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Interesting article:
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Members of the East Bay Amateur Radio Club and UC Berkeley’s radio club are teaming up to launch a high-altitude balloon to near-space, and they are inviting the public to come track its journey.
http://www.berkeleyside.com/2017/03/16/amateur-radio-groups-send-balloon-stratosphere-back/
The Elecraft folks have a very nice Soldering Tips document that will provide some additional soldering guidelines. The end of the document includes a list of recommended solders from a variety of sources. Also noteworthy is their list of solders types to avoid.
While building or repairing an electronic Circuit Card Assembly (CCA) you may have to remove and replace a soldered component. Commercial tools exist that make this process easier but a good job can be done with limited resources.
A spool of a good quality Solder Wick is almost a must for your toolbox. Good ones will employ a tightly woven braid of copper with a built in flux. The braid is positioned over the lead solder joint and use your soldering iron to heat the back side of the solder wick. Limit the time that heat is applied to just a second or two. Re-position to a new unused section of the solder wick if necessary. You can trim off the used portion of the solder wick braid using a good wire cutter.
NOTE: a small amount of solder will always remain on the joint, but the lead can often be freed by gently wiggling it with needle nose pliers.
Low cost mechanical Vacuum desoldering tools will also work. These involve a spring loaded plunger that “loads” the device for use. A button releases the plunger to produce the sudden vacuum force and draw in any liquid solder located beneath the tool tip.
Pushing the plunger mechanism all the way in will allow most of the solder taken into the tool to be ejected from the vacuum chamber.
WARNING: Two types of plunger mechanisms exist: One design can allow the plunger arm to retract rapidly and strike the user in the eye or face, the other provides a shield around the plunger handle to improve safety.
A set of Dental Picks or thin metal scribe tool made of Stainless Steel can be very useful. Stainless Steel will resist the bonding with the liquid solder and can be very helpful in clearing unwanted solder from thru holes. The hole is quickly heated to melt the solder and the small stainless steel tip is lightly inserted into the hole to help displace the unwanted solder while the soldering iron is taken away. The solder should re solidify quickly and then the stainless steel probe can be removed.
Note: A stainless steel SAFETY PIN can also be used in a pinch – Just be careful not to stab yourself with that very sharp pointed tip.
You may want to practice some with an old SCRAP board to help develop a feel for this and help refine your soldering and desoldering skills.
Stainless Steel dental tools or scribe can also be helpful when working with installing or removing surface mount components. Because stainless resists the solder the tool can be used to help hold or position the surface mount component while soldering. When working with a surface mount resistor or capacitor, simply apply solder first to only one of the component pads. Position the part on the board and use the stainless steel tool to hold it in place while reheating the solder you previously added. Remove the iron, and allow the solder to solidify before soldering the other side of the component.
CAUTION: good control of the stainless steel tool is required if you wish to avoid an unexpected game of Tiddlywinks and being forced to try and find where the part was launched to. Extremely small surface mount parts will give you the greatest challenge.
Mike
Hi Ed,
ESD wrist straps and mats are used to bleed off static charges and bring all items to a common level. Large current spikes will puncture and damage static sensitive electronic components. The usual method to safely reduce the static charge and limit the discharge current spike will usually use a wrist strap with a cord containing an in-line resistance between 1 – 10 Meg Ohms attached to the common ground point.
A useful online video about ESD can be found on youtube: How to Avoid ESD Damage (Official Dell Tech Support) this should give you a good practical down to earth information that your looking for and help avoid some of the more serious pitfalls. For a little more in depth explanation you might try watching: Funny video on ESD by Apple.
Some ESD wrist straps are all metal (like a watch band), and some will use an elastic band with built in metal contact points or similar conductive materials. Note: The wrist strap should be supplied with a has an embedded 1Mohm resistor in the lead (usually potted into the cable near the banana plug end).
WARNING: You must Not wear an ESD strap if attempting to troubleshoot an energized circuit with maximum voltage over 500VDC.
As always, take off rings and watches to minimize risks.
Good online sources for wrist straps would be places like Digikey, Newark, Mouser etc. Here is and example of a low cost one that Digikey can supply.
Hope this helps…
I’m recently retired from the computer industry but we used conductive mats on the work-surface that were grounded to the green wire in the closest power outlet. A wrist-strap was attached to my wrist with a conductive wire to the same ground point. That pretty much eliminated any static problems but it may be a bit pricy for the average ham. You could of course provide similar protection by cobbling together similar stuff from what you have hanging around.
I also put a conductive pad under my work chair. I found that the fiberglass wheels on my chair would build up a charge when rolled across the nylon carpet in my office. I fried a bunch of stuff even with a conductive wrist-strap until I figured out what was going on.
Increasing the humidity in the work-area is also a good precaution. Something as simple as a tea-pot would work. I have a whole-house humidifier in my home and don’t have a problem with static as a result.
Rich – KE1EV
I typically never worry about ESD as the parts I work with are easily replaced and cheap.
I do my work in my basement with the wood stove going and handle microcontrollers etc. without any wrist strap or anything.
I do however get a nice shock every time I get up and open the damper on the wood stove to add more wood!
Mike (AB1YK)
Ed — Don’t use rubber gloves. Rubber, like most insulators, can itself hold a static charge of thousands of volts (think of the plastic tv screen on older CRT’S).
Best for you and me at home is to use a wrist strap which has a ground cable attached. This will safely bleed off any charge on your hand and arm sufficiently to handle ESD sensitive items. The wrist strap cable will have enough resistance so that the charge is bled off slowly from whatever you come in contact with. Keep in mind, the board or component itself may have a charge considerable different than you so and you don’t want a discharge to occur from it to you either. The wrist strap will prevent any damaging discharges.
Lost of sources for wrist straps on line most under $10.00 and overnight delivery from Amazon.
Companies handling lots of ESD sensitive items of course have grounded work benches, often with ionizers, ground mats, esd clothes, shoes, carpets, etc…. Most consumers won’t be able to go that far.
Personally, I’ve handle lots of ESD sensitive boards and components (at home) with just the wrist strap and have had no problems.
Mike H.
K1VLB
Hi Ed,
Unless the gloves are ESD compliant, you should always assume NO.
Most of the time when you see people using gloves, the intent is to protect the product from DNA contaminating a board or product.
Static electricity can be stored on any external surface. Gloves too.
Built into the grounding cable, the mat will have a 1Meg resistor in series to ground. The mat protects the product when it is being serviced. The mat will not discharge the static you’ve generated sufficiently unless you are grounded by an actual wrist strap. That usually gets connected at the mat connector block.
Winter is the worst for ESD damage if the area is not humidity controlled to roughly or at least 40%. You can still generate a charge. You can also still create static electricity even in the summer, although less of a charge. Damage doesn’t always show up right away. It can show up at any time down the road (latent damage?). Many times you will not see it until later.
I’m not an expert, but I work in a facility where static discharge prevention is very important.
Just for FYI reference (It’s just the Desco version, but you can, and should check out other sources!):
https://www.youtube.com/watch?v=7T5JgdhTi_s
https://www.youtube.com/watch?v=yZPPytNpkOM
https://www.youtube.com/watch?v=WWtyro49iZo
https://www.youtube.com/watch?v=T2kZHSDOOCQ
https://www.youtube.com/watch?v=op-fPgKnTg0
https://www.youtube.com/watch?v=nLS4SyLkq6c
John, N1ERF
What’s John going to do with all the donuts? Eat them? Save them for the next meeting? Donate them to PART? The possibilities are endless.