I have a rusty railroad signal that I need to preserve. Because of the signal's size (27 feet tall), I will not transport it anywhere for media blasting. My plan, therefore, is to use a rust inhibitor on the steel after first removing surface rust with a wire wheel, scraper, and sand paper.

Twenty-plus years ago, I restored a 15' high, 1915 block signal that way using Rustmort. It worked well. However, about 15 years later, rust bloomed in a few places that were deeply pitted, that I could not reach with my wire wheel during the surface preparation. I guess that's inevitable, though.

For my next signal project, I am trying to decide if I should use Rustmort again, or another rust inhibitor, like Corroseal. I watched the Corroseal application videos last night to learn more about the product: (Link to Corroseal Educational Videos). I used a similar product when I worked as a merchant mariner years ago that was water-based. It left a kind of "latex" coating afterwards the same way Corroseal does, so I think I am familiar with it. As I recall, being a water-based product, it also did not burn the skin, eyes, and lungs the way Rustmort does, which is good.

My question is, can anyone recommend a rust inhibitor product that they feel worked particularly well for them?

Thank you.

After spending the better part of a year consulting this board, museums, and auto/boat restorers, the Alexander Chapter-NRHS decided on POR-15. It ain't cheap at nearly $150/gallon, but it is readily available at about any auto paint shop.

http://www.por15.com/

The stuff brushes on very smoothly and dries rock hard. Part of its claim to fame is that the POR-15 chemically bonds to the ferrous oxide and converts it to the airtight protective coating.

Here are some photos of our first project using this product:

http://www.tarheelpress.com/LawndaleBox ... xcar2.html

Plan on using it ONCE, as it dries so hard the lid on the can are nearly impossible to open!

After it dries, lightly sand the surface to "scratch" it up and coat with the latex or oil based paint of your choice.

Matt Bumgarner
Alexander Chapter-NRHS

Nothing beats Rustolium rusty metal primer for the price.

Thank you very much, Matt. You've helped me a lot. I'm willing to spend some money to preserve this signal for the next generation to enjoy, so this product sounds good. I'll look into it.

OSPHO may not be water based, but comes in recappable bottles and does the same thing. Wear rubber gloves.

dave

How do you get 40 years of performance from consumer-level products? Paint it four times! LOL!

A consumer wanting quality has a real dilemma. Consumer vendors are marketing at you, saturating you with information about what they DO sell, so you won't think about what they DON'T sell. Fact is, the best technologies are not sold in consumer channels. You're willing to spend the money, but the marketing teams have decided the best technologies are too expensive, too hazardous or too complex to justify marketing them to consumers. So you can't walk into Tractor Supply and buy a Variprime or Imron work-alike. They think you'd mess up the mixing proportions, or let your kid watch while you spray it.

Throwing money at the quality problem doesn't work. The marketers are onto that one. They will sell you the same dreck warmed over for twice the price. "You want better than hamburger? No problem sir, we have a lovely ground-round steak!" If you don't know why the chemistry is better, then it's not. If they won't talk about the chemistry, then it's not.

As for rust converter, they come in two kinds. 1. plain old phosphoric acid with somebody's fancy label to try to flim-flam you into thinking it's magic sauce and not just phosphoric acid. 2. Same or other acid mixed with some crud so you get a latex-y kind of thing on top of the converted rust, this is about convenience not performance - avoid. And part of the motivation there may be to avoid the tedious washdown to keep the acid from contaminating the primer. Again the marketers want you thinking about ease of use so you'll reach for it next time.

I would also suggest spot sandblasting for areas you know will be trouble down the road, any cheap sandblaster will do, here's a handy one
http://www.amazon.com/Campbell-Hausfeld ... B0000DD1C4

My choice from there would be a 2-part polyamine epoxy metal primer, cheaper than the POR-15. Then a 2-pack polyurethane topcoat. Sherwin Williams has some of that stuff, though not the highest quality.

I purchased a 2 gallon sample of Amerlock 400 which is a PPG product. It is claimed to be suitable for coating over tightly adhering rust and old paint and is self priming. It smelled of PVC plastic when wet and dried into a hard coating that my fingernail cannot scratch. Roughly $100/gallon, and if the test application holds up over the winter we may decide to use this coating for painting our structures. We have more outdoor steel to take care of than probably every rail museum put together, so we need a good quality coating that doesn't necessarily need an SP-10 sandblast beforehand and will last a long time.

Anyone else have experience with this product?


Carrie Furnaces National Historic Landmark

POR15 has a cyanic base somewhat like superglue, this is why it is almost impossible to get off of your fingers and the lid of the can becomes one with the can after you reseal it. The product works as well as the next except for it doesn't like UV or the sun. It will go away fast when exposed to the sun. POR15 needs a top coat of some compatible paint or perhaps the POR people sell a top coat for their product.

Primer based on superglue? Sure, why not. We have primers based on epoxy, and topcoats based on surfboard polyurethanes (think: Clark Foam).


That is very common. Any epoxy product is also vulnerable like that, as epoxy doesn't have any UV resistance, and all the best primers are 2-part epoxy (as is Amerlock 400, apparently, from my 1-minute research into its chemistry.)

The real trick is - what to topcoat it with? And how durable is that topcoat? As you say your primer doesn't stand a chance when the topcoat fails.

Heavy scale can frequently be easily removed by heating the area with an acetylene torch.
The moisture contained in the scale will expand and cause the scale to pop. This is quite effective if you don't have a lot to do as the fuel gas has gotten a little pricey. The rust pops off with considerable velocity sometimes, eye protection is a must as is appropriate clothing to protect you from flying scale.
Fred Jordan

Thanks to all who replied. I have a plan now for how to preserve the rusty signal.

1) Use a small sandblaster as Robert suggested for the deeply pitted, obnoxiously embedded rust. Sand and wire-wheel other areas.

2) After cleaning the metal, apply the following primer that I purchased from the ship supply store: "6980 Rustlok Steel Primer" by Pettit Marine Paint. Product description says:

"Pettit 6980 Rustlok Steel Primer is a one package moisture cured
polyurethane coating designed for application over any steel or
cast iron surface, including galvanized and stainless steel. Rustlok
Steel Primer contains aluminum flake pigment which forms a
dense, water impervious barrier. The result is excellent corrosion
protection. In addition, Rustloks polyurethane chemistry offers
tremendous adhesive strength and wetting ability. It is this combination
that allows Rustlok to perform well even when applied over
rusted surfaces. Rustlok Steel Primer is recommended anytime an
easy to apply, effective anti-corrosive barrier coat is desired."

Something I noted in the application instructions is that additional coats should be added while the previous coat is still tacky, otherwise thorough sanding is required to roughen the surface between coats. (Always read the directions!)

3) A compatible top coat of the same brand -- they offer several options.

Hi Flo
I'm late to your posting, however I want to add that I have been using Rustmort for 15 years and have have nothing but success with the product .

#1 cheap= $15.00 Qt. A qt. goes a long way
#2 easy of appliacation =59cent paint brush or a rag after a putty knife or a wire brush.
#3 24hr waiting time
#4 water rinse and air dry, or heat gun if your in a rush.

I used Rustmort on 24 steel doors 15 years ago and then painted them with latex paint. as of yesterday There was no sign of rust.

Dave Wolven

Sorry, but Rustoleum is the last thing I want on any of my rail equipment. It is incompatable with most of the high quality top coats.
Not saying it isn't OK for metal lawn furniture, but as the label says use with or Rustoleum products. And no Rustoleum product will keep a shine like professional automotive paints (Dupont / PPG etc.)

Shiny is not generally historically correct unless you are limiting yourself to interpreting "like new" condition. I've seen very natural and attractive restorations using matte finish paints - the decapod at Spencer comes to mind.

dave

Paint applied by the diesel locomotive builders was from the same line used for automobiles - it DID shine. Matte was only the result of dirt grime or age - same with cars.
I have painted several locomotives - I do not weather them - a modeler can do that with their models.