makes it a lot easier to paint safely outdoors.

Haven’t used them. Checking these out in detail is on my to-do list for when paint time comes. I’m going by memory, which is sorta suspect in my case, but it seems to me that Polysiloxanes generally come in epoxy or acrylic hybrids. Both are very long lasting coatings and aren’t an extreme health hazard to apply. Last I checked, some are available in a range of colors. Don’t know about custom colors yet. They can be applied by spray, roll or brush which is a plus. If I recall, price may be a drawback - something like $250+ per gallon? To get the proper film thickness, a gallon didn’t go very far as I recall. I’d also be interested to know if anyone has tried them.

Strasburg paints their locomotives with Imron, though they brush half of it.