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How to Shoot Gunge???

Posted: Wed Sep 14, 2011 8:31 pm
by mr jd
dear all

i trust you are all well.

bit of a weird question, but has anyone tried, instead of water, to use gunge (you know, the coloured stuff favoured by kiddies tv programmes to pour over each other and poor unfortunates - Natrosol is the formal name) ?

because of its viscosity, i guess maybe an electric pump. i have tried various knapsack type sprayers and they do not produce enough pressure.

any thoughts would be appreciated.



Re: How to Shoot Gunge???

Posted: Wed Sep 14, 2011 9:05 pm
by cantab
I suspect the issue with knapsack sprayers isn't pressure but rather very narrow tubing and valves, that get clogged more easily. You'll probably need quite fat tubing, valves, and nozzles to shoot gunge effectively.

Re: How to Shoot Gunge???

Posted: Wed Sep 14, 2011 9:52 pm
by atvan
APH! The problem may be cost. The founder of this site adds glycerin to his water to increase ranges.

Wecome to SSC!

Re: How to Shoot Gunge???

Posted: Fri Sep 16, 2011 3:51 am
by zeda.beta
Hmm, the viscosity is a good point to start with.

As it seems this is the american equivalent of slime, which is a non-newtonian fluid with an extremely high viscosity compared to the water we are used to shooting, it might be a huge challenge to secure parts large enough and pressure high enough to overcome that.

All in all, can't wait to see how you plan to use it.

Re: How to Shoot Gunge???

Posted: Tue Nov 08, 2011 10:35 pm
by superpants
I have had some experience with this sort of thing....

Firstly, whilst you will be able to get gunge to shoot, you won't reallistically be able to shoot anywhere as far as you will with water. As others have said this is primarily down to the viscosity, which will be massively higher than water. You will therefore need larger bore pipes and higher pressures. Electrical diaphragm or centrifugal pumps are highly unlikely to be able to provide sufficient pressure.

Most materials used to make gunge are not newtonian in behaviour- their viscosity is dependent on the shear rate. The good news is that the most common materials (natrosol, xanthan and guar) are shear thinning, meaning the viscosity reduces as it they are sheared (mixed/ or made to flow).

My recommendation would be to use a pistol that has a simple direct acting pistol pump and drill out the nozzle to a larger size. You could use a pressure sprayer modified with larger bore pipe, but this won't be very effective. I have used this arrangement to enable baloons to be filled with gunge effectively.

Other thing to think about include making sure the gunge is very thoroughly mixed- any lumps at all are likely to block the pistol. You might also want to ensure that the colouring used is fairly concentrated to give the best visual effect (i'd use 3-5% of powder paint.

Hope this helps!