Adding More Air...?

425jesse

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Feb 10, 2013
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4" Dalke Original Compact Dredge, 36" BGT Prospector, 30" BGT Sniper, D&D/Brawn Super Concentrator and Highbanker top, Brawn/D&D finishing table, pans and more!
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My dredge has a T-80 compressor, that seems to work pretty well. I tried to split the air to me and my son (he is a big dude) so we could work underwater together, but there was no way that was going to work just not enough air...any suggestion on how to add a "little more" air? Thanks in advance guys! Cheers!
 

russau

Gold Member
May 29, 2005
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St. Louis, missouri
get a big stainless steel air tank and "T" off from there, id also add a water trap/filter to help eliminate other problems that come with compressing air on a warm day!
 

Reed Lukens

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Make sure the T80 is running at the full 1800rpm - check your pulleys and motor rpms. Also get rid of quick connects and run a beer keg or a couple large reserve tanks, one for each person. Then don't go under until it pops full.
 

Hoser John

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Mar 22, 2003
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A brass T fitting with 2 reserve tanks helps also,one for each. Remove the air filter retainer-you DID clean it thoroughly with liquid dish soap-first. Drill out the holes on the metal dust filter retainer as that compressor will easily allow more air once the restriction is removed, about 40% larger works just fine. Reeds' air popoff info rocks AND your regulator is also adjustable too. Many things to do for more out of a t-80,smaller diameter flywheel-1" max so as to not overheat. Is the reed valve inside the seating?? I'd post a link to another website but they get the censor going again-John
 

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425jesse

425jesse

Hero Member
Feb 10, 2013
588
817
Mountlake Terrace
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4" Dalke Original Compact Dredge, 36" BGT Prospector, 30" BGT Sniper, D&D/Brawn Super Concentrator and Highbanker top, Brawn/D&D finishing table, pans and more!
Primary Interest:
Prospecting
Make sure the T80 is running at the full 1800rpm - check your pulleys and motor rpms. Also get rid of quick connects and run a beer keg or a couple large reserve tanks, one for each person. Then don't go under until it pops full.

Reed, how big should the beer kegs be, and of this style? ImageUploadedByTreasureNet.com1441662730.229126.jpg
 

panningjack

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Apr 16, 2013
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Nampa, Idaho
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A brass T fitting with 2 reserve tanks helps also,one for each. Remove the air filter retainer-you DID clean it thoroughly with liquid dish soap-first. Drill out the holes on the metal dust filter retainer as that compressor will easily allow more air once the restriction is removed, about 40% larger works just fine. Reeds' air popoff info rocks AND your regulator is also adjustable too. Many things to do for more out of a t-80,smaller diameter flywheel-1" max so as to not overheat. Is the reed valve inside the seating?? I'd post a link to another website but they get the censor going again-John

John what do you mean by smaller flywheel? Are you referring to the pulley on the t80?

Also what are everyone's thoughts on increasing the output port on the t80 head one size? I would think that would allow the air to flow more freely. I have a couple of spare heads and I'm thinking about trying it out on one
 

Hoser John

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Mar 22, 2003
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Yes you got it. Volume of air is predicated on piston stroke and flexible plenum( rubberized material) to a great degree-drill out that filter retainer is quick/easy,along with pop off tighten and regulator adjustments-John
 

russau

Gold Member
May 29, 2005
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St. Louis, missouri
John what do you mean by smaller flywheel? Are you referring to the pulley on the t80?

Also what are everyone's thoughts on increasing the output port on the t80 head one size? I would think that would allow the air to flow more freely. I have a couple of spare heads and I'm thinking about trying it out on one
flywheel = pully id open both ports for more air . its nice to have a spare head for your pump to try it out on!!! I was going to do this to my Brown compressor but I didn't need it!
 

panningjack

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Has anyone ever made their own diaphragm? I have some rubber that is just slightly thicker than a standard diaphragm. So I used some punches and made my own. Just haven't tried it out yet
 

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425jesse

425jesse

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Feb 10, 2013
588
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Mountlake Terrace
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Primary Interest:
Prospecting
There is a fella not far from me who makes his own gaskets, he has had a lot of success with them.
 

winners58

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Apr 4, 2013
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One way is to test exactly what RPM's your motor is putting out at operating speed,
most HP ratings come from the motor running at 3600 rpm but most come with the governor set much lower
you can go to a smaller pulley on the t80 but will wear out faster best to get a tiny-tach tachometer

optimal for the t80 = 1800 rpm
to determine pulley size and motor speed
Pulley Calculator. RPM, Belt Length, Speed, Animated Diagrams

example if your small pulley is 2 1/2" and large pulley is 6" RPM @ 3600 your t80 is only turning at 1500 RPM
and the same @ 3200 RPM it drops down to only 1333 RPM

my 11hp uses a 3" pulley but the smaller dredge motors I think use a 2 1/2" pulley, if it is, going to 5" pulley on the t80 would be fine.
 

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panningjack

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Apr 16, 2013
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Nampa, Idaho
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One way is to test exactly what RPM's your motor is putting out at operating speed,
most HP ratings come from the motor running at 3600 rpm but most come with the governor set much lower
you can go to a smaller pulley on the t80 but will wear out faster best to get a tiny-tach tachometer

optimal for the t80 = 1800 rpm
to determine pulley size and motor speed
Pulley Calculator. RPM, Belt Length, Speed, Animated Diagrams

example if your small pulley is 2 1/2" and large pulley is 6" RPM @ 3600 your t80 is only turning at 1500 RPM
and the same @ 3200 RPM it drops down to only 1333 RPM

my 11hp uses a 3" pulley but the smaller motors I think use a 2 1/2" pulley, if it is, going to 5" pulley on the t80 would be fine.

Yes. I think a tiny tach is a necessity for me right now. I have a 2hp motor with a 4" pulley powering my t80 with a 6" pulley. I run at 7/8 throttle and I have enough air without a reserve tank. But I want to maximize the amount of air I'm able to get and increase fuel efficiency.
 

Hoser John

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Mar 22, 2003
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OSH Hardware and Capitol Rubber both carry the NYLON IMPREGNATED rubber materials to cut your own. Simply trace, cut with a xacto and punch out holes with a leather/rubber punch and good to go. Without the nylon strands they don't last. Measure your gasket with a micrometer for correct thickness. ALWAYS remember that the materials from rolls has memory and must be cut with the hump,curve,whatever on the top side so any bowing works for you,in reverse it shortens the life of the materials. Use a polishing cloth on flapper valve as must be clean to seal on the discharge stroke-John
 

Doug Watson

Sr. Member
Jul 29, 2010
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Jesse, The filter retainer is already drilled out on your compressor. Change the pulley size on the compressor to get some more rpm. Was going to do that but I very seldom had another person in the water with me. Unless something changed the reeds and everything were seating fine. I did have the same problem years ago when my brother in law was under with me.
 

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425jesse

425jesse

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Feb 10, 2013
588
817
Mountlake Terrace
Detector(s) used
4" Dalke Original Compact Dredge, 36" BGT Prospector, 30" BGT Sniper, D&D/Brawn Super Concentrator and Highbanker top, Brawn/D&D finishing table, pans and more!
Primary Interest:
Prospecting
Any idea about what RPM it runs at now? When I look at the point where the T-80 mounts at the top, I can tell the engine has not slid, but there is over an inch of play in the belt. Do they stretch commonly? I suppose I should replace the belt before I dredge next right?
 

Reed Lukens

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I don't think we've seen what you have for a motor and air pulley sizes yet, so guessing rpms isn't possible. If it's an inch of play pushing hard then a belt tensioner could be added but it should be fine as long as it's not loose enough to slip. You don't want to stretch the belt to tight because the T80 is mostly aluminum. I have mine set to where I can roll them off and on with a screw driver to start it.
 

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425jesse

425jesse

Hero Member
Feb 10, 2013
588
817
Mountlake Terrace
Detector(s) used
4" Dalke Original Compact Dredge, 36" BGT Prospector, 30" BGT Sniper, D&D/Brawn Super Concentrator and Highbanker top, Brawn/D&D finishing table, pans and more!
Primary Interest:
Prospecting
Reed:). I bought the dredge from Doug, and it was mostly directed at him:) I will post a picture now of my pulley/pump, belt set up, and I am stoked to be getting advise from you. How would I best demonstrate the tension on video on my motor? It's a dahlke 4" micro. ImageUploadedByTreasureNet.com1442802004.558401.jpg ImageUploadedByTreasureNet.com1442802121.611843.jpg . The pulley on the motor side looks about one inch, the one on the compressor looks like 5-6". The last time Jake and I were out I put a splitter on the airline after the compressor and reserve tank, we tried to run 2 regulators, and it was not happening. My son is 6'2" and 230, and I'm smaller than him by a lot. He had the shorter airline and my regulator would barely produce any air, not enough.
 

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