Finishing MDF for a desktop

[DrkSide]

I am getting back into the side home business so I need to get another desk. I have looked for one at the normal places but it seems they are a little out of my price range. I was thinking of just a basic 2x4 structure with a MDF top since it would be easy and relatively cheap. Now what I am looking for is something to seal and protect the MDF since it will soak up water and spills like a sponge. I was thinking of rubberized undercoating or something similar. Anyone have any suggestions or tips as to what to use.

[ludi]

Either a sheet of tempered glass, a sheet of formica, a sanding sealer followed by multiple coats of polyurethane, or some sort of laminate flooring material. AFAIK there isn't much else you can do to make an MDF surface into a smooth, desk-durable surface.

[DPete27]

Buy some solid core oak plywood. Then you can stain/finish it however you want and it will look nicer and be stronger than MDF

[nanoflower]

Using MDF and polyurethane will work as I did that many years ago when I didn't have much money. It took a lot of coats of polyurethane over multiple days and a couple coats of stain but it turned out okay and was a huge table. I had a table that would have sat eight if it was used for dinner and it was strong enough to hold everything that I had in the way of computer gear at the time.

[Darkmage]

I concur on the polyurethane sealant. It will take a lot, as MDF is thirsty stuff.

I built a subwoofer a few years back with two 3/4" MDF disks that I glued & pressed together. Routed the edges, painted it black and then sealed the hell out of it. It still thumps with the best of them and repels liquid spills with no problem. It's a decent amount of work, but it's doable.

[Captain Ned]

Another potential is MDO. Takes paint like a champ.

[ludi]

I concur on the polyurethane sealant. It will take a lot, as MDF is thirsty stuff.

Another good reason to use sanding sealer if finishing over raw material or an oil stain. Dries rapidly, and can prevent the wood from trashing the first 1-2 coats of poly which typically need a half day each to obtain a workable cure.

[JiveMiguel]

Depending on what your size requirements are, instead of MDF, I would recommend a piece of kitchen/bath counter top. I have a 10 foot section of that sitting on a 2x4 frame. The Formica surface is durable and I like that it's got a nice rounded front edge. It's fairly cheap too. The only downsides are that it's only 20 inches or so deep and you don't really get to pick the color. But I just went to the local Menards and found a piece that was fairly neutral. I think it was about $2/foot or so.

As far as covering MDF, I saw a woodworking show on PBS the other month that talked about what to do with edges on MDF...that they couldn't be finished to look as good as the top. They recommended putting a film of joint compound (drywall mud) on the edge. Sand when dry and then the you could paint it and it would turn out as a smooth finish. I'm not sure how that would work if you did that to a whole surface, or how well it would hold up. But that could solve the issue of having to put coat after coat on.

[Jambe]

I don't see why a rubberized coating wouldn't work. My only concern would be that many of those coatings are tacky — you'd probably want to make sure you got one of the slick-curing kinds, unless you want a tacky desktop. lol, you could just get the board sprayed with Rhino Lining (or equivalent).

You could just laminate it with cheap pine 1x's (I've done that to MDF before). Looks nice after you surface and coat them. I like JiveMiguel's suggestion of a counter top. It'd save you from having to deal with dangerous resin-filled MDF dust...

[DrkSide]

Thanks for all of the ideas guys. I will put them to work here in the next few months but for now I am actually buying a desk off of craigslist that I found and will actually fit the size I need. The desks that I was looking at were about $600 and I knew that I could build one alot cheaper than that but since I found one for $100 I am just going to pick it up.