Spray Toning Furniture

Advice on achieving good adhesion and maintaining some grain definition when darkening the existing finish on a wood desk. September 3, 2010

Question
I recently built a hard maple desk, and clear coated using several coats of brushed water base polyurethane. Now the client wants it darker. I can apply some glaze or stain, but I'm worried about adhesion issues with the poly. Any ideas?

Forum Responses
(Finishing Forum)
From contributor B:
Yes, you can use a waterbased stain/glaze over the finish that you have already applied. However. Just as in any coating that does not re-wet (adhere to the previous coats by melting into), you must create a mechanical bond by sanding the cured coats that you have already applied. Scuff sand with a 220, 240 or 280 grit paper, apply your stain. Let dry. Then come back with the clear coats. Another way to deepen your finish is to incorporate some stain into your clear coat and (after sanding) begin applying coats until you reach the depth of color you want. Note: Do not add too much color (stain) to your clear coat. You run the risk of painting out instead of giving it a stained appearance.

---

From contributor M:
I would be careful, as contributor B said, about adding too much color and creating a painted effect. I find that when darkening a stain finish, after the topcoats have been applied, the color tone will be more of a solid appearance. To a degree this can be acceptable, but once done, it's done. You may lose some of the wood grain appearance depending on how much you deepen the color. I would consider making a sample and finishing it the same. Then darken as you plan to, and show to the customer. We toned one project and the customer said afterward that she would have preferred the original color versus the darkened color. She still accepted the work and paid in full, but we could have saved ourselves a lot of work if we had made a sample to show the end result.

---

From contributor P:
You're right to worry about adhesion issues with a glaze or stain. Most stains are only meant to be used on bare wood.

Spray toning an entire piece of furniture is an art, but is done all the time. Getting good results by brush sounds next to impossible. If you can spray, mix a small amount of compatible dye (like TransTint) into the same poly and spray light coats until you reach the desired shade. Watch out for lap marks! If you can disassemble the desk, that might help.

---

From contributor C:
You can get great results (make samples first) by scuffing the surfaces with a fine scotch- brite pad, glazing, and then lightly toning (mix a bit of dye stain with some lacquer thinner and lacquer). Get a sample approved by your client first.