By Daniel Bartlett View In Digital Edition
Safety, Rarity, Quality, Wick, Diversity, and Storage
So, you want to fill your hobby electronics drawers with parts galore and don’t have the money to start? Well, worry no more, as I am about to teach you how to scrounge for those parts.
To scrounge is to forage about in an effort to acquire something at no cost, and this process can be very easily adapted to electronics as a result of the myriad of broken appliances we find due to the advent of the throw-away society. Computers, televisions, radios, car consoles, you name it — we throw it away. Therefore, electronics hobbyists can have a field day getting many normally expensive parts at little or no cost. However, there are a few “rules” to scrounging, some of which are for your own safety and others that will save you a lot of unnecessary time and effort.
Rule 1: Anything acquired by scrounging is to be considered broken and electrically hazardous. Never plug into electricity any item that you have scrounged (from whatever source) unless you know exactly what you are doing; better yet, don’t do it at all. These items were thrown away for a reason and have the potential to electrocute anyone silly enough to energize them.
Also, take note of the fact that capacitors store charges and have the potential (literally) to give you a belting if you touch them or the circuit. Safe discharge of these devices can be completed through the use of an electrically insulated (1,000-plus-volt) screwdriver or similar tool. Ask a qualified electrician for help in this area if you are unsure. One area that I would never dream of touching, by the way, is the back of a television picture tube. If the stored voltage isn’t enough to hurt you, the explosion when you drop it and release a pressure of 2,000-plus-psi surely will.
Rule 2: Only scrounge for rare or expensive parts or something that you know that you will need. There is no point desoldering four-cent, 1/4-watt resistors or standard, small-value, ceramic/monolithic capacitors, for example. You would pay more for solder wick and the electricity to run your soldering iron than you would for these parts. Instead, look for parts that may seem rare or are known to be more expensive, such as larger capacitors, Schottky diodes, pre-packaged diode bridges, microprocessors (Z80, EEPROM, PIC), relays, and even large switches. These parts can be worth $3.00-5.00 or more and are worth the time and effort to desolder them.
The least amount of time you can spend on an appliance the better, so you can re-throw it away and get on to the next one. Each appliance provides its own network of components; dwelling for too long on one appliance only creates clutter by hoarding (an unfortunate side effect of scrounging). Actually, one of the best ways to find out the value of any particular part is to just check the catalog from the manufacturer or yoiur favorite online supplier. Although many of these companies only sell common parts, the expensive ones can quite easily be identified.
Rule 3: Look for obvious signs of deterioration on any particular part. If a capacitor has burst and leaked all over the board, there is no point in scrounging it, as it will not work anyway. Other obvious signs of deterioration include burning/overheating (characterized by blackened areas and that smell), chemical damage (caused by leaking capacitors, batteries, or external fluids), water damage (obvious in itself), and physical breakage (if the appliance has been dropped, the board may have cracked in half, taking many components with it).
Much of this rule is simply common sense; if the component looks broken, it probably is. However, if you are unsure, there are measurement devices that you can build or purchase that will give you a better indication of the condition of a particular component. These devices include multimeters (especially those with a diode test function), transistor testers, capacitance leakage detectors, and others. Sometimes a part may look perfectly fine, but may, in fact, be faulty (for example, a transistor going open circuit). Measurement devices can help you in this regard, but only use them after following Rule 2; it has to be worth the trouble.
Rule 4: Invest in a roll of solder wick. Solder wick is a roll of braided material which “accepts” solder that is removed from a printed circuit board (PCB). I use the type made by Hakko® (www.hakko.com), manufacturers of solder wick in a range of thicknesses, from 0.6 to three mm. Solder wick effectively cleans solder away from the joint, therefore making the component in question much easier to remove. Because the heat is transferred to the wick itself, there is less of a chance of damaging a good part.
While on the topic of desoldering, you should remember that there are also a few rules when choosing a soldering iron, as the cheapest iron will often mean the destruction of many functioning parts. A cheaper soldering iron (of the $10.00 to $20.00, 25-watt variety, for example) will often have a tip much too big for delicate electronics work and, on the other side of the coin, have too little power to be used to solder large battery lugs and such. My advice is to spend a little more money on a soldering iron (even a soldering station), as a one-time $150.00 investment is much better than 20 $20.00 investments, especially over a number of years. I have experienced cheap solder tips degrading from heat only days after they have been purchased and it really isn’t worth the trouble.
Rule 5: Remember that “parts” aren’t the only things that can be scrounged from an appliance. Electrical appliances can be recycled in many ways. They have cases, knobs, dials, rubber feet, gauges, plugs, sockets, leads — you name it. These items are often much easier to remove, as they usually only involve the use of a screwdriver. These accessories can be used to repair other items of the same type or may even provide housings and personalization for projects of your own. Remember that cases do take up a lot of space, so be choosy and keep only what you think you’ll need. Rubber feet, knobs, and screws can be stored quite easily, as long as they are still in good condition (not destroyed by sun damage, for example), so take them out and keep them for a later date.
For those who have not delved into the world of scrounging before, try removing the smaller accessories first. Better yet, try removing them and putting the appliance back together again, as it is often a completely different experience altogether. If you can take something apart and successfully put it back together again, you may have reached the level of care needed to refrain from destroying delicate electronic components.
Rule 6: Store scrounged parts so that they can be found again. There is no use spending an hour or so unscrewing and desoldering parts and accessories from PCBs and the like if you can’t find them when you need them. To explain this further, if you put all of your parts into a big cardboard box, along with a mass of wires, you are wasting your time. Ensure that parts are stored in labeled containers (preferably stackable parts drawers, available quite inexpensively from hardware stores), so that they can be found with a quick glance. You can store them along with your purchased parts, of course, so label drawers with names like “resistors,” “diodes,” “relays,” and the like.
I consider this process follow-up. You get to know where your parts are, so you can find them in a matter of seconds, rather than a matter of terse hours. Also, storing parts in a neat and clean fashion has advantages other than easy recollection; it makes your garage or workshop look a lot neater, while keeping the “other half” happy.
I hope that you will take these few simple rules into mind next time you drag home for stripping your next dump-found broken appliance. They will make your life so much easier, I assure you, and you will save a lot of money. It may be easier to remember the quick version of the rules: safety, rarity, quality, wick, diversity, and storage.
Scrounging is a hobby in itself, but you should scrounge only for what you’ll really use. Please keep in mind that safety always comes first. Nothing is so important that you should take unnecessary risks! NV
When you recycle electronic parts to use in future projects, what equipment do you look for that yields the best or most useful parts? What simple rules of your own to help guide your "Scrounging" would you add to this list?
Join The Conversation!
