Wood Finishing Basics

      A newcomer to finishing gets advice on his formulas and application methods, and on where to learn more. August 9, 2005

Question
I work in a small cabinet shop, and the owner has asked me to help him with a stain/color match for a client. I am a good cabinet maker, but I admit I am a novice at finishing. That’s what I have been doing now at the shop for the past three weeks. I am using an Accuspray HVLP setup and it’s really nice. I want to learn more about finishing and cabinet touch-up and repair on-site so I can be a better asset for my shop. The owner is a great person to work for as he really cares deeply for us employees.

I am looking to find a book that will explain in great detail how to "Color mix and match wood tones/colors", and how to set up proper finishing schedules for the shop. Currently, I wipe on the stain, seal with a 50/50 ratio of ML Campbells Precat lacquer and lacquer thinner. I then scuff sand with 320 grit and then apply my first coat of the same lacquer mixed at a 3 to 1 ratio of lacquer to thinner.

Then I tone if needed with a custom mixed stain from Minwax selections (those are what I have to work with so I am doing my best) mixed with lacquer thinner and poured into the lacquer mix and sprayed on. I then scuff sand again with 320 and top coat. This seems to be doing well, but I am definitely open to better ideas especially if they help speed things up and save money. Any help is appreciated.

Forum Responses
(Finishing Forum)
From contributor L:
I wouldn’t recommend using Minwax as a toning agent, it is not rally compatible (although I admit, I have done the same with good results). You should be using the Micoton tinters from ML Campbell.

As for your thinning of your lacquer, it sounds like too much to me. For your seal coat you should thin no more that 10% (read the specs) unless you are trying to limit your final MIL thickness.

As for your final coat you should be spraying it straight from the can, and you may need to get a larger needle/nozzle setup. I currently use a HVLP gravity cup gun and a 1.7 MM nozzle setup, and works well for me.

For a schedule try this:

1. Stain using a NGR fast drying stain designed for lacquer topcoats (MLC WoodSong II or others).
2. Spray your seal coat using a 10% thinning ratio.
3. Tone if needed, 20 oz lacquer thinner, 2 0z Micoton tint, 4 oz lacquer.
4. Spray your final coat(s) straight from the can. If you have flow problems, use a flow enhancer 5-10%. You should limit your total thickness to 4 MIL, which is usually three coats at 4 MIL wet (33% solids in MagnaMax).



From contributor D:
To the original questioner: You are over-reducing your coating. I might go as high as 20% for the sealer coat and 10% for the topcoats, but this should be sufficient for spraying. If not, you need a larger needle/nozzle setup and Accuspray should be able to recommend the correct setup if you give them a Ford #4 or Zahn #2 viscosity cup timing for the coating.

I would suggest learning how to spray dyes. Nothing looks better and gives you a superior professional appearance than well sprayed dyes. I use Keystone's Nerosols (Homestead's Transtints) and a solvent mixture I came up with using Acetone, Butyl Cellosolve and Dowanol PM. This dries very quickly and looks spectacular.

Color mixing is a trial and error process. Cut up a bunch of 3/4" boards of whatever species you use about 18 inches long and four to six inches wide. These are your recyclable test boards. You will shoot these to get your match and then run them through your planner time and again until they're about 1/8" thick in the end and then throw them out.

I would suggest looking into buying a mini gun from ASTRO. The model I use is the 4020 HVLP, and this is what I use for dye even on fairly big jobs. With dye you build the color in layers, and nothing gives the control you can get with a mini gun.



From contributor M:
To the original questioner: I hope these finishing articles will be a start in the right direction.

http://www.iswonline.com/cwb/mac.cfm



From contributor D:
Mac's articles on colors are very well written for the furniture and cabinet people. When it comes to touch-ups and finish repair, every bit of damage and every defect is unique, but they can still be categorized into what Mac delineates as three types of damages: those that mar the surface film; those that dent or put a groove into the surface film; and those that break through the surface film and rupture the substrate.


From contributor T:
One of the books that I have read is “Understanding Wood Finishing” by Bob Flexner. If you're doing finishing or even thinking about it, it's the best $15 you can spend. Jeff Jewitt also has a book out called “Finishing”.

I also agree that you're likely to get into trouble using Minwax as a colorant. If you need the right supplies, there are plenty of sources online.



From contributor S:
Bob's book and Jeff's books are great. However, they do not teach you how to match colors. They give you an idea how to control the techniques that you will need in matching colors. The books will explain how the look is achieved.

Mac Simmons's articles on color matching are unique. I understood color theory only by reading one book "Blue and Yellow Don't Make Green". But I was only able to apply the information once I read Mac Simmons's color-matching articles. Mac's two articles "Tinting Toner Tips" and "Matching Colors" are all any finisher needs to get started matching the coloring you see on factory look you see on furniture.

Finishers understand that coloring is very much about applying different color steps as in multi-step finishing, and once they begin to layer colors the way that factories layer colors then they can break away from the primitive mindset that you stain and then you topcoat.

There are two aspects when looking at finely finished wood: the colors that you see and the look of the finish. We need to be detectives in guessing at the finish schedule that was used on what we are looking at and trying to match, and also what simplified finishing schedule we can get away with in trying to duplicate that very look that seems to be elusive.

Once you start to play with samples and step-finish boards, you quickly get a grasp of the interplay of laying a ground color. By isolating it with a wash coat, applying a secondary application of color, and top coating you will be amazed at the final result. You also develop a quick feel for how the different colors can be used to develop the final look.

Mac's approach to focusing on the earth tone colors and using the primary, secondary, and tertiary colors to kick those earth tones is a unique approach to teaching how to match colors. That is why I so strongly recommend his article on matching colors.



From contributor R:
I never tin seal, and I play a few games with topcoat to get what I need. I will help you out on color matching. First off, it is not hard to learn. You need to stay away from all those colors in a can like golden oak shaker maple and etc. Most wood finishes come in two types - red and green.

Colors have a secondary to them and if you look you will see them. Burnt umber has a little red cast and is thus called worm. Raw umber has a greenish cast to it and thus it is referred to as cool. Most of the time burnt umber will be good as a jump off color. If you add a small amount of ivory black, bone black or carbon black, it is all the same black. This black is reaaly a very dark brown and that is what is mostly used in wood tones. For the time being, darken with the black I have mentioned.

As for kicker colors - red, blue, and yellow are very broad terms. The question is which color to use. For red, I would use quinacridone red. It is a red with a violet secondary. It will get you all the cherry colors and cordavan colors you would ever use. It is good for many mahoganies as well.

If you want to darken with out-black, and this is a very good idea, use ultramarine blue. This is the only blue that casts a secondary of violet and that is where you want to be. All other blues cast a green second and are prone to muddy up your color mixes. Last is yellow, and I can only say that I like Hansa yellow the best. It does lean to the green side, but it is the yellow with the highest croma you can get, and it is second only to white. You can use it in place to tint out colors that you thought needed white. White TiO2 has a tendency to muddy up colors. Industry will from time to time use it as an opasafier - that is to make a color more opaque.

I will name colors in there greatest use order. burnt umber, raw umber, burnt sienna, and van dyke brown. Be careful of this color in industry, it is referred to as a fugitive color. That is to say it will not hold up and will muddy and fade over time. It really is a petmose, and since epa and wetlands true van dyke is not sold any more, you can get pretty close with burnt umber and black. It is a much better choice for many reasons. Raw sienna is traditional, but it is a dirty yellow that makes more mud than good color. Try yellow iron oxide, and while you are at it try red iron oxide. Most earth colors are no longer sold as the mines have been shut down about five years ago.

Red and yellow will get you most of the sienna’s. Above all – make sure to stay with the basics and keep away from pre-mixes as they do nothing for your learning or your work.



From contributor T:
With regard to color matching, as Mac says at the end of one of his articles - you really have to practice. It is so very true - but it does help to understand some of the theory or at least why colors do the things they do. It isn't a matter of just mixing some pigments together. It continues to amaze me how the color that you see can be affected by so many different factors - substrate color, light type and direction, top coats, substrate finish, sheen, etc.


The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).

Comment from contributor A:
Being able to make adjustments to color is a part of learning about colors. Once the color is mixed and applied, you can not see the true color until it is clear coated over. That's why start to finish samples are so important. It's part of learning to match colors.



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