Composites
From GummyCarbs
Material Selection
Google's cache of the now-defunct www.pe.net/~rpm/about2.htm mentions:
- All gas tanks are made of vinyl ester resin for chemical resistance to gasoline.
- Fenders and side plates are made of iso-flex or DCPD resins, no low grade ortho resins are used.
- All parts are made with iso-flex gel coats to reduce cracking.
Epoxy Resin vs. Vinylesters and Polyesters at Red Rock Store. This is an excellent layman's explanation of the different chemical properties of resins.
- Epoxy resin
- Strongest molecular bond
- Will crack along a single line rather than splintering
- Minimal shrinkage
- Thin resin, easier to thoroughly wet-out fabric
- Excellent repairability
- Vinylester resin
- Essentially polyester resin toughened with epoxy molecules
- Weaker molecular bond than epoxy
- Difficult to repair/patch
- Polyester resin
- Cheapest resin available
- Highest water absorption
- Highest shrinkage
- Spider cracks when stressed
- Difficult to repair/patch
Vacuum Bagging
- Vacuum Bagging On $50
- Glad ForceFlex trash bags are polyethylene and are suitable for vacuum bagging with epoxy.
- Vacuum Bagging Basics is a good overview from a boating perspective.
- Simple Vacuum Bagging Systems recommends using a cheap hand-pump vacuum pump from an auto parts store. They have a built-in vacuum gauge.
- JoeWoodWorker.com has some excellent guides intended for applying veneers to woods.
- Project EVS is a how-to guide for building a very advanced vacuum system for a relatively low cost.
- Uses two vacuum reservoirs made of Schedule 40 or 80, solid-core PVC pipe. Just as an air tank prevents an air compressor from having to run continuously, a vacuum reservoir reduces the strain on a vacuum pump.
- Uses a vacuum controller to switch the vacuum pump on only when additional vacuum is needed.
- Uses a "3-way Mac Valve" to relieve vacuum from the vacuum pump, which otherwise might prevent it from re-starting after cycling off.
- Project EVS is a how-to guide for building a very advanced vacuum system for a relatively low cost.
Examples
- How I Made My Carbon Frame At Home at Brano Meres Engineering and Design. Demonstrates building a bicycle frame without vacuum bagging.