How to put together a MASSIVE marquetry panel ?

[Emma Wood]

I'm really a novice with marquetry - so this is probably a bit ambitious for me, but I'm obsessed with the idea of doing a HUGE panel. I know I will have to do it all in pieces (probably finished all separately too) - but I"m wondering how I would put it together at the end. (And I'm not sure I'm even in the right forum here . . .). My design is more or less a mosaic . . . but in different size pieces . . . My idea so far was to mount it all in say 2ft sq pieces maybe onto 3mm board which would be laser cut to the pieces of the design and then mounted on the final substrate right at the end like a jigsaw. But I'm sure there would be fairly obvious seams done this way. Any advice will be hugely appreciated ??

[Steve Clarkson]

Hi Emma,

It would be helpful if you could post a picture of the mosaic and let us know the overall size of the finished piece.......then we might be able to give you some suggestions. Also, how big is your laser bed (or what is the biggest piece you can cut). Are you asking more about assembly of the finished piece or how to set up the cut file in Corel?

[Lee DeRaud]

I tend to cheat on "marquetry": I cut the individual pieces from PSA-backed veneer and just start "assembly" in the middle and work out. Admittedly, I don't normally do anything bigger than 24"x48", but as long as none of the individual pieces are bigger than the laser's bed, the limiting factor is pretty much the size of the final substrate.

Even using traditional methods, I don't see why you would want to do subassemblies. The glue-up is the tricky bit, but even that can be done in sections.

(Anything bigger than 4'x8', I'm not sure I'd call it "marquetry"...there really ought to be another word for it. :eek:)

[Emma Wood]

Hi Guys,
I haven't finished the design yet, but it's going to be of a HUGE motorbike all made up of triangles. The individual pieces I can cut no problem - but the finished panel will be about 12 foot square - so I don't really know how to go about putting it all together. I have a vacuum bag press and I imagined that I'd press the panel in pieces of say 24" square so I'd have 36 pieces making up the end result. But I'm not sure what to press on to. Maybe a thinner board - which gets mounted on to the final substrate at the end ? Or do I cut up the substrate and mount it directly and then somehow glue it all together ? Aaaargh! Whichever way - I can't work out how I would avoid having obvious seams in the final piece ?
Cheers
Emma

[Mike Null]

Emma

How do you plan to display this panel? It is one thing to lay it flat, another to hang it.

Either way, I tend to agree with Lee; why sub-assemblies?

[Lee DeRaud]

I can't work out how I would avoid having obvious seams in the final piece ?12'x12'?!? You're going to have seams in the final substrate, unless the phrase "concrete floor" enters the conversation at some point.

[John Blazy]

Real simple. Laser cut and bond the veneer onto 1/8" baltic birch plywood into manageable size panels that fit into the larger 12 ft total size, like the 24 x 24 panels (I would design sections that follow the lines in the design), then re-laser the perimeter of those panels, and then glue the panels of 1/8" using glue of your choice to 3/4" birch. Then fill all seams with epoxy - several applications will be needed. first coat will soak in, then second coat might start to fill the minor seams. after each coat, sand surface flush with random orbit sander, but not through the veneer. blow out dust in each unfilled seam, and apply epoxy till all is filled. Sand final, then topcoat.

My boat is essentially a giant pc of marquetry where all the solid and veneer had to come together seamlessly, and when all the seams were filled with epoxy, the topcoat flowed over the whole thing as if it were solid plastic. To this day, the seams have never telegraphed, and I built it 13 years ago.
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[John Blazy]

Forgot to mention that when you glue the sub panels onto the main 12 ft panel, glue the edges well with a non shrinking glue like PL premium polyurethane, but glue only the bottom half of the seam edge, or not at all, just the back edge. You need to create a sealed channel so the epoxy does not simply flow under the plywood and you would be frustrated in pouring ten subsequent fillings of epoxy til it fills. Use West system with the special coating hardener # 207, or use Basic NoBlush by Progressive Epoxy Polymers, but if interior, any bar top epoxy is fine.

[Emma Wood]

I've hopefully got this commissioned WOOP WOOP. So, I will just hand it over and someone else will have to deal with hanging it (it's for a commercial space) !!! BUT this all relies on my working out how to do it. I'm a relative novice at all this (yes, I know, i shouldn't be attempting such a huge thing for my experience level!) so you'll have to forgive me. But not sure what you mean by sub-assemblies ?? Because I use a bag press I will have to do this all in parts (also for my sanity) - is that what you mean by sub-assemblies ? D'you think my idea of mounting each 2'x2' square on to thin board is workable ? And if so, it would feel odd to glue a balance veneer on to the thin board which will then be glued on to the final substrate. This is where my experience level is a massive problem . . . . do any of you have any ideas about that ? And I"m still unsure about how I would avoid having the final piece look like it's made up of smaller parts . . . I've attached a rough idea image of the sort of thing i'll be aiming for . . .

[Emma Wood]

WOW your boat looks amazing !! Thanks so much for all the advice. Yes, I thought cutting the panels to follow the lines of the design might be the way forward. But I'm not a dab hand with epoxy and I bet that takes practise! Hmmm . . . I always finish my pieces with Danish Oil and then Renaissance Wax and I use PVA glue so this sounds very technical for me but i'll do some research. Also - d'you have any views on the balance veneer ? It's counter-intuitive to me to balance the 1/8" board . . . as it'll end up being stuck down on to the 3/4". But there will be a fairly large time-gap between finishing the first few boards and getting to glue it on to the final substrate in which time they could easily have warped especially as it's such thin board ! AND I'll have to veneer the back of the final piece anyway . . . !

[Malcolm McLeod]

I'd probably try to build the substrate first; basically make your own custom sized 'plywood' sheet.

I've no idea of your thickness or weight restrictions, but if you could live with 3/4" thick, layout 4x8 sheets of 1/4" MDF(?) to make your 12x12 first layer. Spread glue of that surface, layout the same pattern of 1/4" MDF - just rotate it 90 degrees. Spread glue on the 2nd layer and repeat the pattern a third time - again with a 90 degree rotation. Bag it and vacuum press it. Don't know where you'd get a bag that big, but assume you could make one up.

Play around with the pattern to make sure that no seams line up in consecutive layers. Once this is done, you can start placing the surface veneer blocks on. Either start in the middle and work out, or start on an edge and work across. Re-close the bag and press areas of a size as required by your glue open time and placement speed...?

Caveat: I've done some veneer work, but nothing even close to this size.

Edit: Quick napkin sketch of pattern leads me to think you might have to rip one 4x8 sheet in each layer (into 2 ea 2x8 sheets) to give you a better pattern and no common seams.
Edit2: Forgot MDF is available in 12' lengths. Simplifies pattern, but complicates handling it.

[Lee DeRaud]

I've no idea of your thickness or weight restrictions, but if you could live with 3/4" thick, layout 4x8 sheets of 1/4" MDF(?) to make your 12x12 first layer. Spread glue of that surface, layout the same pattern of 1/4" MDF - just rotate it 90 degrees. Spread glue on the 2nd layer and repeat the pattern a third time - again with a 90 degree rotation. Bag it and vacuum press it. Don't know where you'd get a bag that big, but assume you could make one up. Sanity check: that's the equivalent of 4.5 sheets of 4'x8'x3/4" MDF...which works out to something upwards of 400 pounds.

If nothing else, I don't see any way to pick it up and move it without flexing it enough to make visible seams the least of your worries.

[Malcolm McLeod]

... any way to pick it up and move it without flexing ...

Larger & heavier sheets of glass are moved every day. Call a rigger. Give them your specs on the amount of flex allowed.

[Lee DeRaud]

IMHO, obsessing over visible seams in a flat picture this big is a bit pointless. (The boat is a bit different beast: like a car, the flow of the surface and defects thereof are what draw the eye, not the intricacies of the pattern.)

Plan A: I'd do the thing as nine 4'x4' chunks on maybe 1/4"-1/2" MDF/ply, paint the edges black, and hang them floating out 2" or so from the wall, with roughly the same size gaps between the chunks. (Am I the only one who remembers some of the wall-sized photos done with Lasertile?)

Plan B: Break up the bike into irregular chunks in that same size range. Front wheel, rear wheel, tank/frame, rider, a couple more for the background. Hang as described above, making the gaps part of the composition.

[Lee DeRaud]

Larger & heavier sheets of glass are moved every day. Call a rigger. Give them your specs on the amount of flex allowed.I see you ignored the problem of getting a 400lb+ slab in and out of the vacuum bag...

[Gary Hair]

I see you ignored the problem of getting a 400lb+ slab in and out of the vacuum bag...

A forklift with extended forks would make that a non-issue. Lift it up, put the bag around it, set it back down.

[Emma Wood]

Lots of food for thought here. Thank you so much. Will mull this over . . .

[Emma Wood]

Yip - my original plan was to hang it with gaps and make it part of the composition as I couldn't figure a way to make it one whole panel. But I can't give up the idea of one massive panel - it would look incredible !! I've seen one as well, made in Mysore, India. I have been desperately trying to locate the guys that made it and see if I can get any tips . . .

[Lee DeRaud]

A forklift with extended forks would make that a non-issue. Lift it up, put the bag around it, set it back down.No well-equipped woodshop or artist's studio should be without one. :cool:

[Emma Wood]

yes, cos of related forklift issues - I'm going to have to press the panel in pieces. Maybe I'll get it all pressed on to 1/4" board in sections and then glue on to the substrate with contact adhesive. If I did it that way, I still don't know how to manage the balance veneer tho . . . any clues ?

[Malcolm McLeod]

I see you ignored the problem of getting a 400lb+ slab in and out of the vacuum bag...

No, I just thought it was fairly simple. Not that it matters, but most folks would just build it on half of a large sheet and fold the sheet in half. Fold and clamp the edges to create a vacuum bag.

[John Blazy]

Veneering panels on both sides of ply or solid is for two main reasons: because of warping due to the shrinkage of the glue during cure, which is why backs need cheap "backer veneer" to balance the panel, and second, the backer seals the back to reduce taking on of moisture that causes warping.

So I have eliminated that in several veneerings that I have done by not using a glue the shrinks. My favorite veneer glue besides epoxy, is PL premium polyurethane constructon adhesive. Way cheaper then Gorilla glue (which I also like), and foams less. Both expand as they cure, are waterproof, and wont shrink lik PVA. I would suggest gorilla glue, due to its lower viscosity, easier to roll, but it will expand through the pores of the veneer and be white when finishing, although I dont know that for sure, just surmising. It may actually be great, so try some on mahogony where it WILL expand through the pores, sand and maybe the clear coat will wet out the glue filled pores. However, I have veneered with PL, and it looks like it wont roll out flat when you squirt it out of a caulk gun, but it will. Use a solid rubber brayer type roller, and it is surprisingly easy to roll out a uniform thickness. When you roll it out and it looks like you dont have on thick enough, it IS thick enough. It will give you lots of open time to position the pcs, then cover with plastic film, caul and press it.

The "balancing" stage will come when you glue these veneered panels to the thicker back panel, which, of coarse, I would use PL to do that. No need to clamp it either, just weights.