Bob,
I made lenses to cover my inset nav lights.
I made a female mold of the area extending beyond the actual area, carefully cut
away the section of the wing tip that I was going to replace with a clear lens,
dropped that section into the mold and scribed a line in the mold above the edge
of the cut out part.
I cut the mold down to about 1/2" above the scribed line and bondoed(sp?) legs
on the mold to support it so that I has a 'trough'(mold) that sat horizontally
on the table. In the bottom I drilled a small hole 3/16"? and then bondoed a
hose barb fitting onto the bottom of the mold assembly. I was worried about the
hole creating an imperfection, but you don't get the plexi that hot, it never
showed.)
I welded up a small angle iron frame about 2" larger in all directions than the
top of the mold and made a second frame that fit into the first in the opposite
direction. The plexi goes between the two frames and then goes in the oven.
When held in place by metal spring clames I got sufficient grip around the
circumference of the frames. The clamps also work well to support the assembly
on wood blocks in the oven.
I found that 340 degrees F works well. The plexi starts to smoke, so have a
vent on.
Place the hot filmy plexi over the mold and using a good canister vacuume at
pretty much full suction, and through the hose barb draw the part into the mold.
You'll likely have to make a 'step down' adapter. I used a PVC pipe end cap
that I drilled a hole in for a corresponding hose barb and then duct taped the
end cap to the end of one of the vacuume's extension tubes.
Mark the part where the scribe lines are in the mold and cut the excess away,
and trim and fit. It will be a little difficult to mark the scribed line
exactly due to parallax when viewing through the plexi, but the trim and fit
doesn't take too long.
I had to make a corresponding insert in each wing on which to mount the nav
light and have tabs into which the lens could be screwed. I formed this up out
of aluminum, but we'll save that for another edition.
Cleve Lee
A198 Mono XS Jabiru 3300 Detroit MI
Fuselage bonded, filling and sanding control surfaces, panel built but not
wired. 800 hrs with only 6 done last year!
The ALL NEW CS2000 from CompuServe
Better! Faster! More Powerful!
250 FREE hours! Sign-on Now!
http://www.compuserve.com/trycsrv/cs2000/webmail/
|