Replies

1. 
   tangomike | Feb 14, 2006 08:39pm | #1

   I'd use MDF for everything. Not only does it machine very nicely, it takes a finish very well and is durable.

   There are fasteners specifically for MDF, call Confirmat fasteners:
   http://www.mcfeelys.com/confirmat.asp

   I rarely have a need for these, glue and coarse threaded wood screws work fine for me (definitely drill pilot holes).

   couple of notes on MDF's finishing characteristics, I use tinted lacquer for my cabinets but this should apply to paint as well:
   1) you really need to use a primer
   2) the edges of MDF are like sponges, need an extra coat of primer and a quick sanding to smooth them off

1. 
   Cephus | Feb 15, 2006 11:16pm | #8

   Same here, I just built a set of matching bookshelves out of 3/4 MDF and they work beautifully. They're simple dado'd shelves, put together with glue and screws from the outside, but they're absolutely rock solid. You just have to remember to prime the MDF before painting since MDF doesn't play nice with liquids, but I can't think of an easier, more economical material to build painted cabinets or shelves out of, so long as you're not worried about the weight.

1. 
   tangomike | Feb 16, 2006 12:23am | #9

   I've heard of another technique for finishing the edges of MDF, use your finger to run a thin layer of sheetrock mud over the edge and sand it smooth. Personally, that seems like extra work for me and since I spray my cabinets I find it easier to shoot an extra coat of primer on the edges before laying down my top coat.It's really impressive how durable and stable MDF is, I even built my miter saw station out of it, shot a clear coat of lacquer over it and it's shown very little wear and tear over 2 years of use.

2. 
   Glaucon | Feb 16, 2006 08:30pm | #16

   <"...I just built a set of matching bookshelves out of 3/4 MDF and they work beautifully...">

   MDF for bookshelves- how much of a span? I'd worry about the shelves sagging under their own weight, let alone that of the books...

   I agree that adjustable shelves are really overkill- most folks never change the shelf height after their original set up.  Measure the books and set up the shelves to accomodate them...

   Just my 2¢,Glaucon

   If you don't think too good, then don't think too much...

1. 
   Cephus | Feb 22, 2006 03:21am | #19

   They're 30"wide, but built for a relatively light load and I put in a center support, just in case. For anything built of MDF that I've had to put a decent load on, I've routed a couple 2" slots in the bottom of the shelf and glued in hard wood runners that increase the strength dramatically and they're completely invisible when the shelf is sanded and painted.

2. 
   notDusty | Feb 14, 2006 08:45pm | #2

   merlvern ,

                         I use Maple shop or paint grade 3/4" plywood instead of Birch , the Maple is much smoother and takes paint better for close to or less than the cost of Birch . If this were for an exterior project the MDO ( sign board ) would be best .

              The problem I see with the MDO is where you sand the edges of the face flush to the face you risk going through the paper face of the MDO , not so sure how that would paint over .

              good  luck       dusty

3. 
   GaryW | Feb 14, 2006 08:52pm | #3

   I build cabinet carcases with a Canadian, pre-finished birch plywood with a hardwood core, at $37/sheet. The clear finish is almost industrible, even to lacquer thinner (good for the painter), and it holds confirmat and euro system screws very well (better than MDF and fir-core plywood). The core is without voids so it edgebands well, and it's stiff enough for long shelves, where MDF will likely sag. I use and prefer MDF core products only for doors, drawer fronts and end panels, because it stays flat in those conditions, and it has a smooth flat surface (unlike veneer core products).

   Gary

   gwwoodworking.com

1. 
   merlvern | Feb 15, 2006 04:56pm | #6

   what's that stock called? does it have an industry name? i'm in new jersey and the cheapest that i've found birch ply (unfinished) is $44.

1. 
   GaryW | Feb 15, 2006 08:34pm | #7

   Merlvern,

   It turns out the latest unit I received from Aura Hardwood - http://www.aurahardwoods.com/ - is stamped on the end "Made in China" and the printed tag taped to it has the grade as "Birch White 18mm G2S PF2S VC." I rejected the first Chinese made units a couple years ago, because they cupped and warped after I pulled them from the stack. We think the first loads may have been layed up with too many core veneers running lengthwise, veneers may have been dried incorrectly, or surface veneers were of different thicknesses. I then got material from Canada, as I'd said, but these latest units from China seem good and flat.  Gary

   gwwoodworking.com

4. 
   mudman | Feb 15, 2006 06:19am | #4

   I agree with every thing you stated. I question using plywood for rails and styles as you indicated. Maple, or poplar are the norm for paint grade. here are a few points I'd add.

   MDF shapes very nicely and dust isn't a problem if you have dust collection. The edges require extra attention or they will appear rought through the paint. I use my finger to apply wood putty (the cheep indoor Elmer's product works excelent) to the edges and profiles. Then I sand with 220. MDF is perfect for raised panels due to their stability and paintability. The two very big concerns with MDF are that water will very quickly ruin the exposed edges, even if painted, and when the corners or edges are exposed (as in a table top) they will dent and ding VERY EASY.

   You left out the most commonly used sheet good in cabinet construction, Particle Board. It is as strong as MDF, sags less and weighs less. For cabinet sides that are not visible from the outside you can paint bare PB. If the sides are visible or if you want the inside to look perfect they sell PB that is laminated with a paper face for painting. It is also availible laminated in every real wood, fake wood, melamine, metal, and specialty coverings you have ever imagined. You can even get one side white melamine (inside cabinet) and cherry (outside face). Or what ever combination you want.

   Mike

1. 
   merlvern | Feb 15, 2006 04:53pm | #5

   thanks,what about (with mdf) the sides of cabinets that have lines of holes for shelf brackets....any concern that the "pegs" over time will chip out the edges of the holes? as for the rails and stiles, i misspoke, they, like the edge banding, i intend to make with solid wood.i guess the whole thing here is that i'm trying to discern how much mdf i can use because its the cheapest. i think if i had my wish, i would make the whole thing from plywood with solid wood edges and door parts, but sometimes it is warped, and there is the cost.

1. 
   mudman | Feb 16, 2006 06:51pm | #12

   I don't usually use MDF for cabinet sides, Particle board or plywood is the norm, but unless the shelves will be carying an unusual amount of weight or they will be repositioned frequently I would not be worried. Again you should consider Particle Board. It costs less than MDF and is just as good for that aplication.

   Mike

1. 
   merlvern | Feb 16, 2006 07:07pm | #13

   thanks mudman....i feel more comfortable with plywood also though i know this is a point of disagreement. i found it interesting to note that a lot of the folks, in this post, and others, felt that adjustable shelving is unnecessary. "books only come in a few sizes", and "i find that people don't adjust their shelves". this kind of opens the door (for me) touse mdf for the sides.

1. 
   tangomike | Feb 16, 2006 08:20pm | #15

   "books only come in a few sizes", and "i find that people don't adjust their shelves"

   Add to that the observation that books only occasionally grace the shelves of modern bookcases. I have moved away from adjustable shevling in much of my cabinet work for the reason that it really is unnecessary and fixed shelving enables you more flexibility in the design.

   I still don't understand the reluctance of using MDF for sides, IMO it outperforms plywood in these applications because of it uniform density. PB, on the other hand, I am not a fan of.

2. 
   merlvern | Feb 16, 2006 08:50pm | #17

   i was just worried about the "peg holes" chipping out over time. may not have been a reasonable concern.

3. 
   Cephus | Feb 22, 2006 03:17am | #18

   Honestly, that's what I've done as well. We found that most of the adjustable shelves we've had over the years never got adjusted, or couldn't be adjusted the way that we wanted. Now, I'm just building fixed shelves that are made for a specific purpose and we're a lot happier with them. As a matter of fact, I'm building a CD shelving unit right now with shelves that are just 1/2" larger than the CDs, just large enough to get a fingertip in and pull them out. Our old shelves couldn't be adjusted to that clearance, so there was a ton of wasted space and we ended up with CDs just stacked on top of each other because it wasn't efficiently laid out.Now, we'll be able to fit almost 2x the CDs in the same amount of space.

5. 
   DaveBarker | Feb 16, 2006 01:23am | #10

   I just went through this same exercise, for a client that wanted a set of built in bookcases and base cabinets to go on either side of a fireplace. I really wanted to use MDO. I've used it in the past and really like it; strong, smooth, machines and paints well. Just too expensive. I settled on using cheap, imported okume plywood for $35/sheet. Awful stuff! It's full of voids. I had to patch several places where the microscopically thin face veneer broke through.
   Next time I'll probably use MDF for non load bearing pieces and birch and solid wood for the remainder.

   Regards,
   Dave

1. 
   merlvern | Feb 16, 2006 04:29pm | #11

   thanks for the tips.....probably just as you thought.

6. 
   KeithNewton | Feb 16, 2006 07:58pm | #14

   You should look into using melamine for as much of the interior parts as possible. There is no way that you can finish the inside of a cabinet as good as the finish of melamine, and there is no spray fogging back on you when spraying the inside of the box.

   You will need to drill the holes for the fasteners, and use the system screws.

   The core for melamine is industrial PB.

   I use T-mold for the edges. It is a plastic radiuses front edging with a leg off the center of the back with barbs to hold it in. You cut the kerf with a router, and drive it in with a rubber mallet. Virutex makes a little tool that trims the edges flush with one quick pass.

   You can buy it with one face for the ends, or just overlay the ends with another layer of MDF.