Monday, June 1, 2015

Low Rent Mortar Sprayer #2

My very simple and inexpensive home made mortar sprayer has served me well until lately, when it started clogging every few minutes. I thinned my mortar mix a little and hosed my sprayer out, but every few minutes I'd have to stop. My theory is that sand has scarred the soft PVC plastic or copper nozzle enough to catch a little mortar and make it accumulate there. Or maybe it was the latex cement I sprayed that makes the mortar stick. Regardless, I had to replace my sprayer, and wanted to do it in a way I could duplicate easily.

As before, I started with a 1-1/4" male threaded cap and a 1-1/2 to 1-1/4 female threaded bushing, I also used a gnarled adapter for my air gun, and a small copper nozzle.

The nozzle and spray hole in the cap need to line up, which can be a little tricky on a rounded piece. I drilled just above the ridge at the bottom of the cap, using the small bit (9/32) first, and drilled all the way through the fitting so I had a hole front and back. Then I enlarged one hole, the spray hole, with a bigger bit (7/16).

I used a Dremel tool to cut the tip off the nozzle, which was too long and didn't allow for enough space between the nozzle tip and the spray hole. I thought I might have cut it too short, but the sprayer works fine.  I sanded the rough nozzle tip and buffed it smooth with the Dremel.

I used the Dremel to cut the ridge off just below the nozzle hole so the gnarled adapter, air gun, etc, will fit and turn freely to tighten. Then I sanded and buffed the area clean

The PVC fitting is too thick. the threads of the nozzle barely go through to the other side, and the gnarled adapter can't grab them. I sanded the inside of the fitting with the Dremel tool a little just around the nozzle hole to thin the plastic a bit, and buffed it smooth.

Here is the fitting with the nozzle and gnarled adapter attached.

The bushing screws onto the cap tight against the gnarled adapter to help hold it in place. The hopper is a gallon jug with the bottom cut out.  The cap threads of the jug don't exactly match those of the bushing.  I've used a large Clorox bottle successfully. A little electrical tape around the cap threads helps hold it tight. I've not had any trouble with the hopper coming loose. Inevitably mortar seeps in and holds everything tight.