Aussie Lapidary Forum

LAPIDARY => Tips and Gadgets => Topic started by: toppster on December 30, 2011, 03:35:05 PM

Title: using gyrok model A tips
Post by: toppster on December 30, 2011, 03:35:05 PM
 :oJust thought id give everyone some good info on using this tumbler.
Firstly unless you have pre ground your stones smooth say with 220 or more ignor the crapy instructions given with the machine,ill tell you why as i go.
first stage grinding-this depends a lot on the shape and roughness of stone but an eg would be agate ck agate rough cut in half.pre grind corners,ALL SHARP CORNERS or stones will crack or chip on the edges cracking will be more likely.use 220 grit no coarser or the bowl wont last long.if you want to get very rough stones cleand up 80 or 120 will do it quickly but 10 batches later you will have a hole in the bowl.also the coarser the grit the more under cutting will occur.when you purchase the machine buy 3 bowls and lids ,this is a must if you want to finnish the stones.use 1 for coarse ,1 for fine grind and 1 for polish.when loading for first grind fill to 1 cm from top depending on size of pieces a bit lower sag 1.5 cm for larger [2inch size]piecesingnore instructions regarding detergent use a tablespoon woth this way if you dont get to check for 14hrs your bit dry stones will still slip around instead of being stationary wearing a hole in the bowl.use 3-4 table spoons of grit[heaped]and 3 hand fulls of fine clean sawdust[pine is best]if you cant use saw dust they wont cut as quick and are more likely to crack from bashing to much.also add some plastic beads or on lrg stones or miked size stones i use reject grade zircons for media[say half a hand full of either or mixture of both]this will grind the concave depresions.when grinding very rough stones run for 2 day remove ,pre grind and go again with new grit mix[you can reuse the media].Water-very important to get this right, well how much,start with one third cup and run for a few min then add a little till sawdust sticks to rocks keep adding untill you get the odd little splash coming up[this will stop in an hour or so when the sawdust breaks down if not add a bit more sawdust.A few hours later the mix should be moving well and the colour of the stones shouldnt be visible [should be covered in mudy sawdust a bit like toothpaste consistency ].if any mix is splashing up at this stage its too wet.the dryer it gets the slower the stones move[finding the right consistency should be easy after a few batches
run for three days if stones are farly smooth to begin with or repeat after to days as the grit WILL be smaller after 2 days.
fine grind- USE A DIFFERENT BOWL[GRIT WILL IMPREGNATE THE BOWL].FOLLOW THE SAME PROCESS as the coarse grind but use 360-400 grit and a teaspoon or two more grit,run for 2 days.then repeat using 600-1200 grit for a further 3 days.Stones should be ready to polish if not seperate the ones that arent pre gind agian on a grinding wheel  with 320 then put in another batch at the 360-400 stage.
Polishing {can be frustrating with this machine particlatly if doing slabs or flatish stones]i use cerium oxide but you can use tin oxide.IF THERE ARE ANY HLOES IN THE STONES WHICH THERE USUALLY IS A FEW ULTRASONIC CLEAN THEM WITH A FEW DROPS OF DETERGENT AND WATER BEFORE THIS STAGE,YES I KNOW ANOTHER THING THEY DONT TELL YOU YOU NEED .  USE ANOTHER SEPERATE BOWL .[IT WOULD BE A BETTER MACHINE IF THIS BOWL WAS FELT OR LEATHER LINED.add 3 table spoons polish 2 handfulls of plastic bead cut up leather in strips or paper towel in strips add quarte cup water ,tablespoon detergent run for a few minutes, you want consitency a liitl dryer than with the grit add water if needed but do slowly or youl need more polish[100$ per kg can be expensive if you stuff it for 3 days then checkstones they may need a day or 2 longer.
Title: Re: using gyrok model A tips
Post by: mehoose on May 16, 2012, 08:24:45 PM
Crikey, that was a write up...and I missed it.  :o
Thanks for sharing your findings/technique. Certainly gives a new comer somewhere to start.
The more write ups by others gives options to try something new if they hit a snag with a type of material or polishing medium.
In a nutshell...  beers