crotch veneered raised panel with mdf??
In the past, I have always made my raised panels out of solid wood. However, I am presently working on a cabinet job with 8 doors. It’s a library over cabinets, and I have resawed the veneer out of a slab of crotch mahogany. I want each door to look identical, and so far, so good. (bookmatched)
First, I’ll explain what I have available, and what I think I should do. Then, I’d like some pointers from those of you who SUCCESSFULLY do this regularly. I intend to miter-wrap the mdf panel with mahogany just slightly larger than the shaper profile of the raised panel cutter. I was going to biscuit join the mahogany all the way around, as well as at the miter for strength. I know that I need to keep the biscuit low enough, and in enough, to avoid having it show in the profile. I will veneer both sides of the panel, with the back side veneered with some regular mahogany. I have a vacuum press for the veneering process. I was going to veneer the panels all the way covering the solid mahogany edges, and when complete and dry, raise the panel, exposing the solid stock for the profile.
- Is my technique correct?
- Are the biscuits necessary for joining solid stock and mdf?
- Can lightweight mdf be used, or should I stick with the heavy stuff?
- Is there a better way to join the solid stock to the mdf, i.e….pocket screws on the back side with plugs?????
- How much do I have to worry about the solid stock swelling, and telegraphing a line through the veneer?
- What am I forgetting???
Thanks for any help you can provide! This is for a previous customer who has hired me twice before, and of course I want it perfect.
Jeff
Replies
I've made quite a few raised panels in a way that is similar to what you describe. I would not use MDF as the substrate, this is an economy material and inappropriate for the work you're doing, IMO. I think a good cabinet grade plywood will stand up better over the long term, better moisture resistance, better joining for the perimeter. You could use mahogany and skip the veneering on the back. Instead of biscuits, I like to cut a full length tongue on the perimeter pieces and a groove all around the panel with a slotting bit. I raise the edge of the perimeter pieces before I miter them around the frame. On large jobs, I sub out the necessary lineal footage to a company with a foursider. You can get some unusual profiles with a foursider. On smaller jobs, I make my own. In the picture, are some red oak pieces that were left over from a recent job.
I haven't dared to apply the perimeter, veneer the whole thing and then cut the profile. Unlike a solid panel, there are miters at all corners. The chance for a blow out on the last cut are high, since you can't back it. The edge of the veneer will show and there is also the possibility of putting scratches across the veneer or tearing out delicate grain. I feel more comfortable veneering the panel and then applying the raised molding. This method adds a degree of difficulty and labor. It's always a help to have the profile of the perimeter molding either cover the edge of the veneer, stand proud and/or have a shape that makes the junction seamless.
I don't think you will be able to get an FF biscuit in the miter of most raised panel profiles at 3/4". If you use a back cutter for a flush panel, there is no room. Obviously, you have to be neat with the glue and fast. The T&G is a lot faster in glue ups for me, it also slides a little better when you are trying to get the miters to close. I do my back cutting afterwards, but this is a fairly small cut and dosen't really show.
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How big are the doors going to be? Your approach sounds as OK as possible to me, however the weak link is the transition in substrate between MDF and solid. Your substrates different expansion rates will make the veneer telegraph the transition line, unless you place it precisely at the edge of the veneer. This causes problems with no fudge room when raising.
I use solid door blanks, and just veneer over a solid substrate. You'll avoid the expansion differential that way, and the veneer substrate transition line is reletively insignificant as well. Plus you'll save time, and you won't have the cross grain at the top and bottom to obviously scream MDF.
Jeff,
I've done it this way once, and decided that in general it's too much trouble. The client can have either solid wood panels, or veneered panels but not raised. But it's just a question of time invested, not a problem with the results.
I see no problem of telegraphing through the veneer. The mahogany is quite stable, and the difference between the thickness of solid and the MDF is going to be negligible. If you have one, run the glued-up doors thru an oscillating drum sander to at least have a perfect starting plane for veneering.
I would prefer MDF or solid-core panel to plywood for the substrate. Don't see any advantage of ply in this case. And I would keep the biscuits. It's another 5 minutes of work and they keep everything aligned. Much quicker than T & G for me, at least.
DR
Jeff, I don't make raised panel doors, but I've glued up 1,000's of ft of veneer. So take my advice from that perspective. What you want to do will work fine without problems.
Don't need biscuits, and use a reg mdf interior. The tricky part is to have as little edge under the veneer as possible. I would shoot for an 1/8" or less, if you have any telegraphing at all it would be very hard to see. When you glue up your panels use a urea resin glue (powdered plastic resin, Unibond 800 or similar) Allow your panels to dry out fully at least a couple of days. Then if possible run them thru a wide belt or drum sander to remove any deviation in thickness. Then glue up the veneer as normal.
Wow, 4 replies, all contradicting each other. I feel like I've created a tug of war here. At 7/8's thickness for the finished panel, as well as the solid edging, I wonder how much the mahogany will move causing telegraphing. I was planning on only having 1/8" under the veneer, cutting it real close to the end of the profile. The profile I'm using, which the customer has already used on a large cabinet job I built for her, is 2 1/2 inches wide.
If I use 3/4" mahogany veneer core plywood, will I need to add veneer to the back side, even though it already has a veneer of mahogany from mfg. on it? Is this necessary to keep the ply balanced??
I think I can control any blowout at the mitered corners by backing them as I pass the corner through the shaper cutter. This is what I do with solid panels, with good success. The mahogany edging will be straight grained, and has always milled with EXCELLENT results in the past, so I wasn't really too concerned about that.
Last but not least, I'll be out of town for a week starting 10/17/05, so please don't think I'm not interested in your replies by not replying back. I'll be back next Saturday, and will check all replies then.
Thanks again!!
Jeff
Jeff,
The method you outline will work just fine. We used exactly that process on doors and drawer fronts for a multi-million dollar yacht at a shop where I worked a few years ago. The engineer for the yacht builder specified MDF cores for stability. By rasing the panels in three steps, there was no problem with tear-out.
Regards,
Bill Arnold - Custom Woodcrafting
Mensa Member
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You say you made the veneer from a slab, so I assume it is thicker than normal. Crotch will move like crazy; even as a veneer it is best to two-ply it to a backing veneer of the same species. So be sure to back the panels with same thickness and number of ply/direction.
We use MDF for the core for super stability and great glue surface, then miter, glue and clamp - using splines at the miters if the raise is wide. Since your veneer is thick (assumption), you may want to do all the veneering first, then miter wrap, leaving a slight reveal at the solid/veneer line. Accent during finish with glaze, and it'll look as if you planned it - because you did.
Dave S http://www.acornwoodworks.com
Dave
Thanks alot for the reply. You confirmed the exact process which I plan to follow.
Jeff
Bill
Thanks for replying, and thanks for the help.
Jeff
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