You are not Logged In! -- Please consider creating an account. (It's free!)
This is the BETA version of the Articles Library -- Expect occasional bugs -- Report them to Daemon_Lotos => [Here]
[ Articles Home | Newest Articles | Submit an Article ]
[ Random Article | Search Articles ]

Spot Welding Maille: A How To
Article © MAIL User: Freyr

As of January 12, 2010: PLEASE NOTE THIS IS CURRENTLY A WORK IN PROGRESS. IF YOU HAVE SUGGESTIONS REGARDING CONTENT, CLARITY OF INSTRUCTION OR PHOTOS YOU WISH TO SEE INCLUDED PLEASE LET ME KNOW ON THE FORUMS UNDER ARTICLES DISCUSSION IN THIS THREAD



DISCLAIMER: I am not responsible for any harm that comes from these instructions. If you do not understand what you're doing it is on your shoulders. All actions taken are the sole responsibility of the individual person taking them.

(The fact I have to put this in irks me)



This article is for people who wish to use a commercially available spot welder to make armour using round wire. It involves mostly how to ramp back the power enough to not instantly fry your links in addition to some discussion on technique and principles of the weld itself. If you are using a home made welder from an old transformer you can still use this article for technique and power control just keep in mind I'm basing technique on standard sheet metal jaws of commercial units (so you can rig up something along those lines and it'll be more or less the same).

This article is broken down into the following parts:

1) Welder modification

2) Ramping back the power

3) Technique discussion


For the safety conscious and those with no common sense. WEAR SAFETY GLASSES WHEN WELDING. Gloves also might be a smart idea. Non-flammable ones.


1) WELDER MODIFICATION

First up you'll need to get yourself a spot welder. Ebay is a great source of these for about $150-200 new or possibly cheaper if used. You don't need something top of the line for this since power output is not an issue for us. Quite the opposite is our problem unless you're making some seriously massive maille. Also make sure it’s the same voltage as your household (in North America 110v; in much of the rest of the world it's 220v).

Steps involved for modifying the welder:

Materials:

- 1 110v spot welder (many are 220v; make sure you don't get one of these unless that’s what your household current is)

- 1-7 metal file(s) (depending on how many you have laying around with no teeth on them)

- 1 pinup calendar

Steps:

1) File the tips of the jaws down to about 5/64-1/8"(2-3mm) or so in diameter. This is to give enough room to rest the ring on. If you feel you can get away with less do it as you can always file it down later (and if you fuse the jaws together, which you probably will at some point, you'll have to).

2) File a shallow V-groove in the ends of the jaws using a triangular file. MAKE SURE YOU DON'T GO TOO DEEP!!! Going too deep will result in the V completely surrounding the link and you'll get a copper on copper contact, which will fuse your electrodes. So best way to do this is to cut just a little and stick a butted link in there to see if it kicks out when you clamp the jaws down on it. Keep trying it until it sits firmly in the groove (it really does take barely any groove to do this). Try to keep it even and make sure the top and bottom grooves are parallel to each other.

Note: On this step you may find your jaws don't line up perfectly. The adjustment for this is where the jaws clamp into the spot welder. Just loosen the bolts slightly and turn the arm of the jaw to where it needs to be (check to see if you have them lined up vertically from the front). Make sure you don't loosen it too much since many spot welders clamp the wires going to the welding jaws in the same clamp and they can fall loose, which is a pain to fix some days.

3) Install the pin-up calendar in your workplace in an easily viewable area. (your wife will have to let you...it's in the instructions...and you're reading them!!...extra points!)

Your welder should now be good to weld maille. If you're anxious you can try and weld a few links this way to see what happens. I find you can't let off the switch fast enough to get a good weld and you'll likely fuse your jaws when you try for the first time. To separate fused jaws I found what works best is side cutters. Just stick the edges of the blades right in the joint and squeeze. Should pop right apart.

2) RAMPING BACK THE POWER

Moving on to the semi-hard part. Your welder will have far too much power to consistently weld good maille so we're going to have to come up with something to ramp back the power. Now personally I used 4 light dimmer switches hooked up in parallel to do this (if you’re an electrician you just cringed), which is not recommended. I rigged this up without first understanding how dimmer switches in the modern day work and lucked out it seems. I have a theory as to why this worked but we're going to go through some more intelligent ways of doing this.

PLEASE NOTE THAT I HAVE NOT TRIED THESE TWO METHODS PERSONALLY SO ANY ISSUES THAT ARISE PLEASE LET ME KNOW SO I CAN UPDATE/FIX THE INSTRUCTIONS. I WILL BE TRYING THE DIODE METHOD SOON, HOWEVER I DO NOT HAVE THE RESOURCES TO CONFIRM THE FAN CONTROLLER METHOD AT THIS TIME. (Jan/2010)

SAFETY NOTE: I'm not an electrician. Likely you aren't either. Don't screw with this stuff if you don't have the first clue about what your doing. Also make sure the wire used is rated for a standard household outlet in your country. This one is written for North America, which runs standard 110V 15A circuits in households.

Method 1: Using an electric motor controller or Variac

First method up is the dimmer switch technique, and no not the one I used. This one is simply taking what is effectively a 15amp dimmer switch designed for fans or motors and wiring it into the circuit. Finding these can be tough, however I've found several on Amazon.com for around $50-60. These can easily get expensive ($100+) so shop around a bit. Alternatively you can use a <a href=http://en.wikipedia.org/wiki/Autotransformer>Variac</a> in place of the electric motor controller which would actually be better. Variacs are expensive new so I would browse Ebay for one.

Materials

- 1 15A 110V electric motor control or Variac (if using a Variac see step 1A)
- 1 electrical box to mount the switch in (this will change in style depending on the size of the controller)
- 2 lengths of 14ga three strand (+/- and ground) insulated copper wire (about 3' (1m) each)
-1 set of male/female electrical plugs (available at most/all hardware stores)
- Some screw connectors (for connecting 2 wires)
- Screwdriver
- Wire stripper or knife

Steps

1A) If your using a portable Variac you're done. Plug your welder into it and have fun! If your using an uncased Variac you have a bit more work ahead of you as you need to build a case for it and then wire it into the circuit. This will not be covered in this article so you will need to seek outside advice on how best to do this (most will need a custom approach so its just easier to deal with case by case).

1B) If you're using the fan controller run one wire into each the electrical box that will house the controller and then cut back the outer insulation back about an inch or so (2-2.5cm) to free up the individual wires. Remove the cut insulation.
Note: Be sure not to cut the insulation on the individual wires.

2) Cut the insulation back about a half-inch (1cm) on each of the individual wires and remove it.

3A) If there are wires coming out of the controller connect them to either the black or white wires using the screw connectors depending on what the instructions that come with the controller state. If no instructions come with the controller just pick one color of wire and go with it since its an AC current (the current changes direction at 60hz so direction of the current doesn't really matter).

3B) If there are screw connectors on your controller form a hook on the ends of the wires that will fit nicely under the head of the connection screws on the dimmer switch itself and then wire them in place. Be sure to have the wire running in a clockwise direction around the screw so that it pulls the wire into the screw as you tighten it. Once again which wire to use is determined by either the instructions that come with the switch or by just selecting one of the wires if no instructions are available.

4) If there is a ground directly on the switch connect the ground wire to it. The ground wire is usually bare copper or it will have green insulation on it (Note: convention is usually green = ground). If there is no connection for a ground on the controller then connect it the electrical box, which will house the controller. The ground connects to two screws usually in the bottom of the box, one wire to each screw (for the two wires entering the box).

5) Connect the remaining input/output wire using a screw cap.

6) Screw down the wires in the box using the clamps where they enter the box. DO NOT OVER TIGHTEN! This will cut the insulation on the wire and you'll have a short. I've done this before and it's not fun. The clamps should only be tightened to the point where a firm pull on the wire does not pull the wire out.

7) Mount your controller in the box and screw it down.

8) Connect the male/female plug ends to the input/output wires (doesn't matter which end they go on). To do this, first unscrew the screws in the face of the plug to remove the back of the plug. Cut the outer insulation that holds the wires together back a few inches (3-4cm) to give yourself enough room to connect the individual wires to each screw. Next cut the insulation on the individual wires back about a half-inch (1cm) and bend the ends of the wire into small hooks. The hooks should be sized as to fit snug beneath the screw head. Run the whole wire through the removed back (this contains a clamp which may need loosening first). Next we need to connect the wire to the screws, which are color coded so you know where each wire goes where. Black to brass, white to white, and ground to green. Now position the first wire so that the hook runs clockwise around the screw hole and screw it in place. Do this for the other two wires. Now screw the front and back of the plug back together followed by tightening the clamp on the back of the plug. Only tighten the clamp to the point where you don't pull the wires out with a firm pull.

9) Test the unit out by plugging it into the wall. If there is a short in your system you just blew the breaker. Unplug the unit and go back through it and try to find the short. Its usually at a connection where there is some bare wire sticking out or else in one of the clamps if its too tight and cut the insulation on the wire (look for black marks/burnt insulation). Repair it and try again.

Congratulations! You now have a functioning (hopefully) unit with which to control your spot welder's power. Just plug your welder into this unit and you should be able to fully adjust its power.

Method 2: Cutting power using a diode

This method involves using a diode to cut the sine wave of an AC current in half. It does not have the variability that a fan controller or Variac would have, however is cheap and easy to make. Likely your spot welder will still have almost too much power but it will be far more controlled of a weld than not using one of these.

Materials

- 110v 15amp rated diode (or higher)
- 2 lengths of 14ga three strand (+/- and ground) insulated copper wire (about 3' (1m) each)
-1 set of male/female electrical plugs (available at most/all hardware stores)
-1 electrical junction box and matching cover
- Screw connectors (for connecting wire)
-Screwdriver
-Soldering iron/solder/flux
- Electrical tape and heat shrink tubing if you have it.

Steps

1) Run the two lengths of wire into the junction box.

2) Strip the last few inches (2-4cm) of outer insulation off of the wires to expose the individually insulated wires.

3) Strip the last half-inch (1cm) of insulation off of each wire.

4) If you have heat shrink tubing now would be a good time to put some on each of the wires you wish to solder the diode to. Pick EITHER the black or the white wires and solder them to the diode's connection points. One wire to each point.

5) When the solder joints are cool, insulate them with the heat shrink tubing or electrical tape so that no bare wire is showing.

6) Use a screw connector to connect the remaining wire to its counterpart (Black or white…whichever you didn't use in #4).

7) Connect the ground wires (bare wire or green insulated) to the ground screws on the bottom of the junction box, one wire to each screw (there should be 2 or more that you can use). To connect a wire to a screw first strip the last half inch (1cm) of insulation off the wire. Next form a small hook with the bare wire that will fit around the screw nicely and screw it in place. Be sure to have the wire running clockwise around the screw as if you do not it will force the wire out from under the screw.

8) Draw the wires and diode into the junction box so that they fit nicely and clamp the wires in place where they enter the junction box. Be sure to not tighten the clamps too much or you will cut the insulation on the wire and short it. Just tight enough so that a firm pull does not pull on the wires inside the box.

9) Screw the faceplate for the box in place.

10) Connect the male/female plug ends to the input/output wires (doesn't matter which end they go on). To do this, first unscrew the screws in the face of the plug to remove the back of the plug. Cut the outer insulation that holds the wires together back a few inches (3-4cm) to give yourself enough room to connect the individual wires to each screw. Next cut the insulation on the individual wires back about a half-inch (1cm) and bend the ends of the wire into small hooks. The hooks should be sized as to fit snug beneath the screw head. Run the whole wire through the removed back (this contains a clamp which may need loosening first). Next we need to connect the wire to the screws, which are color coded so you know where each wire goes where. Black to brass, white to white, and ground to green. Now position the first wire so that the hook runs clockwise around the screw hole and screw it in place. Do this for the other two wires. Now screw the front and back of the plug back together followed by tightening the clamp on the back of the plug. Only tighten the clamp to the point where you don't pull the wires out with a firm pull.

11) Now you should have what appears to be a mini extension cord with a junction box in the middle of it. Plug it in to test it (be sure NOT to have your welder hooked up). If the breaker blew you have a short, go back through your connections and wiring and look for bare wires that could have caused this. Check to make sure your clamps didn't cut the wire and look for black marks to indicate where the short occurred.

Now all you have left to do is try it with your welder. Plug in your welder to this unit and it should drop the power by half of what it would have normally. Have fun welding with this unit!

3) TECHNIQUE DISCUSSION

Cutting rings

First off, the way this set up is designed to weld is with overlap of the ring. I find about 1/16" or so makes for decent welds and not too much "squish". To get this you can either cut the rings with an overlap or if your not concerned with the "perfect" ring you can just cut normally and overlap them when you close it. Your choice really since the functionality of the maille is not affected and usually there isn't much deformity.

Alternatively you can use about 1/8" overlap or some combination of the two and do a full on weld. Using more overlap is easier to weld by far, but does not look as nice. It’s a trade off really: easy, fast, and reliable vs. harder and less reliable. All comes down to preference.

Also, I've only welded down to 16ga(1.6mm) wire with this rig. 18ga(1.2mm) is likely possible however it would be highly dependent on whether or not there is enough space between the electrodes for them to not short directly to each other. Anything smaller…well that’s up to you guys to figure out.

Welding rings

Now on to the fun part. Welding the rings is by no means a set process. Time the weld takes varies greatly (1-2 seconds) and is dependent on size of the wire and amount of overlap to the weld. The way to tell when a weld is done is that you'll feel the ends of the ring sink into each other. When flush can be hard to judge as I know I have a tendency to let off the power too soon and get not quite completely melded ends. The weld is still extremely strong and functional, but doesn’t look as nice. Tumbling the piece may remove some/much of this squish out in addition to smoothing it off so it doesn't look as bad or snag as much.

One thing I started doing is having minimal overlap so that the ring sits at a slight angle in the jaws, which allows the ends to melt into each other at more of an angle. What happens is that when the joint heats up, since its sitting at an angle the ends don't melt flat into each other but rather skid off each other a bit to form a less ugly joint. Getting it right is harder but it looks better. Too little overlap and the jaws will just force the ends past each other before they are at welding temperature.

Setting your power right is critical. You want it to weld fairly fast but under control and to not get too hot. If you get a spark or anything ejected from the weld it is buggered (look close there is now a little hole in the weld and its brittle) as when spot welding you don't actually want to melt the metal. It is much more of a forge welding process which involves heating the metal to the point where the crystal structure expands enough to allow the second piece to merge with it (sort of "pressure melting" at the contact point). If the metal melts and becomes a liquid it has a tendency to be violently ejected from the weld because of the electrical current running through it and various magnetic fields being generated. For more info look up "rail guns" as it’s a similar process.

I also recommend either welding every ring as you put them in or else doing a row and then welding since welding in the pattern could quickly become difficult. I personally find it easiest to weld every ring and therefore don't accidentally miss any.

Metal type

Spot welders are designed to weld base metals (steels specifically) with low conductance relative to copper. Welding copper and its alloys may be difficult and unreliable with this welder. I've never tried it so I'm not sure. (Looking at weldedchainmail.com though Knuut does silicon bronze so I guess at least that is possible.)

If you're trying to weld reactive metals such as aluminum and titanium your probably going to need an inert gas as shielding (argon). I know Knuut at Weldedchainmail.com does titanium but I'm unsure of aluminum.
Original URL: http://www.mailleartisans.org/articles/articledisplay.php?key=573