refinishing knoll marble table (transparent polyester coating).  

Marble
One of the reasons for coating these tables is that marble is notoriously susceptible to damage: It stains easily; saarinen tops can break from being lifted by the top with the base still on; an ex Knoll guy told me that chips (in the early ones) were common; Using something as standard as 409 can etch marble. And yes, it's a shortcut to actually polishing the stone.
Using an abrasive to remove the coating would probably mean cutting into the softer stone. Too much heat (from trying to soften the coating) would damage the marble, as a sculptors assistant, decades ago, I used to use torches to make polished granite surfaces pop off for a more textured look. Marble is much more fragile. The separation may be due to the two materials having a different co-efficient of expansion. I would keep it out of direct sun and away from other concentrated heat.

The evidence
presented in this thread convinces me that stone table tops should remain uncoated. They should be treated with care, polished and perhaps waxed periodically. Shortcuts to a high-gloss appearance and easy maintenance are probably just that: shortcuts.

Knoll Table repaired
Hi to all who have marble problems, we have a coating in Australia called .... that will fix your problems this has been used on bar tops for more than 10 years it can be repaired re polished or taken to a matt finish at any time, it is about to be launched in America and other parts of the world.We repaired a Knoll table with it recently it looked great.
You can have a look at the inventers web site
Steve
(edited by DA - no advertising please)

saarinen table top has crack in the clear coating
I too have a saarinen table which has developed silver dollar size bubbles that have a single crack running through each of the them, 4 of them. This is a problem with the clear coating that came with the table. I would like it refurbished but no one seems to understand what I am talking about. Is there a place that deals with this kind of stuff? Your help is much appreciated.

.
Tung oil? Maybe, just did a couple of quick searches and some people do you use it, this link is interesting though, perhaps you could just strip the coat with thinners and then do it yourself, it might not have the look of a glossy spray coating but if the yellowing and peeling is inevitable perhaps thats a good thing.
http://www.stonecaretechniques.com/36_m.htm

Ok so there are a few good...
Ok so there are a few good suggestions to recoat the marble. Try them on small untreated marble pieces and see the result. However if you can't remove the existing coating there's really no point. A friend just sent me a photo of his table with a large stain on it from lemonade.
Has anyone tried to remove the coating? Been (un)succesful?
thanks

Yago7
The Saarinen tables are available from Knoll with either coated or uncoated marble tops; your friend appears to have chosen uncoated.
The damage is typical for acid spills on uncoated marble. The etched surface must be re-polished, so it's not something your friend can easily do himself; he'll need to hire a stone care professional.

Thanks fastfwd, I had no...
Thanks fastfwd, I had no idea. I helped him find the table a while ago through a vintage dealer. I'm just glad it can be fixed. I'll let you know how it works out. Also if he chooses to coat it.

CHIP IN CLEAR COATING
Has anyone had success filling in a chip in the polyester coating? Even Knoll has not been helpful.

I had
a chip in my Knoll coffee table which I painstakingly (is that a word?) filled with about 10 coats of clear nail polish. It came out pretty well--I know it's there but nobody else notices it.

Delaminating Knoll marble table
Great idea. My table, after 20+ years, is delaminating because we had a small hole in the poly surface & put a plant on top of it - protected by a tray, which was cracked, unknown to us - and ended up with a circular delamination. Apparently water seeped under the poly coating through the very small hole/crack & ruined the finish.
All advice is welcome - esp. address of anyone who could remove the finish & apply an identical finish. Thanks so much.

Delaminating Knoll marble table
BTW - I'm in the Bay Area - East Bay.

Finished
I have just come across this thread and feel I need to share my new found knowledge. I have spent the last two years investigating how to recondition an original Marble Saarinen Dining Table and Coffee Table. Both were in ok condition but the original finish had cracked and delaminated in areas, also showed some yellowing. To cut a long story short, including having a dodgy stone polisher sacked from the job, the best stripper to remove the original finish is Aggro stripper available from Euroabrasives and some elbow grease. I did attempt Silacryl to create a new finish on the coffee table, but I just could never get it perfect, so I removed it. I must also say that now that the original marble is exposed, it is a brilliant finish.
Now I have a young family so protecting the marble is very important to us. We have since had both marble tops professionally polished to a high gloss, by another stone polisher I am happy to recommend, as recommended by CDK (Australia) the importer for Lithofin. A Lithofin impregnating sealer was then applied - 4 coats.
The finish is whiter and has greater depth of colour in the marble than the original, after a week of being very sensitive about anyone going near the table it is back into use as always.

Transparent Polyester Coating ALERT!
Quite interestingly, relative to this thread, you all should know that the following was brought to my attention by an interior designer friend of mine who has extensive knowledge regarding marble stone: she says that Knoll still produces tables with a toxic polyester sheet as a sealer on their tables. This creates a hazard if the tables are being target for use as a dining table. Furthermore, after several years, the polyester sheet may yellow and/or crack, opening the surface up for potentially damaging contaminants. That is the reason Knoll has apparently recently introduced an alternative to the toxic transparent polyester coating. Perhaps due to the negative reaction the reasons for this manufacturing change might create, Knoll has made a particularly surreptitious transition as most of their licensed retailers are now offering an alternative (new satin) finish, or two coats of sealant and two coats of wax to ensure a durable and NON-TOXIC finish. If you're considering purchasing this table (it certainly is a gorgeous piece), it might be wise to opt for a finish of the NON-TOXIC variety. Should anyone be able to share additional information in this regard, please post. It is important that our dining room table not only be beautiful, but also durable and toxic-free!

Name one
toxin released by Knoll's coating, please, and point me to reputable documentation that identifies it.
By "reputable documentation", I mean something like this report, which shows that Tenax's Hydrex coating meets Italian regulations for food safety:
http://www.tenax.it/doc/contact%20food%20report%20Drexy__1787.pdf