Paint still tacky after two days

[rodshaw]

I've been spray painting a resin boxcar and used Rust-Oleum grey primer for the first coat, which dried fine and covered well. I had some Humbrol matt brown and used this for the covering coat but, though it went on well enough, I ran out halfway through. I bought some Rust-Oleum satin brown and went over the Humbrol with this. The finish looks fine but two days on, it's still a bit tacky. Could this be from covering one brand of paint with another, or does satin take ages to dry properly, or can anyone suggest another reason? All the paint I used is acrylic spray.

[John Tomlinson]

I've been spray painting a resin boxcar and used Rust-Oleum grey primer for the first coat, which dried fine and covered well. I had some Humbrol matt brown and used this for the covering coat but, though it went on well enough, I ran out halfway through. I bought some Rust-Oleum satin brown and went over the Humbrol with this. The finish looks fine but two days on, it's still a bit tacky. Could this be from covering one brand of paint with another, or does satin take ages to dry properly, or can anyone suggest another reason? All the paint I used is acrylic spray.

 

I'm no expert, but sometimes paint does pull stunts like this. One particular brand of enamel paints I've used, Hannants Xtracolour for military models, usually seems to take several days to go hard, I don't know why.

 

In your case, if there had been an adverse reaction between the different brands, it might well have lead to blistering, which isn't the case. It may be the Humbrol wasn't properly dry when you oversprayed it, and so the whole thing is taking longer to dry through. If it were mine, I'd put it somewhere warm and clean for a week, so bits of dust don't drop on it and stick, and then see how it is. If it's still tacky you're probably back to square one, but then again you may well be lucky!

 

John.

 

John.

[ian@stenochs]

I was painting this morning and even the Precision stuff dried within minutes! However that doesn’t explain your problem it could be a mismatch with the two types of paint. Strip off and start again?

[relaxinghobby]

Agree with John T. Put it somewhere warm and dust free for a week and see if it dries, eg a shoebox on a high shelf.

Edited June 27, 2018 by relaxinghobby

[rodshaw]

Still waiting. Is it a bit drier? Maybe. No dust on it anyway. Maybe the heat from the brazier will help.

 

[jcm@gwr]

I've found in the past that paint not drying is

normally caused by not being mixed properly.

 

When I use rattle cans, I warm them up first,

either by standing them in a bowl of hot water,

or resting them on a hot radiator, then they get

an enthusiastic shake, for quite a while.

 

Likewise, tinlets get stirred for ages before I 

even think about starting to paint.

 

Is it possible you didn't stir for quite long enough

before you thinned down for the airbrush?

[rodshaw]

I've found in the past that paint not drying is

normally caused by not being mixed properly.

 

When I use rattle cans, I warm them up first,

either by standing them in a bowl of hot water,

or resting them on a hot radiator, then they get

an enthusiastic shake, for quite a while.

 

Likewise, tinlets get stirred for ages before I 

even think about starting to paint.

 

Is it possible you didn't stir for quite long enough

before you thinned down for the airbrush?

 

I think that's quite possible - it was a rattle can and I did shake for the specified time, but somehow it did lurk in the back of my mind that it may not have been enough. I usually like to play safe but I was maybe a bit impatient.

[rodshaw]

Well, it's dry. Almost. 95%.

[relaxinghobby]

I thinned some Humbrul enamal with boiled linseed oil once, the old fashioned way. 

It gave averynice finish on a loco with brush painting but took nearly a month to really dry and harden.

[rodshaw]

It's dry. 99%. The other 1% may be just clammy hands.