Dahlke micro 4b initial thoughts.

Mgumby16

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Jun 26, 2014
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East Coast
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I finally got my dahlke micro 4b in and had the chance to run it some over this past weekend.

A few pieces of info: I did not by the entire dredge from Erich who is the current owner of Dahlke in Sealy Tx. I bought the mono body, the DP150 pump, the dual venturi powerjet, the riffle tray, the miners moss and the frame. I did it this way because I had at least two engines sitting around that would work, and I have enough hose of various types. And partly from Reeds old thread about the Micro 4B and his recommendations in that.

So I got everything in and started assembling it and I decided to put the pump on a Honda GC190 engine that I found non the side of the road and got running. (Yes this was a poor decision lol). I should have put it in the Honda gc160 that I had laying around that was in good running order. More on engines later.

I built my own foot valve out using a 2” check valve and a galvinized foot valve cage from Tractor supply. It made it nice and heavy so that it won’t float to the surface. For the suction hose I’m using 12’ of flexaust PV hose which is super flexible and lightweight and fits the application of the micro 4b perfectly. Time will tell on its longevity.

One thing that i immediately changed was the dampener as the dahlke still comes with a super lightweight dampener that serves almost no purpose. I replaced it with a piece of .25 inch rubber mat that I have used on my 5 inch dredge before. Much heavier and should do great at spreading out the slurry from the tiny flare into the 20 inch box. I did ask Erich about his use of the lightweight dampener and he said that heavier ones caused larger rocks to stick in the box and that it only served to break the surface tension. I disagree on that and the dredge had no problem clearing larger rocks with the heavier dampener.

The micro 4b no longer comes with any carpet but instead with black miners moss. While I love miners moss in dredges the stuff in the dahlke is almost a half inch thick. Not sure how I feel about that yet as most miners moss in dredges is about half that. I may play around with some different miners moss as some point.

The powerjet is a single input dual venturi design and mounts directly to the flare. No more mid jet or other types. I was a little disappointed that it wasn’t the famous dahlke tri-jet but oh well. The jet performed well and I had zero clogs in the jet while running. Only in the suction hose when the hose had tight S bends in it. My fault on that lol. I will say that the powerjet is only about 1 foot to maybe 18 inches long. It makes me wonder that if it had a longer barrel that it may provide better suction based off of what I know of how powerjets operate. I may experiment with this idea in the future.

At 3/4 throttle the micro 4b had decent suction. No as good as my proline 4’inch at 3/4 throttle which rips but good enough for its purposes. But thing that hampered me the most was the lack of a high pressure blaster. But no dredge proline, Keene or otherwise comes stock with a high pressure blaster. I will be adding one before my next trip out.

The engine i put on it started dying after and hour or so of running which is completely my fault for using a questionable motor in the first place. I’m thinking that I may switch to a Honda gx160 or I may use the spare Honda gc160 that I have sitting at home. Not sure yet.

Overall I like the dahlke. I will be making some modifications to have it suits my preferences better but as a new stock one would come it would be a serviceable micro 4 inch for most dredgers. And honestly I believe it is a perfect dredge for most prospectors in the South east US area who are mostly in little streams and creeks and mostly doing day trip outings. I find that I hate lugging the full size proline into a spot to only dredge with it for a single day, and that the 20’ hose of the proline is generally too long and too stiff for most of the small creeks.

More to come as i use the dahlke more and get a better handle on its quirks and operation.
 

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Reed Lukens

Bronze Member
Jan 1, 2013
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Congres, AZ/ former California Outlawed Gold Miner
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It looks like you need at least another foot added to the power jet. I can't believe that they're still using that lame excuse for their cheap damper...
Was the material loading up between the riffles?
Being in the over 60 crowd these days, I've thought about buying another Dahlke myself. Yours looks great 😀
 

Reed Lukens

Bronze Member
Jan 1, 2013
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That thicker Miners moss should work perfect with the inflatable bottom. It was hard to get the riffles to seal on that dredge if the mat was too thin, so that's a big improvement over the Keene blue carpet that mine came with... 17 years ago now... lol.
 
OP
Mgumby16

Mgumby16

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Jun 26, 2014
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It looks like you need at least another foot added to the power jet. I can't believe that they're still using that lame excuse for their cheap damper...
Was the material loading up between the riffles?
Being in the over 60 crowd these days, I've thought about buying another Dahlke myself. Yours looks great 😀
Reed - I’m going to be playing around with powerjet lengths on it and a vacuum gauge to see if I can have some numbers give positive proof of the effect of the length of the power jet.

The material seemed to always fill the dovetail riffles about 3/4 full. I’m not sure if that’s how they typically run or not. I had it with as much drop as I could get out of the adjustments. I’m just not familiar with dovetail riffles and there is pretty much no info on them. The box as a whole holds more cons then my proline 4 inch holds even after allowing it some time to clean itself out.

I’ll have a video up with some better views of it and my initial thoughts hopefully later this week.
 

Reed Lukens

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Jan 1, 2013
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The gold travels up the bottom of the hose then gets churned up as it goes thru the jets. The added length is to let the gold settle back to the bottom so it can just drop out into the front of the sluice.
You may need to slide your motor back a bit more. With the 20" wide box, we ran that motor full out and it kept the riffles looking great. When we built our own dovetail riffles, we widened the space out a touch and increased the angles. They work great 👍
That thing will handle every bit of water that you can put thru it 😀
 
OP
Mgumby16

Mgumby16

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Reed I can’t currently move the engine back any further if I do it won’t be able to lock down on the frame rail. But once a compressor is added that should help balance the weight out better.

If I can’t get the current engine I put on it running correctly I’ll be switching it out to a Honda gx160.

What pump was on yours? They are currently sold with the DP 150.
 

Reed Lukens

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We ended up putting cloth bags on the back, hanging from the tie downs and adding rocks to them to get it running right.
I mean, mine definitely had some problems in the beginning, but it was a great dredge after all of the mods we made. I think the jet that Bob ended up sending me was 24" or more.
 

russau

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May 29, 2005
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Mgumby16 Back when ,I used to do lots of testing on equipment that I built , I wanted to do my own testing to achieve the "best" suction / engine speed I could get and I also used a liquid filled vacuum gauge on the front part of the nozzle and a P.S.I. gauge on the rear of my venturi (for tuning purposes )for getting the most out of my pumps for the conditions I had. I think I learned a lot doing this BUT my back won't let me do it anymore.:BangHead:
 

cobill

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Jul 24, 2007
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Laporte, CO
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Minelab GPX 6000 and 5000, EQ-800, AQ Limited, GBII, AT PRO, Keene 3" 2 1/2" ,2" and Dahlke 4" dredge.
It looks like you need at least another foot added to the power jet. I can't believe that they're still using that lame excuse for their cheap damper...
Was the material loading up between the riffles?
Being in the over 60 crowd these days, I've thought about buying another Dahlke myself. Yours looks great 😀
Reed,
After watching OP's YT video, your's & my own 4b experiences, I'm beginning to believe that the current design by Erich is based on "portability only"(A+) and NOT gold dredging(F). I ended up mounting a GX200/Keene P180 pump and 2" jet inlet , scrapped those dovetail riffles for rubber low-profile matting covered by expanded metal like Bob's original design, etc. etc, etc! My buddy took the Dahlke 150 pump and installed it on a Keene 2 1/2" dredge with GX120, a great match.
I don't believe the current 4b has EVER been tested by Erich in real world gold dredging environments....total FAIL!:BangHead:
 
Last edited:

Vance in AK

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Feb 15, 2010
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Kenai, Alaska
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I am currently looking at a used Micro 4b (I think? Looks identical)of unknown vintage. The guy had the dredge body with riffles & the motor (5hp Honda?)/pump assembly stored at his home and the suction hose & jet stored in another location. He thinks he can get ahold of the hose & jet but isn't sure what is there or if it had the standard or mid jet (belonged to a brother who supposedly purchased it new, & used it very little then gave it to this guy when he moved). My question is is Dahlke still in business & kind I get a new jet? If not will a standard jet like a Keene fit? I like the compact design & the price is right.
 

cobill

Jr. Member
Jul 24, 2007
49
31
Laporte, CO
Detector(s) used
Minelab GPX 6000 and 5000, EQ-800, AQ Limited, GBII, AT PRO, Keene 3" 2 1/2" ,2" and Dahlke 4" dredge.
I am currently looking at a used Micro 4b (I think? Looks identical)of unknown vintage. The guy had the dredge body with riffles & the motor (5hp Honda?)/pump assembly stored at his home and the suction hose & jet stored in another location. He thinks he can get ahold of the hose & jet but isn't sure what is there or if it had the standard or mid jet (belonged to a brother who supposedly purchased it new, & used it very little then gave it to this guy when he moved). My question is is Dahlke still in business & kind I get a new jet? If not will a standard jet like a Keene fit? I like the compact design & the price is right.
Hi Vance,
Yes Dahlke is still in business and Erich Lessing is the owner in Sealy, TX. (979) 885-4653.
 

Vance in AK

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Feb 15, 2010
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Kenai, Alaska
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Fisher GB II. Whites GM II.
Thanks cobill. Hopefully I could pick up some type of jet from him if I need it without breaking the bank on shipping to ak.
All the websites I found for them were dead so I thought they were too.
 
Last edited:

Reed Lukens

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Jan 1, 2013
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Congres, AZ/ former California Outlawed Gold Miner
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Reed,
After watching OP's YT video, your's & my own 4b experiences, I'm beginning to believe that the current design by Erich is based on "portability only"(A+) and NOT gold dredging(F). I ended up mounting a GX200/Keene P180 pump and 2" jet inlet , scrapped those dovetail riffles for rubber low-profile matting covered by expanded metal like Bob's original design, etc. etc, etc! My buddy took the Dahlke 150 pump and installed it on a Keene 2 1/2" dredge with GX120, a great match.
I don't believe the current 4b has EVER been tested by Erich in real world gold dredging environments....total FAIL!:BangHead:
Yuk...
I've never talked to Eric... I like the dovetails myself but this was the first dredge that I ever bought that I had to completely rebuild straight from the factory... which is why I sold it...
You'd think that they would have it together by now...
 

Reed Lukens

Bronze Member
Jan 1, 2013
2,476
4,946
Congres, AZ/ former California Outlawed Gold Miner
Detector(s) used
Tesoro Vaquero, Whites MXT, Vsat, GMT, 5900Di Pro, Minelab GPX 5000, GPXtreme, 2200SD, Excalibur 1000!
Primary Interest:
All Treasure Hunting
And here I am watching your video 😀 it came up on my suggestions just now 😀

I think that you said that you read my article, but here's the link... 17 years ago with the same problems... 😀 I am going to buy another 4b frame here soon though and build the rest from parts that I have here.
 
OP
Mgumby16

Mgumby16

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Jun 26, 2014
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And here I am watching your video 😀 it came up on my suggestions just now 😀

I think that you said that you read my article, but here's the link... 17 years ago with the same problems... 😀 I am going to buy another 4b frame here soon though and build the rest from parts that I have here.
Yep I’ve read the post many times. And did most the things that you recommended. I didn’t buy the complete dredge. I bought the mono body, the riffles, the frame, the pump and the powerjet.

I put an engine on it that I should have and have since put a better engine on it. We will see how everything does on its second outing possibly this weekend.
 

exosis

Newbie
Sep 12, 2022
2
3
The Dahlke website is down, so is their facebook. I tried to e-mail Erich at his old gmail account, no response. If Dahlke is still in business, how to get a hold of them? Phone calls only?
 

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