The Planted Tank Forum - View Single Post - Convert Lux meter to PAR meter?
View Single Post
post #42 of (permalink) Old 06-21-2012, 04:44 PM Thread Starter
Planted Tank Guru
Hoppy's Avatar
Join Date: Dec 2005
Location: Sacramento, CA
Posts: 19,675
Originally Posted by audioaficionado View Post
How do you prevent the solvent glue from melting and clearing up the frosted surface of the half sphere?
That was a problem. Weld On #16 is pretty viscous, so it doesn't flow like the almost pure solven glues do. I put a bead of the glue over the end of the tube, working as fast as I could to beat the time it takes for it to skin over. Then I grabbed the half sphere and quickly put it in place (about 1/64" off, but that isn't a problem). The glue didn't run, and grabbed the pieces quickly. After about 5 minutes I ran a bead of glue around the joint, and let that cure for 30 minutes, then ran another bead. After an hour I tested it by weighting it with a fingernail clipper and stuck it into a glass of water. I checked for water inside every half hour or so. No leaks!

I knew this part was going to be difficult, so I bought 3 of the half spheres (45 cents apiece). I was lucky to make it work in two tries.

It is interesting to see what the optical effect of a half sphere is. It seems to act as a lens, as it has to, but it collects light over a large area and concentrates it into a circle about half the diameter of the sphere. With the flat side frosted it diffuses the light so there is just barely an image visible through it.

Hoppy is offline  
For the best viewing experience please update your browser to Google Chrome