Friday, May 1, 2009
Glastron Boat Windshield Fabrication
Glastron boats, as well as many other OLDER outboard motor boats, have thermoformed plexiglass acrylic windshields. After a few years, usually 30-40 years, owners want to spiff up their motor craft and put a new windshield in. Problem is, Glastron doesn't make them anymore.
Here's Bryan with a recent windshield sent in to the shop for a replacement. We don't have a mold either, so I thought I would share a few pix from the process....
The boat windshield starts out as a FLAT sheet. A rectangle that fits the outline of the finished windshield if you could lay it out flat. Now, when the plexiglas is heated up to forming temperature, about 350F, the material will SHRINK about 2%. But according to the laws of expansion and contraction, the material will also EXPAND when heated. So a fabricator has to be a bit of an artist to attempt this particular job.
But wait - there is no mold. Or is there? Our man Bryan has decided to use the OLD windshield as a mold. It's not a perfect mold - if you lay the heated plexiglass OVER the old windshield, the new one will be slightly bigger. Using the inside as a mold will result in a windshield that is smaller. We decided to use the outside as a mold and then use a heat gun to wrap the sides after the windshield has cooled - a secondary operation.
The end result? A perfect match - new for old - and the new windshield is masked to protect it on its journey back to its owner.
Posted by Plastic Genius at 8:10 PM