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repairing 40 yr old marquetry coffee table

by worldgeezer
posted 11-28-2018 01:29 PM


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61 replies

61 replies so far

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shipwright

8378 posts in 3305 days


#1 posted 11-28-2018 01:50 PM

Your picture will help a lot but:
-The pieces can be flattened easily by spraying with a little water and pressing (preferably between hot cauls but not necessary.)
- Liquid hide glue (Old Brown Glue preferred)
- If the pieces are flat you only need glue on the substrate but it certainly doesn’t hurt to coat both surfaces. (Nothing to do with relieving tension.)
- If you can assemble the piece on tape first and apply as one piece, that is definitely the way to go.
- 1/8” is pretty thick for marquetry so a good sanding won’t hurt it. It will also bring back the original colours.
- I like shellac, French polish to be exact, but a padded or even brushed shellac finish will look great and more importantly be reversible.

Feel free to PM me if you like.

-- 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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Rich

4969 posts in 1096 days


#2 posted 11-28-2018 02:49 PM

Of course you can PM about this, but if you’re amenable to keeping it in the thread, I’d like to follow along and learn something.

-- There are 10 types of people—those who understand binary, and those who don’t

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worldgeezer

37 posts in 323 days


#3 posted 12-01-2018 11:17 PM

hello shipwright

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worldgeezer

37 posts in 323 days


#4 posted 12-01-2018 11:20 PM

well, for some reason, photos don’t post …

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worldgeezer

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#5 posted 12-01-2018 11:23 PM

still working at cleaning up the various pieces of veneer, almost done with that.

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worldgeezer

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#6 posted 12-01-2018 11:33 PM

however, given that I might get to taping the various pieces together (prior to re-laying on the substrate), and that these pieces are about 1/8 thick …

should I put glue on the edges when assembling them together? Except for the center “medallion” (about 6” x 6”), the pieces are reasonably large.

Thanks,

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shipwright

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#7 posted 12-02-2018 12:18 AM

A picture would really help. You should be able to attach one by clicking on “img” above the comment box and following the prompts as long as the picture is stored on the device you are using.
Failing that PM me and I’ll give you my email address. To PM me click my avatar to go to my profile page and then click “send message” under my avatar there.

Welcome to LJ’s. It gets easier.

-- 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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worldgeezer

37 posts in 323 days


#8 posted 12-02-2018 02:53 AM

note to Shipwright … used Internet explorer to attach pictures; chrome browser wouldn’t work

light colored warped veneer is birds eye maple; it’s still flexible enough that I can flatten it by hand;
the center dark-red is Amaranth / Indies; it also has some warp but not as much as the maple;
dark lines are ebony, some of which is brittle.

I’ve gotten all veneer pieces off now, scraped & sanded off all the adhesive. Will likely need to rough sand ( # 50 ) to enhance adhesion of glue.

the border (multi-veneer) is still affixed to the substrate. it doesn’t seem to be coming loose … though I’m wondering whether it would be better to remove it … probably also attached using double stick tape.
What are your thoughts?

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shipwright

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#9 posted 12-02-2018 04:13 AM

The picture makes a lot of difference. Is the ebony just the border around the maple or is there a strip between the maple pieces?
To keep thinks manageable I think I would try to get the ends done first probably one at a time. This would include the ebony strips and the maple pieces.
I would recommend Old Brown Glue and whatever you have for pressure. First choice mechanical press, second vacuum, third clamps and slightly curved cauls. All will work.
Once that is secure you can get the amaranth done and finally the smaller pieces. They could go in as a group with tape.
Dry fit as much as you can to be sure things will fit and be prepared to make little adjustments if necessary.

When all that is back together you could give the other pieces a little pry to see if they come off. They will be easier to place with the centre all done.

Does that sound doable to you?

-- 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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worldgeezer

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#10 posted 12-02-2018 07:53 PM

reply

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worldgeezer

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#11 posted 12-02-2018 08:01 PM

replies to comments above:
The picture makes a lot of difference. Is the ebony just the border around the maple or is there a strip between the maple pieces?
> ebony border outlines all major pieces. See attached above. I’ll try to attach a top-down photo to this message. Ebony strips are about 1/8 wide.

To keep thinks manageable I think I would try to get the ends done first probably one at a time. This would include the ebony strips and the maple pieces.
> ok

I would recommend Old Brown Glue and whatever you have for pressure. First choice mechanical press, second vacuum, third clamps and slightly curved cauls. All will work.
> will have to be mechanical press using clamps and blocks. Would love to use a vac bag, but not sure that I have enough time to apply OBG, then place pieces in sections, then get it all in the bag. Or?

> With your earlier suggestion on cauls (hadn’t heard about them before), ... seems that I would need enough cauls side by side to cover the entire top, because of the number of different sized pieces and the layout, eh?

> OBG … have done some reading on it. Seems that it needs to applied hot? That could make things interesting.
> Would PPR glue be easier to handle?

Once that is secure you can get the amaranth done and finally the smaller pieces. They could go in as a group with tape.
> great idea to group amaranth with medallion

Dry fit as much as you can to be sure things will fit and be prepared to make little adjustments if necessary.
> right. great suggestion

When all that is back together you could give the other pieces a little pry to see if they come off. They will be easier to place with the centre all done.
> Ah, OK. makes sense.

Does that sound doable to you?
> very helpful comments. Many thanks. This is evening enjoyment after regular work, so quite likely I would need to do it in steps.

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Rich

4969 posts in 1096 days


#12 posted 12-03-2018 12:13 AM

One tip I picked up to locate loose veneer is to just tap it sharply with the tip of your finger. You’ll immediately be able to distinguish between the sound of a solid surface and one that’s separated.

-- There are 10 types of people—those who understand binary, and those who don’t

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shipwright

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#13 posted 12-03-2018 02:01 AM

Vacuum bags are over rated IMHO except for very large pieces. I have one and have never used it since I built my mechanical press. I have several reasons but they aren’t relevant here.
All you need is a piece of 3/4 MDF or plywood (the platen) the size of the area you will be pressing and two or three or more if you like pieces (like 2×4’s) that are slightly curved on the bottom (the cauls) to clamp across the platen. The curve means that when you clamp the ends the centre still gets pressure. The amount of rocker should result in even pressure on the centre and edges. It doesn’t take much.

OBG will give you lots of time. It doesn’t need to be hot, just warm. It is hide glue so it is reversible. You want that.

Did I miss anything?

-- 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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worldgeezer

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#14 posted 12-03-2018 02:51 AM

Thanks for all the help, Paul.

I think there might be two questions still:
a) since the veneer is about 1/8 thick, should I try to get some glue on the edges of veneer pieces that are contiguous. Perhaps some of this will happen anyway.

b) try this project as a whole (all at one time), OR in three parts 1. birdseye maple + ebony strips, 2) amaranth and medallion 3) birdseye maple + filler ebony strips.

and a new question: should I score (or lightly sand with # 50 paper) both the substrate and the underside of the veneer to enhance glue adhesion? Both seem rather smooth due to scraping off the old glue.

eric

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worldgeezer

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#15 posted 12-03-2018 02:55 AM


One tip I picked up to locate loose veneer is to just tap it sharply with the tip of your finger. You ll immediately be able to distinguish between the sound of a solid surface and one that s separated.

- Rich

Hi Rich, thanks for the tip.
I’ll give it a test tomorrow.
Seems likely that I might find some places where this is true since the original adhesive was double sided tape, and it wasn’t all that difficult to remove the veneer in the central part of the design.

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shipwright

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#16 posted 12-03-2018 03:58 AM

- I think it will happen incidentally anyway but there is no harm in wetting the edges as you assemble.
- if you can assemble it all ad dry fit it successfully then glue up and go for it. If you want to take it a little at a time, that will work too. All at once will require an organized and fairly quick moving process as well as a bigger platen and more cauls and clamps but if you can pull it off it is the best way. I think you have more opportunities for it to go sideways that way however.
- yes scratching it up is a good idea. You can do the substrate with opposing diagonal scraping with a hacksaw blade.
(If I thought you had a toothing plane I would suggest that.)
You can also wet the substrate (warm water) before applying the glue if you are using OBG. It will enhance your working time.

-- 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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worldgeezer

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#17 posted 12-09-2018 01:23 AM

Hi Paul
Have another query for you:
All 8 large pieces (amaranth, birdseye maple), are currently “in press” to straighten the curl or warp. I dampened them, then wrapped in paper towel, pressed for an hour or so, then switched to new/ dry paper toweling, then put them back in the press. They are cool to the touch (it’s about 55 degrees F in the garage). I rather doubt they are completely dry yet.
Since it’s likely to be next weekend before I get back to this project I’m wondering if there is some way to stack these pieces so that they air dry completely?
Perhaps in layers with slats in-between, all under a weight of some kind?
Thanks

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shipwright

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#18 posted 12-09-2018 02:29 PM

The best way to keep them flat is to keep them pressed. Just change te paper every day. You can dry the used paper and use it again. If you let it air dry even with weight, it may curl again. Best to keep it flat until it is pressed to the substrate.

-- 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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Sylvain

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#19 posted 12-11-2018 10:12 AM

Paul, what do you recommend between the veneer and the platen to prevent them gluing together?

-- Sylvain, Brussels, Belgium, Europe - The more I learn, the more there is to learn

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shipwright

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#20 posted 12-11-2018 02:40 PM


Paul, what do you recommend between the veneer and the platen to prevent them gluing together?

- Sylvain


I always use a couple of layers of paper between the glue-up and the platens to prevent unintentional sticking. The paper can be removed with water after the (hide) glue dries. I use clean newsprint, available as packing paper in convenient size from stationery suppliers and movers.
It is also perfect for drying wet veneer when flattening.

-- 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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worldgeezer

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#21 posted 12-22-2018 05:30 PM

finally getting back to this project.

Paul, you’re correct I don’t have a toothing plane – hadn’t heard of it before.
A little research led me to think that I could use a coarse saw blade to scrape the surface to achieve the same (or at least a similar result. Seemed to work well both for the substrate (40 yr old plywood) as well as for the underside of the large veneer pieces.
See pictures.

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worldgeezer

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#22 posted 12-22-2018 05:36 PM

Well, not quite (but I don’t know how to orient the picture correctly).
Definitely a digital migrant, I am.
Any of you admins have my blessing to turn the pictures correctly.

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worldgeezer

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#23 posted 12-22-2018 05:42 PM

When I started to prep the underside of the center diamond (about 6” square), I realized that it had too many loose joints and the ebony trim (about 1/8) around the edges were mostly loose, so I blue- taped the upper side, cleaned off the old glue where possible between loose joints, then used OBG between the loose joints, covered it with wax paper then put it in my “press” (1” MDF)
see picture.
We’ll see tomorrow how this center piece turns out.

And if anyone really wants to know, my “workbench” is the freezer in the garage, covered by a discarded piece of counter top. No drawer space though. :)

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worldgeezer

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#24 posted 12-27-2018 03:08 PM

27 December update
25 December pm: re-glued all the veneer, laid down wax paper, put it in my “press”
27 December am: opened it all up, used damp warm rags & flat scraper to remove squeezeout OBG. Not too difficult to do, other than where there is difference in thickness between veneers. The ebony stripes are noticeably thinner than the birdseye maple, and some squeezeout had filled in there.
I layered it with paper towels to dry the veneer again … will change those out regularly over the next several days.

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worldgeezer

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#25 posted 12-27-2018 03:08 PM

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worldgeezer

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#26 posted 01-01-2019 05:19 AM

Background
have now re-glued (OBG) the central pieces of the design back on to the substrate.

I’ve removed all the “loose” (=easily removed) veneer ribbon around the edges. Most of it needed to come off. It was glued to something like card stock which was then glued to the substrate. Or, perhaps it was double sided tape that has disintegrated. One section seems to have been repaired earlier, based on the observation that it is (now) firmly glued down. (will try to post pictures tomorrow). I have all the ribbon pieces taped together into several larger “units” using blue tape.

I’ll need to clean (and rough up) the plywood substrate.

Will need to do the same to the underside of the ribbon, though this could be a bit challenging since it’s just taped together (very little glue between the pieces). Any suggestions on how to approach this?

Then, after gluing all the pieces back down, I’m going to have a fairly uneven surface since no two types of veneer are the same thickness.
It’s almost a philosophical question.
a) This being a “restoration” job, just re-glue the veneer pieces, don’t change the original work any more than absolutely necessary.
b) after re-gluing the pieces that make up the ribbon, scrape it to where the various veneers are reasonably level. This could be a lot of work.

On a somewhat related question, and especially if option “b” is chosen, then would I use some sandpaper to smooth away any scraper-marks?
Which grade of sandpaper?

Your thoughts?

thanks

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shipwright

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#27 posted 01-01-2019 04:46 PM

Sorry, I’ve been away. I ended up in the hospital for a week over Christmas.
Looks like you have it well in hand and at doing a great job on the restoration.
To answer your questions:
-Use a finer blade like a hacksaw on the more fragile pieces. Actually it is all that is needed anywhere. Even coarse sandpaper would be fine.
-Your choice about leveling or not. Personally, I would. You can scrape or sand whichever you like. If you sand just be careful not to oversand the edges. Start coarse (60-100) to level and then go through grits down to ~240. Random orbit works better on marquetry than linear sanding as there are so many opposing grain directions.
You are doing a great job!

-- 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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worldgeezer

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#28 posted 01-02-2019 04:06 AM

Hi Paul,

Many thanks for the suggestions. Glad you made it out of the hospital.

Now that I’ve completed cleaning the underside of the ribbon, (I have it all taped into about 8 pieces plus some pieces of longer veneers), I’m wondering the best way to get OBG in-between all the little pieces of the ribbon.
Only idea that occurs to me (obviously a newbie here), is to leave it taped, but fold along the joint lines, apply glue along the joint lines, then straighten it again (some squeezeout is inevitable, but will be on the underside, hence not a big problem.
Then, apply glue to the substrate, press the taped sections in place, wipe down, then wax paper, clamps, etc.

The alternative seems to be to glue and hand-place each separate piece. Sure to be a sticky job.

Scraping that old glue from the veneer pieces … found at least four different glues, including white glue in a few places; other places – some kind of brown glue that had crystallized; in some places likely some kind of epoxy;
In other places some other kind of brown glue that could be scraped off in a flexible layer (?possibly an OBG or equivalent? but it didn’t respond to warm humidity like standard OBG does).
I finally figured out that it helped to use warm water and damp rags to try to soften some of the glue, though that didn’t work everywhere.

There was (something like) card stock under all of the ribbon. Would have been interesting to ask him about it. Where the card stock was missing … veneer had come evidently loose and somebody used one of those other glues mentioned above.

I know he had a table saw; I don’t know of any other electric cutting tools for use when making these ten coffee tables. I’m thinking that he must have had a backsaw and miter box or some sort of jig to cut the various angles.

I know he had catalogs from lumber and veneer sellers in Chicago, and made several trips there to pick out veneers. I wonder whether he might have purchased the ribbon already pre-cut (which might explain the “cardstock” underneath the ribbon). But even so, he would have had to cut at least some of the angled pieces by hand.

One or two of these tables have “checkerboard” patterns in the middle (mine does). But the squares were not uniform in dimension as I discovered when I tried to reposition many pieces that had come loose.

There are no written records of his work, and likely no photos either.

Thanks for your help. Paul.

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shipwright

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#29 posted 01-02-2019 04:50 AM

Your method should work fine. I wouldn’t try placing the individual pieces one at a time. That would just be messy. I think you’re doing very well. Keep us posted.

-- 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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worldgeezer

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#30 posted 01-03-2019 01:05 AM

three photos .. final glue up.
a) spreading glue into ribbon joints (taped together, blue tape)
b) detail of corner 4 (the last one)
c) all re-assembled, next: cleaning, then to press

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worldgeezer

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#31 posted 01-03-2019 01:08 AM

Is there some way to orient the pictures “correctly”?
Not finding it in the help files here.
thanks

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shipwright

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#32 posted 01-03-2019 01:28 AM

Looks good.

Edit each picture after you re-orient it. Just a tiny crop will do.

-- 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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worldgeezer

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#33 posted 01-29-2019 01:45 AM

after some work related travel to Europe … an update
had to re-do some of the veneer pieces in the ribbon … too much space between them … not sure why this occurred though some of it seems due to micro size differences in original cutting.
I’d guess some is possibly due to shrinkage. But I don’t really know.

Now, to shellac…. are all shellacs the same? or are some shellac better than others for a veneered coffee table?
What should I look for in a shellac at the box stores? Or would it be better to visit Rklr in the next town over from here?
How does one apply shellac – rag or brush?
I’m also guessing that “in a cold garage” might not be the best idea …what is an ideal temperature?

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worldgeezer

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#34 posted 01-29-2019 01:54 AM

OK, I have a color puzzle

Grandpa described the four veneers in the center medallion as
gray – popular
gold – mahogany
black – ebony
tan – birds eye maple

See attached photo.
birds eye maple, yes, 4 squares
ebony pieces, yes 8 of them (4 pairs of 2)
mahogany (not gold color) 4 pairs of 2 in center.
which means that the poplar picked up a green tint somewhere. I only discovered the green while sanding.
There are some 20 pieces of veneer which have this tint. Interestingly, though, there are other pieces (identified as “hollywood” – visible in the ribbon) which do not have this tint. The birds eye maple also did not pick up this tint.
I have no clues on the original finish, other than that it would have been something available 40+ years ago.
Any ideas?

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shipwright

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#35 posted 01-29-2019 06:18 AM

Green is normal in freshly cut or sanded Poplar. It won’t stay green but will be somewhat greener than other wood near it. I have several shades of green Poplar veneer.
For the best work I like to French Polish with fresh super blonde or platina shellac made up from flakes but for a brushed finish or a simple padded finish the Zinser products are fine. The secret IMHO to a great brushed finish is the brush. Look for Taklon brushes. I get mine from Homestead Finishing Products.

-- 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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worldgeezer

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#36 posted 01-30-2019 03:27 AM

Very helpful … learning all sorts of interesting things here… :)
I have a piece of poplar veneer left over from a different project … not a hint of green in it.

wondering whether I need to apply a sanding sealer to the veneer prior to using the shellac …. or is the shellac sufficient by itself?

How many coats?

And should
a) I apply shellac to the veneer + substrate; and separately to the walnut frame*, then assemble it when dry, or
b) reassemble the table into its walnut frame and then shellac it all?
c) Or?

The walnut frame is about 2.5×3/4 wraps around the table, has a dado-ed groove that the veneer+substrate slides into and locks it into place. It has 45 degree corners … (I’ll have a separate question about the frame, tomorrow).

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shipwright

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#37 posted 01-30-2019 05:45 AM

Poplar comes in many shades.
Don’t need a sealer. Shellac is a great sealer.
Until it looks like enough. Sorry but that’s how I do it.
Assemble and shellac when all done and prepped.

-- 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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worldgeezer

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#38 posted 02-01-2019 02:56 AM

OK, next steps …

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worldgeezer

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#39 posted 02-01-2019 03:09 AM

OK, next steps … the top is sanded reasonably flat, still want to use a higher grit … tomorrow.
Should be warmer and more suitable temperatures for applying shellac.

Different question this time. The top is framed by 4 pieces of walnut. There is a dado into which the top will slide. It’s not a tight fit in any dimension. I presume that’s OK. The shellac may essentially serve to lock the pieces into a single unit.

Gramps (or someone) used metal brackets to attach the four walnut pieces into a frame. See picture.

While it held the frame together, yet the four corner joints were very loose.
I’d rather not do that.

Thus this question: what would be an appropriate way to solidly join the four pieces of walnut? I can think of
1. using biscuits, since if I get it right, they would be concealed … though they wouldn’t be really deep into the 45 degree face of each piece. This one isn’t 100% sure, though since I only have hand-held tools to work with.
2. dowels. not an option that I can visualize
3. just glue … but this would be a rather weak joint.

Any ideas?

Thanks for all the help. This has been a fun project.

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shipwright

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#40 posted 02-01-2019 05:19 PM

If the dados are glued, there should be little strain on the corners and glue alone should do but you could always put a spline in (matching or contrasting, your choice) as people often do in mitred boxes.

-- 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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worldgeezer

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#41 posted 02-02-2019 11:12 PM

Well … what can a dime tell you

While while doing a light sanding after shellac coat #1, the thought occurred to me to check the (relative) flatness of the table, now that the veneers are reglued back in place and sanded level (some were thicker than others)

see pictures

There’s a curve equal to the thickness of a dime. On the top side (veneered), the curve is in the middle, on the bottom side it’s measurable on the two ends.
In other words, the table top has a drop-curve (a slight sag) in the middle,
US Dime = 1/16 inch

What to do?

My guess at this point is that there might not be much one can do.
..except perhaps find some way to clamp it flat for a day or two … or three or

And it’s not hugely noticeable except when one lays a straightedge on it. But round objects would most likely roll to the center

I will note that the bottom side of the plywood substrate is not sealed, so I may well put a coat or two of shellac on it.

Your thoughts?

eric

first picture is at center, from top side of board (straightedge is touching the edge at both sides, on the top)

second picture is at edge, on bottom side of board (same thickness at both edges)

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shipwright

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#42 posted 02-03-2019 12:00 AM

Best practice is always to veneer both sides to balance forces. This is the predictable result of not doing so. It is often not that necessary when the substrate is restrained as in part of a box etc and where the veneer is modern see-through thickness but with your substantial veneer thickness I’d bet that is the problem. I would try even at this time to apply a crossband veneer on the bottom of the plywood. Try for at least 1/16” if you can.
Or you can live with the cup. The problem is it may not be finished cupping…...

-- 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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worldgeezer

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#43 posted 02-03-2019 03:53 AM

Hi Paul,
Ok, we’re well beyond my pay grade on this one.
A quick internet search on crossband veneer … appears to be (essentially) applying a cross-grain layer of veneer underneath the “show” veneer. If so, that makes a lot of sense to me.

I don’t know whether this curve was already present when this coffee table was brought to me, or whether it’s a recent issue.

What I’m working with … substrate is 1/2 inch plywood: 3 internal layers of just over 1/8 inch each, then a top and bottom exterior layer of just under 1/8 inch each, (probably sanded) to reach the 1/2 inch overall thickness. The grain-direction of the top and bottom pieces run parallel to the length of the substrate.

So, “cross band” in this instance means: apply several strips of this wood or veneer to the bottom (the underside) of the substrate.

Most of the veneer (all 8 of the larger pieces) on the surface runs parallel to the length

The “theory” seems to be:

because the curve is 90 degrees to the length,
glue several strips of veneer running across the width. This seems to make sense because it runs 90 degrees from the direction of curve.

Q: Would the actual width of those strips be of significance?

Q: What type of wood is recommended? (If you can list several, it increases the possibility that I can find one locally).

Some of those strips may cover some of granddad’s writing in which he describes the various kinds of veneer in this pattern. Small price to pay to try to stop or at least slow down the curving.

Then, when those cross-band strips are glued and dried, apply several coats of shellac as sealer across the entire bottom. At present, the bottom is completely unfinished.

Thanks again for the considerable help.

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shipwright

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#44 posted 02-03-2019 06:07 AM

The fact that the veneer wasn’t hard glued the first time probably saved it from cupping originally. You always try to place veneers at cross grain to the preceding one. This is what you want to do on the bottom. That’s why I called it a crossband. Obviously you can’t do that with marquetry but the one underneath should be done that way. Width doesn’t matter and use whatever you can find in decent thickness.
By all means take pictures of the writing. There are ways to transfer printouts of it onto wood.

-- 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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worldgeezer

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#45 posted 02-03-2019 06:36 PM

Late thoughts …

1. sanding the top to remove the fresh coat of shellac, let the top re-acclimate to current weather and humidity (quite humid over this past week),
Then after about a week, shellac both sides.

2. Attach angle iron to the underside, rather than wood strips. Less likely to stretch (though I don’t know how much wood actually stretches under tension).

eh?

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shipwright

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#46 posted 02-03-2019 11:36 PM

Worth a try.

-- 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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worldgeezer

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#47 posted 02-05-2019 09:20 PM

OK, have sanded the top.
It’s currently “resting” under about 30 lb of weights laid out over the center of the substrate+top, lengthwise.
We will have variable humidity and about a 30 degree change in temperatures over the next several days.
I’ve found some 40+ year old oak strips to use as crossbanding on the underside. It was about 30 years in an attic in hot summer climate, so ought to be dry enough.
Do you think 4 strips is adequate (about 3.4 inch wide each), placed about 8” apart.

—eric ..............the early bird may get the worm … great for the bird, tough for the worm

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shipwright

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#48 posted 02-06-2019 05:10 AM

How thick? The idea is to be something like the same thickness as the veneer on top and should be a full cover layer but this is an unusual situation. What you suggest may well work. I have no experience in this particular set of circumstances. Sorry.

-- 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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worldgeezer

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#49 posted 02-09-2019 01:46 AM

Paul,
Friday evening, went down to the big box store to look at thin woods, essentially plywood at 1/4 thickness.
It’s quite flexible on both length and width dimensions.

Which leads me to recognize that it would help me (and possibly others) to understand the physics of what we’re trying to do.

The substrate is 1/2 thick. Seems to me that if it’s cupping with the veneer already glued to the top side, then how could a 1/4, several-ply layer effectively restrict or even stop the cupping?

The cupping seems to be relaxing, though just a wee bit thus far. The substrate has been (under weights as described above) since this past weekend. I don’t have significant hope that it would completely flatten.

And your best intuition or guess will be far beyond mine. I recognize that in some way, we’re trying to counteract (what I would call) natural forces of woods, humidity, etc.

Thanks.

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shipwright

8378 posts in 3305 days


#50 posted 02-09-2019 02:02 AM

Plywood is always made with an odd number of layers. It is essentially in balance. When you add another layer to one side, you mess with that balance. Adding a layer to the other side (at least theoretically) restores the balance.

-- 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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