MDF alternatives?

[tentaguasu]

Are there any relatively inexpensive alternatives to MDF for DIY speaker construction? My son has asthma and MDF has a somewhat sketchy health reputation....

 

[Swerd]

Are there any relatively inexpensive alternatives to MDF for DIY speaker construction? My son has asthma and MDF has a somewhat sketchy health reputation....

Plywood won't make the kind of dust MDF makes.

Buy some dust masks, and do your cutting outside if you can.

 

[tentaguasu]

I'm fine with plywood because the "look" of the speakers is irrelevant to me for this particular project.

Is there any (significant) acoustic difference between MDF and plywood? Or is it just about the interior space/configuration?

 

[Swerd]

I'm fine with plywood because the "look" of the speakers is irrelevant to me for this particular project.

Is there any (significant) acoustic difference between MDF and plywood? Or is it just about the interior space/configuration?

There probably is no significant difference in the acoustic properties of MDF and plywood. It's more important to get the bass tuning (interior volume) right. If you add internal bracing, the walls of the cabinet will resonate less.

And ¾" plywood holds screws much better than ¾" MDF.

 

[alphaiii]

Baltic birch ply is often recommended, and some prefer it to MDF not only for health reasons, but it's stronger than MDF while being lighter weight. Also, you can stain/finish the outside, just have to figure out how to build so you don't have exposed edges.

 

[annunaki]

If one will be using ply instead of MDF, be sure to use "void-free" or cabinet grade ply.

I have yet to see quality void free ply that offers the value MDF does. So long as proper precautions are taken, one should have no issues with it.

 

[jliedeka]

There's the rub. You want something as good or better than MDF for less money. There really isn't anything unless you want to get creative. Baltic plywood is superior to MDF and gives off less nasty dust but it usually costs more. Standard plywood won't be as good but in a well braced design, you might not notice the difference. Being creative would involve laminating different types of sheet goods like particle board with solid lumber.

Jim

 

[lsiberian]

Are there any relatively inexpensive alternatives to MDF for DIY speaker construction? My son has asthma and MDF has a somewhat sketchy health reputation....

Two words

Dust Collection.

Most tools can be fitted with a dust collection device that you hook up to a shop vac. This is a must for anyone doing DIY. If you haven't added this luxury you are missing out big time.

Beyond that I suggest using Birch ply for several reasons.

1. It's lighter.

2. It's more rigid.

3. It's stronger

4. It makes a lot less mess.


Beware that it's a bit tougher to machine though. And you must use 13 ply not 5 ply. If you do use 5ply against recommendations then you can make it work ok if you dampen every wall. ( I know I've done it before)

You will want to make sure to get very good blades and bits. Don't go cheap or you can burn out stuff.

Masks are good to use, but I find them to be a bit uncomfortable. And with my Dust collection system I find them unecessary. Before my system I found them to be inadequate.

 

[sawzalot]

One of the greater benefits of ply over mdf is also the weight ply is much lighter and easier to move around as well as holding screws and brads better overall, go with the ply.

 

[vilbig]

Are there any relatively inexpensive alternatives to MDF for DIY speaker construction? My son has asthma and MDF has a somewhat sketchy health reputation....

Another vote for Baltic Birch. If you have a Rockler or Woodcraft store nearby, they sell project sized pieces.

 

[WmAx]

Beware that it's a bit tougher to machine though. And you must use 13 ply not 5 ply. If you do use 5ply against recommendations then you can make it work ok if you dampen every wall. ( I know I've done it before)

You will want to make sure to get very good blades and bits. Don't go cheap or you can burn out stuff.

Masks are good to use, but I find them to be a bit uncomfortable. And with my Dust collection system I find them unecessary. Before my system I found them to be inadequate.

5 ply hardwood cab grade is fine for subwoofers. 13 ply, however, is a better choice for full range.

-Chris

 

[GO-NAD!]

I assume you're aware that plywood contains glue as well as MDF - just not as much? With regards to your son's condition, are you worried about the dust generated during construction, or is it off-gassing after the speaker cabinets are finished?

I would be most concerned about the dust, as opposed to off-gassing. When you think about it, off-gassing can't be avoided - just reduced. New furniture, carpet, draperies, paint, etc. Anything synthetic will off-gas to various degrees. So, a few speaker cabinets won't make a lot of difference.

I hope you have a dedicated woodworking area, separated from the living area of your house, like a shed or garage. My shop is in my basement, because I have no space on my property for a separate workshop. Dust is a big concern for me, so I've sealed up every little opening I can find and I have a dedicated dust collection system for my tools. Shop vacs can work, but they just don't pull a sufficient volume of air IMO. Plus, you need a HEPA filter cartridge for a shop vac, or you'll just be spreading the dust around more. Dust masks are uncomfortable, as Isiberian says, but I still use one - a proper one that seals to my face and has HEPA filter cartridges. On top of that, I have an ambient air dust collector. You cannot be too paranoid about woodworking dust - whether it's natural wood or MDF.


3/4" MDF is a lot cheaper than 3/4" cabinet grade plywood. However, such plywood can have your choice of veneers - oak, maple, etc. You just need to hide the edges. You can use iron-on veneer strips or mitre all your edges at 45 degrees, which would be a royal PITA.

If I were you, I'd stick with the MDF (make sure your son is not exposed to the dust). Assemble the cabinets with yellow carpenters glue, as it's much healthier than polyurethane glues or contact cement. It also creates a very
strong joint and provides air sealing for your cabinet, if you ensure a seamless glue join. As previously stated, screws don't hold well in MDF. You could also use a low-VOC paint to finish them. You stated that appearance isn't important, but plain MDF is butt-ugly.

Hope that helps. Well, I hope it doesn't hinder, at least...

 

[lsiberian]

I assume you're aware that plywood contains glue as well as MDF - just not as much? With regards to your son's condition, are you worried about the dust generated during construction, or is it off-gassing after the speaker cabinets are finished?

I would be most concerned about the dust, as opposed to off-gassing. When you think about it, off-gassing can't be avoided - just reduced. New furniture, carpet, draperies, paint, etc. Anything synthetic will off-gas to various degrees. So, a few speaker cabinets won't make a lot of difference.

I hope you have a dedicated woodworking area, separated from the living area of your house, like a shed or garage. My shop is in my basement, because I have no space on my property for a separate workshop. Dust is a big concern for me, so I've sealed up every little opening I can find and I have a dedicated dust collection system for my tools. Shop vacs can work, but they just don't pull a sufficient volume of air IMO. Plus, you need a HEPA filter cartridge for a shop vac, or you'll just be spreading the dust around more. Dust masks are uncomfortable, as Isiberian says, but I still use one - a proper one that seals to my face and has HEPA filter cartridges. On top of that, I have an ambient air dust collector. You cannot be too paranoid about woodworking dust - whether it's natural wood or MDF.


3/4" MDF is a lot cheaper than 3/4" cabinet grade plywood. However, such plywood can have your choice of veneers - oak, maple, etc. You just need to hide the edges. You can use iron-on veneer strips or mitre all your edges at 45 degrees, which would be a royal PITA.

If I were you, I'd stick with the MDF (make sure your son is not exposed to the dust). Assemble the cabinets with yellow carpenters glue, as it's much healthier than polyurethane glues or contact cement. It also creates a very
strong joint and provides air sealing for your cabinet, if you ensure a seamless glue join. As previously stated, screws don't hold well in MDF. You could also use a low-VOC paint to finish them. You stated that appearance isn't important, but plain MDF is butt-ugly.

Hope that helps. Well, I hope it doesn't hinder, at least...

Aggreed on the shop vac not having as much power as I want, but for handheld tools it's more than sufficient usually.

I still use a dust mask when appropriate. Screws are unecessary in speaker construction unless you just want to make the process faster. Titebond is sufficient to hold most speakers together. That stuff is very very strong.

 

[suemay]

some kind of plastic wood?

 

[highfigh]

Are there any relatively inexpensive alternatives to MDF for DIY speaker construction? My son has asthma and MDF has a somewhat sketchy health reputation....

Call around to the major plywood and MDF suppliers (call some cabinet shops, if needed) and ask about formaldehyde-free products. Also, if you don't have one, get a good dust collector.

 

[Wafflesomd]

Why not just keep your son away from the cutting area?

 

[highfigh]

I'm fine with plywood because the "look" of the speakers is irrelevant to me for this particular project.

Is there any (significant) acoustic difference between MDF and plywood? Or is it just about the interior space/configuration?

Density and stiffness are two differences. Bracing helps and an MDF box that is glued and stapled is OK but glued and screwed is definitely better (more inert).

Mechanical fasteners make a big difference. Glue coated finish nails, brads and staples are much better than non-coated and either drywall or actual cabinet screws (made specifically for joining MDF and particle board) with a coarse thread WILL make a glued and stapled box resonate less. For anyone who doubts this, make two boxes with glued joints and use staples, finish nails or brads on one and coarse thread drywall screws or cabinet screws on the other.

 

[lsiberian]

Density and stiffness are two differences. Bracing helps and an MDF box that is glued and stapled is OK but glued and screwed is definitely better (more inert).

Mechanical fasteners make a big difference. Glue coated finish nails, brads and staples are much better than non-coated and either drywall or actual cabinet screws (made specifically for joining MDF and particle board) with a coarse thread WILL make a glued and stapled box resonate less. For anyone who doubts this, make two boxes with glued joints and use staples, finish nails or brads on one and coarse thread drywall screws or cabinet screws on the other.

What are you thoughts on using dovetails or box joints? Or how about lock miter joints.

 

[highfigh]

What are you thoughts on using dovetails or box joints? Or how about lock miter joints.

Too much work. In real wood, I like dovetails and box joints a lot, lock miter not as much. I have built speaker boxes with particle board (first ones) and MDF, which were dropped at some point and they just bounced. When I did car audio, MDF was the standard with wood glue and a Senco 1/4" crown stapler, shooting glue coated 2" staples. I always use corner clamps so I don't have to juggle parts (just not efficient) and those staples worked really well. The few times I had to tear a box apart, it was a *****. Never had a box come apart either, and some of these cars were serious rap or competition systems.

When possible, I like rabbets and grooves to have glue contact on three sides of the edge but I don't have a V grooving machine like major speaker manufacturers. They usually havea them set so accurately that they use veneered MDF or plywood, cut the V grooves, apply the glue, load the front and back, then fold it up, taping the open corner together until the glue dries, maybe with band clamps. You can usually tell this is how the boxes were done because the front and back panels are recessed.

 

[Hi Ho]

Mechanical fasteners make a big difference. Glue coated finish nails, brads and staples are much better than non-coated and either drywall or actual cabinet screws (made specifically for joining MDF and particle board) with a coarse thread WILL make a glued and stapled box resonate less. For anyone who doubts this, make two boxes with glued joints and use staples, finish nails or brads on one and coarse thread drywall screws or cabinet screws on the other.

I used biscuit joints with polyurathane glue for my speakers and sub The cabinets pass the knuckle test. I feel no vibration when playing the system at high levels.