How to fix soft enamel paint?

[Squirrel Murphy]

Hi all. New here and coming with a little problem. 

I painted a box last August with a Krylon-like generic rattle-can from Lowes and then clear-coated with automotive enamel. It remained soft so I was gentle with it figuring it would dry in a matter of weeks. I didn't know about baking at the time. Well it got a little dented -- it easily indents (not so much scratches). A year later and it's still soft. There's one or two indents that are noticeable (on the top!) but otherwise it's really not very bad. I want to add waterslide art now, so I need to fix this.

Can I respray with enamel and then bake? Will the new spray fill in the indents seamlessly? Or I guess I could sand down the enamel, respray, and bake.

If I spray lacquer over it, I think it may bubble. And if it doesn't bubble, will the lacquer level into the indents and make it seamless?

Last option, I guess, is to sand back to the paint and then shoot clear lacquer over it.

For what it's worth, I ran out of the clear enamel but I have a new can of clear lacquer. So yeah... I'd prefer to do something with the lacquer.

Thanks for your guidance.

[John Lyons]

If it's soft after a year I don't think there is any hope to bake or re coat the paint.
Baking just speeds the curing time. It does not affect the hardness of the paint once cured. 

[R.G.]

I agree with John. Remove it and repaint.

Some generic spray-can enamels contain a lot of plasticisers to deliberately stay flexible, as the uneducated painter might like this better. It's easy for these to never harden completely.

Lacquer over enamel is always a bad idea, as the solvent in the lacquer attacks most enamels. Use lacquer to start with if you're going to clear coat with lacquer.

Paint remover might be easier than sanding. Actually, lacquer thinner will do a bang up job removing enamels in most cases.

[Lizard King]

Are all "shaker" cans 'o paint crap?  What do you paint boxes with?

Thanks.

[davent]

When using rattle cans probably best to stay within a brand for the various paint elements, primer/paint/clear. I get good results with an airbrush spraying artists acrylics (multiple brands) for colour and waterborne lacquer for clear. No noxious fumes and stink.

dave

[Squirrel Murphy]

Some generic spray-can enamels contain a lot of plasticisers to deliberately stay flexible, as the uneducated painter might like this better. It's easy for these to never harden completely.

That's gotta be it. For what's worth, the clear is whatever Autozone sells in their touch-up department (I don't remember the brand now). It's the clear that's soft from what I can tell.

Thanks for the input gentlemen. I'll give a re-work a whirl and report-back if I learn anything that might help anyone. The color itself is spanking nice gloss orange, so I'm going to see if I can just rip the clear off. Fat chance, but I'll try anyway.

[toneman]

if the clear was a urathane, it probably quick-dried before the enamel below did.

sound like the base enamel never really cured (complete evaporation of the VOCs in the paint leaving only the pigment).

when you start to sand it off, if the paint clogs the sandpaper, it's still not dry.

maybe you can remove it with paint remover or, in the case of some model paints: automotive brake fluid.

(assuming you have a metal case)

U can buy automotive acrylic paint and lacquer paint in spray cans (12oz).

They are custom-mixed car colors and Are put in a pressurized spray can.

Jerry's paint and supply does it near me.

Usually used for touch up.

good luck with your project!!!

[Roger Martin]

Way too many misleading tips of how to paint an aluminium box.     
Especially...baking it ? Hahaha you mean like baking a bread dough ?
For sure...the paint will be boiling hot and form ugly micro bubles if you dont know when to stop and get it out.
In your case, remove the paint using acetone or thinner and repaint it again.
Forget it, it can go soft forever and ages.
Repaint it.....this time make sure you do these :
1. Spray or paint thinly with epoxy surfacer (the color is always grey, do not use the olive green one, it's an active primer, not suitable for paint base).
I don't recommend baking it, just place it in a warmy almost mildly hot like 40 celcius environment maybe in a wood box with 5 watt bulb lit in it. Stay in there for 24 hours. 
You'll notice the epoxy will become dry like cement.
2. Wet sand grit uneven surface with not too coarse nor too soft wet sand paper + water.
Make sure the surface is nice and flat.
Now, use 4 little bamboo sticks cut like matches sticks, make sure the diameter is slightly larger from the screw holes.
Stick it into the screws holes under the box for easy handling and not ruining the paint by accidentally touching it when wet.
Do not touch the paint under 6 hours time, it's still wet and will absorb finger prints easily.
3. Now you can spray the paint, 2-3 layers with minimum 15 minutes curing and drying time in between, of course spray it from 30 cm range thinly but all areas get it in each step.
If you see the paint is dry and ready enough for the lacquer, spray it.
4. Lacquer time
5. Wait for more than 24 hours for it to dry, place it inside a warmy place like wood box with 5 watts bulb lit in it or like sunbathing it under the hot sun maybe.

The key is....always apply thin layers each step for both epoxy surfacer and the paint. And......don't rush it. You can't rush it.
I know it takes hours of experience to finally know the trick and master the skill of spraying paint evenly professionally but you'll get over it in the end.
You'll see the aluminium box, the epoxy surfacer and the paint will mingle nicely and neatly like dear best friends forever.
I ever had a few times trying to scrape it using knife + thinner and it was a daunting scraping job to do.