Art & Inspiration crazy paint question

I'm painting a sign. Got an old piece of painted tin, sanded it down, primed it and then painted it white. I went to my paint stash and found a can of omni mtk white, which is intended to use a hardener. I deliberately chose to NOT use any hardener so I could have a decent amount in the gun, and be able to dump it back in the can. It always hardens when you dribble down the can, or spill any, so should be fine I thought. Well, 3 weeks go by and yeah, its dry...sorta. If you press down you could put a finger print in it. So, I set it out in the sun for 2 days. This seemed to help, so I was going to start lettering. As an experiment, I touched a drop of those paint markers on to see if it can be wiped off easily in the event I goof up. Well, what ever paint is in those markers ate into the white omni down to primer, and streaked a little from the wipe. I then dabbed a little lacquer thinner on the rag to wipe out the streak, which it did, but it softened up the white back ground just enough to have a slight texture change visible to the eye. This is not acceptable as I'm sure I will make a mistake at some point and need to be able to wipe it clean, as I have with other HARDENED paint.
So....now the crazy question, what if I spray a mist of the hardener over the top? Wreck it ? fix it ? start over ? Its really not some thing that needs to be perfect, but I would like to be able to wipe out any errors. Your thoughts ?

 

I think I’d start over. Enamel can take a long time to dry, without hardener it might always be soft and other paints might eat into it.

 

strip it, start over

 

Try it what have you got to lose ?

I don’t think hardener over the top will work , but it might . And if the end result is stripping it anyways then giv’er !

 

Well the biggest thing he has to lose is it will make it a lot harder to strip. Right now he could wipe it off with acetone, after spraying hardener it's going to be a half hard half uncatalyzed mess.

Start again.

 

MTK will never really harden without catalyst. I tried to use it for touch up.....not recommended!

 

Try a couple of coats over the top of the same paint, but with the catalyst in it. I have patched up "sticky" patches in fiberglass like this, the hardener in the top coat went through and hardened the bottom coat.

 

Thanks for the response. My thoughts are similar to @36roadster above. When I paint anything, being the cheap ass that I am, I usually only put hardener in the top coats, save money, and at that point its all wet and I assume it will "melt" into the bottom coats due to the reducer in the mix. To spray hardener on now, its not wet, so I assume most will just evaporate off, but my hope is at least some would melt in and provide me with a surface stable enough to wipe off some errors. I had hoped to start lettering tonight, but I have been busy drinking beer and gossiping on the phone, so no time to letter, but time yet for the experiment. I'll spray it tonight and see what I got in the morning

 

Some more info. I did another sign before this with the same paint, but with proper hardener for the white back ground. I could wipe off a mistake with one swipe and fix it. That sign I lettered by hand with a brush. Same deal, I went to my paint cabinet and picked out the colors I wanted. All were MTK ( acrylic urethane ) and I brushed it on, it flowed out nice like one shot, but starts to tack up quickly, so one would think its drying. This time I had the bright idea to use those marker pens like they use at the junk yard. Those seem to be tough stuff, but I wonder what is in them, like maybe some solvent to make an attempt to clean the area for paint to stick. One shot paint and some skill would be the proper method here.

 

Well, I sprayed a mix of hardener and reducer over the top last night. First thing I noticed this morning is it took the shine off the surface to some extent. It feels drier to the touch, not tacky at all, but...it failed the lacquer thinner wipe test, so really I did nothing. Don't try this at home kids, it don't work. prolly should sand it all off and shoot it again

 

It always confuses me why people ask for advise and then ignore the advice the majority of the people give and then end up having to do what everyone said should be done in the first place.

 

You can't learn if you don't try. Its a small part that doesn't really matter much , so nothing lost

 

I once did a homebrewed paint concoction that turned out 'soft' like that.
Fortunately, I had access to some IR heat lamps, and an overnight under those took the 'soft' out of it.