DiyMobileAudio.com Car Stereo Forum banner

1 - 20 of 30 Posts

·
Registered
Joined
·
7,203 Posts
Discussion Starter · #1 · (Edited)
I'm after the best solution for doing a tub in my suv, and this time I want to do it right. I've used cheesy mat and crappy bondo brand resin in the past, and the level of failure I've had w/ fiberglass is just...phenomenal.

So, here's the target:



It has a full deadening layer now, this pic was when I first gutted the back end.

This is what I was working with last time:




This old design uses too little airspace for the incoming DIYMA subs, and the new box will need to be a LOT thicker as well. This one flexed at the bottom because my glassing skills and material choices were lacking. I'll do it right this time with your help, I'm sure of it.

So, what type of fiberglassing materials would you recommend? Where would you get them most economically? I have a lot of ideas but I want some opinions on this one before I pull the trigger.

Thanks!
 

·
Registered
Joined
·
3,861 Posts
Don't use the .75 oz random matt available at most places.

Use the 1.5 oz available at boat shops or FG supply houses along with the fresh resin they offer.
 

·
Registered
Joined
·
1,146 Posts
I really like US Composites B440 resin. There mat builds up pretty strong as well.

Of all the mats I've used, BONDO, US Composites, Evercoat, etc.

I really liked the Evercoat Sea-Glass. It was the easiest to use chopped strand mat. The US composites mat was a little stiffer and harder to get to lay down. It was stronger on the flat spots though for sure.
 

·
Registered
Joined
·
3,861 Posts
Now even though there are a few reinforcing ripples in that metal it is a large broad and flat surface.

You need a thicker build up.

So a few layers of Bi-Axial weave Knytex would do the trick.

I've been using this material for over 10 years and it always builds up fast and THICK.

To maximize the effectiveness you want small pieces of 1.5 oz random strand matt cut up so you can soak up the extra resin.

This will lower the amount of unsoaked resin in your enclosure and be a more efficient use of the materials.
 

·
Registered
Joined
·
7,203 Posts
Discussion Starter · #6 ·
YES! Thank you!

I was thinking a biaxial weave cloth would do it, but I wanted to hear it said as well.

Before I order from the web, I'm going to visit a boat repair place I've seen here in Vegas, but if they start spouting off high numbers I know where to turn to.

So about 5 yards of a biaxial weave, about ~20-26oz? And maybe 2 gallons of polyester resin?
 

·
Registered
Joined
·
3,861 Posts
So about 5 yards of a biaxial weave, about ~20-26oz? And maybe 2 gallons of polyester resin?
It's better to have too much rather than not enough.

I start the enclosure with 3 layers of chopped strand since it's easy to get into the tight spots.

Biaxial isn't the best for the first few layers if you're trying to tightly conform to a shape.... it's best for making the walls thicker.

It is surprisingly flexible for the amount of mass it has though.
 

·
Registered
Joined
·
7,203 Posts
Discussion Starter · #9 ·
If I said "no" to chop mat (just from experiences in the past), would you then suggest a satin-weave cloth to start the form as an alternative? I could see that working.
 

·
Registered
Joined
·
2,802 Posts
i have used both the satin-type cloth and 1.5oz mat and i prefer the mat. i bought the mat locally at boater's supply but i forget the price. rip it into pieces, don't cut it.

b440 is the best resin i have ever used.

use mdf on every flat surface that you can. it is much easier to work with and cheaper too. over large flat areas, like a floor, a fiberglass structure is not as solid as mdf. it's main strength comes on curved areas. if you must you can use pieces of nylon rope soaked in resin, then mat over it. for the little gain it looks like you would get from a fg bottom it is hardly worth the time, effort and money. cut a piece of mdf, glass the sides and make it one piece with the top frame.


get a roller and use it. it will save you lots of resin and remove any bubbles.

i use a spandex-type materials to get shapes. i forget the name but it's the stuff that they make swimsuits and gymnastic outfits from. not too expensive but you can stretch it tight to almost any shape.

that's all the rambling fg tips i can think of at this time. if i remember any more or you post any more questions i'll be back.
 

·
Registered
Joined
·
7,203 Posts
Discussion Starter · #11 ·
i have used both the satin-type cloth and 1.5oz mat and i prefer the mat. i bought the mat locally at boater's supply but i forget the price. rip it into pieces, don't cut it.

b440 is the best resin i have ever used.

use mdf on every flat surface that you can. it is much easier to work with and cheaper too. over large flat areas, like a floor, a fiberglass structure is not as solid as mdf. it's main strength comes on curved areas. if you must you can use pieces of nylon rope soaked in resin, then mat over it. for the little gain it looks like you would get from a fg bottom it is hardly worth the time, effort and money. cut a piece of mdf, glass the sides and make it one piece with the top frame.


get a roller and use it. it will save you lots of resin and remove any bubbles.

i use a spandex-type materials to get shapes. i forget the name but it's the stuff that they make swimsuits and gymnastic outfits from. not too expensive but you can stretch it tight to almost any shape.

that's all the rambling fg tips i can think of at this time. if i remember any more or you post any more questions i'll be back.

The name of material is Lycra :)

I am after the most space possible but I agree with you its often not worth the hassle vs. wood. In a tub situation, those little curves and whatnot do add up though. I'll need around .75 cubes per DIYMA sub, and more importantly I need that box as short as possible to clear my steath-ish design plans.
 

·
Registered
Joined
·
2,802 Posts
no, it's not lycra. i am talking about something else that is far cheaper than lycra.
 

·
Registered
Joined
·
2,802 Posts
yes most people do use fleece but that doesn't mean it is the best thing to use. fleece gives you a much rougher surface when it hardens with resin which only means more sanding later. it also soaks up a lot of resin which ain't cheap.
 

·
Registered
Joined
·
87 Posts
I just finished building my first fiberglass enclosure and the one tip that helped me the most is that less resin = more strength. Make sure you can still see the strands of fiberglass or the weave after you resin it or you used too much. I used chopped mat torn by hand and had to build up 4-5 layers on each portion of the box to get the strength I wanted. I used Evercote resin I got at a Boaters Supply on sale since they are closing their retail stores.
 

·
Registered
Joined
·
7,203 Posts
Discussion Starter · #18 ·
Is that an Escape?
Close, it is a Tribute, 2008 model.

BTW this truck's system has been built. I decided to avoid fiberglass altogether and use relatively lightweight Birch plywood for a false floor for the amps, then I built a conventional small sealed box for the DIYMAs. Why? Because honestly fiberglass pisses me off when I use it. Yes, you can do so much with it, but I HATE the smell and the way it lingers for days and days in the truck, and I also hate the amount of effort it takes to get something done. Wood worked for me in this instance:




 
1 - 20 of 30 Posts
Top