Box construction advice

[icu400]

I am about to build 3 boxes, 2 for my explorer (by about to i mean in like a month, my "big" box works till then) and one for my friend's f150 in like a week. We are each going with 1/2 inch mdf for space conservation purposes. I am using 1.25 in dry wall nails and liquid nails for sealing it all up. My question is about something called fiberglass resin. It seems pretty easy to apply. So my question is is this something defintely worth installing on the inside of the box when I build them? I mean since it is only 1/2 in mdf won't this make it a TON stronger? Thanks a bunch fellas.

Oh, one more thing. As far as installing the sub in the hole, do I need to put any sort of seal on it? My sony drivers came with some weird sticky stuff but i don't see what its point could be. Any point at all to that?

Finally, is there a special secret to cutting the 9.25 inch circle in the wood? I was just gonna drill a pilot hold about 1/2 inch wide on the interior of the cirlce and then go at it with my jig saw, sound good?

 

[jimbo74]

you might want to drill a hole in the middle and use a rotozip to cut it... with a string, nail attached... would work really easy....

 

[mhn3773]

jig saw will work..i wouldnt reccomend the 1/2" mdf though 3/4 is much stronger and MUCH! easier to screw together and it doesnt take up that much more space

the sealent on the sonys is to make sure the box is sealed...if ur are not building a ported box u NEED to seal the box really really well

 

[icu400]

how exactly does the seal strip work? seems like it could go around the edge of the hole in the box, that where it goes?

but wouldn't the resin make 1/2 at least as good as plain 3/4? (my current box is 3/4, but for a stealth box behind my trim i don't know i can spare that much space) 5/8 would be a good compromise if home depot had any

 

[mhn3773]

the only thing about half is that u have to use nails...nails and vibrations dont like each other..plus since its only 1/2 u will probably end up splitting the wood a few times...it can be done just remember to take ur time..i spent 2 weeks on my duel 15 box and it is perfect..no exeptions just go slow! =)

 

[expo5.0]

1. don't build anything from 1/2 unless you are very skilled and its for a 50 watt 8" sub. its much, much harder to work with, its not much cheaper, and its weak.

2. adding resin to things doesn't make them stronger. adding matting and resin does. fiberglass is messy, and nasty to work with. unless it is necessary due to the design parameters of the box you want to build stay as far away from it as possible.

3. using a good gasket to seal the box and sub so there are no air leaks is one of the more important things you can do in a sealed box situation. Make sure to install them properly and make sure you get a good seal.

 

[icu400]

what is matting?

what will happen with 1/2 inch, will the sub literally tear the box to pieces or will it just not sound quite as good? I am looking for an honest answer here, I am not looking to squeeze 130db out of my system (nor is my friend who I am building the 1/2 inch box with for his truck), but we each have limited space and this seemed like a good idea.

We are looking to build the box for his truck next week, out of 1/2 mdf. Liquid nails will hold it together originally and once that dries we will go around with drywall screws. After that we will go around and go after the seams with liquid nails. After that we had planned on simply mixing resin w/ a catalyst in a try or something and applying that to the sides of the box as best we could. It seems like a simple process. I have been building various items for a theater troupe's sets for about two years now and I know how to cut wood and drill holes and all that, but I have never worked with fiberglass. What exactly is matting? When we went to a local audio shop they told us that if we were going to go with 1/2 inch to add resin to the interior of the box to make it stronger. Seems like a good idea to me.

Finally, with the gasket, should I adhere the seal to the sub or to the box? I will be moving the sub to another box in about a month or two, at that time if i have to put it on the box is there a place to get another seal? Speaking of which, my friend has no seals for his subs (got floor model JL W0's for a huge discount) is there a place I can get seals for him?

thanks once again all

 

[icu400]

guys?

i am about to install the subs, like this week when I have a few free afternoons

I mainly need to know about this gasket for the subs. I have two sony xplod's that came with some kind of adhesive strip that looks like they want you to put it around the rim of the sub that will be screwed into the top face of the box. I have no idea why. The box is carpeted, obviously that won't work. Furthermore, the rim of the sub that will be touching the inner circumferance of the box (the 3/4in of mdf that makes up the hole) is not large enough for the strip. So the only sensible thing seems to be adhere this thing around along the wood that makes up the hole. Is this the right thing to do? If I don't do it will there be a huge differance in sound quality?

finally, as far as fiberglass resin goes, how much does the stuff cost, where do you get it? What is matting? My friend wants to build his box this upcoming weekend and we need go get this stuff for it. Thanks guys

 

[mhn3773]

ok listin..ur making a big deal out of the gluing screwing thing...pre drill every hole test fit the whole box together..if u havent fubared anything take it apart butter the seams with liquid nails and screw it back together....wipe off the liquid nails that smuged out making sure to wipe it with the seam to smear it all over the seal to get it sealed...boom done! let dry

gasket for the sub..goto home depot..get 1/4" thick 2" wide foam insulation weather stripping stuff and run 2-3 layers around the hole for the sub (kinda on the inside)....

 

[expo5.0]

once again though- use 3/4" and don't mess with resin when you odn't need to

 

[icu400]

its kinda too late for the 3/4: i told him to get it originally cause thats what my box is made out of, but he bought 1/2 anyway

i have seen tons of people who have build boxes out of fiberglass, so the stuff can't be all bad, even if resin is not quite the real thing

i am just looking to get an estimate on how much the stuff costs, hopefully home depot will sell it, we are gonna go check it out later this week, but if yall have any tips on how to use it (i can always ask home depot, but I would rather ask you) by all means tell me

 

[mhn3773]

RESIN IS NOT 'GLASS!!! theres no quite about it..it has none of the strenght of real 'glass work im not trying to be a dick just frustrating when someone asks for help then doesnt take advice when it is givin to them 3-4 different times

u have all the info u need in this thread to build the box u want...if u want to 'glass then u need to read up on that...good luck

 

[icu400]

verywell, its not glass, i think we can agree on that now

but i I keep asking a simple question that HAS NOT BEEN ANSWERED

How do I apply resin to this box? Something called matting has been mentioned, what the hell is that? I am not trying to be a dick either, but I am telling you what this guy has to work with and what we want to do with it. He has a sheet of 1/2in mdf. I gave him some liquid nails and screws. Some people at the local shop build their boxes with resin inside to improve strength. We were told it would work out well. Look, I am sure I could go to home depot and they could tell me whatever the hell I wanted to know about the stuff, but instead I came here. Why? because I trust yall and I value your opinions. Now, please just tell me what I need to know about the resin. I know 3/4 is better than 1/2, thats why my box is built out of it, but he does not have that. If after his box is done we find out that it is a piece of crap, then I will yell at him and we will make another one, but either way he has very little room under his seat and 1/2 would be better for the room problem.

Alright, I am finished ranting, just help me out with the resin if you can. I solved my gasket problem, thanks for the help on that, but now I need to help this guy build his box so we can get his subs in before he leaves for the summer. thanks

 

[Cartman]

The matting that was mentioned is fiberglass mat, wherever you get the resin from should have mat as well, you soak that with the resin and then let in harden it forms a solid peice, layer a couple together and it is very strong but it takes time, is messy, smelly and you need body filler to get it smooth.

Fiberglass resin useless without mat, here is a site that gives you some idea of what is required to do fiberglass.

http://www.e-kittan.com/fibre.html

 

[icu400]

Thanks for the site man, that is without a doubt one of the most informative sites I have ever seen. I might use that technique to build a kickpanel for my x later on. But all we want to do for this guys f150 box is build the box just like normal, then simply poor the resin into the box and let it harden to each surface. I know it takes time to harden, but when it does that box should be sturdy as a vault. What do yall think? I am in no way trying to mold a fiberglass enclosure, I am just trying to add the material to the 1/2mdf box (started cutting today) and make it nice and strong.

Thoughts?

 

[orion1998_1]

resin is more for ported spl apps

 

[Glowin97x]

resin is going to be a waste of money without something for it to harden (matt, fleece, ANYTHING)

 

[hydroxy]

2. adding resin to things doesn't make them stronger. adding matting and resin does. fiberglass is messy, and nasty to work with. unless it is necessary due to the design parameters of the box you want to build stay as far away from it as possible.

amen.

Another way to think of resin & matt - paper mache`. Similar in building techniques, physical texture, mixing yada yada yada. Just a crapload stronger.

 

[icu400]

so if you just poor the stuff into a box it won't just harden on its own?

well alright, if that won't work I guess we will have to change plans or something

thanks guys

 

[hydroxy]

I dont know what they're talking about resin is useless without mat. It is PLENTY strong without any material in it. I got a couple drops on my bumper.... trust me, it's strong. It might not have as much strength or something without matt, but I dont think the matt adds any strength. My view of the matt is simply a medium which absorbs the resin which can then be molded into place. You can't exactly 'mold' a liquid into specific shapes without something to support it. The matt probably does help prevent something made of fiberglass to not simply fall apart when it is cracked - it adds some malleability to the object.

The only reason that there is 'special' matt is because it absorbs a very high amount of resin, thus when it hardens, it is as close to being pure resin as it can be - there are no hollow parts on the inside where the fabric didn't absorb all the way. (this is all my opinion - I could be completely wrong)

That being said - when you buy a gallon of resin, there are two little plastic tubes of 'hardener liquid' that come with it. There is also a small plastic bowl ontop. A small squeedge of the tube into the plastic bowl full of resin, and then mixed together will cause a chemical reaction which will start to harden the mixture. You have about 5 minutes tops in which to do something with the liquid before it hardens or gets too sticky to work with.

In your case - you could build the box, mix a small bowl full of resin, put the box on a side and pour the resin mix onto whatever side is on the ground. It would even out and put a layer of 'fiberglass' on top of the MDF. I would recommend cutting some fiberglass matt to fit each panel, then soak each piece in the resin mixture and lay that on the inside. 'paint' a small layer of the resin over the board before you put the resin soaked matt ontop of it.