Fordmods Logo

Fiberglass or MDF? 

 

Page 1 of 1 [ 13 posts ] 

 
 Post subject: Fiberglass or MDF?
Posted: Sat Feb 21, 2009 1:18 am 
Stock as a Rock
Offline

Age: 27

Posts: 133

Joined: 10th Aug 2008

Ride: Falcon AUII

Location: Gold Coast
QLD, Australia

Has anyone here done a Fiberglass sub box?
I don't think I've seen any in the 'show off ur boot install' threads...
I'm considering trying out a custom fiberglass box for my 12inch type r. I want maximum sound quality and still a decent amount of boot space.
Has anyone done a custom mdf box to Fit in the side of the boot?
Pics would help out heaps with trying to decided which way to go.

 

_________________

....what goes here?

Top
 Profile  
 
 
 Post subject: Re: Fiberglass or MDF?
Posted: Sat Feb 21, 2009 7:52 am 
Fordmods Junkie
Offline
User avatar

Posts: 11739

Joined: 17th May 2005

Gallery: 11 images

Ride: EL Fairmont, VFR400 racer

Power: 144 rwkw

Location: Melbourne
VIC, Australia

Enclosures should be made from strong material which doesn't flex and withstand higher pressures. I say make the enclosure out of MDF and then use fibreglass to put a design over the top of it...like a costume.

If you want maximum sound quality, you will sacrifice boot space. An enclosure should be built to the subs specifications and with Type R subs, they require a decent size enclosure if I remember correctly...bigger if it is a tuned ported enclosure.

phong =P~

 

_________________

phongus = Post whore 2006
EL XR6 motor, EL ECU + J3 chip, WADE 1673 Camshaft, 3" S/S intake, Pacy 4480, 2.5" Hi flow cat, 2.5" Lukey exhaust.
Max Power = 144.6 rwkw (03/05/2008)

Top
 Profile  
 
 
 Post subject: Re: Fiberglass or MDF?
Posted: Sat Feb 21, 2009 3:52 pm 
ACT Cruise Moderator
Offline
User avatar

Age: 36

Posts: 6275

Joined: 24th Nov 2004

Ride: '06 BF GT-P

Power: 293 rwkw

Location: Canberra
ACT, Australia

Most glass boxes usually have a flat MDF baffle (the front bit the sub screws into), and the glass is used to contour to the boot shape on the back/corner.

As above, a sub box needs to be strong enough to not flex under sound pressure. Flexing reduces output power (it's wasted flexing the box), and you end up with sloppy bass.

How many layers of glass do you need. The answer is usually - MORE. Build it til it sounds like wood when knocked, then add a few more layers. It'll then be good an solid.

Use a box design program (I use WinISD) to determine how many litres of volume you need to get the sub sounding it's best. If you're building a box shaped box, it's easy to simply calculate the required wall sizes. If you're doing a custom shaped enclosure, bags of sand or water become you're friend. Pour a litre (or two, etc.) into a ziplock bag, and start filling you're enclosure to see who many litres it is, and build from that. Remember the space taken up by the ports (if any) and the back of the sub is generally NOT counted by the box design program, so you have to add extra box volume to account for it.

 

_________________

1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow - 97.5rwkw
2006 BF GT-P in Ego, mods. 293rwkw - 12.427@109 - 0-1000m 24.838@221

Top
 Profile  
 
 
 Post subject: Re: Fiberglass or MDF?
Posted: Sat Feb 21, 2009 3:58 pm 
Fordmods Junkie
Offline
User avatar

Posts: 11739

Joined: 17th May 2005

Gallery: 11 images

Ride: EL Fairmont, VFR400 racer

Power: 144 rwkw

Location: Melbourne
VIC, Australia

data_mine wrote:
Most glass boxes usually have a flat MDF baffle (the front bit the sub screws into), and the glass is used to contour to the boot shape on the back/corner.

As above, a sub box needs to be strong enough to not flex under sound pressure. Flexing reduces output power (it's wasted flexing the box), and you end up with sloppy bass.

How many layers of glass do you need. The answer is usually - MORE. Build it til it sounds like wood when knocked, then add a few more layers. It'll then be good an solid.

Use a box design program (I use WinISD) to determine how many litres of volume you need to get the sub sounding it's best. If you're building a box shaped box, it's easy to simply calculate the required wall sizes. If you're doing a custom shaped enclosure, bags of sand or water become you're friend. Pour a litre (or two, etc.) into a ziplock bag, and start filling you're enclosure to see who many litres it is, and build from that. Remember the space taken up by the ports (if any) and the back of the sub is generally NOT counted by the box design program, so you have to add extra box volume to account for it.


Just make a box that is water tight...so a couple of layers of water proofing in the interior of the box and some silicon at the joints will surely make it easier just to pour 10L buckets of water to work out your volume... ;)

If it's water proof, it could also be air proof ;)

phong =P~

 

_________________

phongus = Post whore 2006
EL XR6 motor, EL ECU + J3 chip, WADE 1673 Camshaft, 3" S/S intake, Pacy 4480, 2.5" Hi flow cat, 2.5" Lukey exhaust.
Max Power = 144.6 rwkw (03/05/2008)

Top
 Profile  
 
 
 Post subject: Re: Fiberglass or MDF?
Posted: Sat Feb 21, 2009 4:17 pm 
ACT Cruise Moderator
Offline
User avatar

Age: 36

Posts: 6275

Joined: 24th Nov 2004

Ride: '06 BF GT-P

Power: 293 rwkw

Location: Canberra
ACT, Australia

True, but my way is less messy.

I've also seen done, some fill it up with bean bag balls, scooped in 1L at a time via a jug. That would've been a mess to clean up.

 

_________________

1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow - 97.5rwkw
2006 BF GT-P in Ego, mods. 293rwkw - 12.427@109 - 0-1000m 24.838@221

Top
 Profile  
 
 
 Post subject: Re: Fiberglass or MDF?
Posted: Sat Feb 21, 2009 7:56 pm 
Fordmods Junkie
Offline
User avatar

Posts: 11739

Joined: 17th May 2005

Gallery: 11 images

Ride: EL Fairmont, VFR400 racer

Power: 144 rwkw

Location: Melbourne
VIC, Australia

data_mine wrote:
True, but my way is less messy.

I've also seen done, some fill it up with bean bag balls, scooped in 1L at a time via a jug. That would've been a mess to clean up.


Yes...I never thought about the messy bit hahaha. :P At least you're a water saver...haha

phong =P~

 

_________________

phongus = Post whore 2006
EL XR6 motor, EL ECU + J3 chip, WADE 1673 Camshaft, 3" S/S intake, Pacy 4480, 2.5" Hi flow cat, 2.5" Lukey exhaust.
Max Power = 144.6 rwkw (03/05/2008)

Top
 Profile  
 
 
 Post subject: Re: Fiberglass or MDF?
Posted: Mon Feb 23, 2009 8:08 pm 
Getting Side Ways
Offline
User avatar

Age: 28

Posts: 2515

Joined: 27th Mar 2006

Gallery: 1 images

Ride: FG MkII Xr6t Ute

Location: Brisbane
QLD, Australia

remember you need something to form the shape of the fibreglass off...there are two ways I do it.

If fitting the box against an odd surface lay down a layer of alfoil, then paint the resin and lay fibreglass. Be prepared to do multiple layers and it takes a lot of time. Hightly frustrating and painstaking when doing vertical surfaces too.

For where there is nothing to form against I use a cotton lycra sheet stretched over other parts of the box/enclosure and stuck down with some uber strong glue. You then paint it with epoxy resin and it goes hard (but weak as). On top of this you can then build fibreglass layers.

This is the first thing I did using the cotton lycra method....turned out alright...would have been better but I had a deadline to work to :roll:

Image

Image

 

_________________

EVL098 wrote:
Cramping in the hand from having it on your Wang for an excessive period of time is a definate con.
Seriously do people google "f**k up modifications for Fords owned by Jews" and get linked straight to this site nowadays?

AU,factory fitted tickford kit/IRS, t5,Sports ryder/KYB: gone.

Top
 Profile  
 
 
 Post subject: Re: Fiberglass or MDF?
Posted: Wed Mar 04, 2009 10:53 pm 
Getting Side Ways
Offline
User avatar

Age: 31

Posts: 4946

Joined: 15th Nov 2004

Gallery: 2 images

Ride: Trik'd up EFII XR6

Location: Perth
WA, Australia

hey for working to a deadline you did a pretty smick job - as you know it aint the easiest stuff to work with - espescially all the unusual curves and shapes you need to contour when moulding in a car can be a real pain..looks good though

There is also no issue using fibreglass to mould an enclosure and generall rule of thumb is to glass layer after layer allowing it to set in between and when you cant see your hand through it add a couple more layers and your right - my previous enclosures you can see in my avatar along the boot walls (will be up for sale soon) utise timber for the woofer ring and some bracing but the majority is glass and an 80kg friend could stand on it without flexing....2x Type R 12"s in a very SQ orientated setup produced 132-134db no cracks no flexing and sounded great.

Fibreglass is simply harder to work with, takes longer to come to an end result and is far more expensive then the mdf, pva glue and screws option...but if your after maximising space/or available space and have many contours youd like to shape too then fibreglass is the way to go...if your a serious competitior fibreglass can make be an issue as it is difficult to ascertain volume espescially if going ported..

 

_________________

For Sale: 25 Farad Rockford Fosgate Competition Series Carbon Cap, more to come - pm me if interested

Top
 Profile  
 
 
 Post subject: Re: Fiberglass or MDF?
Posted: Wed Mar 04, 2009 11:12 pm 
Stock as a Rock
Offline

Age: 27

Posts: 133

Joined: 10th Aug 2008

Ride: Falcon AUII

Location: Gold Coast
QLD, Australia

Big Kev wrote:

There is also no issue using fibreglass to mould an enclosure and generall rule of thumb is to glass layer after layer allowing it to set in between and when you cant see your hand through it add a couple more layers and your right - my previous enclosures you can see in my avatar along the boot walls (will be up for sale soon) utise timber for the woofer ring and some bracing but the majority is glass and an 80kg friend could stand on it without flexing....2x Type R 12"s in a very SQ orientated setup produced 132-134db no cracks no flexing and sounded great.

Fibreglass is simply harder to work with, takes longer to come to an end result and is far more expensive then the mdf, pva glue and screws option...but if your after maximising space/or available space and have many contours youd like to shape too then fibreglass is the way to go...if your a serious competitior fibreglass can make be an issue as it is difficult to ascertain volume espescially if going ported..


Thanks for the info, in the end i decided to go with mdf simply because it was cheaper, and money is pretty scarce atm. Im currently about 60% done with the construction of the box but have found that not all the joins with the mdf are perfect (First time using a jigsaw....). Im using a waterbased wood sealent atm to fill the imperfections but am thinking I will need something a little stronger. Would a few layers of fiber glass around the joins (inside and out) fix any air leaks better than a silicone or sealent?

 

_________________

....what goes here?

Top
 Profile  
 
 
 Post subject: Re: Fiberglass or MDF?
Posted: Wed Mar 04, 2009 11:22 pm 
ACT Cruise Moderator
Offline
User avatar

Age: 36

Posts: 6275

Joined: 24th Nov 2004

Ride: '06 BF GT-P

Power: 293 rwkw

Location: Canberra
ACT, Australia

AUII.Denim wrote:
Thanks for the info, in the end i decided to go with mdf simply because it was cheaper, and money is pretty scarce atm. Im currently about 60% done with the construction of the box but have found that not all the joins with the mdf are perfect (First time using a jigsaw....). Im using a waterbased wood sealent atm to fill the imperfections but am thinking I will need something a little stronger. Would a few layers of fiber glass around the joins (inside and out) fix any air leaks better than a silicone or sealent?


Don't use a jigsaw for straight cuts. Right tool for the right job.

A better option, would be to just use the fibreglass resin, unless the gaps are too big to hold the resin alone. If that's the case, best to rebuild the box, get a circular saw/benchsaw etc.

 

_________________

1998 DL LTD in Sparkling Burgundy, daily, 302W, stereo, slow - 97.5rwkw
2006 BF GT-P in Ego, mods. 293rwkw - 12.427@109 - 0-1000m 24.838@221

Top
 Profile  
 
 
 Post subject: Re: Fiberglass or MDF?
Posted: Wed Mar 04, 2009 11:37 pm 
Stock as a Rock
Offline

Age: 27

Posts: 133

Joined: 10th Aug 2008

Ride: Falcon AUII

Location: Gold Coast
QLD, Australia

data_mine wrote:
AUII.Denim wrote:
Thanks for the info, in the end i decided to go with mdf simply because it was cheaper, and money is pretty scarce atm. Im currently about 60% done with the construction of the box but have found that not all the joins with the mdf are perfect (First time using a jigsaw....). Im using a waterbased wood sealent atm to fill the imperfections but am thinking I will need something a little stronger. Would a few layers of fiber glass around the joins (inside and out) fix any air leaks better than a silicone or sealent?


Don't use a jigsaw for straight cuts. Right tool for the right job.

A better option, would be to just use the fibreglass resin, unless the gaps are too big to hold the resin alone. If that's the case, best to rebuild the box, get a circular saw/benchsaw etc.


Nah, the gaps aren't big. Like 1mm, maybe 2mm max at some points. Had a circular saw sitting in the shed but didnt have a blade for it and was too cheap to go out and buy one...

So far I've been using liquid nail sealant as well as lots of screws for the joins. I've used aprox 150 screws so far... maybe a little over the top/ocd.....

 

_________________

....what goes here?

Top
 Profile  
 
 
 Post subject: Re: Fiberglass or MDF?
Posted: Thu Mar 05, 2009 1:40 am 
Getting Side Ways
Offline
User avatar

Age: 28

Posts: 2515

Joined: 27th Mar 2006

Gallery: 1 images

Ride: FG MkII Xr6t Ute

Location: Brisbane
QLD, Australia

Depends how big the gaps are, 2mm is a fair bit, I would use some resin first and then silicon sealer over the top.

Jigsaws are nasty to do straights with, the first (and last) time I tried to do a straight cut I made an absolute mess of it! Felt pretty stupid considering I only did it as cbf getting out the circular saw :roll:

Sikaflex (spelling) is the stuff I use, its great and stays a little flexible. You can use it for the inside edges of boxes, stopping car rattles, plumbing s**t around the house, or even to make exhaust hanger mounts together with old fan belts! (classic past experience)

 

_________________

EVL098 wrote:
Cramping in the hand from having it on your Wang for an excessive period of time is a definate con.
Seriously do people google "f**k up modifications for Fords owned by Jews" and get linked straight to this site nowadays?

AU,factory fitted tickford kit/IRS, t5,Sports ryder/KYB: gone.

Top
 Profile  
 
 
 Post subject: Re: Fiberglass or MDF?
Posted: Thu Mar 05, 2009 11:23 am 
Stock as a Rock
Offline

Age: 27

Posts: 133

Joined: 10th Aug 2008

Ride: Falcon AUII

Location: Gold Coast
QLD, Australia

skidder wrote:
Depends how big the gaps are, 2mm is a fair bit, I would use some resin first and then silicon sealer over the top.

Jigsaws are nasty to do straights with, the first (and last) time I tried to do a straight cut I made an absolute mess of it! Felt pretty stupid considering I only did it as cbf getting out the circular saw :roll:

Sikaflex (spelling) is the stuff I use, its great and stays a little flexible. You can use it for the inside edges of boxes, stopping car rattles, plumbing s**t around the house, or even to make exhaust hanger mounts together with old fan belts! (classic past experience)



Well ill just use a s**t load of fiber glass resin then. The last thing I want to do is start over lol.

 

_________________

....what goes here?

Top
 Profile  
 
Display posts from previous:
Sort by  
 Page 1 of 1  [ 13 posts ] 

Who is online

Users browsing this forum: No registered users and 8 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

 

 

It is currently Tue Dec 19, 2017 1:51 am All times are UTC + 11 hours

 

 

(c)2014 Total Web Solutions Australia - Australian Web Hosting and Domain Names