Best Method for MDF assembly

[martyv]

Hi!
I've always wanted to build a professional quality speaker system, and finally took the plunge. I've decided the Mini Statements fit my situation the best. So far I have the kit from Meniscus, and I've cut all the MDF components for assembly. Dry fit, all holes cut and speakers fitted. I have two questions at this point. 1) What is the best glue and method for a solid assembly result. 2) What is a good choice for veneer and what is the best method to apply the veneer for a professional result.
Anyone out there who can help? I have experience with fine furniture building from hardwood, but never built anything with MDF or veneer so far.
Marty

[isaeagle4031]

I can't speak on veneer as I haven't been brave enough for that challenge yet. As far as glue, I like titebond 2 or 3. Too has a little less open time, but needs less clamp time. Three is the opposite. There is also gorilla glue but I save that for joints that are a little less than sq or dadoed joints as it expands and is a pain for clean up.

[mattsk8]

I use Titebond woodglue as well, but I use Titebond original. The only difference between Titebond original (red label) and Titebond II (blue label) is that Titebond II is waterproof and original isn't. Since my speakers never get wet, I go w/ original.

Its not possible to ever get to a point in the life of a cabinet maker where you'll say "I finally have enough clamps". Basically, glue all the joints w/ woodglue, clamp the crap out of it, and wait for it to dry. You can also use a mildly damp cloth to wipe the excess glue that squeezes out during clamping, or let the glue dry and use a wood chisel to scrape it off. I also brad nail my joints while I'm clamping just for a bit of assurance but this isn't necessary.

If you've made furniture I'm guessing you own a router and possibly also a router table?? If so, I also like to dado and/or rabbet all my joints in my cabinets. This makes assembly a LOT easier, makes the final product very square, makes the cabinet quite a bit stronger, and also eliminates a lot of possibilities for air leaks (although, I still go around all the glued edges w/ some form of caulk on the inside MDF joints).

Hope this helps!!

[meniscus]

Hi Marty,

I think most hobbyists will use a paper back veneer. For that type, the best method is cold press - a pva veneer glue under pressure. A vacuum bag is best, but a bit difficult to use with speaker cabinets. We fashioned a hydraulic press in our shop to press flat surfaces. Whenever possible we buy pre-veneered mdf.

I have heard of others having good luck with the iron on method. Coat both surfaces with the PVA glue, let it dry and then iron it on. The heat activates the glue and then sets again once cooled. I think this is a bit more risky. If you miss a spot with the heat, it might start to bubble up later after you've got your finish applied.

It is much easier to use contact cement on this type of veneer, but I don't think there is a veneer manufacturer that will recommend it. This type of glue never hardens and with two wood surfaces, the material will shift and probably come apart at some point. You might not mind these potential fixes If it is your own project, but if you ship it off to a customer, you don't want it ever coming back.

Mark

[Norm]

Hi Marty.
I'm building my first set of speakers (Finalists). I was using natural cherry veneer, very thin and no paper back. I had some unused speaker baffles to practice on. First I used the recommend latex contact cement on the veneer and on the baffle let dry and put both pieces together. All look good at the start but hours splits in the veneer appeared. Experiment several times with no success.
Next I used carpenters glue on the veneer and on the baffle let dry over night and used a my wife's cloths iron on the wool setting and a paper bag on top of the veneer. The test went not too bad. So next I tried the same procedure on back of my speaker. Got about a third on and the veneer developed a 1/16" split. It was a nasty job to remove glued veneer. I've decide to apply a Cherry 1/8" plywood to the top, bottom and sides. And a texturized paint in the front and back. Hope you have better luck with the veneer than I did.

[martyv]

Wow! Sounds like you didn't have much success with the veneer at all. I think i will have to do more research before buying, as a single sheet of good paper backed could be >$150. Thanks for sharing, and I'll share what I find out.
Marty

[martyv]

Thanks for all the advice guys. I'll report on how the veneer works out. The cabinets are near complete assembly. In the end I dry assembled, pre-drilled and used coarse drywall screws to clamp all joints, and then dis-assembled, glued and re-assembled first the sides, top bottom and braces. Then centered up the front baffle and glued centered up with clamps only (but about 20 of them). Then flush trimmed with router and back screwed on last, to be glued after final testing. First one is wired and at sound testing last weekend, this weekend we do the right channel one... So far it sounds awesome

[bkeane1259]

Paper-backed veneer is a totally different animal than raw veneer. Paper-backed is much easier to apply, IMO and will not split like raw veneer. I’ve used paper-backed, raw and paper-backed with PSA applied. Looking back, I’d have to say that using plain paper-backed is the easiest. You can do the iron-on method with titebond (works great) or use contact cement. The PSA veneer is really good too, but it requires a treated and flawless surface to apply to. With the iron-on method you can get away with a few surface imperfections and still get a good outcome. A good site for research is the Joe Woodworker site: Great info there. Good luck.

http://www.joewoodworker.com/

[IslandHydro]

I've used veneers on lots of speakers over the years. Paper backed are easy, and I generally use contact cement. More exotic veneers such as burls, crotches and butts are a bit more tricky, and often require a press of some sort. My only advice is to use the flammable version of contact cement, I've not had good luck with the water-based versions.

[IslandHydro]

Oh, and for MDF construction, I use 1x1's or 2x2's in all corners (depending on the size of the speaker) and screw down from the outside of the mdf into the corner pieces, the screws act as clamps. My favorite glue for this is liquid nails as it fills various imperfections in the bracing, guaranteeing a good sealed box.

[pgroben]

I've built several speaker systems with mdf and found a method I favor. First, I like raw wood veneer, but I've had good luck with paper backed veneer also. For raw wood veneer, I use cold press glue in a vacuuum press. With paper backed veneer, I use solvent based contact cement and I use the edge of a piece of soft wood to apply pressure to set the veneer. Rollers don't work so well. I cut the sides, bottom, and top with 45 degree miters, lay them out flat with the bevel down, and tape them together with packaging tape. Next, I flip everything over, apply glue (titebond III or epoxy) and just roll them up and tape the last joint to complete the box. The box is pretty close to square and it's easy go get it right on using a clamp across the diagonal. I cut the baffle just slightly larger than the box and flush trim it to the box. Hope this helps someone out there.