Help with nozzle size for dredging with a trash pump

[Paulhag98]

hello i am Paul im new to this forum and to the subject of dredges, i apologize if my english is not very good

i would like to get an extra income and so i am trying to build a dredge with nozzle with a trash pump with 3 inch inlet/outlet 250 GPM 40-45 PSI (i know its not very good, but i cant buy a high pressure pump)
the pressure hose i will stay with 3 inch i don't know if is necessary make a low hose adapter or just can put the reduction in the nozzle.
the nozzle i think to make is 3inch with 2 (or 1.5) suction tube and put a 0.75 (approximate) inch orifice in the 3 inch nozzle curve, all PVC tubing for testing
can anyone tell me if this is possible and give me some advice? it's hard to get help.

 

[russau]

I sent you a PM reply. Save your money and buy a high pressure pump !

 

[Bob207]

I built my 2 1/2" combo and bought a 5 1/2 hp briggs with a 2" 200gpm pacer pump. Its rated to 52 psi at full throttle. Run 2" layflat to a 10 foot piece of 1 1/2 high pressure hose to the nozzle. Nozzle reduces to 1/2" orifice. I run it 3/4 open and has more than enough suction and water volume to run the combo. I only get to about 4 feet in the ground with mask and snorkel and dont lose any suction even lifting the water and gravel up to the header.