MDF in Cope and Stick

[Gregory King]

Made plenty of MDF painted doors. But just made two 5/8" MDF doors for glass. Not sure if it's a good idea or not for strength. Doors are 33'' high and 23" wide. Stiles and rails are 2 3/8" wide. The mutins are 1.25". Think I 'll redo those in birch because of their size. Adding glass to the back using the little turn paddles. Is this a good idea or will it sag with the glass installed? Perhaps I should use panel adhesive instead of wood glue at the intersections

[Mark Bolton]

Most of the MDF shops now are not doing any cope and stick, the doors are routed out of a single piece. Glass is bedded into the "door" with silicone so it becomes a bit of a structural/support feature.

I wouldnt trust a 2" glued cope and stick in MDF (2 3/8" with a 3/8" glass bead) unless it was a major budget job.

You can glue one up and rack it a bit and I'd guess the cope/stick will break pretty easily.

[Frederick Skelly]

I wouldnt trust a 2" glued cope and stick in MDF (2 3/8" with a 3/8" glass bead) unless it was a major budget job.

You can glue one up and rack it a bit and I'd guess the cope/stick will break pretty easily.

+1. I agree with Mark.

[Mike Cutler]

That's a lot to ask from MDF. Great stuff. I hate working with it, but it's got a place. I don't think that is it though.

[Gregory King]

Thanks everyone. When I laid it on the bench before glue-up , I had an uneasy feeling that this wasn't the way to go. Think I'll use a single piece shaker style. Give the inside front edges a 22 degree bevel. And use Mark's suggestion of silicone. I like the latex brand of that.

[johnny means]

Making multi piece doors from MDF seems a bit backwards to me. Adding all that machining to the process wipes out the principle advantage of using a sheet good.

[Brian Ross]

Walz Craft in Wisconsin sell a 5 piece MDF door. There is a wide range in the quality of MDF. It has been my experience that what you by in the big box stores is the bottom of the barrel when it comes to quality yMDF. A couple of manufacturers that I am aware of, West Fraser that sell MDF branded Rangerboard and Roseburg market a MDF branded Medite .They both sell several different grades of MDF .
Brian

[Derek Cohen]

Made plenty of MDF painted doors. But just made two 5/8" MDF doors for glass. Not sure if it's a good idea or not for strength. Doors are 33'' high and 23" wide. Stiles and rails are 2 3/8" wide. The mutins are 1.25". Think I 'll redo those in birch because of their size. Adding glass to the back using the little turn paddles. Is this a good idea or will it sag with the glass installed? Perhaps I should use panel adhesive instead of wood glue at the intersections

As others have pointed out, the benefit from using MDF is that it is a cheap material, and may be shaped from a sheet. When painted, it can resemble solid wood.

What I think you are after are the joinery lines that come with solid wood. It should be an easy enough task to add these lines after routing out the outline, and so complete the illusion.

Regards from Perth

Derek

[Gregory King]

Slept on the whole thing last night. Actually, I have 4 doors in total to make. Two for the china cabinet in the kitchen and two for the display cabinet in the living room. Since the kitchen ones are shaker style, I'll do those in the solid MDF with glass added to back. The cope and stick were a trial run for the living room. I'm going to keep the same style I made yesterday, except I'll run them from solid ash. Complete with the solid mutins. Thanks

[scott vroom]

If the living room doors are paint grade, my preference would be maple over ash as the ash grain will telegraph through the paint. Painted maple shows little to no grain in my experience.

[Gregory King]

If the living room doors are paint grade, my preference would be maple over ash as the ash grain will telegraph through the paint. Painted maple shows little to no grain in my experience.

Thought it might Scott, but I don't think I'll mind that. Don't think it will be as prominent as red oak though. I made a landing tread for a cottage from ash. Stained it light grey. Kind of like that texture bleeding through. Suspect my cabinet client will too. Greg

[scott vroom]

Right-on...everything looks good to somebody!

[Gregory King]

I've got a local pro painter coming to my shop to paint them. Had first thought about laquer paint. He said it was near impossible to spray lacquer unless you've got a high end spray booth. Apparently there is a dust type thing with this. I'm no expert. So, in the end he prefers not to use the newer versions of oil and we've decided on melamine paint. Any thoughts on that?

[Mark Bolton]

RE different grades of MDF, any door work I do with MDF or anything that is going to end up a finished product uses double refined door grade which is night and day to straight MDF we are all use to for $21 a sheet for 3/4". Fluffy core, paper-ish face, lots of fuzzies. The double refined is a 4 billion times the weight (at least it feels like that to my old bones), way harder, machines great, more expensive.

With regards to the finishing in my opinion your kinda gonna be stuck under the thumb of your painter. Lacquer is a dead technology for me in this day and age. Slow dry, mess with regards to the EPA and OSHA in a shop, but its still common because people are use to it. I can spray water ML Campbell or Sherwin Kem Aqua and be perfectly fine. I just sprayed a set of sample boards for a commercial job with 9 different colors of KemAqua custom pigmented from their industrial division that layed down like an automotive finish and sprayed 3-4 extra boards that I torture tested with acetone, laquer thinner, screwdrivers, and left one out in the rain for three days.

Your going to be bound by what routines and rituals your painter has and how dynamic he is willing to be. In my experience in the finish world its one of the slowest parts of the business to evolve so your often stuck with the worst possible mindset of "because thats just the way Ive always done it". Thats a decent recipe for finishing in that why tamper with something that works, but the finish world is changing. Even autobody shops that want to work on "modern" cars now have to be certified to spray water. You either adapt or die.

[Gregory King]

Thanks Mark for the advice. It's apparent that you've taken the time to experiment with a good many lines of finish. When I mentioned going from lacquer to melamine, it's typical of a north/ south thought process. A smooth velvet finish to one of eggshell. Our living room cabinets were done about 10 years ago with a linger lacquer finish. And to this day I'm still glad we went this route. They look as good as they did then. And my wife decorates them for every occasion of the year.

In the end, my client was open to whatever decision we made on these. I guess as long as the melamine finish is durable, she's happy. I never used that type of finish before. Thanks. Greg