Another fiberglass box tutorial..

[dawgdan]

Been working on this one for a little while, finally got the page up. Lemme know what you think.

http://www.gadrivers.net/~dwicker/fiberglass.html

[ocuriel]

Very nice. That is going to be very helpful for a lot of people.

[dawgdan]

Thanks. I have always been a chronic researcher, and I didn't think many of the tutorials out there had enough detail on what to buy and how to use it. I know it's not 56k-friendly, but hopefully it will be of use to some folks out there. :)

[solacedagony]

Awesome tutorial. It makes me feel like I actually have the courage to give it a shot! :)

[Beau]

Please accept my praise and thanks. I will be venturing into fiberglass at some point in the near future.

Now all I need is your home phone (j/k), so you can tell me how to fix what I've botched.

[Lothar34]

Your milkshake is the best. :D

j/k
Nice writeup. Please don't take it down ever because I'm sure I'll need it for reference someday.

[dawgdan]

It'll be up for as long as my buddy's server is up. Thanks for the props. :)

[npdang]

That is a very nice tutorial... feel free to copy it over here if you want :D

[Relax]

Your milkshake is the best. :D

j/k
Nice writeup. Please don't take it down ever because I'm sure I'll need it for reference someday.


Just save the site to your harddrive- go to favorites, add it as a favorite and click "make available offline." Or file save as: and then maker sure you have complete webpage as the selected save type.

[FoxPro5]

Oh man, perfect timing for me! One of the best tutorials I've ever seen! Thanks for the time spent doing that and posting your work. You know it's done right when the final product just looks like it belongs in the car. :D

[scott_fx]

great tutorial! thanks, i'll be bookmarking this!

[dawgdan]

Oh man, perfect timing for me! One of the best tutorials I've ever seen! Thanks for the time spent doing that and posting your work. You know it's done right when the final product just looks like it belongs in the car. :D

Heh, wow, thanks for the compliments. :)

I'm no expert, but I was pretty pleased with the final results.

FWIW, I can't really stress enough the importance of the Knytex biaxial I used. Every other tutorial I've seen and pretty much every other box out there uses plain chopped strand mat. I used chopped mat on some surfaces for this project.. and I only used it because I had to. Knytex is absolutely superior in every way, except when you're trying to do any upside-down surfaces. I don't have the patience to lay 8-10 layers of chopped mat, and the Knytex is totally flex-free with 4 layers. :cool:

[demon2091tb]

What exactly is the Kyntex?

Very nice tutorial btw, nicely done.

I used Extra strength Chopped matting, and 4-6 layers of it gave me a 1/8" of thickness, does the Kyntex stick to the surface or something special, never heard of it.

[Relax]

Where can you get Kyntex also?

[dawgdan]

It's all in the tutorial, near the top of the page. :) There's all kind of commentary about Knytex, why Bondo brand resin sucks, etc.

"What is Knytex, and why use it? Knytex biaxial fabric is made by Owens-Corning. It is made up of essentially two layers of fabric – one side is stranded, and the other side is woven, and both materials are stitched together. Its primary use is for structural reinforcement in boat hulls. In this project, I used it as an alternative to regular chopped strand mat that's often used in fiberglassing projects (including this one). Chopped strand mat is great for certain purposes - tight turns, tweeter pods, and smaller fiberglass projects. But for making a subwoofer box, a thicker material, like Knytex, is preferable. Why? First off, Knytex is incredibly strong. When soaked with resin, using Knytex as reinforcement results in a much faster build-up. For impatient souls like me, this is huge. Three or four layers of Knytex will be as strong or stronger than 7-10 layers of regular chopped strand mat. In addition, for as thick as it is, Knytex bends around corners fairly easily. This stuff is excellent for building up a thick layer very fast."

You can buy it from uscomposites.com under "Specialty Fabrics". I bought 3 yards of the 17 ounce fabric.

It doesn't really do anything special except make for a much faster buildup. It lays up with resin very easily on flat and curved surfaces as long as they don't venture into being upside down (it's got too much mass to stick to a surface upside down). Once you try it, you'll see how much easier it is. :) Seriously, a night and day difference.

[WLDock]

"For over 10 years, I've been into car audio. I've always built big, rectangular subwoofer boxes that take up most, if not all, available trunk space in the vehicles I've owned. After getting married, settling down, and buying a house, it turns out that I need my trunk quite a bit more often than before."

Oh my...you pulled my card with that. I have a 2 and 5 yr old and early this year picked up a nice used 300M and still find myself looking for space. That car has a very nice sized trunk but a box would ruin the layout. A side fiberglass box is the only way to really make use of the side space.

Thanks for the effort!

[tyroneshoes]

Nice job and great write up. Especially because I think we have the same exact car (6?)

[dawgdan]

You got it. :)

[FoxPro5]

How did you secure the box to the car??

[dawgdan]

Heavy-duty velcro. It already was a pretty snug-fit, and it doesn't really budge at all. That area of the car doesn't have a really good spot to sink a screw into, but I may do that anyways.

[solacedagony]

Where did you get your heavy duty velcro from?

[bobditts]

they sell industrial velcro at home depot and lowes

[dawgdan]

Yep, what he said. Lowe's.

[tyroneshoes]

Get the metra kit and a 880prs. Go active man. You got all you need but those passives are holdin you back.

[dawgdan]

Yeah, I know. The 3sixty.2 is on the wish list. For around the same price as the Metra + 880PRS (or any other really nice and flexible HU) I can keep the stock HU. I also need to add a second amp (probably a RF T5002) so that I can use the T4004 to power the each front driver individually.

[illnastyimpreza]

how did u estimate your box volume before hand?

[DaveRulz]

Go active man. You got all you need but those passives are holdin you back.

Agreed, go active! Ijust swapped in CDA-9833 and pulled out my CDT passives. It made a world of difference. There is so much more detail now. Active is clearly the only way to go.

I just need more deadening in the doors, they are rattling like crazy now.

Fellow 6 owner/enthusiast

[dawgdan]

how did u estimate your box volume before hand?

As in, before I started building it? Honestly, there's not really a method to do it - I just sorta knew from past experience that 1.0 cubes, especially with a molded box, is quite often bigger than your mind may think. Basically, I got really lucky with the box volume.


Dave- Yeah, I'm the one who chewed you out on mazda6club.com for recommending Elemental Designs. ;) I will eventually go active when the funds allow. Christmas is coming soon, and my wife is about to receive a long list of items. :)

[illnastyimpreza]

whats wrong with elemental designs???

[DaveRulz]

Dave- Yeah, I'm the one who chewed you out on mazda6club.com for recommending Elemental Designs. ;) I will eventually go active when the funds allow. Christmas is coming soon, and my wife is about to receive a long list of items. :)

I know, I know. Like I said, I've never had a problem with their products and I'm not using them in my car. Sounded like you had some bad experiences with Ben, and I guess it's just one of those situations where everything is just fine until there is a problem with the product and then the true colors come through.

I've had my CDTs running passive for over a year, and had never been super happy with the sound. I started with the tweeters in the stock locations, and they were painful to listen to, even padded down on the x-over. It seemed that no amount of EQ could fix the harshness at high volumes. So I moved them down to in front of the mids. I drilled out the holes in the door panel "grill" and mounted them behind there, aimed up at the listening position. This sounded better, but then it sounded like a lot of the highs were missing. So I reinstalled the stock tweeters in the sail panels, and ran them off of the image tweeter outputs on the crossovers. This was the best sound I could get out of the passive crossovers. When I pulled the passives, and just bi-amped the tweets and mids that were near eachother, crossed at 5k, the whole thing came alive. I remembered why I had gone active in my last full set up years ago.

Whatever, I digress...

I do have a question for you in regards to the sub enclosure. I built a pair of enclosures for a friend's 6 very similar to the one you built (pix below). We used Home Depot resin and mat (because we were dumb and impatient) But I swear, we used 4-5 gallons of that stuff to get them done. Did it really only take a gallon of resin for you to create that entire enclosure? Would you attribute that to the kyntex?

http://www.joereid.com/~avino/JosesSystemPage/images/P1010132.jpg

http://www.joereid.com/~avino/JosesSystemPage/images/P1010133.jpg

http://www.joereid.com/~avino/JosesSystemPage/images/P1010134.jpg

[dawgdan]

Wow, Knytex or not, those are killer looking boxes!

When I did have to use chopped mat, I did notice that I needed to use more resin. So that's probably the case. Since the cloth is what gives resin its strength, I suppose that the dense Knytex fabric simply doesn't need as much resin. I was told by an experienced friend (the one that recommended Knytex) that it seems that most installs on the internet used way too much resin.

But yes, only one gallon to build the structure, with enough leftover to make the Bondo-Glass milkshake. :)

[DaveRulz]

ok, so kyntex it is for the next one! and thanks for the compliments. We were really happy with how it came out. Sounds pretty good too. Not the equipment I would have chosen, but it gets the job done.

[dawgdan]

Trust me, you won't regret going with Knytex. The layup method is a little different than the little strips of chopped mat. You can work with much larger pieces, and pre-fitting them really helps a lot. It lays around curves beautifully for as thick as it is. :)

[Dichotomous]

why did you mold off the interior fabric instead of cutting that away and going back to the metal frame? I would imagine you could get much more box volume without going into the trunk as much. is there some reason why doing so would be bad? if not I intend to remove as much carpet and foam and plastic that will just be covered up anyways as I can, to tuck it deep in there. also did you take into consideration the direction that the sub fires or is that not really all that much of a concern for your install?

[illnastyimpreza]

why did you mold off the interior fabric instead of cutting that away and going back to the metal frame? I would imagine you could get much more box volume without going into the trunk as much...

This is a good point... It would definatly help out the design of the box. But at the same time sort of kill any resale value you might be trying to save...

[dawgdan]

Because it's how I've seen it done before. :)

Actually, my trunk trim is pretty thin. I doubt you'd gain much room behind there, if any at all.

[DaveRulz]

I've taken the side trim out, you wouldn't have gained much if any volume. In older vehicles you might. But in new cars they usually realize that space is a premium and make pretty good use of it. The best part of leaving it in is that it gives you a smooth, complete surface to lay your glass on. You also have to remember that since you're popping a mold, you have to be able to pull it straight out. All of the room that you would gain would make it impossible to pull the mold back out of the car.

Also, as far as placement goes. In the Mazda 6, that's is the best placement. I've moved my sub into about every position possible, and that one sounds the best.

[dawgdan]

Agreed, Dave.

Also, maybe because it's in the farthest-corner of the trunk, I am noticing a little bit of a delay on the sub. The lower midbass (80-140 Hz) "snap" of a kick drum seems to hit just a tiny bit sooner than the seat-kicking thump. Need to get some time-delay soon to remedy that.

[Dichotomous]

never thought of the resale value afterwards, very very good point.
as far as the time delay on the sub, if your sub is firing sideways instead of forward or backwards, there will be a bit of a time delay on it, not much, but a tad bit more than if it were forward/backwards. or it could be in the wrong phase and just SEEM to be delayed.

[cthip]

Trust me, you won't regret going with Knytex. The layup method is a little different than the little strips of chopped mat. You can work with much larger pieces, and pre-fitting them really helps a lot. It lays around curves beautifully for as thick as it is. :)

a note on the knytex: i've read this tutorial before, and always assumed that knytex would be very expensive, but this is apparently not the case!

as i understand it, 17 oz knytex is two layers of woven cloth (approximately 8.5 oz each) with a layer of 3/4 oz chop mat between them. if you were to add up the cost of the three layers individually, you would be paying nearly double what the knytex costs. considering that the knytex may save you some resin money as well if you can use fewer layers, then it sounds like it really works out to be a pretty good deal to me.

[dawgdan]

a note on the knytex: i've read this tutorial before, and always assumed that knytex would be very expensive, but this is apparently not the case!

as i understand it, 17 oz knytex is two layers of woven cloth (approximately 8.5 oz each) with a layer of 3/4 oz chop mat between them. if you were to add up the cost of the three layers individually, you would be paying nearly double what the knytex costs. considering that the knytex may save you some resin money as well if you can use fewer layers, then it sounds like it really works out to be a pretty good deal to me.

Good call. :) On the surface, it may sound more expensive, but I suppose it does work out cheaper. Fewer buildup layers = time saved. In addition, people often forget (or are totally unaware) that resin is structurally brittle. The goal is to use just enough resin to saturate the fabric, and too often I've seen people really goop the resin on by the cupful. The fabric, not the resin, gives the enclosure strength. I only used one gallon of US Composites resin for my entire build, and still have a little bit leftover. :)

[A6Bman]

Thanks for this write-up! This was that one 'snap' article that makes me want to delve into building a fiberglass enclosure in my A6. Much appreciated!

[dawgdan]

Thanks for the kind words. Good luck with your project. :)

[Coyote]

Wow, this tutorial makes me feel like I can tackle this project on my own as well, thanks!

One question, how did you handle the sub wiring? I couldn't find that part.

[dawgdan]

I drilled a hole in the back of the box, in an inconspicuous area, ran wire through it, and sealed it up with some silicone. :)

Not the most professional way to do it, but I didn't want to mess with terminal cups (I don't think there was a flat enough surface for a cup) and you couldn't tell once it was installed anyway.

[ZoNtO]

That's one advantage of running this enclosure. You bolt it to your frame, never take it out, so you don't need a terminal cup. For those tackling the project, make sure you give yourself enough wire slack to pull the subwoofer out of the box once you silicone it through the hole you drill.

Makes me wonder if the one I ran is going to be long enough.....

[A6Bman]

Oh noes! That site is down! Does anyone have a pdf of this fiberglass tutorial?? I hadn't made one yet :(

[Ge0]

Excellent writeup Dawgdan. I read this every once in a while for inspiration. I'm going to glass some kick panels this up coming weekend and wanted to brush up on techniques.

Ge0

[BlackSapphire]

Excellent writeup Dawgdan. I read this every once in a while for inspiration. I'm going to glass some kick panels this up coming weekend and wanted to brush up on techniques.

Ge0

FG kicks are in my near future as well. I wonder if Kyntex is even worth it for such small pieces. I've got tons of chopped mat.

[dawgdan]

Excellent writeup Dawgdan. I read this every once in a while for inspiration. I'm going to glass some kick panels this up coming weekend and wanted to brush up on techniques.

Ge0

Thanks mang! I may undertake a new project shortly in my truck, before the kid gets here. :) Gotta wait for it to cool down though.. glassing in 96 degree heat SUCKS!


FG kicks are in my near future as well. I wonder if Kyntex is even worth it for such small pieces. I've got tons of chopped mat.

In that case I'd probably use the chopped mat. You already have it on hand, and kicks aren't terribly large, so buildup time wouldn't be too bad.

[BlackSapphire]

In that case I'd probably use the chopped mat. You already have it on hand, and kicks aren't terribly large, so buildup time wouldn't be too bad.

By the way Dan (if that is your real name), I forgot to mention that your time and attention to the tutorial was obvious and appreciated.

Thanks.

[sandman661]

I am completely new to car audio minus the deck replacement here or there but this is my first jump into the mobile audio SQ pool, but not new to the interweb, and I have to say that is by far one of the most detailed, easy to follow tutorials on something I figured would be a hell spawned sucubus to try and tackle... I was thinking about having a shop build my box for me (I know I am on a DIY forum) because I had a table saw accident and left me partially thumbless on my good hand (of course it had to be my good hand)...But due to your time and great pictures, I think I am gonna try this myself...you might have saved me hundreds of dollars but just cost me hundreds of man hours...Damn you and thanks...LOL...

[my89_928gt]

Great job. Gives me idears.

[WolfSong]

Excellent write up!!! I'm another newb to the whole car audio thing, but I've been reading up and learning. Didn't want to kill my trunk space either with a big box, so after seeing someone else's DIY I decided to look into doing a fiberglass enclosure. I looked at several DIY's and other tidbits on fiberglassing, and then I happened upon your DIY.

It totally took the guesswork out of what I'd seen before. I've been modifying cars and guitars for years, and I honestly wish that more people spent the time you did to make an excellent step-by-step, well-documented and commented DIY.

Excellent work!!! I've got two cars I need to make enclosures for, and I'm really looking forward to getting started.