blowing boxs apart?

Question

i have 2 mtx 9515 subs hooked up to 2 2 2100 rms @ 2 ohms spl amps now i have blown 2 boxs apart in like 2 months i built them both i put like 2.5 cibic feet per section so the box is apx 50 cubic feet and i used a screw at every 1 inch and i used liquid nail on the seems and im still blowing them apart.....now i used to have a ported box and it al most blew my trunk off so much things rattled so i dynomatted the whole front of my trunk and it still rttled everything so i got a enclosed box but i bleew one box away in 4 days then i built anouther one used liquid nail on the seems and used like 100 screws but it it still blew it apart now what can i do to keep this box sealed so it dont blow up thinking of fiberglass and i will put like 10 coats of resin. help me what to do

my bad i mean 5.0 cubic feet and i did predill hole and i did use wood glue then put the pieces together and then i put the liquid nail on all the seems and i know FIBERGLASS IS STRONGER THAN WOOD. and i used 1'' thick mdf

and you have to use glue with a 800 watt system it would be no box left just wood and also its not blown apart i meean like the air these subs are pushing are blowing the screw out of the wood i could still use them i would just hear this rattling sound

and to the second guy i think
i cannot put a port in this for the reason i explained it rattles everything in the car and when ichanged to a sealed box it stoped it didnt stop all the rattling but most of it so i can listen to music normally

Answer 1

I think you are putting too many screws in the box. Every time you add a screw it seperates the layers of wood which are pressed together. Try using 3.5" or 4" screws every 6-8"and make sure you predrill holes to prevent spliting the wood. I have built over 15 custom boxes all with 1000 watts or more and have never had problems. Also make sure that you use a high quality MDF at least 3/4" thick. A little trick I use is also liquid nails, lay a bead on the edge of every piece you put together. Once the box is complete reach in from your 12" holes and lay a second bead all the way around. Allow at least two days to dry at room temp. If you do this i gaurantee your box will not blow apart.

Answer 2

I agree with the first answer...you're using way to many screws. 6-8 inches apart is the closest you should get. Also pre-drill your screws. Letting them cut the threads themselves puts additional stress on the MDF and it splits. As for doubling up the front baffle...not required. Liquid nails is just O.K. Try Gorilla glue....easier to work with and no solvents in it so it's stronger. Use it on all seams before joining and then use inside to make sure you have an airtight box. You can use air nails if you like...most shops do for speed...not for durability. I've done both and for my own stuff I use screws....customers...nails. Never had one blown apart yet. You can also add triangular braces internal to help support your walls. It gives you additional support and more mounting surface. See the Kicker website and look at a couple of the tech manuals and you'll see what I mean.

As for the guy above saying you don't need screws or nails because all the boxes you buy don't have them. Those are the cheap boxes you see on eBay. That's why they sell 'em for $20. You get what you pay for. I have blown apart those non nailed boxes and they are crap.

FYI...fiberglass is not stronger than wood. Especialy in flat surfaces. You could use the resin though if you want and resin the inside of your box. It will only help seal it though...not make it any stronger.

O.K. doofuss...if you think fiberglass is stronger...then do it. Come on back when it flexes itself like crazy. It's only stronger in curves....then it's like rock...but flat it is very flimsy.

Why ask for help if you know it all already...good luck Einstein!!!

Answer 3

Ok first of all what is the real question, rattles or boxs blowing apart? And let me be the first to point out your box isn't 50 cubic feet, that's bigger then your car.

But to answer your question, build the box tuned and sized to the factorys recommend size. MOST IMPORTANTLY: Use woodglue. Woodglue will outlast your wood, easily that **** will not come apart. Screws press the wood together for the woodglue to set, Most box builders don't even have screws in their boxes. Only use liquid nails around all the corners (from the inside) just to make sure there's no leaks, and it'll help take some of the punishment. Also, double baffle your box (this means to use 2 pieces for the front of your box, making it twice as thick obviously) with a **** load of wood glue and a double baffle in a huge box, if your **** blows apart then you simply cannot build a box. Drench that **** in woodglue and carpet it so she looks nice and pretty. Good luck bud.

Answer 4

don't use screws go to home depot or find a freend with a nail gun
and you need good wood glue like everybody is telling you the glue is what holds the box also brace the box inside to it can hold

I have a 20cf box with 8 12 woofers and 4 mmats amplifier 1400w
and i never ,never,never blown a box open
why are you putting 2 15 woofers on a 50 cf box ? that is the size of my cargo van LOL