Wide Exterior Raised Panel


From original questioner:

I am looking at a job building a large exterior carriage door. Some of the panels will be close to 30" wide. I am thinking of using marine grade plywood banded with solid wood (sipo/utile). The solid wood would be as wide as the profile on the raised panel. That way the step in the profile will be at the glue joint. Titebond III is the glue I would like to use. This is a paint grade door.

I have used other methods in the past. One, a three ply lam. with a marine grade core, Two, two solid wood panels with a foam board core-all floating.

Given how wide these panels are I think this is a better option.

Any opinions or advice?

From contributor Le

Band the plywood or other substrate with your solid. Make it at least 1/16" wider than your panel profile. Then veneer the top of the panel with a suitable veneer. Then run the panel bevel. This will hide your joint and keep a wood edge everywhere, no plywood exposed to the elements.

From contributor Ad

Extira is exterior graded mdf. Spot prime the raised edges twice and seal the back.

Its better than Medex which is also exterior graded mdf.

Those are some rather large panels.

From contributor Ge

Thanks for the responses.

Leo, I understand how you are suggesting to do these panels and how it would eliminate the 1/8" edge of the plywood at the transition between the bevel and flat middle of the panel. Do you really think it is worth the extra effort to veneer over marine grade plywood to avoid that 1/8" edge? I find the okume(spelling?) ply to be great for exterior paint grade mill work. I haven't used it in boat construction, personally, but I know it does regularly.


From contributor Ge


Mdf and water make me nervous. Have you ever done any kind of water test?


From contributor Le

When they do boats with the okume they cover that with marine epoxy so it's not exposed to anything but sealed in epoxy.

The other suggestion of Extira would be OK too.

From contributor Ad


I've used it for raised panels on the exteriors of Nantucket style houses. To be honest I wasn't excited about using mdf outside either. The first exterior grade was Medex. We had a failure about 10 years ago, because of no back priming(idiot painters). The Extira is a better product.

I'm not sure if they use recycled okume marine grade plywood, but it does fine outside in my experience for what its worth.

From contributor Da

We regularly do 30" wide raised panels in pattern grade Honduras Mahogany solids all the time. I don't like them, but I don't have problems, knock knock.

We have done wider raised panels with banded shop made plywood, or thick veneered 2-sided MDO sign board. I also don't like MDF sitting in water. I'm not sold on gluing solids to plywood (for panel raise) either, but with about 1/4" lap, the ply/solid joints are not exposed since we veneer after edging, prior to raising.

From contributor To

Ive done this with extira and they've been outside for 6 years with no problems . I always seal the routed area with a glue size of 1 part water and 1 part titebond 3 and paint with a quality exterior primer and top coat.

From contributor Ge

It still makes me nervous thinking about using mdf/extira, but it would sure be quick. Regardless of the type of panel I use, I would apply one coat of epoxy and one coat primer before they go in the door.

Thank you all for your responses, I appreciate it.

From contributor Ad

You could make it out of dog poo if you are planning on doing a full sealer coat of epoxy. The Extira is not a new product. Its been around for over a decade.

If you don't mind the stink, you could go with an epoxy 2k primer. It will sand better, seals everything, and sticks to anything.

You also don't have to wait a week for the regular epoxy to cure before painting it.

From contributor Ge


Thanks for suggestion of Extira and epoxy primer. I was not aware of these poducts before I started this post. Which was the the point of the post in the first place, to see what sucessful methods other shops are using.

Like I said before, making the panels out of Extira would be a lot quicker then the other methods discussed.


From contributor Da

There have been some good suggestions made so far.

I too have done solid panels that wide, with good results. Honduran mahogany, because it holds up to moisture, and because it is one of the most stable. This stability will help keep you paint film intact, and add to the longevity of the project.

That said, not every project warrants the expense of this material, and of the time it takes to create panels out of it.

That's where MDO (medium density overlay) comes in. The exterior grade MDF is 'alright'... but too close to the border of 'not alright' for me.

MDO is used by sign painters for permanently exposed locations. In the right grade, it's both stable and long-lasting. Before the industry went to aluminum... most Interstate Highway and other road signs were made from it.

But be aware - MDO comes not only in a variety of thicknesses (a good thing), but in various grades (so be careful). If I were you, I'd call the folks at Olympic Panel and let them help you pick a grade, as well as find a local dealer.

So... whether you go with solid wood panels, or MDO panels... I'd go with a solid wood frame - with the panels floating - like a kitchen raised/recessed panel door.

If I were building this - I'd probably propose mahogany frame and thinner MDO panels. This would give strength where needed, while keeping the overall weight down (easier on the hinges and less racking force over time). Both materials take paint beautifully.

From contributor Ad

I have had plenty of experience with MDO, which is kraft paper faced void free exterior plywood. It is/was used for painted signs.

First problem is the edges. They are raw fir ply veneers. Not helpful when making raised panels.

Second problem is very stiff and not usually flat. Generally not good for door panels.

MDO is a good product with very limited uses.

From contributor Sc

For paint grade exterior work Extira is great. We have used it for 10 plus years with no failures or call backs. We do seal six sides before permanently installing within the door. Also prior to priming we seal it with Smith Epoxy CPS

From contributor Ch

We also have used Extira in the past making panels for paint grade doors. Have any of you found a way to save tooling when using Extira? Our knives become dull very quick using this product.