If you have ever used a cheap manual caulking gun you know that it can be frustrating and even painful. I recently had to patch some cracks in our exterior stucco and it was so hard to squeeze the stucco patch out of a tube that I decided to convert my caulking gun to electric. This is a fairly simple project and once you have all of the parts together, you should be able to complete it in around an hour.

Step 1: Tools and Materials

Materials:

Manual caulking gun
P16 series micro linear actuator (I used the P16-200-256_12-S)
DPDT switch
9V battery
9V battery connector

Tools:

Dremel or other rotary tool
Screwdrivers
Drill
Sockets and socket wrench

Step 2: Disassemble Caulking Gun

Remove the mechanism that pushes the caulking out of the tube. All I had to do was remove one nut and slide the shaft out of the back of the gun. Once the shaft is out the rest of the pieces just fell out.

At this time, I would recommend removing the clevis end-tip from the actuator as well.

Follow the instructions found here to be sure that you don't break the device while removing the end-tip.

Step 3: Drill Mounting Holes Into Caulking Gun

I had to drill out the original hole for the gun's shaft just a little wider. The actuator shaft slid right in. After that I made three more holes in the gun.

One square hole for the outer square shaft of the actuator to slide in
One rectangular hole for mounting the DPDT switch
One circular hole for the wiring to pass through

Be careful when you're using a rotary tool to cut the square and rectangular holes. It's easy to make them too large. I made that mistake with the hole for the switch and now I need to sort out another way to secure it to the handle.

Step 4: Mount the Actuator

You will need to connect the actuator to an appropriate power source and extend the shaft for this step.

Of course you could use any material you have lying around for this. We happened to have some square aluminum tubing so I used that. It is mounted to the actuator by the stock rear mounting hole, and bolted to the caulking gun above the handle as shown in the photo. I needed to use a couple of washers between the actuator and the tube to fill the gap.

It is important that the actuator be exactly in-line with the caulking tube holder. If the actuator is off, the shaft will be side-loaded while pushing on the tube of caulking, this will reduce the life of the actuator considerably.

Once the actuator is mounted securely to the gun frame, you can attach the push-plate that came off of the gun to the tip of the actuator. I did this using the male to male threaded end-tip that came in the actuator's mounting hardware kit.

Step 5: Wire the Actuator to a Switch and Power Source

I tested this with a 12V power supply but I found that it ran just a little fast. I decided instead to use a 9V battery. Connecting a 2-wire actuator to a DPDT switch and power source is fairly simple. If you decide to use the Actuonix switch ($6.00), then you can find the wiring instructions here.

I tidied up the wires with some zap straps and hid them inside the handles.

Test the gun before slipping the switch into the hole as it can be difficult to get back out.

Now you're done!