Mortar gun

[Deleted member 192609]

How on earth do I get one of these to work properly?!

My builder says his works perfectly (same Roughneck model as mine) but mine is hopeless!

No matter what I do, when I pull the trigger the water just gets squeezed out of the mix and it goes too hard to be pushed through the nozzle...

I'm mixing it really well with a paddle mixer and a good amount of plasticiser, but nothing seems to help!

 

[Wayners]

I think it helps when gravity is on your side like with slabs but I gave up.
Have you watched YouTube for guidance?
Definitely a knack to it

 

[ree]

dns 1,
IME, They have a long history of uselessness after a short work time, even when using a slightly soft proportioned mix.
They only seem to work with a soupy mix - which is well useless for pointing.
Plus there's the endless filling the tube and/or washing out the nozzle.

 

[Ollyfp]

I use a mortar gun for grouting large areas of ceramic tiles. I use a fairly wet mix and my apprentice (wife) follows up with the grouting tool as it starts to go off.
Yes, I can hear the professionals laughing already!

 

[stuart45]

Getting the mix right with the correct sand is the key thing. In a mixer you need to mix it dry for 5 minutes, then add the water and plaz, but only enough to make it drier than you need. Let it mix for around 10 minutes to work enough air into the mix and you will probably find it's workable by then. Most people make the mistake of adding too much water to getting it workable enough.
Let it fatten up a bit for 10 minutes and then remix for another 5 adding water if needed.
Use a good quality soft building sand. Lime in the mix is also good.

 

[Ollyfp]

Getting the mix right with the correct sand is the key thing. In a mixer you need to mix it dry for 5 minutes, then add the water and plaz, but only enough to make it drier than you need. Let it mix for around 10 minutes to work enough air into the mix and you will probably find it's workable by then. Most people make the mistake of adding too much water to getting it workable enough.
Let it fatten up a bit for 10 minutes and then remix for another 5 adding water if needed.
Use a good quality soft building sand. Lime in the mix is also good.

Stuart brings the science!

 

[Deleted member 192609]

I use a mortar gun for grouting large areas of ceramic tiles. I use a fairly wet mix and my apprentice (wife) follows up with the grouting tool as it starts to go off.
Yes, I can hear the professionals laughing already!

That's a great idea!