Pictures of the newest DIY speaker project (Usher 2-ways) (1 Viewer)

[Chris Tsutsui]

We live in Beautiful Southern California Irving/Laguna Hills area where people like Tony choose to use raw MDF flexys.

Besides, he glued the solid walnut to bare MDF and most likely clamped and glued them together. (By engineered substrate do you mean MDF, or that plastic bed liner?)

Thanks for the tip and heads up though. I've built gates and worked with doors so I know how the Santa Ana winds and humidity levels can cause frustrations.

 

[MarkDesMarais]

I hope he didn't glue to the bed liner! ;-)

Raw MDF in a flexy won't cause a problem for two reasons-

1) All MDF- all expands/contracts at the same rate.
2) Compliant joints- unless the holes are drilled REALLY close, you have some slop.

Here is a basic article-

http://www.americanfurnituredsgn.com/wood_movement.htm

Note the section where they talk about the webbing in a chest of drawers- this is an analogous situation. If the cheeks are fairly narrow, it might be ok. Figuring out how to attach the panels without them rattling might be another whole adventure, although the sliding dovetail mentioned would probably do the trick.

Markd

 

[Chris Tsutsui]

I was just thinking that in humid or hot climates, the MDF may turn yellow or brown due to direct air exposure. (Or perhaps to water stains)

Do you think it's better to seal the MDF? Because I have a raw MDF speaker in my room that i've used for several months now. I guess a bare MDF flex wouldn't have any problems function wise.

 

[MarkDesMarais]

Putting a finish on will slow the transfer of moisture in and out, but won't block it. Key is to finish all sides- especially large flat one in opposition. Otherwise you invite even cupping and warping instead of just overall expansion. Most veneer furniture is veneered on both sides of large panels to equalize the tensions for similar reasons.

Because the speaker is ALL mdf, you probably won't have too serious problems- it will all shrink/grow at the same rate, and being an engineered product, the rate should be pretty low. Unless it is a very large speaker, I wouldn't be too worried. My concerns above related to hard coupling the mdf (low expansion rate) with the solid hardwood (high expansion rate).

Markd

 

[Chris Tsutsui]

. Most veneer furniture is veneered on both sides of large panels to equalize the tensions for similar reasons.

That's something that's not common among many builders here. I rarely hear of people using dual sided laminates, and I never see people install veneer on both sides.

My tempest used a 3/4" laminate which has a high grade maple on one side with a low grade birch on the other. I don't think you can even buy one sided laminate MDF. The sheets are about $80-150 per sheet depending on species, the only problem is we have to setup the lock miter for perfect edges and that takes a bit of time.

What I've found is to get a nice cut in laminates you need to use double bladed table saws or else splintering can occur. I learned a lot from my friend, who's company does work for millionaires and sports stars like Kobe Bryant. I'm very grateful I get to use his shop and help whenever I build stuff.

 

[MarkDesMarais]

Yup- I've seen that a lot of people veneer after the box is built. Just speaking from my experience. Your pre-laminated MDF is how I'd feel best doing it. On furniture, I usually make up all the panels oversize, then cut and make joints. Never built speakers though- I get the feeling that some people experiment with boxes until they get one they like then veneer it for looks.

Scoring saw. . . . that would be nice! Masking tape does a pretty good job for those of us who have to work at home- or scoring with a utility knife for REALLY splintery stuff. Zero clearance saw insert is key too. Cleanup with a router works pretty well if you can't get the others to do the trick.

Markd