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View Full Version : Around what Oz is perfect for fiberglassing?



APitBullT
06-09-2005, 08:45 AM
want to know whats the commonly used Oz for fiberglass? Im new to this and i want to do my first fiberglassed box? also where can i buy the fiberglass mat? what type of fiberglass is there? and which one is good for making boxes?

djjdnap
06-09-2005, 08:53 AM
http://forums.caraudio.com/vb/showthread.php?t=36873

check out the how to links

but i read on one of them that its cheaper to buy from a boat shop, since thats what they iuse to repair them.

BUt i'm going to say that you shoudl find out how man Oz you have them convert it to Cuft. In most cases bigger is better.

UndercoverPunk
06-09-2005, 09:00 AM
Heavy mat will be harder to work in small places, but will lend more strength per layer.

Use a mix of thick and thin.

I personally don't like 1.5 oz mat commonly found, as you have to do a ton of layers to really make it strong. (but there are ways around layer after layer after layer...)

On my next project I'll be using 18oz cloth and 1.5 oz mat.
I should have my opinions of the 18oz cloth up on here in less than a week, as I'm starting my new pods today.

djjdnap
06-09-2005, 09:05 AM
LOL, i thought he meant oz and in ounces(well still), I thought he meant as in cuft=oz..

since you can pour watter in the enclosure to see how big it is. lol, i feel smart today.

AzGrower
06-09-2005, 09:08 AM
3/4 oz chop mat

UndercoverPunk
06-09-2005, 09:16 AM
3/4 oz chop mat

How many layers till you can stand on it?

Honestly wondering

AzGrower
06-09-2005, 09:27 AM
How many layers till you can stand on it?

Honestly wondering

Well when I did my subwoofer box, I used 7 layers of resin/matting, with actually using a dual layer of matting in between letting it harden and I could begin to stand on it a the 4 layer. Here are some pics of my box:

http://www.sounddomain.com/ride/518721/2

APitBullT
06-09-2005, 10:06 AM
also when you fiberglass do you go in one direction the whole time, or can you go vertical then horizontal and then vertical etc...

UndercoverPunk
06-09-2005, 10:13 AM
also when you fiberglass do you go in one direction the whole time, or can you go vertical then horizontal and then vertical etc...

If I understand what you're asking... the more you switch the direction up, the better, it will help strengthen it.

Too bad Ramos is gone, we could really use him now that summer has begun and everyone wants to fiberglass...

APitBullT
06-09-2005, 10:23 AM
im just full of questions today, im just learning and researching on this so i can start doing it. so im sorry for the newbieness. ok another one

how long do you wait for each layer, read somewhere to wait 30 min. and then i read another place to wait 10 hours, is either of these correct?

djjdnap
06-09-2005, 10:29 AM
The resin you buy will have instructions on how much MEKP to mix with the resin. You want to mix relatively small amounts at a time, because if you take too long the resin will 'gel' up and become useless. Also, note that the mixtures listed are for 70degrees F. If it is warmer, you can use slightly less, if colder use more. If you use too little, it will never harden -- to much and your work time will be cut to less than 5 minute

You can lay a second layer of fiberglass right on top of the first one. Although I would not go more than 3 layers thick before waiting for it to completely dry, then restarting the process. When you're done layering, clean your tools and wait. If you mixed you mixture right, it should be dry to the touch in about 1.5 - 2 hours. You can then lay more layers as needed. For this small box, only 2 layers were used. For larger fiberglass boxes I usually use between 7 - 9 layers, thicker if there are any flat runs that i couldnt make out of wood. Also if you use a thicker matt, you obvisouly can use less layers. Keep in mind, however, that a thick matt will not conform to tight corners very well.

http://web.njit.edu/%7Ecas1383/proj/Glassing1/index.htm

req
06-09-2005, 10:34 AM
between 5 and 10 ounces per square foot (thats how they weigh it, per square foot)

thats my favorite. i do have some 32oz biaxial (matte+weave together) and some 6oz cloth (finishing layer).

15~20oz is a little on the heavy side and will soak up a ton of resin, but in the end, only like 3 layers are needed... and its usually cheaper than the 5~10oz - because this is the weight that is most commonly desired, and with the rules of supply and demand, thus the lower price of heavier\extremly low weight glass\matte :)

so 5~10oz per sq foot for its weight is my favorite - cloth is eaiser to use, but matte is a litte stronger :thumbsup:

AzGrower
06-09-2005, 11:57 AM
If you notice the strands of fglass in the chop mat istelf is in different directions, for strength purposes. You can add a nother layer as soon as the first is hard to the touch. I waited about 1 hour in between. I also had an exhaust fan on it to help with the fumes. You can alter the times by adding a few more drop to make it "hot" but your working time is greatly reduced. Try not to mix more than a few cups (8-10 oz of resin) at a time so it doenst harden in the cup whilst you are working.

TPABlazer
06-09-2005, 02:23 PM
as far as the direction you lay the matte, as far as strength goes, it really doesnt matter too much, scine the choppe is random. it will help for finishing to go various directions as you wont have any high spots (or as many, as noticable etc).