Replies

1. 
   johnnyd | Jul 19, 2004 06:07pm | #1

   Look into MDF, Medium Density Fiberboard.  Takes paint really well and is structurally stiff.  Machines well, but the dust is a pain. 

1. 
   DanH | Jul 20, 2004 08:40pm | #9

   If I'm understanding you correctly, MDF should be fine. I built the cases of some cabinets in our family room using MDF for the carcass and they've held up fine for about 10 years now. (Used plywood for the shelves and doors.) And MDF is cheaper and easier to work with than most of the alternatives.

   For actual shelves another alternative is Homasote (not sure what the generic term would be, if any). It's prized by model railroaders (as a base for layouts) because it light and easy to work with but doesn't sag over time.

1. 
   Sphere | Jul 20, 2004 10:23pm | #10

   not homasote..

   Homasote is cardboard fibers. 

   Spheramid Enterprises Architectural Woodworks

   Repairs, Remodeling, Restorations. 

1. 
   jackplane | Jul 20, 2004 10:52pm | #11

   ditto what he said. Homasote is like papier- mache. Not at all recommended for shelves.

2. 
   djohan | Jul 19, 2004 07:44pm | #2

   Actually, I would avoid using MDF because it has so little lateral strength, especially if the shelving will be in the open where it can be seen.  MDF does finish nicely, but it needs an unusual amount of support to stop the shelves from becoming wavey from the load.  Even a 3/4 MDF board supported 24 inches on center supporting it's own weight, will sag in the period of a few months.  I use 3/4 plywood for shelving and reinforce the front and back edges with 1-1/4 inch solid stock if you want really strong shelves.  I support 40 inch long shelves this way loaded with National Geographic magazines.  I estimate that the load on the shelf exceeds 40 pounds, and after 10 years of storage, there is less than a 16th of sag across the length.

   Regular AC plywood finishes very poorly with paint, so you need to buy birch plywood, which is much more expensive.  With careful layout ahead of time, you can maximize the amount of shelving from a sheet of plywood, and overall, the price is not too bad.  I would consider using a sanding sealer first coat sanded lightly, then a couple coats of good paint.....oil base if possible.  The edges of the plywood will have to be covered with iron-on wood tape made for that purpose.  Do not use the white iron-on tape uses to cover sides of MDF boards since it will not take paint.

   Good luck.

1. 
   1110d | Jul 19, 2004 08:35pm | #4

   Perhaps MDO is your solution.

2. 
   johnnyd | Jul 19, 2004 09:12pm | #6

   Agreed, but he said the shelves will be GLASS.

3. 
   UncleDunc | Jul 19, 2004 08:30pm | #3

   Fine Woodworking #170 (June 2004) had an article on MDF for casework. Looked informative to me, and addressed painting in some detail. Should still be available from Taunton if you can't find it at magazine vendors or at the library.

4. 
   DANL | Jul 19, 2004 09:00pm | #5

   I think Tim had a good idea--MDO (medium density overlay) also known as signboard. Strong and takes paint well (highway depts use it for street signs and such). The shelves will be glass, if I understood you correctly? Another material that is supposed to take paint well is poplar. If you were to use some other wood because it's cheaper or whatever and you are worried about sap and such, use white pigmented shellac as the first coat to seal those things in.

1. 
   MrTK | Jul 20, 2004 05:11am | #7

   Thanks for the insight.  I haven't used MDO before so a little investigation is required.  I too thought of Popular.  Thanks again and will let all know how the project turns out.

1. 
   DANL | Jul 20, 2004 02:45pm | #8

   Good luck with it; yeah, I'd like to know how it turns out.

5. 
   Davo304 | Jul 22, 2004 09:14am | #12

   Poplar paints up very nicely. Go to a hardwoods dealer and ask for some S4 boards ( S4 stands for sanded on all four sides)...these will be 100% free of knots. A cheaper wood would be white pine or even doug fir...I'd buy 2x material from my loacl lumberyard if using these and then plane them down to about a 1inch thickness.  As mentioned earlier, use shellac based primer and knots will not bleed.

   MDO is very expensive. Homosote is not acceptable choice...I use it for bulletin boards! MDF will definitely work but is EXTREMELY dusty when milling.  Price is economical...but no good if case is taller than 8ft since sheet goods come in 8ft. I imagine this would not pose a problem since proposed cabinet is to fit underneath existing stairway...right?

   Anyway, if me, I'd go with real wood.  Poplar would be my first choice. It can be expensive, unless you buy from a regular hardwoods  wholesale lumberyard.  But, compared to avearge construction grade materials, working with poplar is a joy to work with... it cuts and mills easily...takes paint extremely well, and has a nice solid feel to it. Poplar is definately an INDOOR wood only...will rot fast if used as an exterior product. But for your needs, it would work nicely.

   Davo