Fiberglass Mat or Cloth? From a newbie . . .

**j.c_photos** · 07-13-2006, 01:15 PM

I’ve been lurking for a couple of weeks now and I want to start my own project. I want to fabricate a rear deck for my speakers (4 6x9’s) in a 94 prizm. I was noticing that mat requires A LOT more resin than the cloth does. Of the Professionals (or professional quality amateurs) out there, which do you guys prefer – mat or cloth? The deck will have some mild curves and maybe a couple of tighter ones too. I was thinking of laying down 6 layers of 6oz cloth (which uses less than a gallon of resin) as opposed to mat which would need well over a gallon just for one layer! Cost is one factor, but it also sounds like that mat would be really thick.

Would the 6 layers of 6oz be strong enough? How many layers of 1.5oz mat do you recommend if I should go that route?

What other tips do you have for a newbie out there trying to start a really aggressive first project?

Josh

**Shadow** · 07-13-2006, 01:29 PM

For you, cloth. Mat is really hard to work with for people with no to not much fiberglass experience. The random threads pull out and make a huge sticky mess. Cloth also lays down flatter with less work needed than mat to finish.

Make a frame out of MDF that has the parts that hold your speakers at the correct angle as well as a baffle. Also make ribs that are the high points and the correct shape for your shapes. Then get some very stretchy cloth (fleece works well and it's really cheap in the summer) and stretch it over the whole thing. If it doesn't lay down correctly, either staple it down or change your frames so it will. If it wrinkles, pull it out. Get it as tight as humanly possible and then soak it in resin. If you soak it correctly, it'll be really hard and shouldn't take much prep to get smooth. I'd say since it's mostly for looks anyhow you'd be good with just that layer as long as you don't sand it too much. If you're concerned about stiffness you can lay up mat or resin on the inside of the form after you've done the fleece.

I'd say that 80-90 percent of your fabrication time should be spent in prep.

**FC3S** · 07-13-2006, 02:09 PM

Originally Posted by Shadow

If you're concerned about stiffness you can lay up mat or resin on the inside of the form after you've done the fleece.

inside? thats if he has enough space to get to the inside, if its a box, put the fibreglass outside the fleece, lol

**GoHybrid** · 07-13-2006, 04:37 PM

i think mat gets alot easier if you buy one of those rollers to get the air bubbles out and compact the laminate. that, and wait for the resin to get a little sticky before pouring it on... plus getting around compound corners, with mat you just tear off what you need and mash it down. Cloth does mean less sanding in the end, but i find that the bias of the cloth can make it difficult to make certain curves and shapes without a wrinkle or needing to cut it apart. I guess it depends on the shape.

**Shadow** · 07-14-2006, 09:40 AM

Originally Posted by FC3S

inside? thats if he has enough space to get to the inside, if its a box, put the fibreglass outside the fleece, lol

If you put it on the inside, you don't mess up your nice shapes that the fleece made. You get the stiffness without having all of the pain in the butt of sanding down ANOTHER layer and using all of that body filler. He's not making a subwoofer box, just for some full-range speakers. It doesn't even have to have a bottom.

Another option is to put another layer of fleece on the other layer of fleece.

**FC3S** · 07-14-2006, 09:43 AM

doesnt have a bottom eh

then nevermind me at all, lol

**RedGTiVR6** · 07-14-2006, 02:16 PM

don't use fiberglass to give you strength, use DuraGlass. It's a much better product.

Stretch with fleece/t-shirt/carpet, pour resin on that, let it kick, then on the underside apply the DuraGlass (or similar product)

PS: you can get it here for one place to purchase it from: https://www.fiberglasswarehouse.com/fillers.asp

or here: link

or at a local paint and autobody supply shop.

**j.c_photos** · 07-14-2006, 08:26 PM

I think what I'm going to do is mask the bare deck (metal frame) with foil and tape. Then put in a BASIC frame for the speaker mounts out of MDF.Then stretch pantyhose to get the basic bottom shape. Then I'll put some resin to herden those hose. With this hardened I'll pour or spray on some expanding foam (does the polyester resin stick to the hardware stuff or do I need to use the pouring polyurethane foam?). I'll shape the foam and fiber (6oz mat - I've decided) over that with few layers. Then cut me holes and finish it all off. I know there's some small intermediate steps in there I'll do along the way, but does this sound like a good plan?

I know this is more complicated than everyone is suggesting, but I want a little more than just a basic shape . . . I want some of my own style in it too. I'm either going to use black gel coat to finish or primer and paint(some other color. Hopefully I can order the stuff this weekend and have it by Friday . . . (fingers crossed!!).

Thanks for the comments so far guys!!!

**GoHybrid** · 07-14-2006, 09:28 PM

i think expanding foam is a great idea. polyurethane is pretty benign once it's hardened. you will have some surfacing to do once you've got your basic shape, but instead of working with straight bondo to fill in the holes (i like evercoat products personally), mix whatever polyester filler you're using with a little bit of resin until it becomes brushable. this lets it self level to some degree as well as get deeper penetration into the foam part. you'll have less sanding to do that way.

**RedGTiVR6** · 07-14-2006, 10:01 PM

Originally Posted by j.c_photos

Then stretch pantyhose to get the basic bottom shape.

I would recomend using something that will hold more resin than pantyhose. Something like an old t-shirt even. a yard of fleece, or even some old speaker box carpet. It's better to get a decently stiff layer at first that will give you something to work from instead of something that's more likely to flex on you while you try and work with it.

What's the deal wit the expanding foam? I'm a little unclear on the purpose of it?

Thread: Fiberglass Mat or Cloth? From a newbie . . .

LinkBack

Thread Tools

Search Thread

Display

Fiberglass Mat or Cloth? From a newbie . . .

Devil's advocate...

basic idea?

cool!

Similar Threads

Fiberglass Sub Enclosure project

03-05 Honda Accord Fiberglass False Floor...WIP

mat vs cloth

Yet another fiberglass thread

Non-permanent fiberglass mount

Bookmarks

Bookmarks

Posting Permissions