SPRAY RENDERING


26/9/07


This is it folks, our new, you-beaut Tirolessa stucco spray unit.

Supplied by Nolan Scheid and mortarsprayer.com

This is a quick posting about our new lightweight spray unit. It is the Tirolessa sprayer manufactured in Mexico and sourced from the U.S.
Think of it as a shovel with an air supply channelled up the handle. Hook up a decent sized air compressor, scoop up some render, point it at the wall and let rip!

Below are a couple of short clips of the sprayer in action. Our multi-media technology is still a bit primitive at the moment, although we are working to improve the quality, but you get the general idea.



All up there is about $1500 worth of investment - the sprayer, a petrol air compressor and various attachments but not including the mixer or barrow. Because the cement mixer and compressor are petrol powered, and the spray unit only needs an airline, and the render is delivered by wheel barrow, the whole unit is totally independent and can be set up anywhere - be it in a small back yard or in the middle of a paddock. As you move around the site you just keep the compressor in hose range (up to 20m in our case) and the wheel barrow - like the Force - will always be with you.
+
Grotty but hardworking mixer and "materials delivery device" - a barrow!
Sexy air compessor, 20m air hose, and not one,
but two Tirolessas -
one wall sprayer and one overhead sprayer.

The clip below demonstrates it's flexibility. It's only on when the air trigger is depressed. So you can start, stop and be intermittent as you wish. It takes about 5 to 10 seconds to empty the hopper when flat out - a healthy shovel and a half worth.



So far we have had quite a bit of fun with this set-up. It takes a lot of hard grunt out of putting the render onto the walls, although there is still plenty of loadbearing exercise, and does a better job over reinforcing mesh than trowelling. The final finish is not suitable unless you like "really" textured, but the final coat is easily floated after spray application. Lumps and stones in the hopper will cause blockages, but these are easy to fish out as you go. However, life is a lot easier if your ingredients are clean and the blockages don't occur in the first place. Otherwise you will spend valuable time hoppin' around and singin' the "Constipation Blues"!! Because of the simplicity of the setup, you can do an hours worth of rendering when you have a spare moment. Just knock up two or three mixes, spray them on, and washing up is no more than if you had done the whole job by hand.

Speed of application seems quite good too. Two of us, one on the mixer and the other on the sprayer, can cover 40 lineal metres of 8 bale high strawbale wall in a full working day. So a building 7.5m long by 5m wide can be coated inside and out in one day. Three days (with curing time between) and the building is completely rendered. We were impressed!

Due to the nature of the strawbales, it is worth the time straightening and plumbing the walls, and then using a whipper-snipper or line-trimmer (weed-wacker) to trim and shape them. The first coat is quite a rough coat, with the high points and really fuggly bits knocked off with a trowel. The second coat is what I would call a "corrective" coat. It is not a second coat in it's entirety. It serves to fill the gaps and hollows produced by the first coat, and establishing a working plane for the final coat. It is floated or screeded to set the levels, and its high points are the datum for the final, or float coat. All sounds really technical but is quite straightforward with a bit of practice.

The Tirolessa sprayer simplifies this process. Point and squirt. Fill in here, bit of a squirt there, load up an area over yonder. Let it go off a bit and then trowel or float it. In fact, as you get your eye in with the sprayer you can eliminate a lot of the floating. By working off the peaks and dubbing out the hollows, you can get quite an even plane. It makes the job of levelling an area a lot easier.

Obviously the final coat needs to be floated to a desired finish, but again, judicious use of the sprayer makes for an easier finish, with less waste of render.
After some deliberation we decided to lash out and get the overhead spray unit, and this is a photo of ours to the left. We had gone this far with the system, so it made sense to round it out.

We have tried it out and the end result is a bit messier than the wall sprayer. What goes up, if it doesn't stick, must then come down. However, it does angles that the wall sprayer can't do, and that makes all the difference. They are a matched pair, and if you are contemplating rendering that involves overhead work, you really do need this unit.

With this baby, ceilings, arches, domes, caves - it's all up for grabs!

Spray render machines have wide potential application. They are particularly useful in ferrocement construction, or other modern variations in lathe and plaster. We will be giving this a go as some of our walls are stud framed, and we want to clad them to match in with the rendered strawbale. So with an appropriate system of lathe and two coats of render, it should work out quite well. Vaulted ceilings are also on our wish list, but we will experiment on the chooks first!

As we get further into the rendering we will post more information about the sprayer and our experiences.










Stay Tuned - More to Come

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