Fiberglassing Tips? - Page 6

nodnarb · 05-14-2006, 11:08 AM

I have a hatchback and the reardeck is removable. I have lost the rear deck and don't intend to buy a new one. I want to cover the existing speakers w/ fiberglass, and have a fiberglass span the gap between the two existing speakers. I will put two speakers in the deck. I need somthing strong eneoug so that the fiberglass dosn't sag. Any suggestions? I will eventually have a sub layout in the back. I am hoping for a seamless transition between the two.

nodnarb · 05-14-2006, 11:10 AM

forgot to add pics.

JasonWW · 05-14-2006, 11:31 AM

Your new rear deck could simply span the entire legnth covering the 2 speakers on the end.
Do you not want to get a used factory deck to start with and use as a foundation? Sometimes that's the best way to start.

If you want to start from scratch you could make something from wood or steel depending on how strong you want it.
Are you going to cover the factory speakers so they won't be usable and then install new ones just inboard of the old ones?
Or still use the factory locations and integrate a grill of some kind into the new deck?
Are you wanting to add some kind of grill in the center of the deck to let the bass flow into the cabin?

I would look around for some type of grill material like expanded metal or mesh of some kind.

nodnarb · 05-14-2006, 01:11 PM

no, the existing speakers I want to be gone, and never to be used again. Now that I think about it, the grill in the center to let the base come through is a good idea. I have some 1/4 inch mesh that would be good under some sort of metal "grill". The only thing with the existing deck is that it dosn't cover the speakers, and I would have to put 1 1/2 inch of fiberglass to get to the heighth that I want.

Sidewalksalvage · 05-14-2006, 01:13 PM

what kind of car do you have? I suggest finding an old rear deck for your car at a junk lot and begin on that. It will be strong enough and will be an excellent template shape. The fiberglass, once dry will, if made correctly, most likely be strong enough to support itself, but during drying you may want a wooden support of some kind, if not a perminate one. As for the subs, you may want to build the entire unit now. This will ensure a seamless transition. Also if you plan it ALL out now, it will work better in the future.

JasonWW · 05-14-2006, 01:40 PM

Quote: Originally Posted by nodnarb

The only thing with the existing deck is that it dosn't cover the speakers, and I would have to put 1 1/2 inch of fiberglass to get to the heighth that I want.

I'm not sure I follow you, but are you saying you want the new deck to be 1.5" higher than the stock speakers?

If so, then it's pretty easy. Just get a piece of 1" mdf and cut it to fit all the way across and sit it on top of the stock speakers. That would make for a good foundation. The front and rear edges can be rolled over, new speaker holes can be made, grill openings can be made, whatever.

For the grills, you cut the opening to whatever shape you want, add about a 1/4 rollover bit around the top edge, router the back side about an inch all around and about a 3/4 deep. That way you have a 1/4" lip around the opening. Mount your grill material from the bottom. Add a layer of fiberglass, sand it all smooth, add bondo if needed and then paint it.

nodnarb · 05-14-2006, 01:46 PM

I have a 1993 Dodge Shadow ES. I will get back to you on the details later.

nodnarb · 05-15-2006, 08:33 AM

very helpful thanks, It's about 1/2 inch to 3/4 inche from the top f the speaker to where I want it.

JasonWW · 05-15-2006, 01:00 PM

A piece of 3/4 MDF would be about right. It's easy to cut and work with. Just don't cut any holes that are too big from front to rear as it will weaken the board.

Have you thought about using a higher quality wood? After the edges are beveled or rounded over, sand it, stain it and clear it when your finished. Might look real nice.

Sidewalksalvage · 05-16-2006, 12:15 AM

Quote: Originally Posted by JasonWW

Have you thought about using a higher quality wood? After the edges are beveled or rounded over, sand it, stain it and clear it when your finished. Might look real nice.

He has a point. My first sub box had no fiberglassing, it was just finished MDF. And personally i think it looks great.

JasonWW · 05-16-2006, 03:48 AM

Quote: Originally Posted by Sidewalksalvage

He has a point. My first sub box had no fiberglassing, it was just finished MDF. And personally i think it looks great.

I've stained MDF and it looks OK, I was actually thinking he could get a real, "solid" wood. That way you could see the grain in it.

nodnarb · 05-16-2006, 04:19 PM

thanks but I wanted to paint it green W/ black or the other way around. How many layers would I need to put on the wood and how thick would it be? There would be three substantial holes in it. One of them would be the air hole. Also, When ever I do the subs, do the coils need to be on the inside or the outside of the enclosure?

Sidewalksalvage · 05-16-2006, 09:18 PM

For the speakers you want the voice coils on the inside because they are usually directionally designed. 1/2 or 3/4 inch wood is plenty, especially if there is 2" or mor around each hole. What do you mean by layers? The paint? I find that a nice sand, followed by 1 coat of primer and 1 coat of color. If the color is still two light or not quite right, add a second coat. That should work alright. Remeber to sand inbetween primer and color. If the sand takes off to much primer. Add a second coat and sand again.

JasonWW · 05-16-2006, 10:13 PM

Subs can be mounted either way. Sidewalksalvage says inside, but I don't understand his reasoning behind that.

Sidewalksalvage · 05-16-2006, 11:18 PM

Oh im sorry i thought it was the speakers on the rear deck...Yes subs can be installed either way. There are two reasons to install coil out. 1 the box can be smaller because volume does not need to include the speaker coil. Therefore bigger base with a smaller box. and two, if you have one sub coil in and another coil out it cancels what is called phase inteference. Its not really a big problem and most dont even hear a diffence, but for some audiophiles its a big thing. There are many ways to install subs, the most common being coil in basically for looks but there are also push pull systems and more complex set ups (including bandpass and other special boxes) if this is your first install, i suggest a basic sealed box and choose coil in or out depending on asthetics. Note however, a coil out sub is more vunerable to dammage.

The reason i stated before coil in, is because with mid range and especially high range, the seakers are generally designed to be coil in because of directional design. Subs produce low range sound which up to about 100Hz or so is omnidirectional and position and direction is not so important.

sorry for the confusion.

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