Painting tinplate

If the original paint is adhering to the metal, then it should act as a good base for the new paint. Make sure the new paint does not react with the old paint and cause it to lift.

Most likely needs some tooth to stick. Liquid sandpaper will work well.

RoyBoy posted:

If the original paint is adhering to the metal, then it should act as a good base for the new paint. Make sure the new paint does not react with the old paint and cause it to lift.

Thanks.  I am thinking about painting a new MTH car over for a custom job.

I guess if the paint lifts, I will need to strip it. 

OK, I see there is something called Klean-Strip Easy Liquid Sandpaper that deglosses surfaces.  I could do this, but would like to know if anyone has done what I am attempting without using this step.

Why would you eliminate a step, to end up with a crappy job.  If you want it to look right, and expect it to last, then you do ALL the prep work before painting, to ensure a good lasting finish.  There is no reason to side step a prep stage, before painting a finish you want to be proud of.

TeleDoc posted:

Why would you eliminate a step, to end up with a crappy job.  If you want it to look right, and expect it to last, then you do ALL the prep work before painting, to ensure a good lasting finish.  There is no reason to side step a prep stage, before painting a finish you want to be proud of.

To be clear, are you recommending stripping completely or prepping with liquid sandpaper?

Not looking for a crappy finish.  Just trying to understand if the base paint job will work as the primer coat.  Why should I remove it only to reapply a primer?  If the new paint won't adhere, then I need to remove it or otherwise prep it with the liquid sandpaper.  However, if it is new and clean and the paint will adhere, why should I waste my time.  

I have usually had to clean strip and repaint, because the original paint was badly damaged.  This is the first one I am doing where it is new.

Paint just needs something to grab on to, doesn't matter what the surface. Bare metal needs a light scuff of fine sandpaper for the paint to properly adhere.

In this case, the paint will bond to the MTH paint as long as the surface has been scuffed. Either a liquid sandpaper or just a quick wet sand with fine sandpaper will do the job. If you do not treat the surface to be painted, your paint job will suffer.

Thank you all.  This is helpful. I know what to do now.

Sorry to chime in on this, If the car/engine is already painted and you wanted to paint top of that detail of the piece may be lost or not as sharp (thickness of paint). Even with the Rustoleum 2X paint I still use their primers.
I never painted over an existing paint.
Always stripped and used the metal etching primer (all my paint jobs are on old beat up prewar cars/engines).

You can try it your way and if it does not work out, then strip it and repaint.

Just a note of caution, make sure the paint in between coats are completely dry, if not and you cleared a piece for the finish coat your paint may wrinkle (crustoleum paint job). This happened to me with clear over black, trying to put clear on buffed flag stations on a 248 engine.
Just have fun and learn/be patient. 

Thanks RonH.  I have some time before I start this, so all replies are welcome.  I just ordered the car.  I guess if I needed to use the liquid sandpaper anyway, the stripping is not that much more effort.  

I use a paint oven that I made out of an old subwoofer speaker.  It worked pretty well on my last job, the 218.  I only bake the primer with one bulb, as the can says not to spray in high heat.  I used the second bulb to bake the finish coat and it came out really hard and smooth.

George

For painting, prep is always way more important than the actual painting.

Stripping the paint is a tremendous amount of effort compared to treating the existing paint with liquid sandpaper.

Paint sticks to paint as long as they are chemically compatible and you give the under coat of paint some "tooth". Well, there are exceptions... A latex house paint won't stick well to auto enamel and some other examples, but if you stay within the enamel or synthetic enamel range (i.e. most spray paints) they will stick to each other.

In my opinion, deglossing the MTH paint with Liquid sander and maybe hand sanding some areas will be enough prep for a new coat of paint to adhere. Be sure to clean any dust off and do not introduce any water. Do not wash with water unless you can get the car completely dry (i.e. baked).

And as I always suggest, try using better quality spray paint than Krylon or Rustoleum. Both have a huge amount of plastic and dryers in them to make the paint more user friendly, with the trade off being a less durable finish. And thicker as RonH found out. Try automotive touch up paints like Duplicolor.

Painting a tinplate toy train is just like painting a car, just on a smaller scale.

Good luck.

I'm just curious how much success you guys have had copying the sheen, the overall look, searching for the right word.  The awesome semi shiny finish that prewar standard gauge train cars have that must be so hard to duplicate.  I have one terra cotta color 515 tank car that is a restore, and though it's a great color, in perfect shape with trim and all, but it just doesn't have that sparkle.  Is that why you bake it?  Still a rookie here, probably will be for a while.  Cheers!

William,

I painted this one several years ago with a Train Paint Enamel that I think I got from George Tebolt to match the original.  I did not bake it, but it was warm in my garage in the Summer.

It is one of my shiniest cars.

This one I just did with Rustoleum enamel in a can.  I had to thin it with mineral spirits to run through my paint brush.  I put it on a little thick and baked it.  I had some areas that 'pooled' a little, but I left them, because I thought it looked 'dipped'.  It is a very shiny and hard finish.

For reference, this is my finest original, untouched car (I think and hope, because I paid a museum price for it).

P.S. I can't seem to get a good picture of the dump car.  It looks much better in real life.  I think it is the recesses and rivets casting some shadows.  When I use a flash, it changes the color.

I tried the deglosser, but it didn't seem to take any gloss off.  Maybe I didn't use it right, but I thought if I wiped it for a bit it would dull the paint. It didn't. Maybe the MTH paint is too hard or the deglosser I bought is not strong enough.  Anyway, I am stripping it.  My spray on stripper seems to work.  

Weird, I am seeing pink run off, but the paint is a dark gray green?  There must be some type of top coat; maybe a poly.  Maybe that is why the deglosser didn't work.

Wow, my stripper is struggling on this MTH tinplate.  I have some bare metal, but other parts are shiny new.  I am going to take my steel brush Dremel to it next.  I just washed it and am baking it in my paint oven.

Be careful, if the car has print or logo's stamped or silk screened they might show through your new paint job...At the very least I would sand the lettering smooth.

gene maag posted:

Be careful, if the car has print or logo's stamped or silk screened they might show through your new paint job...At the very least I would sand the lettering smooth.

Very good point.  When I got the car, I could feel the raised area of the silk screening.  This is not lithography.  There was really no way to use liquid sandpaper and the car had to be stripped.  Even then, the MTH paint is so hard!  I got the silk screening off with scraping and the Dremel steel brush tool.  I cannot get all of the paint off though.  My Dremel is getting too hot!

I am priming what I have tonight to see how it turns out.  The back will not need to be primed.  The base paint has some tooth in the finish and is hard on the metal.  Will update everyone with results...

I got the car down to bare metal.  It required scraping.  I messed up the first coat because I didn't wash it with soap and water.  I stripped it and started over.  Now, I am having some trouble with the top coat running.  I didn't think I was putting it on that thick.  Maybe I was holding the can too close...

Question is, can I sand these areas and apply a second coat or am I doomed to start over?

Thanks,

George

George S posted:

I got the car down to bare metal.  It required scraping.  I messed up the first coat because I didn't wash it with soap and water.  I stripped it and started over.  Now, I am having some trouble with the top coat running.  I didn't think I was putting it on that thick.  Maybe I was holding the can too close...

Question is, can I sand these areas and apply a second coat or am I doomed to start over?

Thanks,

George

Depends on how bad the runs are and how thick the paint is. A few light runs can be sanded off; if the paint is thick and the runs are heavy, better to start over. With glossy paint in spray cans, it's always a struggle to prevent runs. You need to hold the can a foot or so away from the workpiece and keep it in constant motion. Keep the coat thin - you are better off with several thin coats than trying to do the whole job with one coat. You'll have to experiment with how far away to hold the spray can - every nozzle is a little different and it also depends on temperature and humidity. 

Thank you.  I thought the spray can would be easier, but maybe I should have set up my Floquil and bought the paint in a can...