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the other side. Don’t enlarge the holes, get proper water pressure. I have a ham nozzle tip that was used without the rubber liner; it has a flat spot on it from betting with a hammer to keep concrete from sticking.
These are just a few of the “don’ts” I have seen in 50-years. For hi-tech/hi-quality work, I like the 1 1/2” double bubble nozzle. Sometimes aI have used an adapter that snaps 2 tips together for a longer mixing chamber. This can help control “smoke” at the nozzle (I don’t like the word dust) when shooting without a pre-dampener. I prefer not to be the nozzleman without the pre-dampening.
When shooting swimming pools, canals and slopes, the old ham nozzle is probably as good as any. The long tapered nozzles and spiral type riffle the material out a long way. The nozzleman that uses this type usually tries to stand a long way from their work so they don’t’ get dirty. Their nozzle can be very good when used properly and in the right job. Each nozzleman must decide which type of nozzle is suitable for the job and works best for them.
“Hydra nozzle” personally I don’t’ like them. This is where the water ring is placed back 5’ to 10’ from the nozzle tip, material will build up in the hose and velocity will drop, then it will blow out and velocity will go back up. This is especially a problem when using an accelerator or sticky material. If it works for your project, okay, but I would question the quality of in place concrete.
I have placed a water ring back 50’ from the nozzle and a separate water hose and needle valve at the gun. The gunman will turn on a small amount of water and the nozzleman will use his water valve as usual the nozzelman will have the gunman adjust his water so there is enough moisture to get proper water at the nozzle. I have used this method to produce 10,000 PSI concrete.
Test panels/mock-ups: I always shoot these with at least 100’ of hose. At the job site it is rare not to have at least 100’ of hose. Material is usually smoother and 100’ than at 50’ and I want everything in my favor to get good quality concrete.
Responsibility of Nozzleman:
· Pick right nozzle and hose size for job
· Check water pressure and potable water
· Large enough compressor and pressure at 100-110 PSI, airline free of oil
· Layout hose without sharp bends
· Make sure mix meets spec