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BOULLE MARQUETRY WITH BRASS, PEWTER AND FAUX TORTOISE SHELL - a beginners approach #3: Preparing the marquetry panels for gluing down, and sanding the panels ready for engraving.

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Blog entry by madburg posted 04-14-2017 12:59 PM 2207 reads 0 times favorited 4 comments Add to Favorites Watch
« Part 2: Materials used, making up the packets, sawing the packets, assembling the design Part 3 of BOULLE MARQUETRY WITH BRASS, PEWTER AND FAUX TORTOISE SHELL - a beginners approach series Part 4: Engraving the panels »

Probably the best of the color combinations. A Premier Partie with a back ground of black and faux tortoise shell.

PREPARING THE MAREQUETRY PANELS FOR GLUING ONTO THE SUBSTRATE

I had already decide to use epoxy glue for my assembly – but more on this later ………. With the marquetry ‘jigsaws’ assembled on the gummed paper I used a black pigmented epoxy to fill the visible saw kerfs in the design. Traditionally, crushed charcoal mixed with shellac was used. I applied my pigmented epoxy to the back side of the panels and pressed them again in my glue press.

A key aspect to the pressing was putting linoleum and/or polystyrene packing sheet, together with a polythene sheet on the face side of the panel, and a flat board covered with a polythene sheet of the back side. This gave me an almost flat back side when the glue had set and the panels were removed from the press. Epoxy doesn’t stick to polythene hence its use. Inspecting the marquetry once it was out of the press enabled me to spot glue any bits of kerf that hadn’t been filled. The use of epoxy to fill the kerf gave me quite a stable marquetry panel, with all ‘bits’ glued together!

With the kerfs filled, I scraped the back side to remove the excess glue. I decided that any slight hollows in the back side would be taken up with epoxy once they were glued onto the substrate. I found both a sharp cabinet scraper, and small size scraper plane worked well, and even scraped the brass and pewter.

The marquetry panels were now ready to have the bandings and boarders added. I attached them using veneer tape on the face side. I then used my hacksaw blade scraper again to re-key/tooth the back side of the marquetry.

Finally I cleaned the back side with isopropyl alcohol to degrease the surface, rather than the traditional methods of rubbing with an onion, or garlic, or washing with vinegar!!! They marquetry jigsaws were at last ready for gluing onto my substrate.

GLUEING THE MARQUETRY PANELS ONTO THE SUBSTRATE

Much can be found on the internet about gluing marquetry and Boulle work. Traditionally hide glue was and is often still used for marquetry. But for gluing Boulle marquetry, where metal is included in the design I found these suggestions:
- Add a little Plaster of Paris to animal glue, or add 1 tablespoon of turpentine to 1 pint of glue
- Add a little garlic to animal glue
- Use strong scotch glue with the addition of lime and glycerin. Stir them in while hot.
- Fish glue
OR use Epoxy

The glue I used throughout the assembly of my Boulle marquetry to the substrate was West Systems GFlex epoxy. I was told by the supplier that it had a degree of ‘flex’, enabling the woods and metals to ‘move’ without delaminating. It is used extensively in boat building trade in Western Australia where woods and metals are being glued together. The GFlex is mixed 1:1, so a small set of $10 digital scales purchased from eBay, enabled me to easily get the correct proportions.

The marquetry panels with their boarder and string were glued down onto slightly over sized substrate panels. These went into my press, again with linoleum/expanded polystyrene packing foam to take up the unevenness of the face side, and a polythene sheet to help in release.

My substrate was 10mm marine ply, that had previously had a counter veneer of cherry glued to the back side, and a 12mm cherry strip glued along the top edge. These were glued using Titebond, yellow glue.

Delaminating is an age old problem with traditional Boulle panels, with almost every piece of fine Boulle furniture having been restored several times due to the traditional glues giving way. Sanding them flat after re-gluing often removes quite a lot of the fine engraving. This delamination has provided work for generations of antique restorers, adhering quite rightly to their ethic of ‘not doing anything that cannot be reversed’.

Fortunately I didn’t make any mistakes in gluing up, so didn’t need to use the reversibility of fish/hide glue, and hopefully my Gflex will prevent my panels from delaminating in time honored fashion. If they do I won’t be around to worry, and I doubt my boxes will be valuable enough to warrant being restored anyway!!

SANDING THE MAREQUETRY PANELS READY FOR ENGRAVING

Once out of the press the marquetry panels needed to be sanded flat. Traditional methods suggested the use of scrapers and files ……… I wasn’t convinced. Remember that the wood veneer and faux tortoise shell was thicker than the brass and pewter. So, I took a bit of a risk, and passed my panels, with great care and a bit of apprehension, through my sanding thicknesser, covered with 120 grit. I managed to get the thicker wood veneers and faux tortoise shell down to the metals, without generating too much heat, which I was worried might just have ‘melted’ the epoxy. It might have just have done that if I had used hide glue though….. At the first hint of the drum starting to sand the metals I stopped.

This is where the masking tape, that I mentioned earlier, caused a problem. It really did gum up the 120 grit cloth on the drum! I did try to scrape the masking tape off before putting the panels through, but I didn’t get it all off – epoxy sticks to most things really well!!!!! What seemed a good idea, as the masking tape was flexible and glued well to the metals, caused a lot of wasted time, in cleaning up and/or replacing the sandpaper roll on the drum. Needless to say I used gummed brown paper tape to assemble the rest of the panels.


The five best top panels after the initial sanding

With this initial sanding completed I decided now was the time to seal the wood. I knew that the sanding would generate very fine brass and pewter dust, which could easily fill the open grain of the surround veneers and boarders. This sealing was a key part in the whole sanding process. I used polyurethane diluted with turps and applied around 3 coats as a ‘sanding sealer’. Then I proceeded to ‘finish’ the panels working through the grits 180, 240, 320 etc up to 1200 grit. This was done in one direction along the length of the panels. I did try a small palm orbital sander, but even the 1200 and 1500 grit left circular scratches that were visible on the metals, particularly the soft pewter.


A complete set of sanded panels

So the surface of the Boulle marquetry was flat and ‘polished’, and was now ready for engraving. Sealing the wood veneer’s worked well, though I still needed to do some selective sanding of the boarders and strings to get the colour back. The brass, and pewter dust in particular, which is black, still muddied the stringing and bandings but nothing like as bad as on my trial pieces, where I hadn’t sealed the grain. Be warned!!

The alternative would have been to completely finish the Boulle panels including the engraving and application of the finish, and then attach the boarder and stringing. So a sunken Boulle panel surrounded by a raised boarder would have over come the sanding issues.

In the next of the series I will describe my biggest learning experience of this whole project – the engraving of the brass and pewter.

Thanks again for reading and getting this far. I look forward to any comments and additions you may have.

-- Madburg WA



4 comments so far

View tinnman65's profile

tinnman65

1362 posts in 3556 days


#1 posted 04-14-2017 01:23 PM

Thanks for sharing, This is a great read for anyone interested in trying this type of work. I have to disagree with your comment ” I doubt my boxes will be valuable enough to warrant being restored anyway!!” These are going to be beautiful ! I look forward to your next post .

-- Paul--- Creativity is allowing yourself to make mistakes. Art is knowing which ones to keep. — Scott Adams

View Jim Rowe's profile

Jim Rowe

1051 posts in 2455 days


#2 posted 04-14-2017 01:33 PM

Martin
This is a really interesting process and journey that you are describing for us. I shall continue to spectate!
Jim

-- It always looks better when it's finished!

View Redoak49's profile (online now)

Redoak49

3522 posts in 2131 days


#3 posted 04-14-2017 01:48 PM

Amazing work and very interesting blog.

View shipwright's profile (online now)

shipwright

8086 posts in 2940 days


#4 posted 04-14-2017 03:09 PM

Well done Martin. Lots of innovation and learning going on here.
It’s all going in the memory banks in case I ever get to metals.

-- Paul M ..............the early bird may get the worm but it’s the second mouse that gets the cheese! http://thecanadianschooloffrenchmarquetry.com/

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