October 4, 2021

Bigger Better Dual Injectors

This is my Bigger Better Dual Injector setup…  My last setup was a little small for some things and the pistons had a tendency to stick in the tubes because I didn’t use proper high temp o-rings so I decided to make an improved set.

I started out with some raw materials including some 1.5″ diameter aluminum tubing, aluminum bar stock, steel rods, high temp o-rings, some 3D printed parts, and some miscellaneous hardware.

After a few days of machining, designing, and 3D printing I had all the parts ready to assemble.

The first step in assembly was attaching the tubes to the cross braces. The tubes had a groove machined in the outside to match the tab on the cross brace… this is to prevent the tubes from sliding in the brace.  The tubes were also polished inside and out for a smooth finish.

The rear cross base had nuts embedded mid print into them to accept the mounting screws.

Four screws clamp the two pieces of the cross braces together, securing both tubes in place. There is a few pieces of sticky tape inside the cross braces to keep the tubes from spinning. (not shown)

The rear 3D printed end caps are secured to the tubes with thumb screws for easy remove to clean the insides of the tubes. These are also vented (oblong hole) to allow air to escape while the pistons are retracted.

The handle was also 3D printed and secured to the two steel rods with 4-40″ screws.  I might switch these to thumbs screws also so I can easily change to two separate handles for pulse injections.

Here are the two pistons that screw onto the rods.

Here they are screwed onto the rods with the handle in the full down position.

These are the two nozzles. I did different knurling on each one just to keep them in the same tube every time.  You can also see the locking pins that keep them in the tubes. (these are just test o-rings and will be changed out as they are nicked up.)

The rear end of the nozzles… I added a nice chamfer on the holes thinking it might make the flow easier when injecting.

Here you can see how they lock onto the tubes. (If you buy injectors I highly recommend finding ones with these types of locks.  I had a nozzle pop off once and took a good plastisol burn in the process.)

The finished dual injectors ready to go.  Each one holds 7 oz. of plastisol so these should be big enough for what I do now.

Now I just need to reprint my blending block as I spaced these different from my last dual injectors.

To be continued…

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