Making a box.. gotta few ?s

[QuestionMan 0]

I started the cuts today, and want to put it together soon, but theres a few things i'm missing. I know i need to pilot the holes, but what size screws? I was thinking 1 5/8" Drywall screws. And for the glue.. should i just use regular carpenter glue/weldbond or something special? Also i read that MDF is porous, so should i seal it? and with what? And someone on a different forum mentioned to do seomthing different for the edges/corners.. .any idea what he meant?

1. 1 5/8" drywall screws?

2. Weldbond/carpenter glue or something else?

3. What kind of sealant if any? (recommendations?)

4. What should i seal edges with?

I know its long but thanks for readin.

[brent338 0]

I used;

2" wood screws.

Titebond wood glue

liquid nails

and some 3" screws for the 2x fronts.

wood putty for counter sinks.

be liberal with wood glue, get dirty and use your fingers to press it in along edges and such. wipe off excess. go over edges with liquid nails for that extra piece of mind.

router to edges and corners if you want, then sand...done, get to beating...

[QuestionMan 0]

Do you have to sand? just curious.. and also, i really dont want to carpet my box, but i saw a nice paint job, real thick and protective it seemed on a freinds box. almost looked like a rhino bedliner, any idea what i could do for that?

[brent338 0]

well you dont have to sand if you dont want to.

yeah you can pick up a can of paint/roll on bed-liner and give your box a real custom look. I'm thinking about that myself, but have not felt to urge to do so yet. wood looks good to me, and after they hear my chit, doesnt matter what it looks like...

[QuestionMan 0]

So you never put sealant in the inside of your boxes? just glue on the edges?

[johnecon2001 82]

I'll used window caulk on the seams inside the box

[brent338 0]

So you never put sealant in the inside of your boxes? just glue on the edges?

no, I said I use liquid nails, silicon caulking to seal the edges. as far as sealing the box, as in sides... I see no reason. but thats just me, I'm no master builder... but it works 4 me.

[Mark LaFountain 1,054]

1. 1 5/8" drywall screws? Good length but those are weak screws, heads will snap off, don't go longer then that, you'll split the wood near the edges.

2. Weldbond/carpenter glue or something else? I use tightbond II(or III)

3. What kind of sealant if any? (recommendations?) Anything cheap with silicon in it.

[creyc 1]

Always make it a good practice to seal ALL inner edges and corners with silicone caulk after the wood glue has dried.

Woodglue, while strong on wood, will not "seal" a box. On the other hand this is practically the reason for the invention of silicone caulk, to seal things like window frames, doors, subwoofer boxes, etc.

Some people run a bead of liquid nails but I've found as it dries little tiny air bubbles form, ruining any chance of obtaining a true "seal".

As far as sealing the MDF, it is a good idea. I have to get back to you with the name of that product, my brother recommended it to me. He works in a professional sign shop and they use it to seal wood and foam-based signs (very expensive signs!) from the elements.

[///M5 2,833]

Deck screws are better than sheetrock.

I too am a fan of the titebond and silicone.

[///M5 2,833]

Make sure to pre-drill all your screw holes as well.

[kandiman71874 0]

Being that you haven't mentioned the amount of power you will be using or what kind of goals you are trying to obtain here (spl monter agreesive Sq or Sq) the thought of fiberglassing the inside of the box is an idea as well. will help aid in the sealing process and will add extra strength. Something for you to contemplate. If the thought appeals to you and you are not sure on working with fiberglass as to the processes, search around the forum. There are plenty of informative articles.

[QuestionMan 0]

I'm just looking for a loud daily driver, no termlabs or competitions for me, at least not for now. Thanks to everyone for their replies it helps a lot.

[Acidburn 10]

Make sure to pre-drill all your screw holes as well.

and countersink

[ANeonRider 3]

Titebond Glue, clamps (no screws ftw), & a mixture of MDF dust & glue for the internal joints to ensure a solid seal.

[///M5 2,833]

Hmm, I actually save my mdf dust for huffing.

A quick clarification on the fiberglass comment, resin adds absolutely no strength for structure you need the glass itself. Of course, I don't feel this is logical in an enclosure when it would be easier to just use some more wood. Bracing can be your friend, whether it is made from wood pieces or threaded rod.

[dem beats 1,223]

Hmm, I actually save my mdf dust for huffing.

A quick clarification on the fiberglass comment, resin adds absolutely no strength for structure you need the glass itself. Of course, I don't feel this is logical in an enclosure when it would be easier to just use some more wood. Bracing can be your friend, whether it is made from wood pieces or threaded rod.

Even in ported you are of the opinion to brace rather than glass the inside?

Just curious. Glassing boxes has become in fation for sure, and I never saw the point but some saw in a ported box it messes with airflow.

[///M5 2,833]

I don't understand your question. Resin adds NO strength, actually it weakens the box. If you are talking about actually laying down matt on the inside of the box, why not just use a thicker piece of mdf in the first place? And yes, bracing big expanses can be more effective than just making them thicker/stiffer.

[dem beats 1,223]

I do mean to say using matt and resin, when I said glass. Sorry about that.

What I am asking is, I have heard that when you brace the interior of a box it can affect it negatively for airflow in ported aplications. I understood that some people to avoid bracing the interior will choose to use matt and resin to make it stronger, without obstructing airflow or some other issue I don't quite grasp.

It seams like any bracing would have minimal effect, but I am not educated in the art of designing a box, or how the air flow works internaly

Edited March 28, 2008 by dem beats

[creyc 1]

Maybe you're confusing bracing the box with bracing near or in the port.

Putting anything in the port, bracing included, will disrupt the flow of air and cause audible turbulence. You need to keep the port area open and free of any obstructions. If you have large flat port walls it is best to brace the from the back side, either with a second layer of MDF or 2x4's etc.

Bracing the box portion itself doesn't present the same bracing limitations, with a reasonable box design. The volume of the box is much larger than is the port, so turbulence is generally not a problem here unless you've done something quite wrong. There are a few things to keep in mind when bracing however. If there's a pole vent stay 2" away from it with any braces, likewise around the back of the cone. Any place there is fast moving air there is a possibility to create turbulence when you disrupt that flow of air.

Hope this helps!

Edited March 28, 2008 by creyc

[JimJ 11]

If you have access to an air nailer and are painting/covering the box, I would use brad nails. Saves so much time.

I used clamps only for the BIB's, and it added lots of time to the build...

[dem beats 1,223]

Maybe you're confusing bracing the box with bracing near or in the port.

Putting anything in the port, bracing included, will disrupt the flow of air and cause audible turbulence. You need to keep the port area open and free of any obstructions. If you have large flat port walls it is best to brace the from the back side, either with a second layer of MDF or 2x4's etc.

Bracing the box portion itself doesn't present the same bracing limitations, with a reasonable box design. The volume of the box is much larger than is the port, so turbulence is generally not a problem here unless you've done something quite wrong. There are a few things to keep in mind when bracing however. If there's a pole vent stay 2" away from it with any braces, likewise around the back of the cone. Any place there is fast moving air there is a possibility to create turbulence when you disrupt that flow of air.

Hope this helps!

Makes sense to me 100%. I thought the same, some people just resin and matt the inside to avoid bracing, which to me, sound slike 2 times as much work for no noticable help wiht the issue.

[///M5 2,833]

Bracing is always a good idea (*excluding SPL apps where a box mode can add sound).

Here is an example of some stellar factory bracing that indeed go into ported speakers that don't sound all that bad

http://www.bowers-wilkins.com/display.aspx?infid=788

edit: stupid links don't work so well to B&W so click on the little bracing piece near the bottom of the page for more details

[dem beats 1,223]

Bracing is always a good idea (*excluding SPL apps where a box mode can add sound).

Here is an example of some stellar factory bracing that indeed go into ported speakers that don't sound all that bad

http://www.bowers-wilkins.com/display.aspx?infid=788

edit: stupid links don't work so well to B&W so click on the little bracing piece near the bottom of the page for more details

I love b&W I nearly purchased large bookshelfs for my HT from that brand. I went with energy towers though. Great link TY.

[kandiman71874 0]

And i was refering to laying glassmat and resin, thats how you properly do glass work, not just gob straight resin everywhere...