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Messages - FlashGP

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1
Ask a "Silly" Question / Re: Can you refreash laps?
« on: January 22, 2020, 08:08:33 AM »
Antibacterial Palmolive Dishwashing liquid with lemon is acidic enough to brighten your lap without pitting it if you use it straight with a scourer or a bit of cuttlefish and wash it off straight away.

Don't let it sit on the lap for long.  I pit a couple of shallow pits on the surface of a zinc lap (zinc is more reactive) when I put it down covered in detergent to run an errand.  Two drops of water hit the surface and in the 5 minutes I was gone, reacted with the zinc pitting it.

The pits were shallow and have since burnished out with euccessive cleaning and dressing of the lap.

2
Hi Alan,

Get in contact with Peter Stringfellow or Gary Gatfield when he is at NBLC and have a chst to either of them.  They can point you in the right direction.

See you at the February Motrton Bay Facetors Group meeting.

Regards
Gordon

3
Ask a "Silly" Question / Re: facet cutting speed
« on: January 20, 2020, 07:17:09 PM »
I sourced my 150w 12v dc motor from them.

4
Hi Kylie, there are several lapidary clubs in Brisbane, all have faceting nachines. 

Some have waiting lists, but depending on his level of experience he may be able to find a club with a machine he can use at the club while waiting for a machine to buy.

Let me know your grandfather's location and I'll give you a list of local clubs.

Also, try contacting Gemcuts in Balina.  Brian boughtvthe Gemmaster business lastcyear and has been fitting dc motors to older motors.  I understand he is gearing up to make new Gemmasters, but maay have heard of 2nd hand machines for sale.

5
Ask a "Silly" Question / Re: facet cutting speed
« on: January 14, 2020, 09:04:30 AM »
12v power supplies range in price.  A conventional transformer based power supply to drive a 120w 12v motor  can cost more than $500 for parts and an electrician to build ut.  The big cost is in the transformer which is big and heavy.  But they are robust.

As a rule of thumb, you need about twice the wattage in your power supply as in the motor.  E.g . 120w motor needs a 240w supply.  At 12v that is 20 amps.

This is because at low speeds the motor impedance is lower so it draws more current.

BUT you can buy a Chinese 25Amp (300W) switched mode 12v supply for about $35 from Banggood if you don't mind waiting 6 weeks for it to arrive.  Aussie electronics suppliers have them as well but a little bit dearer.  If you blow a couple, it us still cheaper than a traditional supply.

 You should keep them under a little load for a longer life.  I use a 10w 22 ohm load resister across the 12v rails.  It dissapates 6w.  But a 33 ir 47 ohm resistor would be better, it wouldn't get as warm.

A 40amp reversable pulse width modulator (speed controller) costs abt $15 from banggood.

All up my power supply for my concave machine cost me about $100 to build, including a housing (half the price) and terminals and fuses (I put fuses on both speed controllers as I only have 10 amp wiring as my concave machine has 2 motors, both less than 60w.  My 2nd speed controller was a single direction 10 amp pwm costing abt $4.  It regulates oscillation speed.  You don't need it for a faceting machine.

I over rated the supply as a 25amp supply is only a few dollars dearer than a 10amp supply, and if I needed a bigger motor, I don't need a new supply.

I also have a 150w 12v motor as a spare for when my faceting machine motor blows.

Regards
Flash

6
Gemstone Faceting / Re: Looking to buy a Patriot machine. Any comments?
« on: January 09, 2020, 07:27:04 PM »
Hi Ghost,

Bunnings sells 1/4 inch aluminium rod in metre lengths for abt $6.

At a pinch your club member msy be able to make his/her own dops u ntil they can source brass ones.

The Hall dops are the perfect size for making bullets for 303 rifles as they are about a thou under the bore size.   >:(

I have been thinking of making some 25cal concave cutter mandrels from the aluminium as I don't have a lathe, but it should be relatively uniform in diameter.  Being soft it should take a good charge, but may need to be recharged after a couple of stones.

Any thoughts?

Regards
Flash

7
Gemstone Faceting / Re: Info on Batt Lap
« on: January 09, 2020, 07:07:50 PM »
Lapping it on wet and drt on a glass surface works fine and is faster than lapping a metal lap.

  Andrew at Aussie Sapphire can also machine it for you.

8
Forum Announcements & Rules / Re: Christmas
« on: December 20, 2019, 07:04:32 PM »
Aye, merry Chrjstmas to one and all. 

Lets hope for some rain in the fire affected areas to regenerate the bush.

9
Gemstone Faceting / Re: Info on Batt Lap
« on: December 20, 2019, 07:02:43 PM »
It looks like a Darkside Lap.  Jon (Gearloose) Rolfe makes both.  It is pollible it has been mislabled


The Darkside is a ceramic lap good for a wide range of hardnesses.  Magic with oxides as well as quite good for use with Diamond.

Use microscopic amounts of polishing compoind.

I apply 2 squirts of diamond to a facewipe, then a few drops of extender to the facewipe and waive it over the surface of the spinning lap, actually I use the facewipe to clean the lap, this transfer s a  invisible amount of polish to the lap, that is sufficient.

If using Bat Stick, draw a ring near the centre of the lap and slow drip water  on it, what flushes over the lap is enough to polish with.  Periodically renew line.

Happy Faceting

10
Gemstone Faceting / Re: Stepper motors Fantasy machines
« on: November 18, 2019, 07:14:39 PM »
Welcome to the forum Gasdasmi.

I am not quite sure what you are asking.  Would you please elaborate?

Regards
Flash

11
Gemstone Faceting / Re: please advise on lap choice
« on: October 31, 2019, 07:34:49 PM »
Thanks Frank,

I'll give it a go on the next stone I polish.  I am about ready to convert my BAT lap into a prepolish lap because it keeps glazing up and throwing small specs of lap surface while polishing with 100k diamond.

I'm blaming subsurface damage from the initial cut nrrded to temove diamond when I had it machined.

12
Gemstone Faceting / Re: please advise on lap choice
« on: October 31, 2019, 08:33:56 AM »
Hi Giel,

Bugger all diamond means you put a tiny amount of diamond on the lap and then wipe it off before you polish.  When I first started faceting Bob Boddington advised me to use a tooth pick to take a small amount of polish and put it on the lap.  Then to add 4 drops of diamond extender to the diamond and smear the slurry over the lap with my finger.  Then to wipe it off before I started faceting.

I now mix my own diamond spray, 2cts diamond, about 3/4 fiamond spray bottle of isopropyl alcahol and 10 squirts of Orange Power bench spray, any thin spray and wipr detergent will work.  This is to make the diamond disburse in the alcahol better and stop it clumping.

I then put several drops of extender on a face wipe used for makeup removal and 1 or 2 sprays on the facewipe.  This is then used to clean the lap as I facet.

I have a creamway and a darkside lap.  The darkside is more versitile and will take oxides or diamond.  It is particularly good for oxides.  I use Batt Sticks to draw a light line of oxide near the centre of the lap then slowly drip water on the line.  The small amount that washes over the lap is sufficient.

Zinc, copper, typemetal and bearing metal (pewter) all trap diamond in the surface of the lap.  I spray 4 evenly spaced squirts of diamond mix on the lap and using a roller bearing fron skate board wheels on a handle, roll the diamond into the lap surface changing direction once I have gone from side to side.  Then wipe the excess diamond off the lap.  I do this on the table before faceting to support the lap and avoid diamond spray contaminating my machine.

Use a different bearing for each grade of diamond.

You will need to recharge occasionally depending on the hardness and number of stones you cut.

I often just add extender to a facewipe and rely on the impregnated diamond to do the cutting.  I can even flush a charged lap with water when cutting quartz.

Regards
Flash

13
Gemstone Faceting / Re: MB concave build
« on: October 28, 2019, 08:33:54 AM »
Hi Giel,

Necessity is the mother of invention.  Yours looks a bit nicer than mine,  maybe I should buy a 3d printer.  Rej (Gem Cut Studio) Poirier madr his faceting machine using one.

The neatest oscillator I have seen is on the VJ, it is two disks with a ball bearing race and offset locators that screw to the machine's platten and the base of the cutter housing.  But this is way beyond my capability using silversmithing tools and a bench drill.

14
Gemstone Faceting / Re: MB concave build
« on: October 28, 2019, 12:29:17 AM »
Hi Giel,

I just used a small 30rpm 12v motor from Banggood.  It is tiny and looks like a motor from a model, but it is geared with a worm drive and  works better than a 2w turntable motor from a microwave oven, safer too.

I made an arm that fits on the worm drive  out of some 10mm square rod drilled and tapped with my bench drill.  The taps are 5mm threaded holes and I cut and filed that part of the  arm o 5mm thick using a hacksaw and file.  The holes are offset and spaced at 15, 20 and 25mm from the centre giving me adjustments for the length of travel.

I then bought a male and female tie rod ends from Banggoood and connected them, one end to the arm on the motor, the other to a post on my base plate of my concave cutter.  Polarity isn't important for the oscillator,  the rotary motion of the arm pushes and pulls the cutter head equally well in CW or CCW rotation.  It looks a bit like a steam engine crank.

I just use a 12 to 36v 775 motor from banggood.  It does 3500rpm at 12v, 10,000 rpm at 36v.  With small diameter cutters, 3500 rmp is about OK.  I wouldnt use a slower motor, it takes too long to cut.

Switch mode power supply is the way to go.  They are cheap and have 110/220v terminals and 12v and ground terminals on the 12v side, plus an earth terminal.  They are about 1/4 the cost of a traditional supply and pack more punch.  I bought a 25amp supply for about $35 Australian.  It would have cost me about $300 for the 2 transformers needed for the same current  for a traditional supply.  I went big as the price difference between a 10A and 25A supplĂ˝ was only $10.  I figured if I needed bigger motors, I would already have the power supply.

The basic circuit is, mains in to the switch mode supply, with the Active Brown wire, rumming via a switch.  Two 12v wires 10A to from the power supply, one each to a pulse width modulator (dc speed controller). One set of wires from each pulse width modulator to a 4 pin plug, both motors are fed via this plug so I cant mix them up.

The small motor is controlled with a 10A PWM, one direction only, that cost about $4.  The big PWM can handle up to 40A at up to 50v.  It cost about $12  from Banggood.

next supply I make, I'lllhouse in an old computer case or CD case from the recycling shop, the plastic electrical box I bought cost me abput $50 and everything was a tight fit.

lastly, put a 47ohm 5w resistor across one of the 12v outputs.  Thiskeeps the switch mode supply under load when the motors arenot turning.  It is supposed to make the switch mode supply run better.

Regards,
Flash

15
Gemstone Faceting / Re: please advise on lap choice
« on: October 27, 2019, 11:59:40 PM »
I have been cutting and prepolishing using  3000 and 8000 on zinc, it is a little more aggressive tha n copper.

I have found a water drip works really well on both when prepolishing thr Quartz family, but Topaz and harder stones prefer an oil based lubricant.  Even Snale Oil  was too thin for a piece of Topaz I recently cut.  I had to thicken it with a couple of drops of 3 in 1 oil on my charging/cleaning facewipe.

Regards
Flash

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