Comparative Strength?
Printed From: the12volt.com
Forum Name: Fiberglass, Fabrication, and Interiors
Forum Discription: Fiberglass Kick Panels, Subwoofer Enclosures, Plexiglas, Fabrics, Materials, Finishes, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=82151
Printed Date: May 12, 2025 at 9:30 AM
Topic: Comparative Strength?
Posted By: bigc33
Subject: Comparative Strength?
Date Posted: August 28, 2006 at 12:24 AM
After reading through about 25 pages in the fiberglassing part of the forum I have a few questions of my own that hopfully you guys can help me with. 1. Will fiberglass mat or cloth be stronger for impact strength (not rigidity) when used on a smooth evenly curving surface? 2. Are there any spray on products that can be used to: a) make a high even, and smooth build that are reasonably rigid? b) make a rigid negative mold that will have a smooth interior surface and easily be used as a negative mold without much bondo/sanding work? 3. What type of plastic should be used in a vac bag setup for the interior porous bag and for the exterior bag? Thanks a bunch for any help you can provide! Evan
Replies:
Posted By: jlord16
Date Posted: August 28, 2006 at 3:30 AM
matting is generally stronger in all applications then the cloth/weave type, as for question 2 and 3 im sure someone else will help you
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Posted By: bigc33
Date Posted: August 28, 2006 at 10:42 AM
k so here's the tally so far mat = 1 cloth = 0 I was personally thinking that for Impact strength cloth would be stronger so I would like as many opinions (preferably educated ones) as possible. Thanks
Posted By: cutlass013
Date Posted: August 28, 2006 at 3:15 PM
it depends on the weight (oz) of the material your using personall i thing for waht your talking about the woven or cloth i guess would be stronger the mat is just a bunch of little chopped up glass put together thinly its like pulling apart a t-shirt ir a cotton ball wich is harder the shirts...just my opinion
Posted By: bigc33
Date Posted: August 28, 2006 at 3:44 PM
Well I found some info on the net and it looks like Cloth wins this round. It is stronger on a per weight basis after resin. Since mat absorbs more resin it is stronger per mat weight after resin is absorbed. Cloth will be stronger but also requires more layers. I am also looking into the use of Carbon Fiber and Kevlar. Kevlar has the best impact strength but worst tensile strength. I figure a combination of S2 glass for rigidity, Carbon Fiber for looks, Kevlar for peircing strength and glass mat for build will be best. Anyone have answers to the 2nd or third questions?
Posted By: Melted Fabric
Date Posted: August 29, 2006 at 2:09 PM
1. Will fiberglass mat or cloth be stronger for impact strength (not rigidity) when used on a smooth evenly curving surface?
Fiberglass gains it's strength not only from curves but also in the number of layers applied to your piece.
2. Are there any spray on products that can be used to:
a) make a high even, and smooth build that are reasonably rigid?
Not sure I understand the question.
b) make a rigid negative mold that will have a smooth interior surface and easily be used as a negative mold without much bondo/sanding work?
For that, instead of re-inventing the wheel, I will direct you to read MOLD CONSTRUCTION
3. What type of plastic should be used in a vac bag setup for the interior porous bag and for the exterior bag?
Also, while you there look at this link. The product you are looking for is called bagging film. Vacuum Bagging Equipment & Techniques------------- I have not failed. I've just found 10,000 ways that won't work.
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Posted By: bigc33
Date Posted: August 29, 2006 at 2:13 PM
Thanks a bunch....for the second one, I am looking for esentially a stiff silicone that can be used from a spray apperatus.
Posted By: Melted Fabric
Date Posted: August 29, 2006 at 2:19 PM
I can't but think of the scene from ghost busters II where they use the "goo" and hose down the bad guy with it.
Well, I have no clue other than getting a little crazy and mixing up a batch of resin with hardner in it, throw it into an old spray gun and risk ruining the spray gun.
Hopefully someone has a better idea.
Although the ghost buster thing might work if you can find the same goo.
 ------------- I have not failed. I've just found 10,000 ways that won't work.
When you do not know what you are doing and what you are doing is the best -- that is inspiration.
Posted By: xtremekustomz
Date Posted: August 31, 2006 at 9:35 PM
bigc33 wrote:
After reading through about 25 pages in the fiberglassing part of the forum I have a few questions of my own that hopfully you guys can help me with. 1. Will fiberglass mat or cloth be stronger for impact strength (not rigidity) when used on a smooth evenly curving surface? 2. Are there any spray on products that can be used to: a) make a high even, and smooth build that are reasonably rigid? b) make a rigid negative mold that will have a smooth interior surface and easily be used as a negative mold without much bondo/sanding work? 3. What type of plastic should be used in a vac bag setup for the interior porous bag and for the exterior bag? Thanks a bunch for any help you can provide! Evan
On number 2 are you actually wanting to make a mold? If so you will have to make your form and probably have to do alot of sanding on it and possibly paint it to get a really smooth surface. After that you can use a mold release and gelcoat for your initial layers inside the mold them add fiberglass matt and resin. I don't know if that answered your question or not but it was worth a shot.
Posted By: DYohn
Date Posted: August 31, 2006 at 10:11 PM
Melted Fabric wrote:
Although the ghost buster thing might work if you can find the same goo.
Isn't it called ectoplasm? ------------- Support the12volt.com
Posted By: auex
Date Posted: August 31, 2006 at 11:40 PM
Oh no DYohn is in the fiberglass forum, watch out for the stay puff marshmallow man!!!
How did ghostbusters come up?
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Posted By: Melted Fabric
Date Posted: September 01, 2006 at 10:45 AM
DYohn] wrote:
Isn't it called ectoplasm?
I guess so, lol. I have not watched it in a very longtime. Just remember those little details I posted. They should consider coming out with a part three to the movie and use Resin and hardner on the ghost then wrap them in fiberglass mat and lock them in their "ghost prison"
Then again, I am bored at work and I am letting my imagination run crazy.
Auex]O wrote:
no DYohn is in the fiberglass forum, watch out for the stay puff marshmallow man!!!
How did ghostbusters come up?
LoL, I imagine DYohn covered in uncured bondo walking around the install bay scaring customers, hahaha.
In Ghostbusters Two, when the "river of slim" was running under the city and going into that museum when the renaissance looking dude had stolen the little baby, etc.. Back to the slim, it reminds me of resin for some reason. And when bigc33 asked his question number two, that was the first thing that popped into my head.------------- I have not failed. I've just found 10,000 ways that won't work.
When you do not know what you are doing and what you are doing is the best -- that is inspiration.
Posted By: crazyoldcougar
Date Posted: September 04, 2006 at 11:46 AM
sorry for the late chime in...
comparing fiberglass "weaves" is almost like comparing apples to oranges...
each is different product is meant for a different and a more or less specific use...
but i hate to say that all fiberglass has the exact same strength capabilities...fiberglass is exactly that, glass fibers...regarless of size they all share the exact same properties, it is just easier to see on certian scales..it is kinda like saying what is stronger a foot long bar of cold steel or ten foot long bar of cold steel...?same properties, just because one is longer then the other doesnt make it any stronger...same goes fiberglass fibers..
for instance milled glass has the exact same compressive strength as short strand or long strand regardless of it's fiber arrangement...as for tensile strength, this is where the products differ, as the greater strength is along the axis of the fibers..not that longer fibers are stronger, but the arrangement of the fibers will give strength in different directions..
Fiberglass Cloth like other Bi-axial weaved fiberglass products are specifically used for projects that require strength in two opposing directions (generally)
Mat is used as a high build product that is used on projects that require strength in multiple directions..as the fibers are arranged randomly in every direction...
milled glass is used a filler product with extensive strength in all directions, as once again the fibers are arranged in every possible angle on all three axis'...
cured fiberglass will all share the same piercing properties at relative thicknesses, the fibers are very brittle and once cured have even less pierce strength...
Carbon fiber is pretty much exactly the same as fiberglass, with higher tensile strength capabilites and much less weight, however it is more brittle then fiberglass...
Kevlar is a product that has at least ten times the abrasive and compressive strength properties of fiberglass, with lighter weight...GOOD LUCK trying to cut it though...
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