is most 1/4" plwood raelly 1/4"?

[franklin pug]

I am making some cabinet doors and plan to use 1/4" plywood instead of the usual raised panels for the floating panel.

Is 1/4" plywood truly 1/4" or is that a nominal measurement?

(please pardon me spelling in the thread title, I didn't realize I couldn't edit it!)

[gear junkie]

Most are 1/32 undersize. The big router makers offer a undersized router bit set for this very reason.

[franklin pug]

is that too much "wiggle" room for a door panel with a
1/4" recess?

[gear junkie]

Maybe, maybe not, it has to meet your standards. You can shoot some brads in the backside to keep the panel from moving but still allowing for movement. Run a test piece to see if you can live with the extra wiggle room.

[oldslowchevy]

just put a little glue in there and it should be fine though i would test fit it frist

[jbergstrom]

You could also pre-finish your panels to help take up the slack...

[Newman]

Rockler has a 15/64'' bit for 1/4'' plywood. You can also use a 3/16" bit and make 2 passes - that way you can fine tune the slot.

[franklin pug]

You could also pre-finish your panels to help take up the slack...

I like this idea! Do you think the finish (stain and 3 coats of poly) would eat up 1/32nd?

[jbergstrom]

I like this idea! Do you think the finish (stain and 3 coats of poly) would eat up 1/32nd?

It just might Franklin...

It's a good idea anyways because even though plywood will not expand/contract the solid wood in the rails and stiles will, however slightly.

By finishing the panels first you eliminate any chance of raw or bare ply showing at those junctions months or years later.

3 coats of poly would actually equal 6 because of both sides so it very well may equal 1/32". It depends on how much you sand off between coats.

[CARPENTERDON]

There are lumber yards that still carry true 1/4" cabinet grade plywood stock, but you could finish the panels before inserting them in the stiles and rails. Although I would not glue them in place. The wood of the rails and stiles will expand and contract with temp. and humidity changes. The S&R could split if they are glued to the panel. The panel should "float" in the grooves.

[Gofor]

If all you have is a 1/4" cutter to make your groove (dado) and the panel is a bit thinner, you can put some small pieces of the foam insulation (like that you use to seal entry doors) in the grooves for the panel. They will keep it centered during expansion and contraction as well as stop rattles if it is too loose and works well for all floating panels, regardless of fit. I would not put a loose insert on an exterior door, but for a cabinet door or interior door it will work well. Finish the panel (at least prime or one coat of the stain/finish of the final coat) before assembling it to avoid any unfinished areas showing during expansion/contraction of the frame.

You can use a small dab of glue in the center of the top and bottom, or each side (not both) to keep it flush with the outer face if you feel it's too loose, but you must try to keep the panel centered when doing this. The foam will do this for you.

It is a cheap alternative to "space balls" used for the same purpose.

Go

[NailBanger]

Make space balls. Make little dabs of silicone sealant on wax paper and allow to dry. Once dry insert a few into the chanels before inserting your panel this will prevent the usual rattle associated with panel doors.

[The Wood Meister]

From my experience over the years, there are still true 1/4 products out there. If you order up "domestic" plywood, it will be 1/4". If you get "imported" plywood, it's usually 4.5MM and real loose in the groove.

The ONLY time I used imported plywood is for BACKS of cabinets. For doors, I use 1/4" MDF core veneer. It's super stable, super flat and has a good veneer.

One other thing. The import ply usually has a top veneer of .005-.010 thick. One slip with the sander and you go right to jail and cannot collect $200! Also, the glue they use overseas is either red or very white, so if you just get close to sanding through, it's going to show.

The domestic veneers are running about .022 thick and they still use a clearer glue. It may cost a few bucks more but it's worth it with the final "fit and finish".

Mark

[Wood_Junkie]

There are lumber yards that still carry true 1/4" cabinet grade plywood stock, but you could finish the panels before inserting them in the stiles and rails. Although I would not glue them in place. The wood of the rails and stiles will expand and contract with temp. and humidity changes. The S&R could split if they are glued to the panel. The panel should "float" in the grooves.


A suggested tip from FWW is to put a dot of glue just at the center of each end of the panel. Keeps it from moving around in the groove, but doesn't impede the expansion wood movement, since that goes outward from the center (supposedly somewhat symmetrically).

Two cautions about the thickness question:
- Baltic birch plywood is almost precisely 1/4". Unlike cheaper veneered plywood which will be somewhere around 7/32" or 15/64".
- Veneered MDF is going to be almost exactly 1/4" thick.

Pre-finishing the panel is a good idea because as CARPENTERDON mentions, the rails & stiles themselves might reveal unfinished smidges of the panel. How big of doors are you talking, however? Smaller doors = small movement, which might negate the need for thorough pre-finishing (maybe just a single coat on the normally non-visible parts).

[franklin pug]

I did find some true 1/4" red oak veneer MDF at the local lumberyard, and will certainly use it. The veneer quality is far superior to the plywood veneer and it is good on both sides.

The last time i made doors like these I planed my door inserts from rough lumber down to 1/4" using a 26" planer - too bad my course is over!

Thanks for your help guys!

[Ross Creek]

For doors, I use 1/4" MDF core veneer. It's super stable, super flat and has a good veneer.

Mark

I also use 1/4 MDF core G2S for all doors. It always stays straight and is right on the .250 mark so "panel rattle" in never a problem. Sometimes you have to look to find it, but it is out there even in home improvement type stores.
On occation you can also find plywood core, good 2 sided red oak and maple but it's very hit & miss. :)