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Mosaic Knobs


Mosaic Knob Instructions by Dish

These instructions describe the method I used to create my mosaic knobs.  Cindy Beckley and Angel both provided valuable advice that I used to develop my "battle plan."  Please note that these knobs have not been installed or used at the time these instructions were typed, so they are not wear or use-tested.

Non-Glass Supply/Tools List

  • wooden knobs
  • belt or table sander
  • water-based polyurethane and/or latex paint
  • spackle or wood putty (optional, for 1.5" knobs)
  • block of styrofoam or other item that screw ends can be "stabbed" into for support
  • clear contact paper
  • spray adhesive
  • Weldbond More Than Great Glue or Liquid Nails adhesive
  • plastic knives (picnic tableware)
  • cotton swabs
  • toothpicks
  • mineral spirits
  • non-sanded polymer-enhanced wall tile grout (suitable for ceramic wall tile, for gaps 1/16"-1/8" wide)
  • acrylic paint or grout colorant (optional, for tinting grout)
  • small rubber kitchen spatula
  • sponge
  • 0000 steel wool
  • grout sealer (if you do not seal with polyurethane)
  • small craft paintbrushes (if you seal with polyurethane)

Knobs
  1. Round wooden knobs (1.5" or 2" diameter) are available at home improvement stores like Lowe's or Home Depot.  They are packaged with the screws used to attach them to cabinet doors/drawers - [fig 1].
  2. Using a belt or table sander, sand the domed top off the knobs so there is a flat base for the glass.  It doesn't matter if all the knobs are sanded to exactly the same level - there can be a little bit of a beveled rim (leftover dome).  Grout covers a lot of variations - [fig 2].
  3. On 1.5" knobs, sanding usually exposes the top of the screw hole.  Smooth a little spackle or wood putty into the top of the hole, and level it with the knob top.
  4. Apply two or three coats of water-based polyurethane or paint (whatever finish you want showing on the "stems" of the knobs) to the entire knob.  I found this easier to do if I inserted the screws just a little way into the knob and used the screw as a handle while I applied poly, then stuck the screw into a sheet of styrofoam when I was done - [fig 3].
  5. Optional: if you used polyurethane on the knobs, rather than paint, but have some glass that's not opaque (I used a wispy for one color), you may want to apply one coat of white latex paint to the top surface of the knob (Debbie Lee suggests using Krylon Looking Glass mirror spray on the back of transparent glass instead of applying white paint to the knobs and says this gives the glass a 3D look).

Glass
  1. I printed my pattern on a sheet of cardstock, then used spray adhesive to attach it to a sheet of sticky-backed label or pattern paper.  Warning: before using any sticky-backed paper that is not pattern paper, test it to be sure that it will peel off the glass easily. Some does, some doesn't.  If you don't have sticky-backed paper, just print your pattern on whatever you are accustomed to using and use glue-stick to attach it to the glass.  I recommend template cutting (sticking your pattern pieces to the glass and cutting and grinding around the pattern piece).  I cut outside the black outline of each design with regular scissors to maximize the size, then I cut the individual pattern pieces apart with foil shears to allow space for grout.
    [NOTE: Here's how Cindy says she did things: I cut and ground all my designs free hand, using rough sketches.  The only time I used a pattern is when I made somewhat complicated duplicates (like the duck).  I would scan the actual completed knob and cut out the pieces from the printout (I always made a prototype).]
  2. I printed another copy of my pattern on cardstock, then used spray adhesive to glue the cardstock to the non-sticky side of clear contact paper.  Peeling the backing off the contact paper provided a sticky surface for me to "park" my cut/ground/cleaned pieces of glass on top of the layout pattern until I was ready to glue them to the knobs. Note that if the pieces are damp when you put them down or the contact paper has lost its stickiness, you may have to use glue-stick.

Attaching Glass To Knobs
  1. Remove the screws from the knobs.
  2. Using a plastic picnic knife (or other disposable utensil), "butter" the top of the knob with a very thin layer of Liquid Nails (what I had on hand) or Weldbond More Than Great Glue (Angel's favorite).
  3. Position the glass on the glue, pressing each piece firmly against the knob - [fig 4].  Toothpicks are handy tools for moving glass around, spacing the glass pieces apart, and digging out any excess glue that oozes up into the grout channels.  Cotton swabs dipped in mineral spirits are useful for cleaning up errant dabs of glue on the glass and on your hands.
  4. Let the glue dry at least 24 hours.

Grouting
  1. I used a wall tile grout described as polymer-modified wall tile grout, designed for use in openings 1/16"-1/8" wide.  This is non-sanded grout.  Lowe's carries MAPEI KER 800, which is what I used.  I mixed the grout as thick as I could (using an electric mixer when the going got tough, and cleaning the beaters as soon as I finished mixing), which was a bit thicker than brownie batter or peanut butter.  I could not find a premixed color I liked, so I used white grout and tinted it with liquid acrylic paint I found in the crafts section at Wal-Mart.  I added the color after mixing the grout to the consistency I wanted.  The wet grout should be a couple of shades darker than you want the dry grout to be. Angel pointed out that there are powdered grout colorants available from Delphi and Glass Crafters.  Mix a measured amount of colorant and a measured amount of grout, then make a small quantity of grout from that mixture, spread it on a paper plate, and let it dry for 24 hours or so.  Experiment until you've gotten the color you want.   After you have gotten the right ratio of grout to colorant, you can mix small batches of grout from your premixed colorant/grout mixture.
  2. Using a small rubber kitchen spatula, I worked the grout into the space between the glass and over the top of the knob.  Cindy describes this process as rather like icing a cupcake, although this is much more difficult.  You have to work the spatula in all directions around the glass design to get the grout firmly against the glass - [fig 5].
  3. Use the spatula to scrape as much excess grout off the top surface of the glass as possible, then use your fingers to shape the grout, rounding the edges - [fig 6].  This can be a little tricky when there is glass close to the edge of the knob.
  4. Once the grout is shaped, dip your fingertips in water and pat the grout gently (this will leave a little water puddled on the grout) to smooth it - [fig 7].
  5. Clean as much grout as possible off the glass with the dampened corner of a clean sponge or with cotton swabs.   You will probably have to do this several times, letting the knob rest a few minutes between cleanings.  If you don't get all the film off, you can use 0000 steel wool on the glass after the grout is dry.
  6. Use a sponge to clean any grout residue off the knob "stems".
  7. Let the grout dry thoroughly, say 4-7 days - [fig 8].

Finishing

The grout must be sealed, and the instructions I've seen said to use grout sealer.  Although that's probably the preferred method, I chose to seal the grout with polyurethane because I don't like the dull finish that grout sealer gives, and I am afraid that it might protect against water seeping into the grout, but not provide protection against normal wear and tear, dirt, chemicals, etc.  My knobs are not in use yet, so I cannot guarantee that using polyurethane on the grout results in a sturdy finished product.  Proceed with this step at your own risk.  Photos of the stages in grout sealing can be seen in [fig 9].  On the left is a grout sample divided to show no sealer added and conventional sealer only.  On the left is a grout sample illustrating the use of 3 coats of urethane sealer on one side vs. 3 coats of tinted urethane sealer on the other.

The grout was not dark enough to suit me (I mixed too much grout and didn't have enough acrylic paint), so I tinted a small quantity of water-base polyurethane with the same acrylic paint I used to tint the grout.

  1. Using small brushes, I brushed the tinted polyurethane only on the grout.  I used damp cotton swabs to remove any polyurethane from the glass and a damp sponge to remove any tinted polyurethane from the wooden part of the knob.   (Note: if you use clear polyurethane, you will still want to remove it from the glass.  I made some test knobs and applied the polyurethane to both the glass and the grout and was not happy with the look of the polyurethane on the glass.)
  2. Dipping the brush into water and dabbing it on a damp paper towel helped keep it soft and pliable.
  3. I applied three coats of polyurethane, letting each coat dry a couple or three hours and using fine steel wool on the grout between the second and third coats - [fig 10].
Even though I used satin polyurethane, the finish on my knobs is shiny.  If you don't like the shiny look, use 0000 steel wool to remove some of the sheen.

Warning about the screws: before installing the knobs with the screws that come with them, check the length of the screw against the depth of the knob and the door/drawer.  The screws may be too long.

Resources:


[fig 1] [fig 2] [fig 3]
[fig 4] [fig 5] [fig 6] [fig 7]
[fig 8] [fig 9] [fig 10]