SHOP NOTES A workshop air filter

EASY WAYS TO DO HARD THINGS

WHEN IT GETS COOL, the amount of workshop time spent with the garage door down is going to increase. That means more sawdust and other particulates in the air and your lungs. Reader Larry Brannock has a solution: a box fan rigged with a furnace filter. Brannock simply duct-tapes the filter to the back of the fan – a common size for both is 50 centimetres square. Placed as close as possible to the source of dust, his device traps the bad stuff and outputs clean air. One thing to keep in mind: the higher the rating of the filter, the harder the fan will have to work to pull air through.

A TIP FOR SPRAY-PAINTING FASTENERS

If you find yourself spray-painting a batch of fasteners, poke their shanks through a piece of cardboard so they stand like lollipops on a candy-store counter. This allows you to easily coat all surfaces in one pass with the paint can. NAIL POLISH REMOVER REMOVES OTHER THINGS For spot treatment in a minor mishap – like touch-up paint that has dripped on a door hinge – acetone nail polish remover can help. Use it to dampen a rag, then hold the rag briefly against the splotch before rubbing it clean.

LIP BALM WHEN THE WEATHER TURNS Lip-ice isn’t only for lips: apply it to seams on tents, shoes, or packs for temporary waterproofing. Rubbed into the teeth of Ziploc bags or the threads of jars, it gives them insurance against water penetration, too.

FIX THE ONE THING DUCT TAPE CAN’T If there is a problem with duct tape, it’s that rolls of it take up a lot of space – carrying it in a backpack or glove box can be a hassle. Alleviate this problem with mini-rolls made by wrapping a short length of two or three metres around another useful item, like a pencil or AA battery.

How to read resistors

Manufacturers indicate the rating of a resistor with colour bands. Each band represents an input for a complicated formula. Here’s how it works for a fourband resistor: 1. The first two stripes represent digits (see chart, below). String them together. If stripes are yellow and violet, start with 47. 2. The third stripe is a multiplier. Its product with the digits is the resistance rating. In the example, an orange multiplier stripe (1 000) means the rating is 47 000 ohms. 3. The tolerance stripe indicates how much performance may vary in practice.

Note: On five-band resistors, the first three stripes are digits. Everything else is the same. The rare six-band resistor has an additional stripe that rates the resistor’s performance as its temperature changes.

HOMEMADE BIRD FEEDER

A cheap but effective bird feeder can be quickly constructed from an old pan. Cut a half-moon of wire mesh w with a diameter slightly larger than the mouth of the pan. Fix the mesh to the pan with a bit of solder, leaving the top half of the pan open. Remove the handle and nail the bottom to a tree. Use the opening to fill the feeder with suet or other bird food that won’t fall through the mesh. PM