Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Mar 8, 2012 1:23:48 GMT -5
From the maker of a working toilet bowl plunger vibe tumbler comes this new idea. If I took a modified sandblaster nozzle or made something similar and combined it with a pressure washer could I make a water jet ? I'm thinking I might have to adjust nozzle and venturi sizes but it just might work.
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Post by geoff on Mar 8, 2012 2:22:40 GMT -5
Not sure you can get high enough pressure from a little pos pressure washer. Also, don't they add abrasive to the stream?
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Post by johnjsgems on Mar 8, 2012 9:35:50 GMT -5
With high enough pressure it would work. I know they cut soft stones like the granite pictured with water. The Boerne rock shop has a guy that cuts shapes out of the Texas limestone in his area and has a giant state of Texas out front that is 3-4" thick.
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carloscinco
fully equipped rock polisher
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Post by carloscinco on Mar 8, 2012 10:11:34 GMT -5
The tip of the water jet nozzle is typically tungsten carbide or other very hard material. Other wise the tip wears away very quickly.
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NDK
Cave Dweller
Member since January 2009
Posts: 9,440
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Post by NDK on Mar 8, 2012 17:22:04 GMT -5
Wow! I never knew they cut rock with a waterjet... I suppose it works on metal, why not rock. Good luck on this build Scott, I hope ya get it working! Nate
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Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Mar 8, 2012 19:42:33 GMT -5
Geoff I'm thinking the grit should be able to get sucked in with the venturi just like in a blaster. I probably won't build one because I don't have or need a pressure washer. It was just an idea I was throwing out there. Maybe someone who already has one can put one together. The blaster nozzle is cheap.
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Deleted
Deleted Member
Member since January 1970
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Post by Deleted on Mar 8, 2012 22:00:37 GMT -5
Waterjet cutting machines operate at 50,000PSI
so... no.
The actual cutting is done with AlOx slurry not plain water.
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Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Mar 9, 2012 0:22:47 GMT -5
Well that says pressure would be a issue. Pressure washers only run about 3000lbs. Never did think plain water though hence the blaster. Pretty obvious you need more than just water unless you have a lot of time to wait. I would still be curious to see if you could get any reasonable amount of cutting from it. Even a drip given enough time will erode stone. Might still be able to use it like a trim saw on slabs or you might just get really old waiting.
Somebody out there must own a pressure washer already, the blaster nozzle is only about $20
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Post by catmandewe on Mar 9, 2012 1:22:02 GMT -5
I have a pressure washer I will donate to the cause if you wanna try it.
Tony
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Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Mar 10, 2012 0:36:40 GMT -5
Looks like we have a volenteer!! I just wanna know if it will do anything. Stick a nozzle in it and tell us what happens Tony.
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Post by NM Stone Supply on Mar 10, 2012 9:38:14 GMT -5
I have a pressure washer and the output on the nozzle is smaller than the output on my sandblaster making the exist nozzle stream better than the larger output of the sandblaster nozzle. The thought sure is good. I would love to make one too but just the table itself would cost a ton of money to make. I tried cutting my alabaster with the pressure washer a few years ago and it cuts it slow and the erosion of the stone does not leave a pretty cut. Great post, Good luck Jason
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Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Mar 11, 2012 12:45:31 GMT -5
Were you adding grit somehow Jason or just using the washer only?
I was actually thinking more along the lines of something hand held. maybe could use it for carving?
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peacemaker
off to a rocking start
Member since February 2012
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Post by peacemaker on Mar 11, 2012 20:02:59 GMT -5
Yikes!
No way that is going to work... 60,000 psi to 87,000 psi is the going rate for a machine that actually 'cuts' properly... You would be looking at a 'MINIMUM' of 24,000 psi to do even some of the softest rock with any degree of accuracy, not to mention the fact that 'water alone' will not work. You need carbide or similarly hard abrasive and that just won't fly with the aforementioned setup.... I would honestly say that a high pressure Blasting cabinet would have more 'affect' on pieces, but even then 'gouging' out shapes would be tough.
There's no doubt in my mind that you would have more luck 'carving' with proper bits using a Foredom tool and/or a die grinder with the proper attachments and of course, carbide bits.
Cheers,
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Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Mar 12, 2012 1:47:06 GMT -5
I guess I should have stated my question more clearly at the beginning. My bad. This just seems to be confusing quite a few people. Everyone stop wondering if it has enough pressure and yes I'm planning on using abrasive. A cutter at the pressure from a pressure washer is absolutely possible. Here is a link to a low pressure (5000psi) rock cutter developed for use at Gateway Arch in St. Louis. tinyurl.com/7vuwgp5If you reduce the orifice size of the nozzle you will increase the water exit velocity. Just like putting your thumb down on a garden hose. It is the speed of the water/abrasive that does the cutting not the pressure. The pressure just allows you to have a larger stream for the same velocity. The pressure is all lost the second the water exits the nozzle. Google bernoulli's equations if you doubt me on that. The real question that needs to be answered is if we have a small enough orifice to get enough water/abrasive velocity at the relatively low pressure and more importantly low volume that a pressure washer can put out can we get grit to go through a small enough nozzle or will it simply plug up? Sure I could calculate it out but how much fun would that be? At gateway arch they had a pump that put out 160L/min at 5000 lbs but they were also trying to make a much larger cut than we would be interested in. For our best neatest cutting we would want an orifice only slightly larger than the grit. This however might very well be too large for a pressure washer to supply the needed velocity required.
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drjo
fully equipped rock polisher
Honduran Opal & DIY Nut
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Post by drjo on Mar 12, 2012 10:31:13 GMT -5
You can always tell when cabin fever kicks in up in Canada ;D
I would think you'd use about 400 grit, held in suspension with a wetting agent. (you wouldn't be able to reclaim grit economically either)
I don't find a cheap, ready made orifice (would have to be ceramic or ruby/sapphire).
Get appropriate pressure hoses that are Teflon lined so the grit doesn't abrade them too.
Could make an interesting tool for cleaning off/light carving softer stones (notwithstanding, patience would be a virtue here).
Thought provoking still.
Hope it warms up for you up there SOON!
Dr Joe
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Post by johnjsgems on Mar 12, 2012 11:48:18 GMT -5
Dr Joe, that was long Summer vacation.
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Post by mohs on Mar 12, 2012 12:53:14 GMT -5
high pressure slurry maybe for final polish on rock sculpted piece ?
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Post by Rockoonz on Mar 12, 2012 22:32:54 GMT -5
Industrial water jets are fully enclosed CNC machines with safety interlocks. A hand held water jet cutter would be incredibly unsafe. It could easily inject water/grit directly into your body through the heaviest sandblasting gloves.
Lee
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Saskrock
fully equipped rock polisher
Member since October 2007
Posts: 1,852
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Post by Saskrock on Mar 12, 2012 23:19:17 GMT -5
hmmm, probably a good point with the safety. Probably a lot easier to slice off a finger than a rock........... Not much fun unless its hands on though. That might be the point that kills it for me. Always someone who has to go and ruin a bad idea.
And I do not have cabin fever, your just all out to get me and my rocks!!!! What was I talking about? I should go outside probably.
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drjo
fully equipped rock polisher
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Post by drjo on Mar 13, 2012 11:48:55 GMT -5
If you made it with a 3 ft wand you could only get a toe or something I tried to seek up on you and get your rocks but I only made it as far as St. Augustine and it got to cold Dr Joe .
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