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Post by bluethermal on Feb 12, 2009 9:51:31 GMT 12
howdy all, was wondering if there is a any easy method to make a air reserve when using a compresser or is it best to buy one from keene/proline, may gold be with ya matt
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Post by RKC on Feb 12, 2009 11:58:31 GMT 12
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Post by bluethermal on Feb 12, 2009 20:45:41 GMT 12
Hi Rob, thanks for the info, have been doing abit of snipping in varies streams and creeks with abit of sucess but accessing the deeper holes that hold some good gold is pretty limited with just mask and snorkel. Am in the process of building floats for my dredge and equiping it with a compressor to get into these places. Using my dredge with suction nozzle and motor on the bank is fairly limited to the ground you can access, OK for really small streams but not so great for larger water ways. The only problem with learning the ropes dredging is i have not done much detecting this summer, had lots of new areas mapped out for this summer but have not done much at all. The weather has been fairly up and down anyhow. Any idea on the size pulleys to use to run a T-80 compressor with a 6.5 hp motor? all the best matt
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Post by roscoe on Feb 12, 2009 21:55:09 GMT 12
Hi, Bt and Rob. Mate built one out of PVC and decided to pressure test it with his paint compressor. Think it exploded at around 100 psi. We never did get all the shrapnel out of the plaster walls of his double garage. Fit a blow-off valve to avoid this. Lubo`s tank looks like mine, an ex-aircraft receiver in stainless steel. Lots of yachties use them as mooring buoys. You could get an extra valve stem vulcanised in a truck tube and use that. I think you get used to the rubber taste after about 100 hours. ;D
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Post by RKC on Feb 13, 2009 14:55:19 GMT 12
G'day Matt, This might be the first South Island summer ever that The Coast has had better weather than Otago! Its been an incredible summer here and all the rivers are as low as I've ever seen them. The hobby fossickers were out during the Christmas holidays with their sluice box's and in greater numbers than any previous summer ... thankfully most have now gone back to their "real jobs". You really will make things much easier for yourself if you can float the motor. During the early 90s most Otago dredgers used to sit their motors and pumps on the riverbanks and I could never understand why they did not just put some floats under their motors. It must have been incredibly time wasting for them to be continually moving the motor, especially when sampling (prospecting) a stream. You can see from the following photo img.photobucket.com/albums/v172/Coochee/P1010007-1-1.jpg?t=1234488223 the size of the pulley you need ... about 6"+ or so, in diameter, for the pulley on the compressor, and a pulley as small as possible on the motor. The type of compressor you are using runs at relative low pressure and 'nothing' will blow up. There should be a pressure relief valve at the top of the compressor img.photobucket.com/albums/v172/Coochee/thomascompressors-1.jpg?t=1234487837 that can be adjusted to regulate the pressure and you will need to experiment with adjusting the valve to determine the best adjustment to give you enough air. Also, those compressors need to be handled reasonably carefully. They are made from cast aluminum and the threads in the base of the compressor can be easily stripped. To protect the threads, the compressor can be bolted to a solid (rigid) steel base and holes put in the steel base to then attach it to the dredge frame or wherever its to be attached to. This avoids screwing bolts into the cast aluminum each time the dredge is disassembled or assembled, which will eventually strip the threads. Or alternatively there can be stainless steel thread inserts put in the threads. However, as long as you are aware that the threads can be easily stripped its then just common sense how you go about preventing the problem. That is if there are threads in the base of your compressor ... a modern compressor like you have might be designed differently. Its prudent to use only stainless steel bolts and nuts on dredges. Additionally, those compressors need to be regularly maintained by being taken apart and cleaned. Even in a freshwater environment the aluminum will corrode and clog things up inside the compressor. They were never intended to be used outdoors. When you start using the compressor for long lengths of time its probably advisable to attach a filter at the compressor outlet so dust particles of aluminum are not breather in. Regards, Rob (RKC)
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Post by roscoe on Feb 13, 2009 19:10:50 GMT 12
Sorry, Rob, I should have made it clear that a few dredgers use a non-return valve next to their air tank in case a fitting or hose blows between tank and compressor. Then you might need a relief valve if you have a suspect tank. Although 45psi or thereabouts isn`t great, it can still cause trouble.
A better place for an inline filter might be next to your demand valve in case of hose shedding, critters in the tank between dredge trips, etc. ;D
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Post by bluethermal on Feb 17, 2009 20:35:40 GMT 12
Hi Guys, thanks for advise, think i will get a reserve from keene, was looking at regulators on trademe and see that there are first and second stage regs, which is the go for using on a dredge? may gold be with ya matt
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Post by RKC on Feb 19, 2009 11:40:30 GMT 12
G'day Matt, It might be worth first trying Miners Den in Melbourne for a reserve tank as they may have one in stock. They might even have a second hand tank thats worth buying. I have always been under the impression that the type of demand valve used with a hooker has to be a demand valve specifically designed for use with hooker systems and that the demand valves used with a scuba system are not suitable. If this is right the demand valves advertised on TradeMe would probably be unsuitable. You really will need to have this clarifed before you go ahead and purchase a demand valve. Maybe someone could post here to clarify this for you before you part with any of the folding stuff. My demand valve img.photobucket.com/albums/v521/NZGOLD/Equipment/cromAAAA_14.jpg?t=1234998802BTW: I just checked the gold price and its very close to NZ$2,000 and ounce at $1,926.04 NZD ... here on The Coast all the diggers and screens are out digging any ground they can find that has not been previously mined. Regards, Rob (RKC)
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Post by RKC on Feb 19, 2009 15:45:40 GMT 12
G'day Matt, I had a quick search through the Internet dredging web sites and came up with this www.akmining.com/cart/ker1.htmI think you are going to be forced to buy your demand valve (Hookah Air Regulator) from a mining store so you can be sure you have it right. Regards, Rob(RKC)
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Post by dgr on Feb 19, 2009 19:44:56 GMT 12
Hello Attached is an Australian Supplier which may be of some help www.powerdive.comCheers
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Post by roscoe on Feb 19, 2009 20:26:42 GMT 12
Regulator gets bandied around and newbies get confused about which is which. I started off scuba diving and the doovie that sits on top of the tank was always called the regulator. The mouthful you bite on was always called the demand valve. While I used a proper hookah demand valve (Air-dive?) for a while, I changed rigs and took my scuba demand valve (U.S.Divers) to a tank-testing shop in Briz, and the servicemen reset the valve from around 80 psi to probably around 40. Only took him a couple of moments and I never had any trouble after that adjustment. Probably would need re-setting if I used it back with the scuba setup.
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Post by roscoe on Feb 19, 2009 20:40:15 GMT 12
Looking at AKMining/Steve Herschbach`s site reminded me. Are you mad Kiwi dredgers using neoprene drysuits as advertised on that site? Pricey, but if you`re gonna jump in the water with icebergs, it`s the way to go.
In my book, I wrote that dredgers should fit a relief zipper to avoid Rash City. I said an 8 inch zip was sufficient, but some may need larger. Some dill wrote to me and asked why would some need larger? ;D
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Post by RKC on Feb 20, 2009 11:11:57 GMT 12
G'day Roscoe, My personal experience using a neoprene dry suit was a disaster and proved very expensive ... and my advice to any dredgers new to dredging would be to stay well away from neoprene dry suits. In fact I would strongly advise any serious dredgers to stay away from all dry suits and only use wet suit heaters to keep warm. Dry suits sound good in theory, but in practice they have far too many disadvantages. golddredgingforum.proboards.com/index.cgi?board=archives&action=display&thread=13BTW: Full face masks are generally only used when dredging in cold water, so no skin is exposed to the water. They are difficult to get on and off the face, and in fast water they can be ripped from the face when the head is turned to the side. At any other time a normal diving mask is best used. Regards, Rob (RKC)
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Post by roscoe on Feb 21, 2009 15:43:58 GMT 12
I had a debate with Steve H. on the Alaska forum a while back, with me pushing wet suits/heater. He said the neoprene dry`s were the only kind used there. Since the Alaska boys only start to jump in when the rivers start to ice over and slow the water flow, they must get a degree of battering. Horses for courses, I guess.
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Post by bluethermal on Feb 22, 2009 17:52:45 GMT 12
Hey fellas, thanks alot for all the help, im starting to think the advice to buy a dredge complete from the states would have been the go, but didn,t have the $ and building one will be less that half the price and can buy parts as $ allow, should be finished about end of autumn, great timing i know. Have built a hot water system for my dredge, in most of the streams around q-town i can last only about 1 1/2 hours sniping before cold drives me from the water, then the sand flys are ready waiting. all the best matt
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