i started makin the box today for 3 12s for my crx, (got the beginnings of the top baffle started, ill post some pics later tonight) im glassing the sparetire well in then building up w/ wood to the top of the trunk area so i can get lots of space for the subs. but should i put some kind of sound dampining material inside the enclosure since most of it will be made out of fiberglass? if so would that rubberized undercoating work if i sprayed alot of it inside the enclosure?






Modified by lowlife4life at 11:52 PM 9/12/2003

 

eh, i wouldnt say it's a necessity... if you want some sound dampening maybe a little cotton might work, but other than that, i think you'll be just fine

 

heres a pic of the progress on my box for anyone that cares...it doesnt look all that great right now tho, but soon its gonna hold 3 12inch rockford hx2's

 

looks nice, you might want to add a few more layers though. nice start

 

yeh im gonna ad prolly 5-7 more layers
or jus til i think its strong enough.

 

when that thing is sanded and painted it'll be nice man, keep us updated

 

Makin good progress

 

thanks for the replies you guys, i took a break from that and started my amp rack today. not doing any planning is kicking me in the face right now, i cant figure out how to make the amp rack flow w/ the enclosure and everything else. ill post some pics up of everything set up in my car tomorrow.

 

I believe you just want to fill it with this stuff: http://www.crutchfield.com/cgi...avf=N

 

wha? polyfil? i dunno if that will help i jus didnt want the waves from the subs to...resonate? the glass. is that the right word, so it doenst ya know like ping and stuff....

 

dynamat inside the box won't do anything for you. I'd say not to worry about the glass. It's the plastic panels inside and your license plate that rattle.

 

I have 3 suggestions for you:

1. Knytex - know it, use it, love it!!
2. For trim panels, if you want to build them up quick, but don't care about the backside...Dynaglass - beautiful stuff. It almost seems that 90% of the Alpine Demo cars are made from this stuff
3. Use Milkshakes - from here on out, I always coat the inside of boxes with this stuff (the 'glass portions). Go and get some cab-o-sil filler (very fine powder) Mix up some resin, mix in cab-o-sil until thick like a milkshake and brush it on. It will completely seal ANY pinholes that you have, and leaves a very smooth surface.

 

we definetly need some after pics of this

 

well ive dynamatted my whole car w/ 2 layers everywhere and nothin rattles. ill take some pics of it today.

 

Looks good to me. You're gonna have some fun sanding though.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lowlife4life &raquo;</TD></TR><TR><TD CLASS="quote">heres a pic of the progress on my box for anyone that cares...it doesnt look all that great right now tho,

</TD></TR></TABLE>

 

heck yeh haha i like sanding it tho..so its ok. i just glassed over my amp rack i made today sooo ill get some pics up of that and everything in the car when i get out of school.

 

look into to some stuff called "Tiger Hair" it's a really thick blown fiberglass look material. Used for reinforcing boat hulls...doesn't resonate...makes it rock solid..supalite.

 

where can i get it?

 

if your using some 1/4" MDF and using lots of fiberglass and resin, then the box should seal properly...

any other joints or creases, just use silicone or wood glue to seal up....

paint it and it will come out like mine in my daily grinder!!!! good luck have fun!!!

 

dang! thats nice. sometimes i wish i had a trunk so i could do something like that.

o yeh, for building up layers and getting strength, what about bondoglass? ive used it on some other stuff like the console i made before and it seemed stronger than the normal fiberglass, i was jus thinking of going and getting another can of it and end up putting all of it on the underneath of my enclosure baffle to strengthen it. it would be useful in some areas that are hard to get to for laying mat, etc.
so what do you think about it.


Modified by lowlife4life at 12:44 PM 9/17/2003

 

I wouldnt use that stuff to build up layers. Use a thicker mat -- dont mix the fiberglass and the bondoglass stuff. It will make the sound weird - since they both have differant densities.

Looking good though.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by lowlife4life &raquo;</TD></TR><TR><TD CLASS="quote">o yeh, for building up layers and getting strength, what about bondoglass? ive used it on some other stuff like the console i made before and it seemed stronger than the normal fiberglass,
Modified by lowlife4life at 12:44 PM 9/17/2003</TD></TR></TABLE>

I'm not 100% sure what bondoglass is, I searche for it and couldn't find much, but I'm going to assume that i's fiberglass reinforced filler. Now while that's great for cosmetic panels and the like, I wouldn't use it soley to reinforce a fleeced part in a subwoofer enclosure (especially with three woofers!!

I would suggest you use knytex like I posted. It's a hybrid b/t a mat and cloth. It builds up very fast, and is extrememly strong. Remember, when building composites, the piece only gains strength in the direction of the fibers. Longer fibers are stronger then short ones....this is exactly why a piece made from fiberglass cloth is stronger per unit mass then the same piece of mat - instead of short, randomly oriented fibers, you have longer, stronger fibers. I always advise that people try to mix the orietations of any kind of cloth they use to gain strength in all directions.

My other recommendation is to go and get a fiberglass roller. This will allow you to get all of the air bubbles out. also, make sure you are using a laminating or build up resin and not a finishing resin.

Your biggest areas of concern are going to be the large flat areas, so definitely concentrate on those.

I wouldn't feel against using a reinforece filler on the edges where mat will be difficult. IT's a great way to add mass to a panel very quickly, but I wouldn't consider it a substitute for actual matt. You want to get lots of fiber on there.

Mixing product density is not a problem, so long as the wall of the enclosure is thick enough to not vibrate, every thing will be just fine.

 

Thats what I was getting at though. If you have half a wall of full fiberglass and then a huge chunk of the fiberglass filler, you wont have the same reactions - and youll most likely get stress cracks or possibly have the filler pop out all together.

 

i guess ill just get the cloth instead of the mat and use some of that see if it makes it stronger. thnx

 

Just because cloth is stronger per unit mass then mat doesn't mean I would recommend cloth for this application....use mat or you will be there all day. If you can find knytex, use that - trust me, you will thank me later.

Sparq....I still don't really see what you are getting at....if you put on filler so thick that it cracks, then what do you expect?!?! But using some fiberglas reinforced filler to add mass to your fiberglass parts won't affect the sound of your box. Half of the Alpine Si is dynaglas!