So you say you would like to build an Elecraft K2, or any other electronic kit for that matter.  But you have very little kit building experience or none at all.  The intent of this guide is to give you an overview of the basics that are necessary to successfully complete building a kit.

First, you must have the tools to insure proper construction and to ease the task so that it is an enjoyable experience rather then a chore.  In years gone by, building a kit was a way to save a significant amount of money and still wind up with a useful piece of equipment.  In today’s market, the monetary savings are not as big an incentive as being able to "homebrew" your own equipment.  Since the incentive is mostly enjoyment, we want to make the process as painless as possible.  For that reason I have included some tools in my recommended list that while they are not essential, they will certainly increase the enjoyment of the project.  Listed below is my Suggested List of Tools for Successful Kit Construction.  See photo 1.

  Variable temp. solder station (700 - 800 deg) like Weller 921ZX
        (Solder station should be ESD rated - grounded tip)
  Small diameter IC grade solder - Kester 62/36/2 - low residue
        (60/40 rosin core is an acceptable replacement)
  Solder sucker (ESD safe)
  Desoldering wick
  Magnifying visor
  Small lighted magnifying glass
  Conductive wrist strap
  Small diagonal cutters
  Small long nose pliers
  Small pair of tweezers (90 degree curved tip)
  Wire stripping tool
  Jewelers screwdrivers
  Assorted standard and philips screwdrivers
  Assorted plastic alignment tools
  PanaVice for holding the circuit boards while working on them
  DMM for measuring resistors, capacitors, voltage, etc.
  Parts tray - separate parts into groups - resistors, capacitors, etc.

  Use as much light as possible, the more the better

A 15-25 watt soldering iron is a suitable alternative to a solder station.  Also, if this is your first kit, you will probably not want to invest a large amount of money (typically over $100) in a soldering station until you determine that you will be building additional kits in the future.  The PanaVice is also a non-essential tool, however, it does a wonderful job of holding the boards while you stuff the parts and then solder them in place.  See photo 2.   The last item mentions using as much light as possible.  Identifying small parts is very difficult.  I recommend using a magnifying glass to read component values and tolerances.  Colors on resistors can easily be mistaken if insufficient light is available.  Installing an incorrect part value is a major cause of problems experienced when building kits.  Always use sufficient lighting and double check the component value before installing it. 

The Art of Soldering

Next, a word about soldering.  While soldering is not the most difficult task, your successful completion of a kit does require a certain proficiency in this area.   Improper soldering is a major cause of problems when kit building.  Cold solder joints, missing solder connections solder bridges, and components damaged by excessive heat are major causes of kits failing to perform properly.  Since the art of soldering is a major topic all by itself, I will not attempt to cover it in this guide.   An excellent paper on this topic is "THE BASIC SOLDERING GUIDE", written by Alan Winstanley.

The Step by Step Guide to Kit Building

I hope you have decided to give kit building a try.   If you do, the first step is to decide which kit to build.  Your first kit should be a relatively simple one that is recommended for beginners.  There are a number of kit suppliers from which to chose a kit of this type.  For a list of kit suppliers you can review the links page on this web site.  The kit suppliers are listed in the EQUIPMENT -  KITS category.  Companies like Kanga US and Ramsey have a number of kits that can be successfully completed by the beginner.

Okay, you decided to give it a try.  You picked out a kit, ordered it and it just arrived.  What to do next?  The first thing to do is to dig out the instructions and read through them very carefully.  Also, check to see if the manufacturer has included an errata sheet.  Do to the high cost of printing and the many improvements and corrections that are made to the kit designs, kit manufacturers can not reprint the instructions with each change.  Instead they provide an errata sheet with the latest corrections and enhancements.  Make sure that you mark any changes listed on the errata sheet on your set of instructions so that you don’t miss the changes when you are performing that particular step.

The next thing to do is to inventory the parts.   You can sort them using the parts tray that was on the list of suggested tools.   You want to make sure that you received all of the parts and that they are the proper values.  This step will also familiarize you with the parts so that you will be able to recognize the proper ones for each step of the instructions.  See photo 3.

Now, a word about ESD (Electrostatic Discharge).   Another cause of kit building problems is damage to static sensitive parts.   When handling CMOS chips or MOSFET transistors care must be taken so that the device is not damaged by static discharge (ESD). Several precautions that can be taken are:

The next step is to actually start construction of the kit.  Follow the directions very carefully in the order that they are listed.   Most kit manufacturers have a reason for listing the construction steps in a certain order.  This really becomes critical in kits that are designed around the build a section test a section concept.  With these kits you build a section of the project and then perform some tests that ensure that the section is working properly.   Obviously, if you do not follow the proper order of construction, it is very likely that the section to be tested will not perform as described.

Now you will begin to actually "stuff parts" on to the board.  I use the following procedure, which has kept me from installing components incorrectly.

1. Identify the part based on the value specified in the instructions and the component markings.
   
2. Measure the part value with a meter.  I use a DMM (Digital Multi-meter) that can measure the value of resistors, capacitors and inductors.  When building kits you should have a basic DMM.  These will only measure current, voltage and resistance.  In this case you will only be able to measure the value of resistors.
   
3. If you were unable to measure the component value, as described in the previous step, double check that you have selected the correct component.
   
4. Locate the position that the component is supposed to be installed in.
   
5. Bend the leads of the component to fit the hole spacing on the circuit board.  I use my small long nose pliers to make the bends.   With practice you will be able to judge where to hold the component lead to make a bend that will fit the hole spacing in the board.  In most cases the components should be mounted as close to the board as possible.  This is especially critical in circuits that operate at vhf and uhf frequencies and above, where lead length can contribute to stray capacitance that can affect the performance of the circuit.  The instructions will usually give you guidance how the components should be installed.  Example: resistors flush on the board, transistors 1/8 inch above the board, etc.
   
6. Install the component on the board and bend the leads on the bottom of the board to hold it in place.
   
7. Double check that you have put the component in the proper location.
   
8. In some cases the instructions will call for installing a number of components (example: 10 resistors) before doing any soldering.   It is always best to follow the instructions, however, I will sometimes solder after only stuffing 3 or 4 components on the board, otherwise, it becomes difficult to do the soldering with all of the leads sticking out of the bottom of the board.  If you do this you must be careful that the instructions were not having you wait to do the soldering because other components needed to be installed first.  This is where reading through the instructions before starting construction really helps.   Also, just before soldering a component lead, double check to see how its pad is located with respect to the rest of the board.  This will help you detect if you create a solder bridge (unwanted solder between two adjacent pads).
   
9. Solder one lead of a component to the pc board.
   
10. Check the component to make sure it has not moved and is still positioned on the board as described in step 5.  If it has moved, you will need to reheat the solder joint while applying pressure to the component to properly position it.  The component will get very hot, so you should be careful so you do not burn yourself.  If there is a danger of being burned, I will usually apply pressure to the part using a cloth or a folded piece of paper.
    
11. Solder the remaining leads of the component to the pc board.
    
12. Inspect the solder joints. They should look shinny, smooth and rounded without any voids. Double check that no solder bridges were formed.
    
13. Reheat any solder joints that did not look as described in the previous step.
    
14. Clip off the excess lead above the solder joint.

Always double check the solder joints and make sure you have not caused any solder bridges.

Just a quick comment about holding components in place while soldering.  Some components, such as IC’s, trimmers, connectors, etc don’t stay in place, even if you try to bend their leads. Also, I don’t like bending the leads of an IC.  For these components I use a piece of  tape to hold them in place on the top of the board while I solder one lead on the bottom of the board.  Then I check to make sure the component is positioned correctly.  If not, I reheat the soldered connection while applying pressure as I described previously in step 10.   When the component is positioned properly with one lead soldered in place, I remove the tape and then finish by soldering the other leads.

Once you reach the end of the construction phase you may need to do some circuit adjustments (alignment).  The instructions should walk you through this step.  If all has gone well you will reach the end of the project and it will be working properly.  Many of the kits provide a troubleshooting guide in the event that you experience problems.  There is usually a number that you can call to get technical assistance.  Some of the kit manufacturers are also providing support via the internet using e-mail and mail bulletin boards (reflectors).  This can be very useful for getting quick assistance if you experience problems.  If you experience the worst case scenario and the kit will not work, most manufacturers will repair it for an additional fee.  This is usually explained in the warranty section of the manual.

You will probably want to install your kit in a nice enclosure.  Many of the kits either come with an enclosure or one can be purchased at an additional cost.  If you would like to "roll your own", enclosures are available at your local Radio Shack store.

Now one final note about the appearance of the board. Standard rosin core solder leaves a residue after soldering.  This usually causes no problems. In fact some of the kit manufacturers advise against trying to clean the boards.  Solvents used for cleaning the residue can damage plastic components.   This is why I recommended the low residue solder in my list of suggested tools.   It leaves very little residue and makes the project look very professional.

I hope this guide will be useful and help you get through that first kit building experience.  There really is nothing quite like building your own equipment and experiencing that thrill when you tell the station you have just contacted that the equipment you are using is homebrew!

73,
Mike WT9W

 e-mail WT9W