[Travisphoto]

Ok, well some of you showed a lot of knowledge and interest when I was asking about an external speed controller, lets see how you do on panels LOL

I made my first raised panel door last night. I made the rails and stiles from poplar. The raised panels are 3/4" MDF. I routed the panel down until it fit in the groove.

Here is the question, how tight or loose should the panel be between the rails and stiles?

As it sits right now, the panel just fits in the groove. I've read a lot of articles that state not to glue the panel in as it's suppose to "float" between the rails and stiles for expansion and contraction from weather. I don't see how it's suppose to float if I had a hard time pushing it in there in the first place.

Any thoughts?

Thank You

 

[Stick486]

Here is the question, how tight or loose should the panel be between the rails and stiles?
I don't see how it's suppose to float if I had a hard time pushing it in there in the first place.

Any thoughts?

Thank You

you have the panel too tight...
things need to give a little...

 

[Salty Dawg]

When I built my raise panel doors, the panels fit tight also even though I had an 1/8 inch gap all around. The bit set I bought came with extra bearings & shims with no instructions. I realized later after making a few doors what the problem was, the raised panel bit bearing is a large one made for the first pass then you were to change to a smaller bearing for the second pass, now they go together a lot easier.

 

[al m]

They should defiantly "float"in the rail an stile.i like to add "barrels",little rubber items you put in the groove before the panel goes in to keep the panel from shifting.Lee valley has a couple sizes.
You may also want to consider pre finishing the panel before assembly
Note that with a mdf panel expansion and contraction is not the issue it would be with a solid wood panel

 

[DesertRatTom]

You could also consider "space balls," which are small rubber spheres meant to fit in the groove in the rail and stile to help center the door, while compressing with expansion of the panel. Most woodworking outlets have them.

 

[walowan]

You can glue MDF panels if you want, the door frames will not expand/contract enough in the long grain direction to cause problems.

 

[Travisphoto]

The bit set I bought came with extra bearings & shims with no instructions. I realized later after making a few doors what the problem was, the raised panel bit bearing is a large one made for the first pass then you were to change to a smaller bearing for the second pass, now they go together a lot easier.

Yeah, I don't have instructions with mine either ... also no extra anything

 

[Travisphoto]

They should defiantly "float"in the rail an stile.i like to add "barrels",little rubber items you put in the groove before the panel goes in to keep the panel from shifting.Lee valley has a couple sizes.
You may also want to consider pre finishing the panel before assembly
Note that with a mdf panel expansion and contraction is not the issue it would be with a solid wood panel

Ok, I'll take a little more off them then. Thanks.

Isn't the "barrels" and "space balls" basically the same thing? I saw a post that Stick had made saying rubber screen spline would work. That's probably cheaper.

That's good to know about the mdf not expanding as much as wood. I've never read that anywhere. Maybe I don't have to worry about it quite as much as I thought I did.

Thanks

 

[Semipro]

usually cut my panels 1/8" less on height and width but does depend on wood speciesand and the climate that you live in

 

[MT Stringer]

You could also consider "space balls," which are small rubber spheres meant to fit in the groove in the rail and stile to help center the door, while compressing with expansion of the panel. Most woodworking outlets have them.

That is what I have used when making raised panel doors.

 

[Stick486]

You could also consider "space balls," which are small rubber spheres meant to fit in the groove in the rail and stile to help center the door, while compressing with expansion of the panel. Most woodworking outlets have them.

http://www.routerforums.com/diy-renovation/47961-space-balls.html

 

[Travisphoto]

That's good to know about the mdf not expanding as much as wood. I've never read that anywhere. Maybe I don't have to worry about it quite as much as I thought I did.

I've found an article that contradicts this statement.

Controlling Wood Movement

In this article they quote

"Our years of experience have exposed us to a popular misconception about MDF products which is, “that unlike solid wood, “MDF is stable; it won’t expand and contract”. This seems to be a commonly held belief, although as many of you already know, it is incorrect. As with solid wood, MDF is a hygroscopic material (meaning it readily takes up and retains moisture), thus its moisture content depends on the relative humidity and air temperature in the surrounding environment. As the moisture content of MDF changes, it is subject to dimensional changes."

The article goes on to state that

"Unlike solid wood which sees the greatest expansion and contraction parallel to the growth rings but changes very little in length (0.15%), the composite nature of MDF causes it to expand and contract equally in both width and length (0.3%)".

Here is where it gets good..

MDF vs Solid Wood

I found another article that suggest MDF may be a better choice than wood for raised panel doors. The article goes on to state that MDF allows CNC machines to cut the door in just two pieces instead of the traditional 5 piece. In this article they also state that MDF will expand and contract.

Just thought I'd pass this on so I can get your thoughts on it.

 

[Stick486]

get MDF wet and it swells like a sponge just before it disintegrates...
just look at a MDF sink cabinet that has gotten wet...
that's why you are going to seal those panel edges before you put the doors together...

 

[Travisphoto]

I took a good look at my raised panel door I made the other night with the 3/4 MDF. I thought it looked a little odd because it was really raised about 3/8 of an inch above the rails and stiles. So, I went to HD and got a piece of 1/2 inch MDF. I made a panel from it and installed it in the other frame and put the two side by side. I really liked the look of the 1/2 inch better. So, I'm switching to 1/2 inch MDF for my doors.

I cut my new 1/2 inch panels 1/4 of an inch shorter in width and length. That will give me 1/8 inch per side to allow for expansion. It may or may not be necessary but I figured it couldn't hurt. On Sticks recommendation "see I do listen LOL" I bought some screen spline and will use that for a spacer between the panel and frame. I bought a rather large diameter one (0.20 inch) because I thought it would just be easier to compress. Will see how it works.

I also did some testing, I had read a different article about using MDF for panels and in that article the author suggested putting a thin coat of either drywall mud or spackling compound over the machined area of the panel. Then lightly sanding once dried. This is suppose to eliminate the rough finish that would happen as the material was raised due to soaking up the primer. I took a few scrap pieces and applied primer on straight MDF to one area and on the other applied spackling compound, sanded then primed. The test panel that I put the spackling compound on was smooth to the touch and the one without the spackling compound was rough. By using the reflecting light inspection method, you could see the difference as well as feel. I'll post some pictures of the test pieces tomorrow. It was quite an interesting experiment .

 

[Travisphoto]

get MDF wet and it swells like a sponge just before it disintegrates...
just look at a MDF sink cabinet that has gotten wet...
that's why you are going to seal those panel edges before you put the doors together...

Yes I know, I tossed out a beat up 3/4 inch piece that was used for a workbench top (no I didn't build it) out in the yard when I was repairing the bench. It laid outside for several days. When it rained, it went from 3/4 inch to probably over 2 inches. I knew it would expand like crazy but was rather surprised it expanded that much LOL. It did make it easier to break up and dispose of though :yes4:.

 

[Stick486]

spline doesn't compress worth a fiddle...
good plan on the spackling...

 

[al m]

Interesting idea with the spackling.i have used white shellac ,sealing all cut or machined surfaces ,then sanding the exposed details,applying anouther coat of shellack,sanding again and repeating until smooth.
Takes several coats,your method should speed things up.
I would still consider a coat of the shellack,a coat of primer and one finish coat before assembly.
Btw
What ever spacer you use,the idea is not to compress them,just very lightly if so,just enough to keep the panel from shifting.if expansion takes place they will compress instead of cracking or buckling your door

 

[Travisphoto]

What ever spacer you use,the idea is not to compress them,just very lightly if so,just enough to keep the panel from shifting.if expansion takes place they will compress instead of cracking or buckling your door

You have to compress it some or they will all fall down to the bottom. Friction is all that holds them in place.

 

[MAFoElffen]

By rule of thumb, I use 1/16 inch, all the way around, depending on what I'm using as a spacer.

The reasoning for the extra room is that cross-grain (like across a wood panel glueup has) expands faster, more and at a greater rate than long-rain (as with rails)... so if you get a big change in temperature or humidity, you pop your joint apart between the rails and stiles.

The reasoning for using something that compresses between the panels and the door's R&S is that if it does have extra space there for that expansion ... and if you don't have something there, then the panels rattle when closed.

The old-school of doing that without, or rather before people started using some kind of compression filler, was to give 1/16" additional for each side of the panel and none extra for the top and bottom... Then to pin or dowel the center of the panel into the top and bottom rail. That way there is room for the cross-grain to expand. And the pinning keeps the panel from sliding inside the door (centered).

BUT-- Remember that the OP's medium for his panels is MDF right? MDF does not expand like crossgrain. Heck, MDF does not expand as fast as long-grain. Most doors using MDF panels do not require expansion joints. It would be better if it had. The joints usually do not pop apart, but some do end up rattling after age if you do not.

Another old-school technique I've seen on lower-end wood raised panel cabinet doors- is to give 1/16" extra on the sides, make the top and bottom snug. Then when you assemble, you center the panel in the rails, with just a dab of glue in the center of the top and bottom panel edges. This gives the same effect as pinning (not as strong, but). Some of these I've seen are over 100 years old and are still going.

 

[al m]

You have to compress it some or they will all fall down to the bottom. Friction is all that holds them in place.

I thought you used spacers all around ,both top,bottom and sides to prevent just that
I may be wrong,have been many times.
I do believe this is all more important in solid wood.
I have built all pine,all maple,maple and poplar and maple and mdf doors and did the same with all
Seemed to work,the pine are the oldest, now being replaced with the maple/ mdf,not because of issues with the doors but she wants a updated look
Sure everyone knows what that is