Spray paint on wood

Its your paint, not the fact that its a wood model. No problem here with Floquil, Tru Color, or SEM paint.

Pete

Oil and enamel paints can take weeks to fully harden/cure. But, their durability once properly applied and cured is much better than other types of paints.

what type of wood ?  oak, birch, pine?

and how dry was the wood?

I couldn't tell what wood as I am not a wood person, I bought the laser cut kits.  The wood is hard and the cells look dense unlike balsa.  Everything seems dry, but I don't have nay device to measure moisture content.  Would have to be something commercially and easily available.

Gray

It may not be wood but rather a composite material, like the material I use in my laser cutter.

If it is, it will take a lot of paint and time to dry.

I would think that the solvents in the Krylon (enamel based?) reacted with the lacquer you used to prime the wood even though the lacquer was dry. Lacquer sometimes doesn't play well with other types of solvent paints.

It should harden eventually with time.

Jim

Lacquered? Lacquer hasn't been made in years. There are sealers made for wood. I'm wondering if you aren't having a reaction to the "lacquer"? Krylon and Rustoleum can be questionable depending on the mix.

The rattle can said Lacquer, that's all I can state.  Testor's  Gloss and Dull Cote states it is a lacquer.   

I have had a bear of a time with Rustoleum to the point that it is my least-used paint, even on steel. This seems especially hard if painting in the hot sun, or on something still a little too warm from welding. My limited knowledge tells me that the problem is the vehicle (solvent) being driven off too quickly, leaving gummy paint behind that is now in no hurry to cure on it's own. Maybe I'm nuts, but unless wood is sealed somehow prior to spraying, the wood may be sucking the vehicle out of the paint in a similar fashion.....

I don't recall having much trouble with Krylon, but then I seldom spray anything wood. The EPA has forced a lot of products that actually worked well off the market, but that's another discussion. Think: hornet spray with NO odor. You need to use half a can on 2 hornets that are laughing as you spray.

I too have found that Krylon is notoriously "gummy" and takes too long to cure.

As for primer, whenever possible, I use Zinssers 1-2-3 Bullseye primer, the recognized champion of primers.  It is very thin, and dries very quickly.  It totally seals the wood, or whatever you put it on.  It is water based, for quick clean up.

Unfortunately, it doesn't come in a spray can, so you would have to hand brush it on.   If your cars have lots of tiny details, then it would probably not be for you.

Mannyrock

Certain types of lacquers, such as those used on automotive finishes, have been discontinued, but lacquers have different bases and the Krylon ones are acrylic based lacquers and still being mass produced.

To speed up drying of paint place in the sun or use a light bulb and reflector, for hours usually.  Old enamel, that may not contain all of its mineral sprites or turpentine will take an extra long time to dry.

Normally enamel can be painted over lacquer or dope but lacquer can not be used over enamel.

Charlie

Simple solution I didn't see above or maybe missed. Spray CLEAR COAT on bare wood before painting! Then paint and spray clear again if you want it to "pop"!

@endless tracks posted:

I have had a bear of a time with Rustoleum to the point that it is my least-used paint, even on steel. This seems especially hard if painting in the hot sun, or on something still a little too warm from welding. My limited knowledge tells me that the problem is the vehicle (solvent) being driven off too quickly, leaving gummy paint behind that is now in no hurry to cure on it's own. Maybe I'm nuts, but unless wood is sealed somehow prior to spraying, the wood may be sucking the vehicle out of the paint in a similar fashion.....

I use Rustoleum paints outside on wood cars all the time.  No problems at all. You have to put it on using just enough paint, using light coats just covering, and let it dry. I'm also doing this on good hot days about the blacktop so it's getting baked on pretty rapidly. Dries in ~20-30 min depending on how much sun. Humidity seems not a problem when painting over that black top that acting a huge heat sink under the painting area - like working in an oven!

When in doubt or over a complicated mixed surface, gray primer 1st.  Do everything, and after it's baked on under the sun and over the blacktop,  I give it overnight inside before the next color.  Another day and then it's gloss. Another day, then decals, another day, then clear matte. Done!

My brother in law was a painter in a well respected custom car and motorcycle shop. He prepped and painted for almost 40 years before he retired.  He told me if painting from a rattle can you should allow 48 hours or more between coats.  He explained to me that each coat of paint drys from the outside in, and if you rush the second coat it will slow down the curing process of the first coat.  I know the OP was using Krylon but I have a can of Rustoleum in my hand and it states “the second coat should be applied in less than an hour or after 48 hours”.    If a second coat is applied in less than an hour it melds into the first coat acting as a single coat.   If the second coat is applied after one hour and before 48 hours it can cause the paint to feel soft for an extended period of time.  This is for rattle cans only.  

@Keith k posted:

My brother in law was a painter in a well respected custom car and motorcycle shop. He prepped and painted for almost 40 years before he retired.  He told me if painting from a rattle can you should allow 48 hours or more between coats.  He explained to me that each coat of paint drys from the outside in, and if you rush the second coat it will slow down the curing process of the first coat.  I know the OP was using Krylon but I have a can of Rustoleum in my hand and it states “the second coat should be applied in less than an hour or after 48 hours”.    If a second coat is applied in less than an hour it melds into the first coat acting as a single coat.   If the second coat is applied after one hour and before 24 hours it can cause the paint to feel soft for an extended period of time.  This is for rattle cans only.  

That makes sense, but is that all at room temperature w/o baking the paint on?  When I'm outside painting above the blacktop, I've found when I'm painting brass or other metals, it gets hot enough that I can barely touch the metal. Wood seems not as hot but then it's heat capacity is different.

I believe that was room temperature and I am sure that heat would speed things up.

KeithK  wrote:  "He explained to me that each coat of paint drys from the outside in, and if you rush the second coat it will slow down the curing process of the first coat. "

Precisely!!

It's all about the vehicle. (solvent). If you paint within the hour as recommended, it melds together seamlessly. If you wait longer but less than the 48 hours, the solvent from the first coat, which is still trying to evaporate, gets trapped under the second coat and has to fight it's way out, hence the goo, which now seems to take forever to dry.

I have found Rustoleum lately to be better than what they put out  years ago, keeping in mind that spray can propellents have changed dramatically in the past few years due to the Montreal Protocol. My father has patents on spray cans and nozzles in particular  so I used to hear all about the stuff at the dinner table...Boy, do I miss him!!!

Rustoleum is good for what it name states...prevents rust. For wood or plastic models it's Krylon Fusion for me hands down. Drys as fast as yesterday! Clear coat for dry wood first. Again after to protect paint.