Birch box construction

[cha0 10+ year member]

Despite what other people tell you, USE SCREWS.
During my box building spree before finals I forgot to put screws on only ONE EDGE of the box while the rest was all screwed down.

I didn't use the box until the next day and when I did, I learned the hard way that glue alone will NOT hold a box together in my application. The first full tilt burp completely broke that edge of the box.

Some people don't realize exactly how much pressure is building inside a box, in my case about 170 dB worth.

For lower power situations it can do fine, but my 9515 has broken several boxes that were screwed AND glued because it still wasn't strong enough.

I use 1 5/8" coarse threaded screws about every 5-6".

i wish i was pushing 170 DBs for daily. granted i would be deff, it would be fun. all im running in this box is 2 9910s and a z1a.

wednesday i am actually doing some tests of birch vs. mdf concerning spl. in the evening i will make a thread and post the results. basically i am making 2 identical box's. illuminating all the variables i have control of.

i think it has been established that MDF is much more flexable then birch. making it pretty shitty for SPL...

 

[tommyk90 5,000+ posts]

i wish i was pushing 170 DBs for daily. granted i would be deff, it would be fun. all im running in this box is 2 9910s and a z1a.



i think it has been established that MDF is much more flexable then birch. making it pretty shitty for SPL...

You're probably doing 160's INSIDE the box. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif That's what I meant by my 170 dB comment. I measured my single 10" box doing a 170.0 inside the box.

Still a LOT of pressure.

Birch (GOOD birch) is known to be stiffer than MDF, while MDF is more dense. Both can work just fine for SPL enclosures and daily driving enclosures.

 

[Lakota 5,000+ posts]

Despite what other people tell you, USE SCREWS.
During my box building spree before finals I forgot to put screws on only ONE EDGE of the box while the rest was all screwed down.

I didn't use the box until the next day and when I did, I learned the hard way that glue alone will NOT hold a box together in my application. The first full tilt burp completely broke that edge of the box.

Some people don't realize exactly how much pressure is building inside a box, in my case about 170 dB worth.

For lower power situations it can do fine, but my 9515 has broken several boxes that were screwed AND glued because it still wasn't strong enough.

I use 1 5/8" coarse threaded screws about every 5-6".

Send the boxes that you don't want this way I could free up some of your clutter.

 

[tommyk90 5,000+ posts]

Send the boxes that you don't want this way I could free up some of your clutter.

One of the boxes is out next to the garbage if you want it. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

 

[cha0 10+ year member]

One of the boxes is out next to the garbage if you want it. //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

haha, knowing im so close to your hood, its tempting...

 

[kmanian 5,000+ posts]

If you are looking for the a better situation than screwing into the grain of the ply or MDF I will highly suggest the use of KREG pocket screws and glue. With this type of fastening system you are actually screwing into the layers of the wood at 75 +/- degrees to the screw, so you are not relying on the end grain to hold the screw threads. I would also suggest using "gorilla glue" it expands into the grain and makes a superior bond to common wood glue (wear rubber gloves though)

 

[PSturmer 10+ year member]

If you are looking for the a better situation than screwing into the grain of the ply or MDF I will highly suggest the use of KREG pocket screws and glue. With this type of fastening system you are actually screwing into the layers of the wood at 75 +/- degrees to the screw, so you are not relying on the end grain to hold the screw threads. I would also suggest using "gorilla glue" it expands into the grain and makes a superior bond to common wood glue (wear rubber gloves though)

gorilla

gorilla (the new stronger-faster)

and pocket screws do not go deep enough into the wood.

 

[kmanian 5,000+ posts]

gorilla
gorilla (the new stronger-faster)

and pocket screws do not go deep enough into the wood.

I am not sure what you mean by they don't go deep enough into the wood, they go cross grain, you can use screws that are long enough to go straight through the plywood, and finally you are using them in 2 capacities, 1) clamp the wood while the glue cures, 2) as reinforcement for the bond created by the glue. If you have any doubt as to the holding capacity of the system, I will build yo a box to your specs, ship it to you unassembled, you can put it together with the supplied glue, then I defy you to destroy the box with a any sub powered by any amp.

Secondly, how long of a screw are you putting into MDF and how often are you putting them. because of you penetrate MDF with to large of a screw and to often of an interval you hav comprimised the strength, you will split it apart.

 

[tommyk90 5,000+ posts]

I am not sure what you mean by they don't go deep enough into the wood, they go cross grain, you can use screws that are long enough to go straight through the plywood, and finally you are using them in 2 capacities, 1) clamp the wood while the glue cures, 2) as reinforcement for the bond created by the glue. If you have any doubt as to the holding capacity of the system, I will build yo a box to your specs, ship it to you unassembled, you can put it together with the supplied glue, then I defy you to destroy the box with a any sub powered by any amp.Secondly, how long of a screw are you putting into MDF and how often are you putting them. because of you penetrate MDF with to large of a screw and to often of an interval you hav comprimised the strength, you will split it apart.

Wood glue has been shown to be superior over anything else when bonding wood.

After all, its WOOD GLUE.

Wood glue causes a chemical reaction that actually bonds the wood pieces to each other, whereas gorilla glue (and other types) merely have a surface bond.

Use wood glue for enclosures. Period.

 

[miker 5,000+ posts]

Might be a good idea to dip the screws in gorilla glue... B/c of the expanding effect...

Any thoughts?

Also a way to hold up the side panels is to put the base down on a large piece of wood, then place boards tightly around the wood, and screw them down. Then cut out a piece to brace across the middle. Once you get the main sides up the port should be pretty easy to finish.

 

[kmanian 5,000+ posts]

Wood glue has been shown to be superior over anything else when bonding wood.
After all, its WOOD GLUE.

Wood glue causes a chemical reaction that actually bonds the wood pieces to each other, whereas gorilla glue (and other types) merely have a surface bond.

Use wood glue for enclosures. Period.

I agree with you in theory, however when using MDF typically guys building boxes do not clean off the residue (powder) cutting the MDF. the gorilla glue tends to work around this powder enveloping it and bonding to the fibers that are firmly attached to the panel. Also with standard wood glue, guys tend to run a bead of glue on the end grain of the cut, they do not typically spread a layer over the entire cut end of the wood, therefore they are not receiving the full benifit of the chemical bond, with the expanding effect of a poly glue you acheve a much larger adhesion base. If "wood glue is used properly, it is a great adhesive, it needs to be placed across the entire area that is being bonded, with the dust from the cut being removed prior to the placement of the glue. I am saying this out of practice, not theory, I have been a professional carpenter for 20 years, once again I will be willing to back up any recomendations that I make with a sample as proof.

theory and the real world are two totally different things.//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[Towlieee 10+ year member]

Wood glue has been shown to be superior over anything else when bonding wood.
After all, its WOOD GLUE.

Wood glue causes a chemical reaction that actually bonds the wood pieces to each other, whereas gorilla glue (and other types) merely have a surface bond.

Use wood glue for enclosures. Period.

Just out of curiosity, does liquid nails pass as wood glue?

I always just used liquid nails to bond wood, and in the corners inside

 

[tommyk90 5,000+ posts]

Just out of curiosity, does liquid nails pass as wood glue?
I always just used liquid nails to bond wood, and in the corners inside

liquid nails is not wood glue.

 

[miker 5,000+ posts]

Use lots of glue clean up later? To ensure you get a good even layer.

Also the screws "pull" the wood together very nicely.. I'm thinking (haven't tried) that nails would more hold it together, not pull it together, but if you it clamped really tight nails and glue might be OK.

 

[kmanian 5,000+ posts]

Just out of curiosity, does liquid nails pass as wood glue?
I always just used liquid nails to bond wood, and in the corners inside

The problem with using construction adhesive in joining panels is that you are using a adhesive that has body, it is creating a space between the 2 substraights that is filled with the adhesive, the adhesive is then the weak spot, the adhesive it self has a very low tensel strength, so once again this is in theory, so depending on the service it is going to see it may work just fine. I will say that using it in the corners of the interior of the box is adding strength to it as apposed to latex caulk.