| Author | Message | ||
     Sven-Ake Eriksson New member Username: Sven Post Number: 25 Registered: 11-1999 |
I have talked to several builders trying to use kevlar composites. Common problem to all of them are the way kevlar behaves when sanding it. All edges sanded the normal way gets the look of a "used toothbrush". This problem limits kevlar use to places where it will be totally contained inside other structural parts. Now I found out that it is possible to sand kevlar edges with good result. I used normal water sanding technique with no:120 grit and this will give you a smooth edge just as when sanding a fiberglass counterpart. | ||
| Allen F. Kittleson New member Username: Al38kit Post Number: 8 Registered: 07-2007 |
Putting a 1 ply Bid of glass on top helps too. | ||
| Jim Oyler New member Username: Midniteoyl Post Number: 119 Registered: 07-2003 |
Careful using water as Kevlar will wick it up and delaminate.... Best bet it to use a ply of glass over the top as suggested. | ||
| Eric Holmberg New member Username: Erich Post Number: 119 Registered: 05-2002 |
Where are you using the Kevlar? Are you using it for puncture resistance? | ||
| Sven-Ake Eriksson New member Username: Sven Post Number: 26 Registered: 11-1999 |
I am using it to reduce weight on parts where it does not matter with the stiffness difference between kevlar and fiberglass. Wheel pants, strut covers ,inspection doors and so on. Also I use it where you can take advantage of the higher stiffness because it needs far less layers than fiberglass to achieve the desired stiffness. I never use it on highly loaded structural parts as this should neeed a careful calculation when mixed with fiberglass parts. Lots of the modern sailplanes use kevlar/carbon laminates due to weight/stiffness reasons. I have also never heard about water making delamination in these planes structural parts as water normally do not affect resin bond when cured. Also always "seal" the ground edges with resin. You do not want an exposed fiber end neither in fiberglass or kevlar/carbon. |