- Joined
- Jun 8, 2002
- Location
- Melbourne, Australia
gone_fishin said:
If that were true, then it wouldn't be used for anything. Protective visors would be cracking in front of peoples faces (they have multiple holes in them for fasteners around the edges as an example).
Five out of six tries that cracked tells me the method was bad, how about you?
Don't know about you. I ride motorcycles. Yes, I've had more than a few visors develop cracks around the stress pressure points where they attached to the helmet. The visors that didn't do this were the more expensive molded visors, which is a totally different method to making visors than the bent plastic sheet with holes cut into it.
Be careful with what you're comparing here. Vacuum formed pre-shaped plastics vs machined/cut plastics. In my experience, the machined/cut visors are more fragile and do develop cracks at the pressure points.
Yes, 5 out of 6 tries does imply something wrong with the method, there's no denying that. What I'm saying is that almost no matter what you do, when you machine plastics you can't guarantee 100% that it will not crack at the pressure points. Yes, you can greatly reduce the chance of it happening, but some will still happen.