Powder Coating Cast engines

Hi Ed, you must have been reading my mind. I often thought about this same subject, but not too sure how thick the actual coating would be and how much detail would be lost under it. It look's beautiful on auto parts, but that's better left to another style forum. Bill

Process works better on thicker coatings.  Techniques used to do thin films is as or more expensive than traditional painting.   The curing temp is well below that of the melting point of zamak so that isn't an issue.  You can use a commercial oven ( and some computer hardware hackers do) to trick out their custom built equipment (I don't think I'd want to eat anything that cameout of their kitchens.)

Regarding the heat.  The instructions for the one i was looking at said to pre-heat the oven to 300-500 degrees.  That is a very large variation.  I do not know the reasoning for higher vs lower temperatures.  Is is the thickness of the desired coating, size of object, etc.

i am really going to be doing  this to restore some very old Tonka trucks for my grandson.  I just got to wondering about how this would work on some old lionels I have.

thanks,

Ed

Try Scale Coat, baked at about 190 degrees for an hour.  You will find it fairly scratch- resistant, and a whole lot cheaper than powder coat.

Opinion.

Ed, I have also thought about that. 

I do a lot of powder coating using the Eastwood system for large objects and the fluid dam system for small objects.  Most of my coating are done on fishing lures from as small as 1/2" in length to 12" saltwater lures.  The coating are extremely durable but to coat a cast loco shell I'm afraid you'd loose any casting detail.  Any way the Eastwood system would be used.  Here's a PDF on how to use this system.

  http://www.eastwood.com/images/pdf/10198Q.pdf

I agree on the loss of details, We have many enclosures Power Coated at work.

Thickness runs average 0.005" on the flat but it fills in angles and corners much thicker. That's your details being blobbed right there.

Check this out, might be worth a try. I have used it before, but not on trains.

http://duracoat-firearm-finishes.com/

Seems like loss of details is a problem.  I know nothing about powder coating but I was wondering if you can dictate the thickness of the coat?  Is that why there are different numbered nozzles

I was also thinking about some of the PW accessories.  I have colected a number of them over the years.  Most of them have some rust for cracking paint on the.  I am thinking that most of those parts have little or no detail per say So they ought to be a good candidate for powder coating.  

Admiddedly simply stripping and painting diecast shells is probably simpler.  I just though it might be fun to experiment with train items since I already will  be doing toy trucks.  I don't biy or restore trains for their collectible value.  I rum them and I like them looking sharp. I would imagine  trying to color match powder coat to the old colors would be a challenge.

Re: using scalecoat.  What is the purpose of heating the paint after its sprayed on?  I know with powder coat the heat melts the paint particles together.  

I also admit my desire to try this is more curiosity and to learn something new.  I think 

i need to find a junker and  give this a try after I finish the trucks.

Thanks to all for the interesting feedback.

Ed

Heat variations are from the different binder platics used.  The guncoating product doesn't "need" heat but can take weeks to cure at room temperatures.  Not sure how well these products would react to different base metals, aka zamac casting with brass or aluminumum detail parts especially if those were "glued" on and might not do well with the electrostatic applicator.

enamel paints take a long time to cure at room temp.  Dry to the touch is not want you really want.  Baking the paint drives off any solvents trapped in the paint and cures the actual binder.

I think the problem would be that the electrostatic charge flows across sharp inside corners. The plastic dust would not get into inside corners and around fine detail, leaving these areas uncoated.  It would be interesting if someone had a junker to try it on and see how it came out. I have seen some post war steam locos repainted with an air brush after proper prep and it comes out very nice.  Better than the original Lionel paint, which must have been fairly thick. 

My son bought a 671 steam turbine that had been in a flood. The inside was caked solid with mud. We soaked it in water to loosen up the mud and cleaned it up.

Everything worked after this but the shell was badly pitted. My son sand blasted the shell and it sat for awhile. One of my students who worked for his grandfather asked me if I had anything that I wanted powder coated. He said that his grandfather had just bought powder coating equipment and he was trying to learn to use it but the only color that he had was black. I gave him the 671 shell and it came back looking real good. The rivit detail looks good and most of the pitting was filled in. I will try to take some pictures tomorrow in the sunlight and post them here. Taking pictures of something that is black at night doesn't work to well.

PW castings aren't as elaborate as what we've come to expect on modern trains so these might be good candidates for powder coating.  

BTW, the "pitting" on the 671 shell was probably there all along and was one of the reasons for the extremely heavy coating on the original paint job.

This is a good idea but on balance it seems like the benefits would not outweigh the problems.  The loss of detail on detailed castings (modern high end locos) is a real concern.  On older (pre-war, postwar) stuff there isn't much detail to lose, maybe, but then the powder coating would make it very non-original. 

I've had good enough luck with repainting that for me "nothing is broken" to fix.  Despite that it is an interesting idea and I hope someone pursuses it just because it would be a fun project with a lot to learn - and then posts a tutorial or meaty thread with details here.

As Chuck said, different temperatures are required for different resins. All coatings need cure time at cure temperature, for instance 20 minutes at 350°. Some resins crosslink at lower temps, some higher. The actual part has to obtain that parameter - a casting can take much longer to reach the required temp. Undercured coatings will be shiny, chip easily, and have very little chemical resistance. The good news is, you can pop them back in the oven.

As Dave said, the coating will be thinner in the inside corners and heavier on the outside corners. A lot of that depends on the average particle size of the powder used. On a smooth surface, any dirt in the powder will show up as a bump. And don't use anything silicone on or around the part, makes for tons of fisheyes.

Color control is tough without good oven control; too high of a temp will make colors shift to yellower hues, red turns orange, blue turns green, white turns yellow, etc. That makes a good arguement for using black!

Powdercoating a boiler casting could be a challenging project, but may not be worth the expense.

One other thing - to remove a bad powder coating, you would need to sandblast the whole casting. Or, you could bake off the coating in an oven - 800° being required. The melting point of zinc diecasting is ~750° so the coating will disappear just after the casting disappears...

Love the results from the powder coating process. All of the railings on my boat are powder coated and after nine years, they still look like new. Very hard and durable on stainless steel. Interesting thought.

As GWT noted once the powder is applied you're really stuck with the finish.  If you just want to play around with it and have the extra $ laying around  for the equipment go for it.

Besides inside corners, powder coating won't go into small openings like smokestacks, window frames, coupler pockets, or water tube pilots.

While it might stand up to normal handling better than conventional paint, if you drop it or run it into something hard it will still chip. 

Pete

Here are photos of a 671 that has been powder coated. The details still show although on a highly detailed model they would not. The finish is very glossy, more glossy than I remember original Lionel paint.