The absolutely most important thing to know about working on a garage door is to use ONLY 100% acrylic paint. NEVER use any oil based or alykyd based paint or sealer.
So the first thing is to prime the garage door. Typically new doors like this one have a white paint on them. It is an aluminium or steel door that has been painted with a factory finish on it. So what I do is prime it with a primer called Benjamin Moore Fresh Start, that is an acrylic based primer for interior slash exterior and you can paint.
What I like to do is tint the primer before I paint with it. If you can't find a paint store that will do that you have to paint on the white primer and then put a basecoat on before wood graining.
A really good basecoat to use for a walnut look is a Benjamin Moore Peanut Butter or one called Dark Mustard. It will look pretty gold when you paint it on but don't worry about that. The reason you want a very gold base is it will give the wood look that warm undertone it needs to look authenic.
If I am trying to make the door look more mahogany or cherry I use a Sherwin-Williams color called truepenny 6355. That will make the door look like a pumkin at first but it gives the final wood tone you want. Typically when I use Truepenny for the cherry look I use a SW color Fiery Brown for the actually wood tone.
You want to use acrylic paint and not oil. You can use a similar color paint from Benjamin Moore using their Mooreguard line for exterior.
Back to the walnut colored door. I use a SW color called Java for the wood tone. (By the way use exterior paints.) A quart is way more than you will need to do a double garage door. After painting on the grain pattern with the Java color and it dries I take a black and mix it with the Java about one to one. Then I go over the same area again with that thined down a little with Floetrol or use some of the clear seal product that I use to thin the paint. That product is called Varathane Spar Urethane Waterbased. I buy it a Lowe's.
At this point you just want it to be a transparent pass like a glazing effect. I have found out that using this two color pass technique really makes it work to where the door will look real.
Take a look at the first picture.
In this picture you can see I have done the top two rows. You can also see how I have taped off the vertical areas to paint. Now with all the garage doors I have done, the factory imprinted grain pattern goes horizontal, that is fron left to right. But if this were a real wood door that would not be the case. The areas I have taped off would have vertical grain pattern. So that is the way I paint it reguardless of the imprinted grain pattern. Just inform your client about this before hand.In the next picture you can see what I mean better.
See how the grain goes vertical in the places it would if the door where constructed out of real wood. When that dries I tape it off to do the horizontal grain direction.A caution here is only use the blue tape that says its for sensitive areas. Don't use the regular blue tape. Because typically like this job I only have about 30 minutes to an hour between coats so the regular blue tape would rip off the freshly painted paint. In the last picture you can see how I paint in the horizontal grain pattern.
After it is all done I top coat it with two coats of the Waterbased Varathane spar urethane.
