clear coat-seal for rusted metal???

[wagin]

I'm currently doing a ornamental cladding job for a client. The work is going into a turn of the century factory building converted into lofts/condos. I aged the steel being added to a nice surface rust. Know I need to seal the metal. The client does not want a gloss clear coat and wants the rough texture( feel) to remain. I have used clear enamels and lacquer on past projects, but both gloss over. Any one know of a sealer that works while having minimum distortion to finish? I will post pics tomorrow.

[Rick V]

Hi Wagin, this is the toughest clear coat stufff I have used.

It's water based and dries clear.
Larger hardware stores and Home Depot usually carry it.
Whether it is available in a semi-gloss, I don't know.

[Supe]

It's going to be a crap shoot either way. Two problems - 1) if the chemicals used to rust the material is not neutralized completely, it will out-gas and cause the clear to blister/fall off. 2) a clear still needs some sort of substrate to bond to, rust not being ideal. The way to cheat this would be to put a ton of something like a polyurethane clear to "bridge" over the rust, but you will start to lose your texture, and it will probably start to degrade the appearance. If you do try a clear, you may want to add a retarder to it to give it time to "saturate" the rust.

Unfortunately, this is a common problem in the sculpture world, and the reason why the people who are really concerned with keeping a long-lasting rusted finish without corroding too heavily are forced to go to something like an A588/Cor-Ten weathering steel.

[bert the welder]

Originally Posted by Rick V

Hi Wagin, this is the toughest clear coat stufff I have used.
Attachment 53713
It's water based and dries clear.
Larger hardware stores and Home Depot usually carry it.
Whether it is available in a semi-gloss, I don't know.

you don't find water based finishes cause rusting under the coating???
I do allot of custom rusting in my work. On lightly rusted stuff, I get it clear powder coated. Gloss, but I used to get a "satin" one too, but used up what they had. The company rep couldn't believe that we where coating rusty stuff. But it's not heavy rust and I do more then just let it rust away to get the finish. Your rust needs may be too heavy for PC.

[wagin]

Thanks for all the great info.
What I've done is scuff the mill scale, soak with water( a few rainy days works best), allow to rust a few days then clean the metal with mild soap and then windex. I tried acids, salt brine, etc...Old fashion rain seem to provide the best, most consistent rusty finish.

[Bob]

Distilled water works equally well.

[wagin]

I discovered some new chemistry, new to me any way. From my recent experimentations in aging-rusting metal, I had a container filled with lemon juice. I dropped a galvanized bolt into the lemon juice and the fun began. Bubbles, mild smoke and some noticeable heat in the bolt. A cool reaction. After a few minutes the once silver-gray finish on the bolt turned to a dark gray, almost flat black. The fumes/smoke concerned me a little. Does anyone know the specs. of this reaction? By-products, etc...

Wes

[Rick V]

At a guess I'd say the lemon juice contained citric acid.
Galvanized means a zinc coating.
Citric acid + zinc = zinc citrate + hydrogen gas

[wagin]

So with a few hundred gallons of lemon juice and several tons of galvanized bolts I could generate enough hydrogen gas to run my car for a few days? Of course the required mods would have to be made to fuel system prior. Any way cool fact.

[Supe]

Not sure you could run your car, but you could sure blow up your garage trying!

[rookie_steve]

Originally Posted by wagin

So with a few hundred gallons of lemon juice and several tons of galvanized bolts I could generate enough hydrogen gas to run my car for a few days? Of course the required mods would have to be made to fuel system prior. Any way cool fact.

It would be cheaper to just use the old electrolysis rust removal method if you want to make hydrogen. But not safer. Fire and explosion are quite possible. A lot people know about it but are usually wise enough to leave it alone, or the others are dead maybe. I guess they call that "social evolution," the stupid die.

From my own experiments with it, I am guessing that it takes more money in electricity to make a small amount of hydrogen. I don't think it is a viable method of creating cheap energy.

Steve

[MoonRise]

wagin,

As mentioned, acid + galv = hydrogen gas and no more galv.

And as rookie_steve mentioned, you use more energy (electrical) to split the water into hydrogen and oxygen than you get by burning the hydrogen and oxygen and turning them back into water+heat(energy). You end up with a net energy loss. And that doesn't even take into account all the process inefficiencies involved! Even in a best-case no process inefficiencies scenario, it -still- takes more energy to electrolysize water into hydrogen and oxygen than you get from turning hydrogen and oxygen into water and heat/energy. But that doesn't seem to stop Democrats and other weak-minded folks from thinking that using electricity to split water into hydrogen is some sort of magic cure-all for energy woes.

Back to the original question.

Most of the time, coatings are made to film over and smooth out. In this case, you want something that does not smooth out. Tough call.

Depending on how much protection you are needing for the pieces will determine how tough and durable a coating you need. Just remember, from back when you first asked your question on how to rust steel, I think I mentioned that given atmospheric moisture the rust would tend to continue. It is sort of a self-perpetuating reaction. That said, maybe a hot wax coating or a hot clear plastic (aka powder coat) could work for you if you first do a thin coat to seal and penetrate the surface rust and pits, and then 'glop' on another coat or more to put some roughness back onto the surface.

Either that, or with a paint/varnish/lacquer coating, put on thin thinned coats either spray or brush or dip/dunk to get the sealing of the surface, and then do a 'poor' top coat with orange peel and 'dry spray' and overspray and pretty much all the stuff you never want to get in a sprayed on finish in order to get some roughness and glop.

[wagin]

At my previous employment, where i worked for 14 yrs until they down sized to mex....,a group of techs. researched and proto typed many hydrogen generator cells. A few were installed into the fuel system of various vehicles. The "lab work" was going fine until the day one tech decided to bubble off hydrogen, capture it in a windex bottle and guess what...fired it off to see if would blow. It did! he lost hearing for 3 days. That ended the R&D dpt.

[rookie_steve]

Originally Posted by wagin

. . . he lost hearing for 3 days. That ended the R&D dpt.

I would say he was lucky!

Thanks Moonrise, for the excellent scientific explanation.

Steve

[Dualie]

The only way hydrogen fuel would even remotely make sense in the least, is if it was generated using nuclear power. PERIOD.

[SuperArc]

Originally Posted by Supe

Not sure you could run your car, but you could sure blow up your garage trying!

Negative... I own a large electroplating shop here in the west coast. We use both Nitric acid and hydrochloric acid to strip zinc (and other metals) off of parts. Using citric acid on nuts and bolts isn't going to blow up the garage.

[rookie_steve]

Originally Posted by Dualie

The only way hydrogen fuel would even remotely make sense in the least, is if it was generated using nuclear power. PERIOD.

Even the product of nuclear power is subject to the current market rates of electricity prices. However, if many more plants were built then electricity prices would no doubt fall, THEN possibly making it a viable option.

But the same environmentalists wanting hydrogen power are likely to block such a possibility from ever happening.

Steve

[rookie_steve]

Originally Posted by Rick V

At a guess I'd say the lemon juice contained citric acid.
Galvanized means a zinc coating.
Citric acid + zinc = zinc citrate + hydrogen gas

Originally Posted by SuperArc

Negative... I own a large electroplating shop here in the west coast. We use both Nitric acid and hydrochloric acid to strip zinc (and other metals) off of parts. Using citric acid on nuts and bolts isn't going to blow up the garage.

I'm no expert but it appears like you missed reading "Rick V's" prior post about creating hydrogen gas from the citric acid and galvanized stuff. If what Rick V says is true then it will create hydrogen gas and possible explosion.

Steve