I've been buying my birch plywood from sloans:
http://www.sloanswoodshop.com/plywoods.htm
As for watts, a watt is a term of measuring energy and comes in many different forms.
In electrical terms a watt is 1 volt potential across a resistive load drawing one amp.
For other uses it is calculated as one joule per second.
You can boil water and the steam generated can be measured in thermal watts. The energy required to lift a weight off the floor can be measured in watts.
A typical glass laser tube might require 200 watts of high voltage to get out 40 watts of optical power. And that 200 watts of electrical power might come from a power supply with 75% efficiency and require 265 watts of AC power from the wall.
That's just an example. I have no idea of the efficiency of your power supply or the power required by your laser tube to generate it's output. The point is that you will not be able to judge optical output power based on measuring input electrical power. |