# Anyone have experience with fiberglass? **URL:** \ **Category:** NYSpeed Automotive\ **Created:** [September 4, 2006, 7:34pm UTC](https://forums.speedlife.net/t/anyone-have-experience-with-fiberglass/16956 "2006-09-04T19:34:54Z")\ **Posts on this page:** 2\ **Page:** 2
**Author:** ![fairgentleman\_Z](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/fairgentleman_z/32/7263_2.png) [@fairgentleman\_Z](https://forums.speedlife.net/u/fairgentleman_Z)\ **Post date:** [September 5, 2006, 3:43pm UTC](https://forums.speedlife.net/t/anyone-have-experience-with-fiberglass/16956/21 "2006-09-05T15:43:29Z")
> [@LAFENGAS](#): > > Why? because fiberglass if very heavy when hand laid (high resin/fiberglass ratio) Unless you have a vacuum bagging system will you be able to make it reasonably lightweight. Vacuum bagging requires a fair amount of mold experience to understand how your mold and plug behave under vacuum. Now you’re just opening a can of worms. What exactly does the vacuum bag do? Just sucks all the air out and puts 1 atm evenly over the whole peice, thus requiring less adhesive (epoxy/resin) to bond the layers? ---
**Author:** ![LAFENGAS](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/lafengas/32/7573_2.png) [@LAFENGAS](https://forums.speedlife.net/u/LAFENGAS)\ **Post date:** [September 5, 2006, 3:48pm UTC](https://forums.speedlife.net/t/anyone-have-experience-with-fiberglass/16956/22 "2006-09-05T15:48:59Z")
> [@fairgentleman Z](#): > > What exactly does the vacuum bag do? > > Just sucks all the air out and puts 1 atm evenly over the whole peice, thus requiring less adhesive (epoxy/resin) to bond the layers? correct. Greatly reduces the epoxy weight and it forces the weave tighter together making it much stronger. Also, with semi-complex parts, it helps actually force form the composite to the shape of your mold. [Previous page](https://forums.speedlife.net/t/anyone-have-experience-with-fiberglass/16956.md?page=1)