# 1/2" MDF thick enough for small 8" enclosure?



## Jsracing (Apr 1, 2011)

I know most recommend 3/4", and some say 5/8" as a minimum. I'm not looking for earth shaking bass and I'm not driving a power hungry sub. I'm looking for a small sealed enclosure for an 8" sub (probably an Infinity REF860W, JBL GTO804, or BA G108) that will be getting around 200W. I'm wondering if a 1/2" MDF enclosure is adequate as the wedge one from sonicelectronix is very cheap, with a net volume of 0.42 cu. ft. Woofersetc also has a small wedge with almost identical exterior dimensions, but made with 5/8" MDF for about 2x the end cost (I have to pay tax).
So is 1/2" MDF adequate?

Thanks.


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## Jsracing (Apr 1, 2011)

nm. I picked up a 3/4" box I found on ebay. Hopefully it's made well.


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## -Kyle- (Feb 5, 2009)

FWIW I used 1/2in for my pair of E8's and it was fine.


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## FartinInTheTub (May 25, 2010)

If you happen to have some fiberglass resin and hardener try coating the inside with a few coats. It'll make that lil 1/2" thick box VERY rigid.


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## nineball (Jan 17, 2008)

resin alone on wood won't add any strength at all but it will "seal" the wood. you need to add glass if you want to add strength.


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## FartinInTheTub (May 25, 2010)

nineball said:


> resin alone on wood won't add any strength at all but it will "seal" the wood. you need to add glass if you want to add strength.


I've used epoxy resin to not only seal but stiffen enclosures for years. A lot of competitors use this method.


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## nineball (Jan 17, 2008)

FartinInTheTub said:


> I've used epoxy resin to not only seal but stiffen enclosures for years. A lot of competitors use this method.


again, it will "seal" the wood but it does not add any strength to it. next time you are working with resin pour some out on a flat surface and let it cure, then go back and try to snap it in two and you will see how easy it is to do. cured resin alone is very brittle.

if you added fiberglass along with the resin it would help with strength but minimal at best. fiberglass is the strongest on a curved surface which is why most enclosures use wood for the flat areas. if using wood is not an option then the next best thing is to use strips of nylon rope with the ends frayed.


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## Bayboy (Dec 29, 2010)

Jsracing said:


> I know most recommend 3/4", and some say 5/8" as a minimum. I'm not looking for earth shaking bass and I'm not driving a power hungry sub. I'm looking for a small sealed enclosure for an 8" sub (probably an Infinity REF860W, JBL GTO804, or BA G108) that will be getting around 200W. I'm wondering if a 1/2" MDF enclosure is adequate as the wedge one from sonicelectronix is very cheap, with a net volume of 0.42 cu. ft. Woofersetc also has a small wedge with almost identical exterior dimensions, but made with 5/8" MDF for about 2x the end cost (I have to pay tax).
> So is 1/2" MDF adequate?
> 
> Thanks.



1/2" is okay for low power as long as it's solidly braced and joints are tightly secured. I've dealt with some of those prefab boxes and some were bonded together quite poorly. Gorilla Glue or something similar is a must. Brads and staples I don't trust without glue. Screws will split it unless predrilled to relieve stress and we know they don't use that method. A minimum 5/8" baffle thickness would be nice.


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## sqshoestring (Jun 19, 2007)

If the joints are good for 200w it should be ok. You can always get some 3/4 square and glue it down the inside corners, across the center of spans. It will take a little volume out of box but cleats help for sure. I use 3/4 ply for many things, it hold screws.

To be technical you need glass on both sides to make a composite that will be much stronger. Resin is very weak, it only holds/bonds the glass there. A one side composite such as glass on the inside only will not help for pressure in the box but will for low pressure where the box wants to cave in. Just resin on the wood might help a little, but nothing like glass. Composites work fine for flat panels most boat decks are flat, they only use glass for boats because it can be easily molded and can flex before it breaks thus distributing impacts. Many boats only core high strength areas like the bottom hull and open deck areas, flat areas. Also depends on how the are building it.


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

nineball said:


> again, it will "seal" the wood but it does not add any strength to it. next time you are working with resin pour some out on a flat surface and let it cure, then go back and try to snap it in two and you will see how easy it is to do. cured resin alone is very brittle.
> 
> if you added fiberglass along with the resin it would help with strength but minimal at best. fiberglass is the strongest on a curved surface which is why most enclosures use wood for the flat areas. if using wood is not an option then the next best thing is to use strips of nylon rope with the ends frayed.


This...


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## sqshoestring (Jun 19, 2007)

When they build a performance boat hull they vacuum bag it; to suck all the resin they can back out. The resin just makes the boat heavy and adds no strength.


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

sqshoestring said:


> When they build a performance boat hull they vacuum bag it; to suck all the resin they can back out. The resin just makes the boat heavy and adds no strength.


And when they build a hull, they also saturate the glass with resin, not just pour it onto the surface.. 

Yes, MDF is semi-porous, not not enough to take enough resin to make a stable enough matrix to produce any sort of "rigidity"... great for sealing and strengthening the joints, but for the flats, useless... Epoxy or otherwise.. 

If you where to be able to vacuum the resin through the MDF, sure, it's be like steel... but you simply couldn't effectively .. 

What it all comes down to is that 1/2" should be just fine for an 8", if there is a concern, add bracing... 

Biggest problem with building with 1/2" MDF is screw tear-out and splitting... 

If you shoot the box with 1/4" crown staples, 1-1.25" long, you'll be far less likely to split the MDF..


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## Bayboy (Dec 29, 2010)

I ran the estimated shipping for my area (FL) and for $35 I can build my own,be sure of it's sturdiness plus with thicker wood. Carpet is extra but not many care. Maybe the OP is closer and it's more economical but for "me" I'd build my own for that price.


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## sqshoestring (Jun 19, 2007)

I could not give up an excuse to use my saw. I bought some boxes a few years ago when they were going for $15-20 on epay, sold most of them but none were for 8s. I tested some subs in the car, now use them for testing amps.


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## Bayboy (Dec 29, 2010)

I guess 19 bucks isn't too bad if it didn't go much over it. Forgot to mention for the $35 I would have enough wood left over to build 1 or 2 more small boxes.


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