Plastic Welding Gun (Plastruder MK4)

by donutman_2000, published

Plastic Welding Gun (Plastruder MK4) by donutman_2000 Sep 19, 2010

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Is your MK4 sitting unused and lonely since you\'ve upgraded to the MK5? Give it a new lease on life and turn it into a handheld welding gun! Use it to patch up any holes or loose threads in your prints or to glue broken plastic parts back together. You can see me welding the lid of a very poorly printed and particularly dangerous teapot shut to prevent accidental use.

The STL files include parts for a hand grip that slips over the DC motor, a finger guard so you don\'t burn yourself on the retainer washer, and a trigger bracket for a push button. SolidWorks 2010 model files are also included.


Assembly Instructions:

  1. Print out the hand grip, finger guard, and trigger bracket.
  2. Glue the finger guard into the slot in the hand grip flush with the bottom of the grip.
  3. Separate the DC motor wires with the black wire towards the back and red wire towards the front.
  4. Slip the hand grip over the DC motor with the black wire in between the slot in the back and the red wire through the slot in the front.
  5. Secure the hand grip to the motor using an M3x15 screw and M3 nut. Do not over-tighten the nut otherwise the tabs may crack.
  6. Insert a 1/4 in. push button through the hole in the trigger guard.
  7. Solder the red wire of the motor to one of the poles on the push button. Solder another length of wire to the other pole of the button. This will be connected to terminal 1A (+) on the extruder controller.
  8. Glue the trigger bracket onto the finger guard.
  9. Connect the black motor wire to terminal 1B (-) on the extruder controller.
  10. Connect the thermistor and heater wires to the extruder controller. You may need to lengthen the wires if you are connecting to an extruder controller mounted on/in your makerbot. If you have a spare extruder controller you can mount it directly to the MK4 and connect to the motherboard using a CAT5 cable, making it much more portable and interchangeable.


Open up the control panel in ReplicatorG and set the temperature to 220C. When the nozzle is at the right temperature, set the motor PWM to 255 and select \'forward\'. The motor will not turn until you push the trigger button, allowing you to control the extrusion manually. Be careful not to operate the motor until the nozzle is fully heated up, otherwise the filament may strip or the nozzle may break!

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id love this, how much is a plastruder?

I, for one, am planning to take my MK6 and make a gun thanks to this thing. I was first thinking how to rotate the extruder motor along the length of the pen and use a worm to feed the filament when I found this gun thing and figure the gun shape is quick and dirty. I'm going to try to eliminate the extruder controller. I'll simply get a 0.5rpm 12v geared motor that I'll voltage-adjust the speed and add a dial for the temperature.

It's not just for repairs or gluing. You could write with it!

Great idea!... but... what's the difference between this and a hot glue gun? Like, welding the models together wise....?

I think welding things together using the same material is always better than using an adhesive, that way the joint has the same mechanical properties as the structural material, like stiffness, melting temperature, etc. Welding with ABS also allows you to sand off any excess material without affecting the finish of the model. Hot glue is much more flexible, has a lower melting point, and can't be sanded easily. It's also fairly easy to peel apart things glued using hot glue.

That's pretty slick, but did you consider this kit from harbor frieght to make other minor repaires? http://www.harborfreight.com/plastic-welding-kit-80-watt-iron-67102.htmlhttp://www.harborfreight.com/p...

That looks like a nice (and cheap) solution as well. The large surface area of the hot end looks like it'd be good for smoothing out surfaces to make them watertight.

this is so awesome!! i can finally plastic weld larger prints together so it looks like one giant print! (assuming i have a steady hand)

sweet you beat me to it!! and way better design that i was conjuring up. I was going to wire it a bit differently by connecting the motor straight to 12v then put a potentiometer inline then the instant on switch. the theory was i would be able to control the extrusion speed right on the gun (slow for fine detail, fast for filling large gaps and off) without having to go to the computer. your parts for this look awesome, very well done.

Hmm...I think this would work but instead of just a potentiometer you might need a simple PWM circuit (555 timer based) using the pot as the frequency control. It would be great if there was a simple temperature sensor and PWM circuit so we could bypass the extruder controller/motherboard completely and make it a standalone welder.

That's brilliant!

this is great. I have been using my spare nozzle like this for a while it's really great for fixing messed up prints, holes etc

This just makes me so, so happy.

Don't cross the streams.