Al -- 2 inch Letrap dredge ?? please give me some info on that.
Ya the R S pump is a winner in my books.
This the only photo I have of my Letrap dredge, (That's my grandson giving it a try)
It has a flare from Angus Mackirk, so I can also use it as a sluice and this adds a stronger base to attach and old Keene box I bought from a friend. It's 2.5 incher which I've necked down to 2, but I think the RS pump might handle a 2.5 suction nozzle. I run it at half throttle with my 2" so it doesn't overload the Letrap with sand. The floats are from a pool lounge chair with a .5 pvc pipe frame. I have beefed up the frame somewhat since this picture was taken. I run the sluice as flat as I can, since the gold here is small and there's lots of blacksand. My suction noozle is from an old Keene P60 dredge and has opening bars to block rocks larger than .5". It works well on this Middle Fork of the Boise claim, but at the full 28 gpm, it fills the Letrap with sand quickly unless it's at a steep angle, which loses most of the fly speck gold.
I made spacers to fill the gaps on either side of the boiler box and the flare. They leak a little water, but I don't want the seal them in place so I can still use the Letrap as a stream sluice. An earlier version had a homemade aluminum boiler box that was sealed to the Letrap with silcone, but it eliminated the stream sluice option. I've checked and found I'm loosing little, if any powder fine gold with the slightly leaky, set up. The spacers are made from spray foam insulation over a layer of aluminum foil and trimmed level on top with a knife and painted with a few heavy coats of laxtex.
The pump sits on light aluminum bars, attached with rivets, and spaced to fit the bottom pump. That's an idea I got from a small Angus Mackirk back pack sluice I have. They brace the sides of the somewhat flimsy Letrap and are great to put a big rock on when sluicing in the river.
It's great fine-gold-getter in either configuration!