Finish on Oak kitchen table, hand-rubbed Poly?

[Douglas Bolt]

Some years ago I refinished an Oak Kitchen table with indoor/outdoor poly. The finish was fine, except it tended to scratch a lot. Probably because they designed the poly for outdoor use and therefore soft enough to expand and contract a bit. Anyway, a couple of months ago, I sanded down the surface with 320 and then re-applied five coats of Maloof's hand rubbed poly. It looked beautiful and felt as nice.

The first time we put a hot plate and a coffee cup on the table, it left a dull stain. It is still very resistant to cold water and everything else I've spilled on it. However, I can see a ring where every coffee cup was placed.

I'd like to know why the surface dulls with heat. And, more importantly, what finish I should use to avoid the problem.

I've placed a picture of the table surface at

Note the uniform dull circles where dinner plates with hot food were placed and the rings where coffee cups were placed.

Can anyone offer any suggestions?

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[DJ Delorie]

I don't know about the staining, but my oak table got three coats of Sherwin Williams floor-grade poly (satin, but next time gloss for all but the last coat). I figured, if it's designed to be walked on, it should work fine on a table. That was about ten years ago, no stains on it yet, and we take plates right out of the microwave to the table.

[Mike G]

Several

Poly takes a long time to cure fully. The more and the thicker the coats the longer it takes. It's the oil in the varnish. They say some of the old masters paintings have yet to fully dry..

Poly, or any varnish for that matter, is essentially plastic.

Plastic and heat don't mix.

You could try one of those epoxy bar top finishes. The ones where one coat looks like 50 coats of varnish. And, of course, coasters comes to mind.

[Douglas Bolt]

DJ,

How long did you let the poly cure before you started using the table? Mike thinks the key is to let the finish cure before one puts something hot on it.

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[DJ Delorie]

I usually wait a week before expecting poly to be tough enough for casual use. But, that's after assembly. Parts get the usual 12 hour wait between coats, and usually sit for a few days before assembly (else the parts stick together).

I'm usually pretty conservative with poly finishes for the first few months, though.

So if it's a cure time issue, I'd miss out anyway ;-)

[Douglas Bolt]

I suspect the problem is caused by not waiting long enough to start using it. I let each coat of rub-on poly to dry 24 hr between each of the five coats, but only 3 days before using it for the first time. Recall that the rub-on did not go on to bare wood, but rather over a well sanded poly put on a couple of years ago.

How would you proceed now? I thought about sanding the entire surface with

400 and then wiping on a couple of coats of a harder poly (or more, if needed to cover the sanding) and then let it cure for a couple of weeks before putting anything at all on it. I thought we might be able to use the table with place mats etc after than.

Do you have any recommendations as to brands of poly?

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[DJ Delorie]

It's a do-over. Hopefully you won't ruin the stain by sanding (I don't stain red oak), perhaps a scraper would be more controllable. Get the poly off. Let it sit for a few days to a week in case the stain wasn't fully cured. Lightly sand at 220 (you want a rough surface for the poly to grab on to) and re-apply the poly. Follow the directions on the can! Poly's strength depends on adequate adherence to the previous layer, and recoating when the directions say to is the best way to do so. Then let it sit for a week before use, and use coasters and placemats for the first month or two.

Like I said, I use Sherwin Williams - whatever the best grade floor poly they offer is. It may not be the prettiest poly on the market, but it hasn't let me down yet.

[Swingman]

Unfortunately, if you really did use Sam Maloof's finish, it is specifically NOT for use on table tops for the very reason you have noted ... say's so right on the can. If you did indeed ignore the warning, your best shot is likely a film coat of something that is compatible with the oil/varnish finish that will withstand the expected use of a table top. Might want to grab a copy of Bob Flexner's "Understanding Wood Finishing".

[Douglas Bolt]

Thanks for the help.

I saw the warning on the can, but I thought it said to not finish up with the oil/was product, which I didn't.

I just ordered Bob Flexner's book used via Amazon for $8.50. Thanks for the tip.

[Swingman]

I am fairly certain that caveat applies to both his commercial finishes, with and without wax. I use the Maloof finish on most of my smaller projects by preference ... IMO, it is an excellent choice for bringing out the beauty of the wood without a factory processed look.

Another option is a glass top for the table. I have an end table that gets quite a bit of use/abuse as it sits between mine and SWMBO's easy chairs. The preferred solution here was to protect the Maloof finished table top with glass.

Short of that, the following is Flexner's ranking, best to worse, of durability of finishes with regard to HEAT resistance ONLY:

Best: Polyurethane and Conversion Finishes Very Good: Varnish (both Alkyd and Phenolic) Good: Oil-Containing Finishes Fair: Nitocellulose Lacquer and Water Based Finishes Poor: Shellac Very Poor: Wax

The above may allow you to make a decision before your book comes in.

You bet ... one of the best books on wood finishing anywhere. If I had my druther's I'd pay someone else to finish my projects, not because of the hassle, but because it is more of an art and science than woodworking and tough to _master_. Short of that, Flexner's book is the next best thing.

[Douglas Bolt]

Thanks for the additional help.

BTW, I liked your website. Nice projects!