Ad Tech Pro200 Hot Glue Gun Trigger Mod

Hi Everyone - this is my FIRST video article... 

I recently started using the Ad tech Pro200 hot glue gun I purchased from FliteTest. Wow, does 200 watts of really heat fast - 2.5 minutes from cold to full flow glue delivery. However, it has one major flaw, the trigger travel is quite inadequate. Half of the trigger travel is used to engage the glue advancing mechanism with the glue. The resulting glue delivery stroke ends up being very short, about half the distance of the trigger travel distance.

The simple modification involves adding a plywood spacer between the trigger and the glue advancing mechanism. The result is the glue is partially engaged from the first movement of the trigger and results in a glue delivery stroke that is twice what it used to be.

Let's get started.

My first hot glue gun I purchased in 2010 was an Arrow TR550. Over the years I’ve grown to love this glue gun, but it too has its problems. At one point the glue just started leaking out of the tip. I’m the kind of guy who loves to tinker, figure things out, fix so I decided to take it apart to see if I could fix it or maybe just to assess what was wrong.

Turns out there is a simple valve mechanism in the tip that is designed to keep the hot glue from flowing unless pressure is applied to the glue. It is made from the tip, a spring, steel ball and a plug with the same curve of the steel ball. When pressure is put on the glue, the glue pushes the steely to the right and the glue flows around the steely. When the pressure is released, the steely seats into the plug and prevents glue from flowing. 

What I discovered was the plug became unseated so the steely had nothing to seat against, as a matter of fact the plug and steely were free floating in the glue heating chamber. I fit it all back together and it worked great for another chunk of time, but soon it recurred. Also, as a part of the fixing I accidently heated the spring with a flame (to remove the glue) and it weakened the spring.

Finally, I purchased a new hot glue gun from FliteTest and put it into action. 

This hot glue gun has 200 watts of glue melting power, goes from cold to full glue delivery in 2.5 minutes. Deficiencies that I noticed the moment I started using it was the short glue delivery stroke and the wide body when compared to my previous hot glue gun, the Arrow TR550. Since this was an upgrade from 40 watts to 200 watts I could understand the thickness of the body increase, so I’ll leave that criticism alone by saying that it doesn’t fit into tight shapes like the Arrow.

The biggest flaw, in my opinion, was a shortcoming in the engineering of this glue gun. It is kind of obvious when a product is designed by individuals who don’t use the product. Ok, off the soapbox and onto the mod. The design flaw was the short trigger travel.

Here is a photo of the Pro200 overlaid with the TR550. You can readily see that the triggers start at two different angles. Not only is the trigger angle shorter, the glue advancing mechanism doesn’t engage the glue until half the stroke is completed. This results in the user having to make several trigger pulls to get long beads of glue delivered. 

At first I wanted to see if I could change the fulcrum location (trigger hinge) in increase the travel distance. I thought I would be able to 3D print a new trigger that would move further.

I took the Pro200 apart by removing the case screws. I assessed the mechanics  of the trigger mechanism and surmised that the internal nylon pivot would be difficult to alter. What I did see was that the slop between the trigger and nylon pivot could be reduced.

I cut a small piece of ¼” plywood to the internal size of the trigger.

I sanded it to shape so that it pressed nicely into the inside of the trigger. This removed all the play between the trigger and nylon pivot.

Boy, that was easy. Reassembled the hot glue gun.

Here is the result. The top and bottom beads were produced with one trigger pulls. The middle beads were “recreated” from what I felt was the length of bead produced before the modification.

For anyone using the Pro200, this simple modification will make glue delivery so much better.

You’ll love it!

HilldaFlyer Nov 2017