2nd attempt at cope and stick

[stephen wood]

I've made two cope and stick doors for a bathroom vanity. They had 1/4 plywood panels.
This time I'd like to have a raised panel on two doors 15" x 22".
They will be painted white so I'm thinking of using MDF for the panel to avoid wood movement issues. I believe this would also increase door rigidity. What do folks think of this?

I seem to recall reading about sealing the mdf before painting.

[Joe Jensen]

MDF Will not move so you can size it to fit perfectly and it can be glued in the slots. If you panel raise the MDF read about sealing the cut edges before paint. I've read about many solutions. One is watered down glue brushed on, another is shellac, another drywall compound. If you don't seal, the cut edge will absorb a ton of paint and it will "grain raise" a ton of fuzz.

[Jim Becker]

It's very common to use MDF for panels in doors. It doesn't move as has been noted and can be machined nicely for things like raised panels. There is some work smoothing and sealing those cut edges, but it's almost the perfect material for a painted situation. Be sure you use good dust control and PPE while machining it...the fine dust is, um...prodigious.

[stephen wood]

Thank you for confirming my approach and the caution about dust.

[Richard Coers]

MDF does move, typically around .3% from a humidity change from 30-90% for length and width and 5% in thickness from 30-90%. How well do you ventilate the bathroom during a shower? Kids use the vanity? If you do use MDF, prime and finish the edges before assembly.

[stephen wood]

MDF does move, typically around .3% from a humidity change from 30-90% for length and width and 5% in thickness from 30-90%. How well do you ventilate the bathroom during a shower? Kids use the vanity? If you do use MDF, prime and finish the edges before assembly.

My first two doors will be in a regular setting--no bathroom humidity issues.
But within the next month I'll be building another bathroom vanity and would like to have raised panels, so humidity comes into play. There will be an exhaust fan in use when showering. Empty nesters so no kids living here, but occasional use by grandchildren.

[Jim Becker]

You do have the option of purchasing exterior grade MDF for your application. It's a little heavier and pricier, but is less prone to moisture issues. However, unless folks are "truly messy" people who also damage the finish, regular MDF properly sealed should probably work fine. A lot of commercial painted doors are made from MDF.

[John TenEyck]

MDF does move, typically around .3% from a humidity change from 30-90% for length and width and 5% in thickness from 30-90%. How well do you ventilate the bathroom during a shower? Kids use the vanity? If you do use MDF, prime and finish the edges before assembly.

That's a non-issue for finished panels in a typical bath. It would be a concern if MDF were left in a steam room continuously, but that's not the case in any normal bathroom. My bath vanity and storage cabinet have hardwood edged then veneered MDF doors and drawer fronts. Five or six years later they are as flat and stable as the day I installed them.

John

[Aaron Rosenthal]

This is MY OPINION ONLY, but I've remodelled houses for years before "retirement" and I only agree with one proviso listed here - Exterior grade.
There is no way to protect against moisture in a bathroom, and once there is any dampness, MDF will deform. Been there and done that.
For baseboards, for example, I always specified finger joint or solid, depending on the budget; for cabinets, plywood.
Now, it depends on the time frame. If your projected time span is 5 years, MDF may be an option. For anything longer, even raised panels, I would look closely at solid wood and know you're protected.
I don't know where you live, but I worked both in high humidity and West coastal areas, and my suggestion remains the same.

[Richard Coers]

That's a non-issue for finished panels in a typical bath. It would be a concern if MDF were left in a steam room continuously, but that's not the case in any normal bathroom. My bath vanity and storage cabinet have hardwood edged then veneered MDF doors and drawer fronts. Five or six years later they are as flat and stable as the day I installed them.

John

You haven't met my wife. She's really cold blooded and refuses to run the exhaust fan while showering in the winter. We'll be married 48 years this month, I don't think she will change soon. She turns the fan on when she leaves the bathroom. Every surface in the bathroom has condensation on it. I find it highly unlikely she is the only person that does that.

[Jim Dwight]

I've changed out all the molding in my house. I used mainly MDF baseboard because it is cheaper and I think the shape is more consistent which helps with copes. But in the bathrooms, I used only finger jointed material. But baseboard sits on the tile floor so it is more likely to get wet. It is at least primed, but...

I think MDF will work for panels but I detest working with it so I wouldn't do it. There is some risk it won't get protected by finish and fall apart but I think that risk is low. I used a lot of it when I was making shutters for my last house and it painted up well - with a good primer on it and extra sanding and finish. I routed the louvers and made most of them out of MDF. So I know it can work. But I would prefer to use something else. Wood is just much nicer to work with. You have to allow a bit of room for it to move and I finish the panels before glue up so I do not have unfinished lines on the panel if it shrinks. Strength should not be an issue. I built an entire kitchen with raised panel oak doors. Panels were 3/4 thick oak. Doors were up to at least 18 inches wide. Joints were little router table cope and stick. No issues at all. If your doors are smaller and your panels lighter (like pine or poplar) you would have even more margin.

[Derek Cohen]

This is MY OPINION ONLY, but I've remodelled houses for years before "retirement" and I only agree with one proviso listed here - Exterior grade.
There is no way to protect against moisture in a bathroom, and once there is any dampness, MDF will deform. Been there and done that.
For baseboards, for example, I always specified finger joint or solid, depending on the budget; for cabinets, plywood.
Now, it depends on the time frame. If your projected time span is 5 years, MDF may be an option. For anything longer, even raised panels, I would look closely at solid wood and know you're protected.
I don't know where you live, but I worked both in high humidity and West coastal areas, and my suggestion remains the same.

Aaron, I am personally interested in your reply as I am planning on building new doors in Hard Maple for cabinets in two bathrooms. The style is Shaker frame-and-panel, replicating the work I did in our kitchen ...



The question is whether the panel is made from veneered MDF, veneered ply, or solid wood. My initial thought was to veneer, but there is the concern that moisture will affect the veneer, plus it is a lot more work to do than using solid wood. The choice is narrowed to solid wood panels, which is what I did in the kitchen, and now the decision is what internal gap is ideal for Hard Maple to expand? Any thoughts on that?

Regards from Perth

Derek

[John TenEyck]

You haven't met my wife. She's really cold blooded and refuses to run the exhaust fan while showering in the winter. We'll be married 48 years this month, I don't think she will change soon. She turns the fan on when she leaves the bathroom. Every surface in the bathroom has condensation on it. I find it highly unlikely she is the only person that does that.

You're absolutely right Richard. After almost 48 years together your wife is unlikely to change her habits. Mine hasn't after 40, though I foolishly keep hoping.

John

[stephen wood]

Thanks for your comments Jim. I’ll consider wood panels.

[Steve Rozmiarek]

My opinion of raw MDF raised panels is pretty poor. By the time you mill, then fix the cuts so they won't react horribly to paint, you could have easily just used a piece of solid poplar and been done with it. Every now and then I test that theory and try some painted MDF again, and always come back to the poplar. Plus poplar is lighter, stronger and pretty easy to find in normal cabinet panel widths so you don't have to glue up to make wider stock.