New Guy Needs Some Guidance

[Bill McDonald]

Hello everyone - new member here. This looks like a pretty nice forum - glad I found it. I'll have a lot of fun reading and looking at the pictures.

I have some questions I hope someone can help me with...

I'm planning on building some cabinets for a room over the garage. Nothing too fancy but I want the finished product to look nice. I'm planning on each cabinet section being about 36"W x 40"H x 24"D. I'll be painting them semi-gloss white. So my question is, can I use 3/4" MDF for the carcass or should I stay with plywood. I'll be building face frames for them so only the ends of the cabinets will be visible on the outside. Maybe MDF for everything except the two outer surfaces?

If I use MDF, is there any special finishing techniques I should be aware of to ensure a smooth finish?

Thanks,
Bill

[John Keeton]

Bill, not a cabinet maker so don't have much to offer except a big WELCOME to the creek!

I have painted some mdf before, and it is like a sponge! I am sure you will get some helpful responses on sealing, etc. to minimize paint absorption. There is also a special screw for mdf - not familiar with the name as I don't use much mdf.

[Craig T. Smith]

Bill, Welcome. I also have read here that there is some concern in respects to the screws you use. You'll learn lots here. Happy Woodworking, Craig

[Joe Chritz]

MDF will make a fine paint grade cabinet but for anything that may take some abuse plywood is usually a better choice. If they are not going to be getting moved around or ran into MDF will work good and it takes paint very well, since it is partly what it was designed for.

If they are going to be white anyway you could also use Melamine (M2 grade if you can get it) although it is harder to cut and get chip free work.

Myself for garage cabs would just go get 3/4 birch or maple plywood and use quality assembly screws available from a number of sources. For the visible sides a dado or pocket screws would work so there are no screws visible. Normally I use an applied panel of plywood or a raised panel but that really isn't necessary for a garage cab.

Also I used to use 1/2 plywood for cabs a lot but the cost difference is almost nothing here anymore so now I use 3/4 and 1/2 for backs.

Welcome aboard and shout out any questions.

Joe

[Bill McDonald]

Thanks for the feedback y'all (yeah, I'm from the south). I will be mounting the cabinets (like kitchen base cabinets) so they won't be moving around. These will be primarily for storage - low use/access. As for the screws, I assume you mean the coarse threads designed for MDF. I have a plate (biscuit) joiner so I thought I'd use that to attach the face frame to the carcass (bad idea?). I also thought I'd use the plate joiner for the face frame. Would investing in a pocket hole jig be worthwhile? I'd probably not use it much after this project.

[Craig T. Smith]

Bill, I use biscuits alot. Just remember they are more for alignment not for strength. I am also thinking about getting into pocket holes. I'm thinking that if you get one you will soon use it for a lot of projects. That's just a few thoughts. Happy Woodworking, Craig

[Von Bickley]

Bill,

Welcome to "The Creek"......

If I was building painted cabinets, I would use 3/4" plywood and use poplar or maple face-frames.
I don't use MDF...... :)

[Eric DeSilva]

Thanks for the feedback y'all (yeah, I'm from the south). I will be mounting the cabinets (like kitchen base cabinets) so they won't be moving around. These will be primarily for storage - low use/access. As for the screws, I assume you mean the coarse threads designed for MDF. I have a plate (biscuit) joiner so I thought I'd use that to attach the face frame to the carcass (bad idea?). I also thought I'd use the plate joiner for the face frame. Would investing in a pocket hole jig be worthwhile? I'd probably not use it much after this project.

I'm guessing he's talking about "confirmat" screws. They are relatively coarse thread, but they are designed specifically for MDF.

One problem with MDF is that it deflects. With a 36" span, I'd spend some time thinking about whether the wide runs will sag. For the bottom, you could always throw in an additional support, but if you have a 36" shelf in the middle, I'd guess it might be a problem.

You indicated it is for a room over the garage--any possibility of moisture at all? MDF is a mess if it ever gets wet.

[Paul Demetropoulos]

I would not use mdf, it's just too heavy. If the main reason you want to use it is for its paintability, think about how much of the carcase will be exposed in a kitchen setting, just one panel on the end units.

I think it would be much easier using plywood which paints up fine with a good primer. If you want a more finished look use an applied panel for any exposed areas. If you want prefinished then use Joe's idea of melamine coated PB.

I personally dislike working MDF. It has its uses for sure, especially in the shop, but its super heavy, messy to work (better have superior dust collection), doesn't hold screws very well, and dulls cutters real fast. And it will be problematic in a wet location.

A great sheet product for taking paint is MDO, it's what they use for the highway signs. It's more like plywood but with a paper coating impregnated with a resin the takes paint better than MDF.

[Bill McDonald]

Y'all have given me a lot to think about. I was considering MDF because of cost and ease of finishing. I've never heard of MDO - I'll have to check into that. Based on feedback, it looks like plywood would be to material of choice.

Since the cabinets will be 36" wide, I was planning on a center support (in the back and behind the front vertical center face frame to minimize the sagging of the center shelf. Hope that works.

Given that only the two ends of the cabinets would show, what grade of plywood is recommended for the carcass? Something different for the shelves?

[Jose Kilpatrick]

When I have to paint mdf, I always lay down a coat of Kilz before applying paint.