[Ben Heck] Builds The Ultimate Glue Gun

glue

For how many can be found on the workbenches and in the toolboxes of makers and hackers the world over, finding a glue gun that does more than just heat up and drip glue everywhere can be a challenge. [Ben Heck] finally solved this problem with a hot glue gun that’s more like an extruder from a 3D printer than a piece of junk you can pick up at Walmart for a few dollars.

By far, the most difficult part of this project was the glue stick extruder. For this, [Ben] used a DC motor with a two-stage planetary gear system. This drives a homemade hobbed bolt, just like the extruder in 99% of 3D printers. The glue stick is wedged up against the hobbed bolt with a few 3D printed parts and a spring making for a very compact glue stick extruder.

The electronics are a small AVR board [Ben] made for a previous episode, a thermistor attached to the hot end of the glue gun, a solid state relay for the heater, and analog controls for speed and temperature settings. After finishing the mechanics and electronics, [Ben] took everything apart and put it back together in a glue gun-shaped object.

The finished product is actually pretty nice. It lays down constistant beads of hot glue and thanks to a little bit of motor retraction won’t drip.

You can check out both parts of [Ben]‘s build below.

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Building a tool to measure melting point

melting-point-apparatus

When working with chemical reactions it may be necessary to test the purity of the components you’re using. This is especially true with hobby chemists as they often acquire their raw materials from the hardware store, garden center, or pool supply. [Ken] figured out how to get around the $500 price tag of a commercial unit by building this DIY melting point test apparatus.

In this image he’s using a thermocouple to monitor the temperature of the melting surface, but mentions that you can do this with an inexpensive dial thermometer and will still have great results. That melting surface is the hexagonal head of a bolt which he drilled out to provide a concave surface for the test compound. Inside the PVC pipe is the heating element from a 40W hot glue gun. He wrapped it in fiberglass fabric which is sold in the plumbing supply to protect the area around pipe joints during soldering. The rotary light dimmer feeds the electricity to the element, allowing for adjustments to the ramping speed.

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