Spectralon Panel Care

Panel Storage (As of 03/24/03)

            All of the 4-8 inch panels are stored in the sturdy card board boxes with internal padding provided by Li-cor. There are two 10 inch panels that have metal covers. Each both is marked with pen as to the panels stored inside. Each box is only capable of storing a 5 inch and a 6 inch panel with out stacking. One box holds two 8 inch panels that are stacked. There is a set of paraffin gloves stored with the 6 inch Do and 5 inch 99 % panel.

There is also one more 99 % panel available that has been cleaned and fixed and is ready for field use.

Supplies for Panel Care:

1.)    200-220 grit wet sandpaper (to sand all panels, two packets of paper is needed).

2.)    Duct tape.

3.)    Small Phillips screw driver & small allen wrench.

4.)    Deionized water (2-4 liters for all panels).

5.)    Rectangular/circular vibrating sander (only if panel needs significant sanding).

6.)    Clean protective gloves.

Process for Panel Care

Assessment (all panels)

            Each panel should be inspected for height of spectralon material above metal siding of spectralon tray. A few panels have reached the thickness where they need to be removed from the panel tray to be sanded. Check all spectralon panels for impact dents, scratches, and general roughness. If a panel is thick enough to be sanded in the tray but has a deep impact it may still have to be removed from its tray to complete sanding. When in the process of sanding, inspect the panels regularly by blowing off the surface and visually inspecting the panel at different angles. This method insures excess specralon material build up is removed from obscuring dents or holes in the panel.

Technique Part 1 (sandpaper)

            Sand paper should be keep wet with deionized water on the surface while sanding all panels. Inspect sand paper for points of spectralon build up every 20-30 seconds. If build up occurs it can create a smooth shiny spot on the panel and also create another indent. Light pressure and a scratching motion with a screw driver or a fingernail is sufficient to remove buildup spots. Be sure to completely remove excess build up so only sandpaper remains otherwise build up will occur rapidly again. Plain water can be used to wash off spectralon material and clean the surface of the paper. Deionized water should be used again as final rinse and wetting before continuing sanding. Full sheets of sandpaper are best to use and should be place on a very flat surface. The black counter top at Robbins 208 is ideal for the placement of sand paper. The sandpaper should be butted up against the sink to provide easy wash off and excess panel material removal.

Technique Part 2 (sanding per panel size).

The round spectral panels for the Cary are small and can be sanded easily. Duct tape the edges of the sandpaper down, wet the surface of the sandpaper with Deionized water, and apply light, even pressure at the back of the spectralon panel while making a circular pattern on the sandpaper. For best results change the circular pattern from clockwise to counter clock wise or vice versa. Keep an eye on the height of the spectralon material above the metal tray it sits in. Do not use your hands or any other material to wipe off spectralon dust. Use canned air to blow off water and dust then wipe down the back of the panel tray with a clean rag. The spectralon is highly hydrophobic. Water and dust are therefore easily removed with air.

Four inch and five inch panels can be sanded either with or without their metal trays depending on the height of spectralon material above the tray edges. For either situation a flat palm with light even pressure on the back of the panel is adequate to achieve a smooth flat finish on the surface of the panel. However when sanding any panel with out the metal tray use fresh clean protective gloves to prevent hand oils from entering the spectralon material. Sand four and five inch panels with a back and forth movement; rotating the panels one quarter turn every 10-15 strokes. This action helps to keep the surface of the panel uniform and flat. When dirt and dents are eliminated blow off the panel and clean the sand paper of all excess spectralon material and any points of spectralon build up.

Eight and ten inch panels must either be sanded in their metal trays or if taken out a very flat backing may be used to provide even flat pressure on the panel. If large scratches and dents exist in the panels then an electric vibrating/circular sander can be used to remove large amounts of spectralon material. The sander, despite its flat bottom creates an uneven panel surface. Machine sand half to three quarters of the dent depth and then switch to hand sanding. Use the same method of sanding as used with the four and five inch panels. These larger panels tend to sand more quickly in the middle of all edges from machine sanding. After switching to manual sanding inspect the surface of the panel regularly specifically looking for surface patterns that indicate the entire panel surface is being sanded at once. This indicates high spots have been removed and the panel is once again very flat and ready for use.