Yesterday I wrapped up my second series of experiments with Marquetry.
If you’ve been following the last two or three posts you’ll see I’ve been working through some of the marquetry processes using a small rose pattern. For a small design there are a lot of pieces, which can make it a challenge. We left off with the pieces assembled face down on shelf paper, backed with blue tape, the shelf paper removed and the faces bedded in hot hide glue (HHG) on an assembly board covered in special kraft paper. I just pulled the clamps, and this is where we pick up the story.
Peeling up the blue taps was concerning, so I went carefully so I could see if it was pulling the image apart. One piece did come up, so I just stuck it back in place with HHG.
Next, it’s time to add the mastic. I skipped this step the first time around. There is a small saw kerf around all the pieces. It’s most noticeable where there are a lot of sawn parts. The mastic is essentially a mix of fine sawdust and diluted HHG. I added a touch of black tempra paint. I made the sawdust by sanding scraps of Walnut. The process is to put maybe a tablespoon of boiling water into a bowl, then take a “brush full” of HHF and swirl it in the water to make a diluted HHG. Then spoon a small amount of sawdust and a touch of powdered paint into the diluted glue. Mix. At this stage we’re looking for a puddling like consistency. Then add a bit more sawdust for a thick frosting or spackling-like consistency. Force this into all of the cracks and gaps in the picture and scrape off the excess.
In class we used Mahogany sawdust, and Patrick said Cuban Mahogany was the “best” for this. The golden rule in his shop is don’t waste this sawdust.
You’ll note that I used the mastic to fill the gigantic thickness difference between the background and the infill veneers on the leftmost image. After the mastic dried for an hour or so I hit it with some sandpaper on a hard block and saw that there were a couple of areas that weren’t filled as well as I wanted. I mixed up a second batch and applied it. After drying I knocked it down (lightly, just enough to level the mastic with the veneer).
Now I can cut the kraft paper around the images and laminate the mastic-coated side onto a substrate. I’m using some cheap 1/4″ “Birch” plywood.
I apply a coat of HHG to both the surface of the plywood and the back of the marquetry. The mastic-coated face is my glue face. I cover them in plastic add a caul and some clamps. Side note, I need to make a veneer press soon, this dance with the clamps isn’t going to work for a larger image.
Out of the clamps the next day, the images look decidedly uninteresting…
I scuffed the paper with sand paper, and sprayed it with water. This step makes me nervous. The glue is water soluble. The idea is to get the paper wet enough to scrape off, without getting the glue in the mastic or under the veneer too wet.
I didn’t take any pictured during the scraping process as my hands were full of paper mache. It seems to take about 3 rounds of wetting and scraping to do the job. The first round gets most of the Kraft paper, the second round gets most of the newsprint that was laminated to the veneer for reinforcement. The last round gets the little bits that remain. One more round of water and a scrub with a scotchbrite gets any glue residue.
Now let the parts dry throughly, then sand. I block sanded with 120, 150, 220, 320. Then I applied a couple of coats of shellac and let that dry. I sanded the shellac with 320, and applied one more coat. If these were for a project I’d repeat this a couple of times to get a glassy-smooth surface. This is enough, I’ll rub them out with steel wool and wax later today. (it’s not a very good picture, sorry)
I like the sand shaded image better than the mixed colors — at least on the rosebud part.
I’m not sure where I’m going next with this. I need more practice on sawing accurately. A small project with scrolls or letters would probably help with that. I need more practice sand shading — but maybe with a slightly thicker veneer and slightly larger parts would be a good idea. I also want to plan a project that will incorporate the marquetry picture rather than just do practice pieces.
All of which to say, I’m not sure what I’m going to do next. It’s certainly going to involve buying veneer as I’m running out of options with my veneer sample pack.