A Simple Guide for Furniture Painters.
One thing that is VERY important when painting furniture, is knowing your substrate. Substrate is the fancy term for the surface you are painting on.
You always want a clean, stable substrate.
This post is a simplified guide to identifying wood types and why.
Is it oily wood? or prone to bleed?
I am not going to talk about prep - simply how to ID your wood and what it means for your paint job.
I refer throughout this post to UNPAINTED WOOD, (that may, or may not, have a seal on it) and assume you are intending to paint using water based FURNITURE PAINT.
First of all, it is not an exact science! Generally, you will eyeball it and take a guess. Often this is your best remedy.
If in doubt TEST. A quick test is by far your best option, rather than making a time-consuming mistake!
Often we are dealing with wood that has been painted and stripped or has been stained or varnished. So it is can be tricky to know what you are dealing with.
If you can't work out what it is - don't worry about it. That is my big takeaway in this post! Not sure - test.
Question 1 - Is it Veneer?
Veneer is usually a very thin layer of real wood that has been glued to the substrate, (see that word again). You can actually see it in the image above.
A telltale characteristic of veneer is a repeating pattern in the wood.
Veneer can also be plastic. Think of laminate flooring.
If it is a veneer, and you intend to sand - be very careful.
It is super easy to add a tiny bit too much pressure and sand right through the substrate! If staining, you will see a noticeable difference in the way the stain takes.
QUESTION 2 - Is it real wood?
It may be plastic or a composite. There are some amazing fakes out there - you should be able to tell by the weight and by the sound it makes when you knock on it. Plastics include laminates - look at the ends - if it is real wood you will see growth rings, a composite you will see something like the image above:
Is it sealed, stained or in its natural state? A light sand should reveal the answer.
If the wood beneath is a lighter - or totally different shade, it has been stained. Check for wax by running your thumbnail over the wood. If a dirty, sticky residue comes up, the wood is waxed. See this blog post to find out how to remove wax.
It is always easier to identify wood in a freshly sanded state - like a clean skin!
You may have read that raw wood always needs to be primed.
Primer helps fill in the wood grain and creates a smooth surface for the paint.
Milk Paint LOVES raw, unprimed wood. You will, over time see knots showing through but this is part of the beauty. If this is unacceptable to you, seal first.
Knowing your wood allows you to choose a primer or a sealer - will it bleed or not?
Primer or Sealer?
Primer provides a foundation for adhesion and coverage.
Sealer is formulated to suppress stains.
Wood Conditioner is a great idea if you are going to stain or seal your wood. It helps prevent blotchyness and streaking.
It can be applied over any wood but is generally a good idea when working with soft or porous woods like pine. The products listed below are my brands of choice.
Lots of older furniture is made using hardwood, because of its variety of textures, the options on colour and the pretty grains.
When painting hardwood the following are good rules of thumb:
Check for wax. Remove wax using Mineral Spirits, (White Spirit).
Use trisodium phosphate (TSP) or equivalent, to clean, in the UK & Europe Sugar Soap is a good alternative.
Sand to create a key - 220 grit paper or above.
Does the wood have a seal on it? If you did not break the seal when you created a key, there is little need to prime or re-seal. But always, always test! If in doubt, seal!
If you are dealing with raw wood and want to be certain that you will not get bleed through, I recommend you always seal. I like the Zinsser BIN Sealing Primers with shellac.
Always seal Cherry & Mahogany if not, it may start to turn pink after a few days.
Typically when painting over Oak, Cherry or Mahogany you will need one coat of sealer and two coats of paint.
Teak I try and avoid - it is very oily and unless properly sealed and primed will cause your paint to bubble.
Poplar rarely bleeds - but can if it is very green. Generally, you can give it a light key with 220 grit paper and paint away. HOWEVER once in a while, it will bleed!
Birch & Ash again rarely bleed BUT occasionally they can. Always TEST!
OAK: generally seal & paint.
Oak has a tendency to release tannins - which will turn white paint yellow. You may not see it immediately.
Oak is porous, and if the pores were not filled when your item was built, the peaks and valleys will show through your paint.
Cherry: Seal & Paint.
I always seal Cherry if not, it may start to turn pink after a few days. Cherry stains and oils well - and ages wonderfully.
Typically when painting over Cherry you will need one coat of sealer and two coats of paint.
Birch: Generally fine to paint without seal or primer - but do a test.
Ash: Generally fine to paint without a sealer or primer. Always test!
Mahogany: Always apply a Sealer / Primer. Mahogany is known for its bleeding.
Poplar: Rarely bleeds - but if very green can occasionally cause seeping.
Teak: Very oily - may cause your paint to bubble and spot if not properly sealed & primed. Not ideal for painting, but can work.
Soft Wood Varieties:
When we say soft wood - we don't mean it is weak or a poor choice, just that it comes from coniferous trees. Varieties such as cedar, fir, and pine. They tend to be yellow or reddish in colour and can be knotty and sappy.
If staining softwood it is a good idea to use a Wood Conditioner.
Pine. Simply seal the knots to prevent sap seepage. If you wish to. you can prime
Cedar. Has a very fine even texture. Prone to bleed so sealing is a good idea.
Fir. A great choice for painting!
Now you know the how and why, here are my recommendations for the very best results. This is my shopping list and, of course you may well have your own preferences!
To make it easy they are all available on Amazon!
I hope you learned something and can use this as a reference!