# My First Fiberglass Sub Enclosure Build (Volvo S70)



## JVCS80T6 (Dec 23, 2009)

Hey guys, I used to read up a lot over here and have now decided to give my shot at fiberglassing an enclosure in the side of my trunk panel. I have limited fiberglass experience besides using it to fix some front lip's that I've cracked.

Bear with me because I have been just taking the occasional iphone picture.

Here's the amp that I have, I got it for $100 from a friend brand new.
Memphis 16-PR1.500 (16pr1500) Power Reference PR Series Class D

and the subwoofer I'm using that I picked up for $40 from a friend
MB Quart RSH 254 Component Car Subwoofers at Onlinecarstereo.com

And here are a few pictures that I have taken so far. I masked the panel with some masking tape and then some pieces of tin foil. Then laid down 2 layers of cloth, followed by a layer of mat, then followed by some strands of rope to add rigidity and then another layer of cloth.









































































and then one test fitted back into the side panel










Tomorrow I'm going to cut a ring and hopefully decide what angle I want to mount it at so that I can get the t-shirt stretched over and filled with resin so I can finish the front.

Any and all opinions or suggestions welcome!
-John


----------



## Jroo (May 24, 2006)

I have never seen rope used. Do they really add strenth in fiberglass?


----------



## DJSPANKY (Dec 15, 2009)

I would assume (I say that b/c I don't know for sure) that the rope is not adding that much of a benefit. Rope by its nature is not load bearing in any direction except when tension is applied- i.e. it is being pulled by both ends, or is stationary at one end and is being pulled at the other. The rope has no compressive advantages and is certainly not rigid. So unless you expect the enclosure to experience tensile forces on it, the rope might not do any good. As far as rigidity- the rope will become rigid once soaked with resin, but is it going to be any more rigid than the FG material itself?

That being said- I believe I've seen this method used and discussed on some FG forums- so there must be some advantage to using it- or else there are a lot of people wasting their time.

Perhaps someone who is in materials manufacturing or who is familiar with FG can comment on this.

Did you have any trouble with the panel warping since you FG it outside the vehicle?

BTW- looks great for a first time FG enclosure. Keep it up!!!


----------



## Maximilliano (Aug 14, 2011)

If resin and hardener were allowed to saturate the rope. It would have to add some level of rigidity to the side panels.


----------



## JVCS80T6 (Dec 23, 2009)

Jroo said:


> I have never seen rope used. Do they really add strength in fiberglass?


I read that when soaked with resin it can add a bit of rigidity... not sure if the extra layer of cloth or the rope added more rigidity. Figured it couldn't hurt.

I did fiberglass it outside of the vehicle, but I haven't seemed to notice any warping. After the fact I realized I probably should have done it in the car because I risked the chance that it might warp but I'm past the point of turning back. Gonna run with this one!

My thought is that even if it turns out kinda ****ty, it's in the trunk, if it works and doesn't look like total **** then I'll keep it, otherwise I can use it as a learning experience and give another one a shot.

I think my biggest trouble was not using too much resin, as you can see there are some serious puddles of resin but it's a learning experience isn't it?

Thanks!
-John

and here's a picture of the car for those who might be curious as to what it looks like!


----------



## schmiddr2 (Aug 10, 2009)

The one time I drove one I really liked it, was a V70 5-spd.

Most everyone uses too much resin, myself included. Having someone mix batches and cut the mat for you is a huge help and caused me to use less resin because I could pace myself.


----------



## Xandr (Jan 17, 2011)

Cool photo:thumbsup:, John!


----------



## JVCS80T6 (Dec 23, 2009)

schmiddr2 said:


> The one time I drove one I really liked it, was a V70 5-spd.
> 
> Most everyone uses too much resin, myself included. Having someone mix batches and cut the mat for you is a huge help and caused me to use less resin because I could pace myself.


Yeah. I've been using the bottom of vitamin water bottles to gauge how much I need. I've gotten better even with the few layers I've done. 

Thanks man! The picture was taken by myself a few weeks ago and then with a little editing it looked even better!

-John


----------



## JVCS80T6 (Dec 23, 2009)

Did some more work today/tonight only to run into an issue of not having hot glue to position the ring and legs to hold it in place so that will have to wait until tomorrow.

But here we go with a few more!

Trimmed and then test fitted


















Made a little jig to draw circles.









cut the first hole! and it fits!









Cut out the second ring to recess it a bit for a cleaner look.









glued and clamped









and a guesstimate mockup of how I want it to sit...









Thanks for looking!
-John


----------



## DJSPANKY (Dec 15, 2009)

Holy hardware Batman!!! That's a lot of mounting holes in that woofer...


----------



## kenikh (Jan 17, 2011)

schmiddr2 said:


> The one time I drove one I really liked it, was a V70 5-spd.
> 
> Most everyone uses too much resin, myself included. Having someone mix batches and cut the mat for you is a huge help and caused me to use less resin because I could pace myself.


A little (or a lot) of extra resin for our purposes is fine. We're not building aerospace parts, after all. In a perfect world, we'd build male/female molds with a perfect cavity for one sheet of pre-preg carbon fiber, then use an industrial autoclave the set the part. The right process for a 787, unnecessary for a sub box. Even vacuum bagging fiberglass is over the top for audio purposes.

I've done a lot of composite work in my day, but my sub enclosure isn't far removed from yours: http://www.diymobileaudio.com/forum...a-sportwagen-sq-install-hat-morel-os-d-s.html

Keep up the good work.


----------



## Teddy81 (Aug 3, 2010)

Cool, I'm going to do the same for my S70.
I think I seen you on a few different Volvo forums, if you use the JVC name there too. I used to have the 850R in which I redid the headliner in alcantara. It was wrecked a couple of weeks ago, so now I got myself an S70. 

Good luck!


----------



## Mirage_Man (Jun 29, 2007)

Looking good.

Just an FYI, rope (or dowel rods) _if glassed over_, will provide rigidity since they create a rib. I used poly rope on a enclosure I built for my 07 Tundra on the flat surfaces of the box. It was kind of a PITA but it did help.

As far as "too much resin" goes... I'd rather use too much than not enough and the resulting air pockets I see so often. The use of a roller or "bubble buster" makes it so much easier. It's like anything else if you work with it enough you will eventually get it down.

BTW here's a few pics of the rope ribbing I did on the Tundra box. If you'd like to see the entire build album you can see it HERE. And the thread on DIYMA HERE.


----------



## JVCS80T6 (Dec 23, 2009)

DJSPANKY said:


> Holy hardware Batman!!! That's a lot of mounting holes in that woofer...


Yeah, half of them are for screws and the other half are how the beauty ring clips in place. haha



kenikh said:


> A little (or a lot) of extra resin for our purposes is fine. We're not building aerospace parts, after all. In a perfect world, we'd build male/female molds with a perfect cavity for one sheet of pre-preg carbon fiber, then use an industrial autoclave the set the part. The right process for a 787, unnecessary for a sub box. Even vacuum bagging fiberglass is over the top for audio purposes.
> 
> I've done a lot of composite work in my day, but my sub enclosure isn't far removed from yours: http://www.diymobileaudio.com/forum...a-sportwagen-sq-install-hat-morel-os-d-s.html
> 
> Keep up the good work.


Yeah, that seemed like the general consensus... better too much than not enough!



Teddy81 said:


> Cool, I'm going to do the same for my S70.
> I think I seen you on a few different Volvo forums, if you use the JVC name there too. I used to have the 850R in which I redid the headliner in alcantara. It was wrecked a couple of weeks ago, so now I got myself an S70.
> 
> Good luck!


That would be me! I'm gonna do a write up in the Audio forum on VolvoSpeed with the same stuff as here, just the guys over there aren't as knowledgeable in this stuff so I'm less likely to get useful information compared to the usual pegs, hid's, r bumper.



Mirage_Man said:


> Looking good.
> 
> Just an FYI, rope (or dowel rods) _if glassed over_, will provide rigidity since they create a rib. I used poly rope on a enclosure I built for my 07 Tundra on the flat surfaces of the box. It was kind of a PITA but it did help.
> 
> ...


I knew I had seen rope used somewhere! haha I'm hoping to make this one, then maybe try my hand at making another one for the spare tire well just to keep myself busy... haha

Thanks for the kind and helpful words guys!
-John


----------



## JVCS80T6 (Dec 23, 2009)

Got some more work done, and now its back to the computer while waiting for the resin to dry!

Borrowed a hot glue gun from my moms work since I couldn't find mine and got to work, mounted up the support legs









then mounted the ring I made









anddd a test fit









I used some tape to mock the shape of the cloth and then had to trim some of the fiberglass so it would clear the trunk arm thing.




























then I grabbed a t-shirt I had kicking around (I work for NOS Energy drink so even though it was a brand new shirt, it was free and I can always get another! haha)

Wrapped, I was able to use the sleeve hole to go where the sub was which helped when trying to stretch the shirt back and forth to get it taught.


















Glued down the shirt starting in one section and worked my way around the outside in increments of about 3-5 inches until I had it tight all around as seen above.

Layed down the resin and let it soak into the shirt and thats where I'm at now!



















Thanks for looking! Hopefully it will dry by later tonight and I can add a layer of cloth on top!
-John


----------



## Mirage_Man (Jun 29, 2007)

I may have missed it but what internal volume are you shooting for?


----------



## JVCS80T6 (Dec 23, 2009)

Mirage_Man said:


> I may have missed it but what internal volume are you shooting for?


Based on the specs that MB Quart suggests for optimal sealed volume is .5 cu/ft for standard and 1 cu/ft for optimal. I'm shooting for somewhere right between those two. 

Page 5 has the info and the woofer is the RSH252
http://www.maxxsonics.net/manuals/mbquart/pdfs/dwh302.pdf


----------



## Mirage_Man (Jun 29, 2007)

JVCS80T6 said:


> Based on the specs that MB Quart suggests for optimal sealed volume is .5 cu/ft for standard and 1 cu/ft for optimal. I'm shooting for somewhere right between those two.
> 
> Page 5 has the info and the woofer is the RSH252
> http://www.maxxsonics.net/manuals/mbquart/pdfs/dwh302.pdf


Gotcha.


----------



## schmiddr2 (Aug 10, 2009)

A shallow sub using 1 cu ft? And you have at least 6" of depth? could have use most any sub. Am I missing something?


----------



## JVCS80T6 (Dec 23, 2009)

schmiddr2 said:


> A shallow sub using 1 cu ft? And you have at least 6" of depth? could have use most any sub. Am I missing something?


It's just the sub I have that I was going to use for the project. Didn't NEED to be shallow, I just had it and wanted to use it instead of the 12" Alpine Type S that I have in a cheap box now.

The shallow sub will operate as low as .5 cu ft for when you actually are space limited... I am not horribly space limited but that doesn't really matter.


----------



## schmiddr2 (Aug 10, 2009)

I hear ya. Those few inches of space really don't make much difference, plus it means you can use it with another sub if you chose to change it out some time.


----------



## JVCS80T6 (Dec 23, 2009)

schmiddr2 said:


> I hear ya. Those few inches of space really don't make much difference, plus it means you can use it with another sub if you chose to change it out some time.


Now we're cooking with fire! That's the plan, give this sub a go and see how it works, and this will leave me an open option to upgrade to a better 10" woofer at a later date without having to rebuild a new box.


----------



## JVCS80T6 (Dec 23, 2009)

first layer of cloth I put down before I left for class this morning.




























That's just the first layer of cloth over the tshirt an I will probably need to do at least 3 more before its solid enough for me to throw the woofer in and test it out. Then i still have to bondo it smooth and then decide if I want to wrap it or paint it.

This first layer was probably the cleanest layer of fiberglass I have ever layed down. Haha

-John


----------



## schmiddr2 (Aug 10, 2009)

For my first layer on the front I wrapped all the way around the edges of the enclosure a good 4-6" which ties the 2 parts together, because the T-shirt with resin has little strength to do this. I also did this with every subsequent layer.

Also, where you have ridges/valleys, you can go ahead with a grinder and remove those to smooth out the surface for the next layers. This will make it easy to make it look good when you cover/wrap it at the end and doing it early means you don't lose strength when you grind them down later. But be careful, a grinder is vicious with fiberglass, removes a lot fast.


----------



## JVCS80T6 (Dec 23, 2009)

schmiddr2 said:


> For my first layer on the front I wrapped all the way around the edges of the enclosure a good 4-6" which ties the 2 parts together, because the T-shirt with resin has little strength to do this. I also did this with every subsequent layer.


That's a good idea. Didn't think about that. I think I might try to build up the junction of those two pieces on the inside so it won't change the outside shape so it still fits in the side panel.

So you're suggesting taking out that whole section and glassing over it? I was just going to smooth it out with body filler at the end since it is on the underside of the box it will rarely get seen.


----------



## schmiddr2 (Aug 10, 2009)

That's perfectly fine. I used a grinder to do mine and didn't need any Bondo when done, has almost no ripples and the carpet went on very well.


----------



## JVCS80T6 (Dec 23, 2009)

schmiddr2 said:


> That's perfectly fine. I used a grinder to do mine and didn't need any Bondo when done, has almost no ripples and the carpet went on very well.


Good to know. I'll take a look at it today when I get back from class and see how feasible it would be to cut it out and replace it with some cloth to smooth it out. Any recommendations of where to get some carpet that will flex/stretch to easily wrap around this? The only type of carpet I have use for sub boxes is not very flexible and wouldn't wrap the contours of this box very well.

-John


----------



## schmiddr2 (Aug 10, 2009)

Double post, so I'll reply here.



Don't use cloth to cover the holes/gaps if you grind it. Just use a length of glass that has enough adhesion on each side that it won't sway down into the hole.

You want trunk liner carpet. Amazingly bendable. It does mimic the surface it's attached to so have the edges as smooth as possible or might be able to use 2 layers to soften/smooth the look of it.


----------



## JVCS80T6 (Dec 23, 2009)

schmiddr2 said:


> That's perfectly fine.
> 
> I went the grinder route then just glassed over the holes, carpet went on fine without any Bondo or sanding.


I'll have to take a look at it and then determine what I plan to do. I might just try to smooth it out with bondo/fiberglass since it will be virtually impossible to see once installed into the car.


----------



## kenikh (Jan 17, 2011)

JVCS80T6 said:


> Any recommendations of where to get some carpet that will flex/stretch to easily wrap around this? The only type of carpet I have use for sub boxes is not very flexible and wouldn't wrap the contours of this box very well.


For future reference, "Ozite" carpet stretches and doesn't have any backing material, so is very good for covering subs and aub enclosures for a seamless look:

eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices


----------



## JVCS80T6 (Dec 23, 2009)

kenikh said:


> For future reference, "Ozite" carpet stretches and doesn't have any backing material, so is very good for covering subs and aub enclosures for a seamless look:
> 
> eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices


That's exactly what I was looking for, I just wasn't sure what people were using to get that true seamless look. Thanks!


----------



## JVCS80T6 (Dec 23, 2009)

Does anyone know where I can buy t-nuts in a store or are the only available online? Instead of using drywall screws like I did with my last box, I want to make this one properly and make it easy to remove and re-install the sub without damaging the mdf.

Thanks!
-John


----------



## schmiddr2 (Aug 10, 2009)

Just search "nut and bolt" in your area. Like this https://www.google.com/search?ix=he...b&fp=ff6386e14018d775&biw=1680&bih=925&ix=heb

They will have them.


----------



## JVCS80T6 (Dec 23, 2009)

Stopped by ace hardware on my way home and they had them so I picked up 8 nuts and bolts. Going to put them in once the fiberglass dries a bit more so I don't get too messy.


----------



## nautic70 (Oct 20, 2010)

JVCS80T6 said:


>


Do you post on VS? I swear I have seen that car before. It is good to see more Volvo owners veering away from just using OEM stuff to do their audio upgrades. This is like the second X70 install this week. I would put up pics of my install but I didn't do it myself so I don't wanna get rocks thrown at me.


----------



## JVCS80T6 (Dec 23, 2009)

nautic70 said:


> Do you post on VS? I swear I have seen that car before. It is good to see more Volvo owners veering away from just using OEM stuff to do their audio upgrades. This is like the second X70 install this week. I would put up pics of my install but I didn't do it myself so I don't wanna get rocks thrown at me.


Oh yeah, I post like a fiend over there... my name is JVC on there though, here my login had to be longer so I went with JVCS80T6 since I used to have an S80 T6, I wish I could change it to JVCS70T5 haha!

I'd love to see pictures of your setup! I linked a similar thread over on Volvospeed for those goons to check out 
S70 Fiberglass Sub Enclosure Build - Volvospeed Forums

-John


----------



## nautic70 (Oct 20, 2010)

I will take some pics tonight when it slows down at work. They will be sketchy EVO cell phone pics but oh well.


----------



## JVCS80T6 (Dec 23, 2009)

Trimmed up the outside of the box from all of the fiberglass straggler parts.



















and sanded down some of the rough parts on the box and all of the air bubbles that I was unable to smooth out.



















Going to slap some body filler on it tomorrow and try to smooth it out a bit. 

-John


----------



## neuspeedescort (Feb 23, 2010)

the over lap of the fabric to the glass back portion should be trimmed down tom minimal over lap. then glass the edge internally and externally really good.


NEUMAN


----------



## JVCS80T6 (Dec 23, 2009)

Yeah I trimmed it down a bit and I put a few pieces on the inside. I'm going to do another layer of cloth on the inside across the seam to make sure I get it all.


----------



## Fotoshark (Mar 22, 2012)

Any new progress on this build ?


----------



## JVCS80T6 (Dec 23, 2009)

forgot to post up pictures once it was done!

Picked up some carpet at Best Buy today for $13 and finished the project with a few bolts. Not a perfect match but it gets the job done!










Here's a pic to show how I ran the wires into the box and the two bolts I used to bolt it to the carpet.










anddd done




























Bad news is... the woofer is blown. but I have a replacement brand new Scosche unit from a friend that he gave me for $25 and its like a $100 woofer so I switched to that for the time being.

And yes, I know the trunk mat is super dirty. I've been trying to find a replacement. I carry a lot of **** back there so it gets dirty pretty quick, plus working on this it hasn't been keeping it clean.

Sorry that took so long!
-John


----------

