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phemps
09-06-2009, 12:27 PM
does fiberglassing the entire inside of enclosures help with getting rid of box flex without extra bracing? a smaller box for a single 12 about 2.5 cubes or so. any experiences?

phemps
09-06-2009, 06:45 PM
nothing guys?

nicksredline
09-06-2009, 06:56 PM
sounds like it might work but i am not sure nore have i had experiace with doing it... try it and tell me how it turns out lol.

plugitin
09-06-2009, 07:04 PM
i did it for my box 8 cubes for a 18. slot port and fg the inside. no other bracing for now...

lovindabass
09-06-2009, 07:11 PM
I glassed the box on the inside for my RE XXX 15d2. It helped me get a little better airflow and i have a lot of bracing so I dunno if the flex was a problem before. But it does help seal the box. and it did make a little difference in the sq

PRIVATEpastry
09-06-2009, 07:13 PM
yes it will help. same concept as adding a 5th layer to a fiberglass box that already has 4 layers.

Blue Fury
09-06-2009, 07:13 PM
Dont rely on it for significant bracing. Do it right and the less costly way. For example, a 2x4 is much cheaper.

TnT_Sounds
09-06-2009, 07:28 PM
not going to fix a dramatic amount of box flex.

Brace it and glass it. All-thread is cheap too

phemps
09-06-2009, 08:30 PM
thanks for all the input. i did consider doing a brace. how about a double baffle? ive never double baffled the front of a box. is it worth it or does it make more sense to just do some cross bracing?

marcotheclepto
09-06-2009, 08:33 PM
im debating on how im gonna brace my box.

Blue Fury
09-06-2009, 08:39 PM
I've read a hundred times, nothing beats member bracing. Double baffle would help too.

phemps
09-06-2009, 08:44 PM
ive read it alot too i just wanted another opinion. ill prob go with both the bracing and fiberglass that bish

BassMechkanic
09-06-2009, 09:28 PM
mdf is not solid, air will pass thru it, bracing and a coat of resin is the best way to go.

snb778
09-06-2009, 09:36 PM
mdf is not solid, air will pass thru it, bracing and a coat of resin is the best way to go.

A... air will pass through it cause its not solid?? WTF you talkin about??

B. Resin will not add any kind of bracing to the box.. might act as a filler like caulk or glue or bondo

C. MDF is not solid?? wtf you talkin about

D. FIBERGLASSING the entire inside might help a little bit... but thats dam expensive for the POSSIBLE result.

E. Fiberglass gains its strength with curves and turns... you've never seen a whole SQAURE or RECTANGLE box made outta fiberglass... Most boxes with fiberglass have the base of the box made with MDF, and then just the top (which is usually curved or rounded somewhat for the cosmetic appeal) is made with fiberglass

F... so, did you fiberglass the whole inside, or just cover it in resin

G.. MDF is not solid and air will pass through it... WTF??

phemps
09-06-2009, 09:37 PM
mdf is not solid, air will pass thru it, bracing and a coat of resin is the best way to go.

no glass just the resin? the glass shouldnt hurt and only add structural integrety id think

snb778
09-06-2009, 09:41 PM
yea... are you using actuall fiberglass mat, or sheet, or just pouring resin on the box...

again.. glass needs to have curves and twists and turns to gain full strength... unless you add like 3+ layers on a square box.. its not worth the time/cost vs just using proper bracing

Jeremy M
09-06-2009, 09:41 PM
it won't help brace it...only make it air tight. u need to add mat and some other forms of bracing.

phemps
09-06-2009, 10:05 PM
A... air will pass through it cause its not solid?? WTF you talkin about??

B. Resin will not add any kind of bracing to the box.. might act as a filler like caulk or glue or bondo

C. MDF is not solid?? wtf you talkin about

D. FIBERGLASSING the entire inside might help a little bit... but thats dam expensive for the POSSIBLE result.

E. Fiberglass gains its strength with curves and turns... you've never seen a whole SQAURE or RECTANGLE box made outta fiberglass... Most boxes with fiberglass have the base of the box made with MDF, and then just the top (which is usually curved or rounded somewhat for the cosmetic appeal) is made with fiberglass

F... so, did you fiberglass the whole inside, or just cover it in resin

G.. MDF is not solid and air will pass through it... WTF??

ahhhahaha this is exactly what i was thinking. maybe he has mistaken mdf with swiss cheese? its a common mistake:fyi:

phemps
09-06-2009, 10:13 PM
yea... are you using actuall fiberglass mat, or sheet, or just pouring resin on the box...

again.. glass needs to have curves and twists and turns to gain full strength... unless you add like 3+ layers on a square box.. its not worth the time/cost vs just using proper bracing

i have alot of mat laying around. i was just gonna say fucck it and try it just for the hell of it. i can see what you mean with the curves of the boxes added the strength but at least if i can do 2 layers it should be a nice seal. unnescesary but oh well

snb778
09-06-2009, 11:48 PM
seriously.. if you're just doin it for the deal... good cuts+glue+caulk should be PLENTY.. .you can use some resin w/o the mat for the edges and corners to be EXTRA safe... but covering the whole inside of the box is completely un-necessary... if it worked.. people would be doin that in comps all the time... and I don't think anyone even does that.... 2 threaded rods in each direction (up and across) would work MUCH better IMO

thegreatestpenn
09-06-2009, 11:53 PM
from my understanding glass as stated before only helps seal better. it only works on curves so a square/rectangular box using resin for strength is senseless. threaded rod or 2x4's is the way to go.

also double baffle doesn't help much either, but it will keep a heavy heavy sub from bending screws out of the baffle.

also if you do a slot port, the port itself as some measure of bracing.

Walled_Taurus
09-06-2009, 11:56 PM
What he is saying is MDF is porous. But resin is not. Build the box with double baffle and put 45s in the corners of it. Listen to it, meter it if you can, then take the sub back out and resin the inside and listen to it then. Better role off and should actually gain a little spl cus all that pressure is being maximized and not getting lost due to the fact of it it going through the pores of the mdf. It may not be audibly louder but on a meter you might gain a couple 10ths. And resin does add reinforcement. Not a **** ton but some.

BassMechkanic
09-07-2009, 12:48 AM
MDF porous,-----i did not beleive it myself until i saw the vacuum test, with shop vac and a piece of 3/4 mdf 12" square, **** the mdf and pick it up, then place another piece under it again, picks both up, and tried a third it started to pick up then fell!. There use to be a utube video of this.. And i have seem many high spl boxes coated with resin - inside and out!

snb778
09-07-2009, 01:44 AM
that test is interesting.. im going to have to try it myself though to believe it... something tells me im going to prove you wrong, but we'll seeeeeeee.

i don't think i've seen one SPL setup on here or wall that was covered in resin for that reason.. nor have i even seen or heard of a setup where doing that increased numbers... but I guess its possible.. I see its possibility, just not probable

hatedonmostly
09-07-2009, 01:47 AM
it won't help brace it...only make it air tight. u need to add mat and some other forms of bracing.

This. And it'll strengthen, but not brace it. Those are two different things.

JimJ
09-07-2009, 01:52 AM
Can someone explain to me how fiberglass mat only has strength as a curve? Can someone explain how a perpendicular layering of material isn't going to have structural integrity no matter what the shape of it is?

Not talking about what's economical, just...:confused:

nineball
09-07-2009, 02:06 AM
mat does have strength on a flat surface, just no where near what can be achieved on a curved surface. as stated most quality fg enclosures use as much mdf as possible because it is stronger than fg on flat surfaces (relative to cost), cheaper and much easier to work with. in most cases if you have to use fg alone on a large flat surface it is best to incorporate some form of bracing like pieces of nylon rope.

think of an arch. if the top was straight it would not have the same strength as a curved arch. check out the roman aquaducts.

basshedz06
09-07-2009, 08:02 AM
as stated a few times fiberglass adds strength to the box not bracing. it does cut down on box flex but if an i man if your gonna do the inside an your doing for spl reasons i would say get a foam roller an do the inside you want that inside as smooth as possiable,
i have put my hand inside some fiberglassed boxes(without fiberglass in this sentence that would totally be funny lol) an felt the insides an it be like glass. a buddy of mind did it once an it was really smooth it was like touching a clean window.

snb778
09-07-2009, 12:32 PM
Can someone explain to me how fiberglass mat only has strength as a curve? Can someone explain how a perpendicular layering of material isn't going to have structural integrity no matter what the shape of it is?

Not talking about what's economical, just...:confused:

kinda of the same concept as building a bridge... I remember back in middle school we had a project to build a bridge with tiny little sticks, then they would apply pressure to it and see whos was the strongest... we were all taught that the more curves (instead of a straight line) and criss crosses for the supports, the stronger it would be

phemps
09-07-2009, 01:53 PM
MDF porous,-----i did not beleive it myself until i saw the vacuum test, with shop vac and a piece of 3/4 mdf 12" square, **** the mdf and pick it up, then place another piece under it again, picks both up, and tried a third it started to pick up then fell!. There use to be a utube video of this.. And i have seem many high spl boxes coated with resin - inside and out!

ill have to try this too... never would have thought it could be that pourous. in theory if suction through one mdf board can pick up another, then you shouldbe able to feel slight air movement on the outside faces of the box? or maybe its unnoticable due to the vibrations of the walls anyway it feels like it moves a little air. either way im def gonna resin the innerr surface of my box after hearing this

mlstrass
09-07-2009, 02:35 PM
I want to know what 2.5^3 enclosure design you have that will have a flex issue? What sub and how much power?

Unless it's some oddball desing a couple of well placed strap braces should be all you need. If it's a 50# sub then double baffle...

For a daily set up resin is a waste, if your chasing tenths on the meter then consider it....

phemps
09-07-2009, 02:43 PM
well the 2.5 cube enclosure is just temporary until i get a second hdc3 and i want to just try something that i can transfer over to the dual 12 box which will be around 5 cubes. and without bracing will most definately flex considering i had 2 ****** mtx subs flexin the hell out of a 4.3 cube box i had tuned to 32 hz. the box was nicely constructed too edges matched up nice qand everything was sealed good but top and front baffle flexed bad

mlstrass
09-07-2009, 02:54 PM
why so big for the 2 12's? You low on power? I've stuck with 4cubes NET on all the HDC boxes I've built as most guys are running around 2k per sub...

fbi90909
09-07-2009, 02:54 PM
Don't bother using fiberglass to brace a box.

Why? Fiberglasses strongest points are when the surface is curved. In a flat surface fiberglass will flex quite easily. You would need layers on layers on
layers of glass on a flat surface to get it rigid enough to not flex.

Save you money. Go to home depot and buy dowels. Cut them to lenght to fit wall to wall inside your box. Glue them inplace and run screws thru them. Or buy threaded rods and nuts and washers and brace it that way. Either of the 2 will reduce much more flex than fiberglassing will.

phemps
09-07-2009, 02:58 PM
why so big for the 2 12's? You low on power? I've stuck with 4cubes NET on all the HDC boxes I've built as most guys are running around 2k per sub...

ill be very low on power for the single aq only 1000 rms for a little while. but as for the dual box down the road i was just giving a rough estimate. it would prob be closer to 4 cubes. aq is very vague wiwth there specs. it says the twelves like 2.5 but you dont have to factor in any displacement. so i meant something along the lines of 2.5 without subtracting driver and port displacements

ngsm13
09-07-2009, 04:38 PM
Wow.

nG

thegreatestpenn
09-07-2009, 04:41 PM
you don't need fiberglass with what you are using. don't waste your time with that.

also I have a box for when you go with 2 hdc3's sitting in my basement. if you're not far from columbus OH you can come get it for a decent price.

snb778
09-07-2009, 08:32 PM
IF............ you choose to glass it... you should test it before glass and after to see if it does anything for you in the future

i still gotta try this vaccum test to see if MDF really leaks air