PDA

View Full Version : Tear the matt or use scissors?



Insomniac119
07-19-2006, 09:11 PM
When your glassing, you prefure tearing the matt into chunks or cutting them using scissors into squares?

I've always just torn them, but I want to know other peoples opinions.

CrazedCat
07-19-2006, 10:21 PM
Tearing it up and intermingling the frayed edges of fiberglass from each piece will make for a stronger overall piece.

bjfish11
07-19-2006, 10:45 PM
I cut it, its easier for me. I get the 90 yard rolls from uscomposites and just cut it to the length i need. Works well.

Ingleside
07-19-2006, 10:47 PM
i usually cut it up before i work on a project.
tearing it is messier and the stuff starts to get all over the place.

dbornotdb
07-20-2006, 12:17 AM
Tearing it up and intermingling the frayed edges of fiberglass from each piece will make for a stronger overall piece.




The Truth spoken.

Flipx99
07-20-2006, 12:20 AM
I cut because I am too weak to tear the mat I buy. I can stretch it and get it apart but it is much easier for me to cut it and manually gray the edges, but I use thick mat

baseballer1100
07-20-2006, 12:32 AM
How much will a fiberglass box cost you normally?

azbass
07-20-2006, 12:38 AM
i cut the matt in pices. then fray the pices up when i lay them.

Insomniac119
07-20-2006, 12:08 PM
How much will a fiberglass box cost you normally?

~$60 in supplies
~$250 if you're paying someone to do it
~$600 for a local shop to do it

dbornotdb
07-20-2006, 12:18 PM
I use 3/4 oz sometimes. Not often.
I have huge rolls of 1.5 and 2 oz mat. I tear them all.
I have a box of 4 oz weave that I cut with shears. Scissors won't even budge it.



Tearing frays the edges making it interlock when putting them down. Thats makes it stronger. Joints are weak points and you get joints from straight cuts.

helotaxi
07-20-2006, 12:19 PM
Tearing it up and intermingling the frayed edges of fiberglass from each piece will make for a stronger overall piece.
This would be true except that you will get the same effect by overlapping the cut pieces. If the strands of glass in the mat are short enough for you to tear it apart, then there is no real strength gained. Real strength comes from long strands running randomly all through the piece. Once the strands are interrupted, or if they are short to begin with, it isn't going to matter much. For maximum strength, you should use the largest piece of continuous mat that you can with the longest continuous glass strands.

tRiGgEr
07-20-2006, 12:20 PM
Tearing. I refuse to cut it. I even tear the edges of the mat that are not frayed...

dbornotdb
07-20-2006, 12:27 PM
This would be true except that you will get the same effect by overlapping the cut pieces. If the strands of glass in the mat are short enough for you to tear it apart, then there is no real strength gained. Real strength comes from long strands running randomly all through the piece. Once the strands are interrupted, or if they are short to begin with, it isn't going to matter much. For maximum strength, you should use the largest piece of continuous mat that you can with the longest continuous glass strands.



The strands are not short. They don't really tear as much as it is pulling it apart. The frayed ends are long.
Overlapping cut pieces can create an air pocket. Air = weak spot.
One continuous lay of mat is a good idea, just not always feasable.

helotaxi
07-20-2006, 12:45 PM
Overlapping cut pieces can create an air pocket. Air = weak spot.
There's only an air pocket if you leave one there. If you roll out the mat and make sure that it is fully saturated, there won't be an air pocket.

The mat is glued together with an adhesive that disolves in the polyester resin. It will fray itself as you lay it, whether you cut it into manageable pieces or tear it and end up with strands all over your garage and your hands.

A chop gun cuts it, for what it's worth.

Insomniac119
07-21-2006, 12:42 AM
Hmmm....this is a close one!

Curel
07-21-2006, 12:45 AM
i usually cut it up before i work on a project.
tearing it is messier and the stuff starts to get all over the place.

X2

I prefer to cut it in strips & use the brush to bring the hairs out. Tearing gets messy.

blue93corsica
07-21-2006, 09:31 AM
fraying it is much easier IMO to work with, bonds together multiple peices almost seamlessly, which is especially good when the project is goign to be covered or painted, it will require less finishing work to get the desired result