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View Full Version : Glue MDF: Is it really necessary



drpeeb
04-28-2009, 12:12 AM
Right now I have a 10" non-ported box I built with 2.5" screws every 4" on all joints.

I don't see this box like flying apart or anything.

I'd really like to leave it un-glued so I can take it apart, change it, whatever, whenever I feel like it ... I'm all non-committal like that, like to tinker/ explore.

Now ... I understand the glue is also to seal the box, but I feel like my joints are tight enough that they "shouldn't" need glue or sealant.

Am I wrong or either or both??

Tks

mazzasec
04-28-2009, 12:14 AM
Its the glue that holds the box together. The screws just help it bond together without it coming apart.

muskyhunter567
04-28-2009, 12:14 AM
does your box leak? and if you want that thing to be hella strong glue it, but if you change it all the time, maybe some foam tape or somthing to seal it up? but if its anything you really want to be good for a long time, glue it i learned the hard way

thegreatestpenn
04-28-2009, 12:14 AM
u need glue/caulking dude

schackel
04-28-2009, 12:17 AM
^^^^^^^^^^^^^^^^^^ x2

SicAudio
04-28-2009, 12:28 AM
without glue it will leak Period. i use liquid nails on every box i make.

Random1010
04-28-2009, 12:30 AM
The glue is what holds the box together, screws aren't even necessary.

Dak446
04-28-2009, 12:32 AM
The glue is what holds the box together, screws aren't even necessary.

x2

i stapled mine, just to hold it together while the glue dried, then screwed in a few places to **** it together

James Bang
04-28-2009, 12:34 AM
search

drpeeb
04-28-2009, 12:44 AM
does your box leak? and if you want that thing to be hella strong glue it, but if you change it all the time, maybe some foam tape or somthing to seal it up? but if its anything you really want to be good for a long time, glue it i learned the hard way

I will definitely glue it once I get it "right".

It's just that could take me a while, though.

Lakota
04-28-2009, 12:44 AM
As much as I'd like to argue, they are right.

Blue Fury
04-28-2009, 12:45 AM
Youre box is leaking however small the amount may be, it is leaking. Seal it.

Random1010
04-28-2009, 12:46 AM
As much as I'd like to argue, they are right.

You scrappy motherfvka:D

IDSkoT
04-28-2009, 12:47 AM
Right now I have a 10" non-ported box I built with 2.5" screws every 4" on all joints.

I don't see this box like flying apart or anything.

I'd really like to leave it un-glued so I can take it apart, change it, whatever, whenever I feel like it ... I'm all non-committal like that, like to tinker/ explore.

Now ... I understand the glue is also to seal the box, but I feel like my joints are tight enough that they "shouldn't" need glue or sealant.

Am I wrong or either or both??

Tks

Glue acts as a sealant, it's true. But not a full sealant. That's why we use silicone / caulk.

Pioneer~Saturn
04-28-2009, 12:50 AM
Glue...for sure.

drpeeb
04-28-2009, 12:50 AM
search motherfucker.

Oh ****, I never thought of that. I did dude ... Searched "glue", read a bunch of the threads, never found the answer to these questions, put the way I put them.

And if it bothers you, the question's right there in the **** in the title ... Don't ****in' click on it. I didn't trick you with words in the title. I'd have to say you're the mother ****er for clicking on a question that pisses you off because you feel it's been asked before. So it easy to solve that problem.

ItalynStylion
04-28-2009, 01:07 AM
When you stated that you might take it apart and change it...what did you mean by that? Change it how?

As many have said, glue it for sure. The nails/screws are just to hold the boards in place long enough to let the glue dry. You never will fully understand how amazingly strong wood glue bonds two pieces of wood until you have glued two pieces together, let them dry, and then realized you screwed up and need to get them apart. It's like solid iron! You will literally, I **** you not, break the two pieces of wood before the glue will fail. That's how strong it is. Now imagine that on every edge of your box. Not at 4" increments like your screws, but every single square inch of contact area between two boards.

THAT....is why you NEED glue

James Bang
04-28-2009, 01:42 AM
Oh ****, I never thought of that. I did dude ... Searched "glue", read a bunch of the threads, never found the answer to these questions, put the way I put them.

And if it bothers you, the question's right there in the **** in the title ... Don't ****in' click on it. I didn't trick you with words in the title. I'd have to say you're the mother ****er for clicking on a question that pisses you off because you feel it's been asked before. So it easy to solve that problem.

:laugh:

looks like you're the one that's pissed.

You **** at searching.

glue
wood glue
enclosure build
box build
glue joints
glue bond.
motherfucker

jmanpc
04-28-2009, 01:43 AM
without glue it will leak Period. i use liquid nails on every box i make.

Liquid nails = huge can o' fail

Titebond ftw.

James Bang
04-28-2009, 01:46 AM
Liquid nails = huge can o' fail

Titebond ftw.

liquid fails.

alvitae
04-28-2009, 01:51 AM
Oh ****, I never thought of that. I did dude ... Searched "glue", read a bunch of the threads, never found the answer to these questions, put the way I put them.

And if it bothers you, the question's right there in the **** in the title ... Don't ****in' click on it. I didn't trick you with words in the title. I'd have to say you're the mother ****er for clicking on a question that pisses you off because you feel it's been asked before. So it easy to solve that problem.

So what if something has been posted before. I learn a lot of stuff from just scanning the new posts and clicking on what catches my eye. I think most every one else that don't know every thing yet learns a lot that way as well. It's hard to search for things you never heard of. Although in this case I have heard of gluing the box lol.

gotparts90
04-28-2009, 01:55 AM
titebond rocks but I like gorilla on the plywood. I like brads better than staples, the stapler just for me was harder to get the depth right and more prone to splitting mdf. for plywood it works fine but I use screws on plywood.

Pioneer~Saturn
04-28-2009, 02:20 AM
Agreed, liquid nails isnt the best route for sure...titebond is a fantastic wood glue, you'd be very hard-pressed to top it.

sound giant
04-28-2009, 05:44 AM
so how do you not get a whole thru the wood when screwing it in blind spots?

gotparts90
04-28-2009, 05:48 AM
so how do you not get a whole thru the wood when screwing it in blind spots?

wat? I like to use glue throughout the whole box.

ngsm13
04-28-2009, 07:41 AM
Titebond II, use it.

nG

RAM_Designs
04-28-2009, 07:44 AM
and predrill if you're using screws, otherwise you're asking for split MDF.

01 S 10
04-28-2009, 08:05 AM
low powered system you might not hear a difference, but if there's even a 1/32" gap, you will lose output. if this is for 1,000w+, glue it.

drpeeb
04-28-2009, 09:44 AM
:laugh:

looks like you're the one that's pissed.

You **** at searching.

glue
wood glue
enclosure build
box build
glue joints
glue bond.
motherfucker


Just confused: When you read my thread title, which is very clearly stated, why the hell would you even waste your time clicking on it when you "know" so **** sure that it's already been answered??????? Seems like it was so you could come in here and type for everybody to see how smart you are knowing that my question has already been asked and answered and hammer on me that I'm a dumb mother ****er for not being able to successfully search at your superior level. Guess I'm actually not confused.

drpeeb
04-28-2009, 09:49 AM
When you stated that you might take it apart and change it...what did you mean by that? Change it how?

As many have said, glue it for sure. The nails/screws are just to hold the boards in place long enough to let the glue dry. You never will fully understand how amazingly strong wood glue bonds two pieces of wood until you have glued two pieces together, let them dry, and then realized you screwed up and need to get them apart. It's like solid iron! You will literally, I **** you not, break the two pieces of wood before the glue will fail. That's how strong it is. Now imagine that on every edge of your box. Not at 4" increments like your screws, but every single square inch of contact area between two boards.

THAT....is why you NEED glue

The thing is ... with no glue at all right now, only screws, my box is holding together great. I did pre-drill the screw holes. So, why do I need it to be glued if it's holding together great right now?

I could understand this if you only put screws in the corners, or like every foot, but mine are 4" apart.

Now, for the sealing issue ... I think I will just caulk the interior joints; Caulk can be removed later.

drpeeb
04-28-2009, 09:51 AM
low powered system you might not hear a difference, but if there's even a 1/32" gap, you will lose output. if this is for 1,000w+, glue it.

Aaaahhhh .. now that is probably the answer.

Mine amp is 110W RMS/ 160W max with a 150W RMS/ 300W max 10" sub in a non-ported box.

Maybe this combination isn't capable of pounding the boxes screwed joints apart?

drpeeb
04-28-2009, 10:00 AM
When you stated that you might take it apart and change it...what did you mean by that? Change it how?

I don't have much experience with car stereo subs, and I have very little space in my trucks extended cab, so I want to be able to re-cut/ re-shape/ re-configure the box until I'm happy with it. With this small space I think I need to maximize the sub enclosure as much as possible.

With it still not glued I can unscrew it, replace a panel or 2 or 3, or whatever, and re-screw it back together.

If it's glued I have to start over with new MDF every time I want to try a different configuration.

For instance right now I want to try it ported, so I will still be able to un-screw it to add a port (either PVC or an MDF slotted port) and then screw it all back together.

And, if I don't like the port, I can unscrew it, remove the port, replace any panel(s) I have cut, and screw it all back together again.

Once I have a final, I will probably go ahead and finally glue it. Until then it's a prototype.

I was just wondering if people were pounding their un-glued boxes apart, because I'm not seeing that on mine. It may just not have enough power to do that with screws every 4".

amartin_72
04-28-2009, 10:13 AM
I use liquid nails and cannot get the boxes apart without the mdf breaking into pieces, not at the seams.

ramos
04-28-2009, 10:33 AM
The thing is ... with no glue at all right now, only screws, my box is holding together great. I did pre-drill the screw holes. So, why do I need it to be glued if it's holding together great right now?

I could understand this if you only put screws in the corners, or like every foot, but mine are 4" apart.

Now, for the sealing issue ... I think I will just caulk the interior joints; Caulk can be removed later.



Main reason for glue is structural integrity down the road. While your screws, brads, staples, boogers, midgets holding it, or whatever seems tight now. They will loosen up their grip on the mdf over time due to vibration, and expansion and contraction of the mdf. :)

Buck
04-28-2009, 10:35 AM
Use glue, not screws :fyi:

It seals the box as well as it will hold it together much better than screws will.

drpeeb
04-28-2009, 10:57 AM
Use glue, not screws :fyi:

It seals the box as well as it will hold it together much better than screws will.

When I do settle on a final box configuration/ shape, then un-screw it, glue it, and re-screw it ... will I notice a difference in sound/ bass?

My seams are all very, very tight right now, although not sealed with anything (it is completely filled with polyfil). I've built homes & buildings, etc. (me not subs!), done lots and lots of shoe molding, crown molding, etc. I'm very proficient with a table saw! (and clamps, screw gun, counter-sinker, router, sander, etc.)

I will post a pic of the worst seam and see what you all think ... just for reference.

Maybe I should've titled this thread: "Glue MDF: Is it really necessary if you have lots of screws, tight seams that are caulked, and polyfil?"

mcsoul
04-28-2009, 10:58 AM
IF you want to caulk it, then do that. At least it's something. I'm with italyn, how the heck would you reconfigure a box? You going to keep the sides and increase the width? What a waste of
time. Just cut some more wood you cheap lazy bastage.

ramos
04-28-2009, 11:02 AM
When I do settle on a final box configuration/ shape, then un-screw it, glue it, and re-screw it ... will I notice a difference in sound/ bass?

My seams are all very, very tight right now, although not sealed with anything (it is completely filled with polyfil). I've built homes & buildings, etc. (me not subs!), done lots and lots of shoe molding, crown molding, etc. I'm very proficient with a table saw! (and clamps, screw gun, counter-sinker, router, sander, etc.)

I will post a pic of the worst seam and see what you all think ... just for reference.

Maybe I should've titled this thread: "Glue MDF: Is it really necessary if you have lots of screws, tight seams that are caulked, and polyfil?"

Then you should be familiar with the fact that mdf has crappy arse screw holding characteristics. :)

thegreatestpenn
04-28-2009, 11:07 AM
the bigger issue at hand is re-using a box in a different "configuration." Even though the price of MDF is rising more and more, its still much easier to just build a new box instead of trying to configure one over and over. the more alteration you do to the current box, the less integrity it will have. It will get weaker and weaker. leak more air after every alteration. All this will lead to less output

Buck
04-28-2009, 11:07 AM
The polyfil won't affect the actual box in terms of how well it's sealed. I've had the sides of boxes stick out a little where the screw went in. Be sure to pre-drill the screw holes and don't use to big of screws. If you have clamps and know how to use them, I wouldn't use screws at all.

ItalynStylion
04-28-2009, 12:30 PM
Aaaahhhh .. now that is probably the answer.

Mine amp is 110W RMS/ 160W max with a 150W RMS/ 300W max 10" sub in a non-ported box.

Maybe this combination isn't capable of pounding the boxes screwed joints apart?

A ported box MIGHT get away with not being 100% sealed since it's vented anyways but a SEALED box will suffer considerably. I highly doubt you've got wood cutting skills that can provide joints true enough to get you any type of good seal. If you're going to use caulk or silicone to try and seal it up you will have trouble taking the panels apart and changing it like you mentioned.


I suggest that you take the time to plan your setup correctly before you start cutting anything. Heck, build a crappy cardboard mock up, sometimes that helps to visualize it in the car. After you're satisfied with the plan THEN cut everything and build the box the right way with wood glue. Don't try to cut corners because you skimped on the planning. Do it right, do it once.

drpeeb
04-28-2009, 02:18 PM
IF you want to caulk it, then do that. At least it's something. I'm with italyn, how the heck would you reconfigure a box? You going to keep the sides and increase the width? What a waste of
time. Just cut some more wood you cheap lazy bastage.

Easy!! Simple example: Keep the bottom and top rectanglular pieces and replace the sides with taller or shorter ones.

Why?: My sub maker recommends a 1.0 cubic foot sealed box or a 1.25 cubic foot ported box, and I want to try both.

Nothing to do with being lazy. Everything to do with efficient use of time and materials (aka money) during the test-it-until-you-like-it phase.

drpeeb
04-28-2009, 02:21 PM
A ported box MIGHT get away with not being 100% sealed since it's vented anyways but a SEALED box will suffer considerably. I highly doubt you've got wood cutting skills that can provide joints true enough to get you any type of good seal. If you're going to use caulk or silicone to try and seal it up you will have trouble taking the panels apart and changing it like you mentioned.


I suggest that you take the time to plan your setup correctly before you start cutting anything. Heck, build a crappy cardboard mock up, sometimes that helps to visualize it in the car. After you're satisfied with the plan THEN cut everything and build the box the right way with wood glue. Don't try to cut corners because you skimped on the planning. Do it right, do it once.

What I meant is ... my sub is currently mounted in a non-ported box. It has the same 150W RMS/ 300W power ratings in a 1.25 cubic foot ported sub, and I would also like to try ported.

99grandprixGT
04-28-2009, 02:24 PM
id glue and screw, but do not go over board on the screws.

bhsdriller
04-28-2009, 02:25 PM
use glue *******

mcsoul
04-28-2009, 02:29 PM
Easy!! Simple example: Keep the bottom and top rectanglular pieces and replace the sides with taller or shorter ones.

Why?: My sub maker recommends a 1.0 cubic foot sealed box or a 1.25 cubic foot ported box, and I want to try both.

Nothing to do with being lazy. Everything to do with efficient use of time and materials (aka money) during the test-it-until-you-like-it phase.

When you don't like the sound of the sealed 1 cubic foot box, your going
to blame the fact that it's sealed? Well it's not sealed.

PatFitz9
04-28-2009, 02:29 PM
Easy!! Simple example: Keep the bottom and top rectanglular pieces and replace the sides with taller or shorter ones.

Why?: My sub maker recommends a 1.0 cubic foot sealed box or a 1.25 cubic foot ported box, and I want to try both.

Nothing to do with being lazy. Everything to do with efficient use of time and materials (aka money) during the test-it-until-you-like-it phase.

You should be able to build both boxes out of one sheet of MDF. I don't understand why people ask for advice and then ***** about it when it's not what they wanted to hear. This site isn't to validate your opinions. You asked a question, we answered. Go buy some clamps and wood glue and build the box properly.

gotparts90
04-28-2009, 02:33 PM
A ported box MIGHT get away with not being 100% sealed since it's vented anyways but a SEALED box will suffer considerably. I highly doubt you've got wood cutting skills that can provide joints true enough to get you any type of good seal. If you're going to use caulk or silicone to try and seal it up you will have trouble taking the panels apart and changing it like you mentioned.


I suggest that you take the time to plan your setup correctly before you start cutting anything. Heck, build a crappy cardboard mock up, sometimes that helps to visualize it in the car. After you're satisfied with the plan THEN cut everything and build the box the right way with wood glue. Don't try to cut corners because you skimped on the planning. Do it right, do it once.


ported boxes need to be sealed at the seams just as tight and they actually build higher pressures inside them when built right.

drpeeb
04-28-2009, 02:45 PM
You should be able to build both boxes out of one sheet of MDF. I don't understand why people ask for advice and then ***** about it when it's not what they wanted to hear. This site isn't to validate your opinions. You asked a question, we answered. Go buy some clamps and wood glue and build the box properly.

My original question was whether glue is really needed in my particular situation, because obviously I wasn't sure it was.

Now, after quite a bit of discussion, I'm convinced that for now it's not making a big difference that it isn't glued. I understand most of you disagree. After some trial-and-error, and after I finally do glue it, I may have a different opinion. I'll certainly log back in and admit I was wrong if/ when that time comes.

I do appreciate all the responses and I hope you all got something out of it, too, so you don't feel you wasted your time.

PatFitz9
04-28-2009, 03:05 PM
My original question was whether glue is really needed in my particular situation, because obviously I wasn't sure it was.

Now, after quite a bit of discussion, I'm convinced that for now it's not making a big difference that it isn't glued. I understand most of you disagree. After some trial-and-error, and after I finally do glue it, I may have a different opinion. I'll certainly log back in and admit I was wrong if/ when that time comes.

I do appreciate all the responses and I hope you all got something out of it, too, so you don't feel you wasted your time.

My guess is that you won't notice a difference right away (assuming your edges are true). The point is, if you want to do it the right way, use glue. Just because something works, doesn't mean it's right.

gotparts90
04-28-2009, 03:11 PM
I understand that you want to try it out a few ways I have just done the same thing but made the box and them I am playing with spacers and poly fill to adjust the sound. I end up where I want in a sealed box by just making one box and making it right.

FF5
04-28-2009, 06:57 PM
*Waits for him to admit he is wrong*

BassMechanix
04-28-2009, 08:18 PM
Its MDF, glue or no glue it will leak regardless, MDF is primarily used for vaccume forming molds not just for enclosure builds. Its very poris so heated plastic can be vaccume formed right through the MDF. If air can go in it can go out too. But Like everyone else is saying "GLUE IT".

sound giant
04-28-2009, 09:07 PM
Its MDF, glue or no glue it will leak regardless, MDF is primarily used for vaccume forming molds not just for enclosure builds. Its very poris so heated plastic can be vaccume formed right through the MDF. If air can go in it can go out too. But Like everyone else is saying "GLUE IT".

what would be better than mdf then? what about if you paint the mdf doesnt it make it non pourus

SicAudio
04-28-2009, 11:38 PM
paint or as i prefer sealing the box with f/g resin :) makes the wood denser and less flex as well :)

drpeeb
04-30-2009, 12:48 AM
... I will post a pic of the worst seam and see what you all think ... just for reference.

OK, here's a few pics.:
26511108

26511107

26511105


Upper-left & lower-right are the worst two joints; About a fingernail thickness wide:
26511106

The "wood grain" pieces are leftovers from an old Sauder brand screw-together entertainment center.

So **** ...

SicAudio
04-30-2009, 01:30 AM
if you can visibly see it , then its gonna leak for sure :( and that is particle wood, it is really crappy for enclosures.

germandark
04-30-2009, 11:47 AM
Cancer.

mcsoul
04-30-2009, 11:53 AM
http://www.changetowin.org/connect/images/fail.jpg

drpeeb
04-30-2009, 02:19 PM
Cancer.

Alright, alright ... I'm on it.

Ordered an Alpine PDX-5 and two Alpine SWS-1043D subs. Gonna put them in small-ish sealed MDF-only enclosures (biggest I can fit under my king cab rear seats), glue them, yes glue them, and just live with 'em that way.

This way I can choose to take one sub out if needed and run it either of these 2 ways:


- One Alpine SWS-1043D (4ohm DVC) sub which would be powered by 300W RMS at 2ohms.

- Two Alpine SWS-1043D (4ohm DVC) subs which would be powered by 150W RMS each at 4ohms.

I need flexibility to be able to pull one out if needed.

Tks ...

SYLrules
04-30-2009, 04:38 PM
since a ported enclosure generally needs to be larger than a sealed one you probably dont want to just add a port to a .91 cu/ft sealed box. it wont sound good. think someone already hit that point? and if you're that low on cash just rob home depot for all the mdf you need!

and by the way use glue :)

drpeeb
04-30-2009, 05:44 PM
since a ported enclosure generally needs to be larger than a sealed one you probably dont want to just add a port to a .91 cu/ft sealed box. it wont sound good. think someone already hit that point? and if you're that low on cash just rob home depot for all the mdf you need!

and by the way use glue :)

Cash isn't really the problem .. space under the rear seats is!

Will glue ... And I'm just gonna go sealed and most likely let that be that.

It would sure be nice to be able to simply flip a switch to hear the difference between sealed and ported, wouldn't it?!!

drpeeb
04-30-2009, 05:46 PM
http://www.changetowin.org/connect/images/fail.jpg



I'm almost always frightened by a pvssy with a strap-on.

SYLrules
05-01-2009, 04:52 PM
ALMOST always frightened...?

haha anyways, yeah i wish it was that easy to hear both setups without having 2 boxes and 4 subs in ya car. ive had my 12"s in a sealed for a few years and ive always kinda been unhappy how they sounded. some rock cd's they're fine and others its not very good. but in my last vehicle theres no way i could have fit in a bigger box! but ive got an SUV now so ive got more room to play with. im thinkin about switching to ported and then puttin a thin mount 8" under my seat and maybe one under the front psgr too. dont have the money for that right now so thats in the future. but if you do go ported, let me know if you like it better than your sealed setup. rock on

ez2hotwire
05-03-2009, 04:54 PM
If you have clamps and know how to use them, I wouldn't use screws at all.

I agree 100%...you can buy long clamps at Home Depot and just do it that way - just make sure all your cuts are exact (of course) but the point is you really don't even need screws.