I’m still very green to wood working and one area im still struggling a little is how to go about finishing a peice. After watching one of my fav movies, it put me in the mood
to try a little sign to add to my halloween decor. Not perfect, but all in all i think it came out pretty nice. Made from solid poplar and spraypaint. Just curious what you guys would suggest for an easy top coat to add a little protection to the surface without altering the colour drastically.
Looks good!
Is your movie that put you in the mood Beetlejuice? 
I see I forgot to mention finish. Like gdon_2003 I use the same process but use spray polyurethane to seal the wood pours for painting. (Works for me)
I finished a tabletop and tried what is in the picture.
I used two coats, so according to the can I have 6 coats.
Worked out really well.
They also have this in a spray can. I’ll most likely try that when I need to buy more spray.
You got it! You know you’re really getting into cnc when you spend have the movie thinking “ooh, i wanna make that” 
The finish depends on what kind of paint you used. If it was rattle can it was solvent/oil based and so a oil based spray polyurethane would work. If you painted it with acrylic then a water based poly like polycrylic would work.
It is not advisable to put oil/solvent based finishes on water based paints. The oil/solvent finishes have more Volitle Organic Compounds (VOC) and off gas and smell much more than water based finishes. However oil/solvent based finishes tend to last longer and adhere better because they soak in to the pores of the wood. Latex and water based finishes lay on the surface and do not soak in near as well as oil/solvent based products.
I always start with dewaxed shelac on raw wood. You can use either oil or water based paint/finishes over the shellac. The reason to seal is paint soaks into raw wood making you paint it several coats to get good solid color. With the sealing it may only take 1 or two coats of finish to get a good looking surface. You can buy this at the box stores and use before painting signs to keep the paint from soaking into the pores/straws of the wood.
Waterbased topcoats will not add any color…whites will stay white. Oil-based topcoats will add a yellow tinge and whites will start to look yellow with each coat adding more yellow.
Edit: Here’s a sample. The outer ditch of this crokinole board is topcoated with waterbased. The inner circle is topcoated with polyurethane since it’s dyed veneer. Both were the same color before topcoating. https://hilinski.net/woodgamesold/crokinole_gallery/Nittany.jpg
Thanks for all the great advice so far. I have experimented with a couple of different spay (for connivence) shellacs and lacquers and got some decent results. I’ve found that doing a light sanding between coats really helps to produce a nicer finish. Does the same apply polyurathane and polyacrylics?
Yes light sanding with 320-600 grit paper always makes your finish better. You get dust nibs falling out of the air, air bubbles in the finish, dust left on the surface etc… There are a lot of things to contaminate your finish and sanding between coats helps fix that or at least flatten it out.
The first coat of water based finishes usually raises the grain making a bumpy surface. You can pre raise the grain by using a damp, not wet, rag over the surface, let it dry and give it a final sand. However the grain will raise slightly even with the pre raising of the grain. So after the first water based topcoat give the project a good sand to remove the raised grain. It may take 2-3 more coats with light sanding in between to get a flat surface.
With oil based polyurethane you still need to sand lightly between coats to get a nice flat final coat. The same dust nibs from the air, dust on the project and so on can make your surface bumpy. Someone mentioned the yellowing effect and I agree. I like the mellowing effect of yellowing on solid wood surfaces. It brings a certain warmth to otherwise dull surfaces. If you have a maple object the blandness of the wood grain is boring to me. So the application of shellac and polyurethane warms up the lack luster surface. Personal preferences vary.
Both oil and water based finishes tend to have a smell when used inside closed boxes. To avoid this unpleasant smell when opening a jewelry box I have started using flavored wax to coat the inside of boxes or other closed objects. This is not important for your sign but you might make other things in the future. I buy this stuff from Craft Supply USA. Of course just plain paste wax would work.
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