Want Advice: Protecting MDF From Water Contact

Whoops! I left out the word don't --- I don't plan to submerge the top.

----------------------------------------------------- Has anyone had experience with a water protective finish for MDF? I have a work table with an MDF top, and I briefly set a glass of ice tea on it, and the wet spot swelled up. Fortunately, it wasn?t permanent. I saw that Pat Warner saturated his router table top with Watco. I wonder how that worked out.

I have on hand Watco, Exterior Watco, Waterlox, and several types of varnishes. What would be best? I plan to submerge the top, but I don?t want water soaking in on contact.

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When it gets crapped up, replace it.

Probably less costly than a can of paint.

Lew

Maybe a polyurethane varnish, floor paint or apply Formica over the MDF. If unprotected wood gets wet, it will swell.

Best bet would be covering it with a layer of something else that is less fragile. Any type of protectant or finish that soaks in may weaken the binders in the MDF, and a pinhole in any surface finish will be an achilles heel.

Plywood, plastic laminate, metal sheet...

A sheet of Formica (HPL from anybody) is, IMO, one of the better solutions. Most adhesives won't stick to it (depending on the choice of laminate finish ie, the satin-like finish works best), easy to clean, and cheap. Many laminate distributors have discontinued colours that they will sell for cheap. I bought 50 4 x 8 sheets for $8.00 per sheet, which I use as backers for custom laminate countertops. MANY of the mish-mash of colours had a good reason to be discontinued, there's some fugly colours in that pile. A simple painter's razor blade scrapes justabout anything right off. We use it for glue-ups all the time. For some reason Titebond III really sticks to it..... mmmmm

I have wiped a couple coats of poly on MDF and hardboard to help protect it. Seems to work OK but I haven't exposed those surfaces to a lot of wear.

A sheet of Formica (HPL from anybody) is, IMO, one of the better solutions. Most adhesives won't stick to it (depending on the choice of laminate finish ie, the satin-like finish works best), easy to clean, and cheap. Many laminate distributors have discontinued colours that they will sell for cheap. I bought 50 4 x 8 sheets for $8.00 per sheet, which I use as backers for custom laminate countertops. MANY of the mish-mash of colours had a good reason to be discontinued, there's some fugly colours in that pile. A simple painter's razor blade scrapes justabout anything right off. We use it for glue-ups all the time. For some reason Titebond III really sticks to it..... mmmmm

I use a cabinet scraper to remove TBIII from plastic laminate.

TBIII will come off alright, just seems a bit more difficult. TBIII pops right off gloss laminate though.

Formica.

On Wed, 9 Dec 2009 20:55:09 -0800 (PST), the infamous " snipped-for-privacy@aol.com" scrawled the following:

I've always loved Waterlox, so I'd use that: 10 handrubbed coats or 4 brushed coats. I much prefer handrubbed to brushed. Use 420 grit between coats if you feel any roughness at all. I handrub two coats the first day, then go to one coat a day at quickest. I really like drying time, even with quick-drying products like Waterlox. More screwed-up finishes have been had from hurrying. None from waiting.

I would let that ring dry out WELL before you sand it and seal it. Otherwise, once it does finally dry out, you'll have a ring dip in the tabletop. A light bulb about 8" off the surface should dry it out in a couple days. Let it cool well before starting, and even though it's not real wood, use a quick wipedown with lacquer thinner or mineral spirits before putting the finish on half an hour later. Again, I wait for the thinner to be completely gone before I start work.

Oh, wait, you said you plan to _submerge_ the top. Forget using MDF for that, -ever-. Any pinhole leak will blow the thing out in 5 minutes.

-- To know what you prefer instead of humbly saying Amen to what the world tells you you ought to prefer, is to have kept your soul alive. -- Robert Louis Stevenson

I agree.

A sheet of Formica (HPL from anybody) is, IMO, one of the better solutions. Most adhesives won't stick to it (depending on the choice of laminate finish ie, the satin-like finish works best), easy to clean, and cheap. Many laminate distributors have discontinued colours that they will sell for cheap. I bought 50 4 x 8 sheets for $8.00 per sheet, which I use as backers for custom laminate countertops. MANY of the mish-mash of colours had a good reason to be discontinued, there's some fugly colours in that pile. A simple painter's razor blade scrapes justabout anything right off. We use it for glue-ups all the time. For some reason Titebond III really sticks to it..... mmmmm

Maybe thats why it is called Titebond. WW

Two part epoxy paint...specifically Rustoleum Industrail Mastic, not cheap but waterproof & very durable. Not great for sun exposure though.

cheers Bob