Polish sticking to drum

[Graham]

hi all,
I have got to the polish stage in my first tumble and not getting a polish after 10 days in 1500 Ali oxide.  I emptied the drum to find almost all of the grit was stuck in a thick paste on bottom of drum despite having more than a cupful of milky liquid to drain off.

Can anyone help or explain why this would happen?

I'm polishing a mix of Mookaite and Noreena Picture jasper and followed Lortone instructions together with all the info I could find in ALF
Lortone 66 tumbler 2x 6 pound drums; 1x12lb drum
The story so far:

broke up a large (5kg) piece each of Mookaite and jasper to approx 25mm largest dimension but good range of sizes

approx 7 pounds of rock mix and about 2 cups of water added to new 12lb drum
24 days in 80 grit SiO shaping in 12lb drum, emptied cleaned and recharged with grit twice at 7 and 15 days
stones sorted and cleaned in soapy water after thorough rinse out of slurry all were well shaped, some little cracks were sent back for the next round

approx 4lb of stone
9 days in 220 grit SiO smoothing no recharge in brand new 6lb drum
stones noticeably smoother so went on to next stage after sorting and cleaning

8 days in 600 grit SiO brand new 6lb drum
3.5 lb, water and a few pellets (250g?) to fill drum to 2/3-3/4 full
stones are now very smooth but not shiny  so onto the polish.

Cleaned the 600 grit drum in fresh water, then warm soapy water twice with a thorough rinse between washes
then I put the stones and new pellets in the cleaned drum, added 3 spoons of Borax as a soap and let it run for a day before cleaning evrything again

made up a charge of 3.5lb of stones, 0.5 pounds of pellets and 12 spoons of 1500 AlO grit and set it going again checking every couple of days when no polish evident after 10 days

thanks in advance for helping this newbie, I have already learned a lot on these forums and hope to contribute once I actually know something

[Andrew]

There is no set right or wrongs with Tumbling but obviously your mixture needs tweaking on the polish stage.

The most likely cause is just that ration of Aluminium oxide to water is too great, easiest thing to try is halve the amount of Al and give it a spin, monitoring what happens. 

You also need to make sure that everything is very well stirred up again if the tumbler is turned off for a period as things can settle out of the slurry even after only a short time of the tumbler not rotating.  I did read of something similar happening to someone who loaded up his barrel but left it to sit while he took a phone call (he might have chatted on for a bit but even so, it isnt a long time).  Is this a possibility??

There are almost as many different ideas out there as there are people Tumbling, you just have to play around to see what works for you in the end. Lortone recommend in their guide to use more polish than Grit, most however suggest to reduce the amount of Polish - some sources even suggest that you can use half as much polish as grit but perhaps try about the same amount first.  Remember that you have many more particles of polish per unit weight than the coarse grit so a smaller amount should still be effective.

Remember also that grade of Aluminium falls into the middle ground of been a Pre-Polish or a polish depending on the type of stone - if it works that's great as it's the cheapest option.  Most recommend a 4 step process but for those recommending the 5 step process, the #1500 AlO is the ideal choice for that extra pre-polish step.  We would normally suggest trying Cerium first as a good choice of polish on most rocks.  Can also try Tin Oxide or a finer grade of Aluminium may work for you.

You're topping up with pellets so the load level should be ok.  I think someone here suggested tumbling with some strips of leather at the polish stage - never tried that but it sounds like a good idea to me if you're having trouble getting the polish to happen. 

Anyone else got any advice?
Cheers Andrew 

[llarson]

   We experinced "polish clump" once, figured we put a little too much rock in the barrel, never over 3/4 full. I always add the abrasive after loading the rock, then fill to just cover the rock w/water. We are believers in using leather as a padding, tried plastic pellets once and found it to float too readily for our liking, lots of people like it, maybe we didn't use the right kind of pellets. Never tried ALO as a polish, we use tripoli. Some quartz mtls. just seem to not really ever polish properly, a run in cheap powdered laundry soap mixed to a pancake batter consistency with water, and padding dedicated to that part of the process, seems to "burnish" the product to a better shine. We let that run for at least a week.
   

[Graham]

Thanks for the tips Andrew and Llarson.
Is any particular type of leather more suitable or can I cut up some old boot leather and use that?
I have redone the batch using more stone and water and less pellets and polish which seems to have solved the problem of the polish sticking to the barrel.
Maybe I'm expecting too much shine  from the 1500 grit. I am getting a satin like finish now which is an improvement from the first go round and now noticeably smoother than the 600 grit. so I am making progress if slowly lol

[mehoose]

Id I liken it to the wheels, I don't tumble, a good fine satin finish at this stage is excellent, gives a good base for polishing stages.

  I just re read your first post You mashed up a 5kg chunk of MOOKAITE AND NOREENA??!!! ARGHHHHHHHHHHH 

[Graham]

Mehoose, apparently the chunks were too fractured/faulty to cut polished faces so were in the bin at my local stone shop, normally I'd be as reluctant as yourself to break them up. and nearly couldn't do it anyway.

My designation as newbie is an understatement to say the least, complete novice would be more accurate as you've probably guessed by now.

Still encouraging to know that a satin finish is not a failure, so will get some finer polish ordered soon any recommendation for jaspers?

[mehoose]

I know on the wheels you don't start polishing till you've hit the 3000, 3000 would still be cutting but starting a polish if that makes sense. I'm guessing the cerium would be good for the jaspers.
I'm sure others will know the next best stage/s better than me for this.

[llarson]

    In answer to what leather to use, we use anything we can get cheap [garage sales, etc.] , but stay away from thin split leathers or heavily died stuff. Old boots, belts ,and purses seem to work fine.
                                             God luck, Larry

[Graham]

Thanks Larry, I will cut up some old safety boots I have in the shed for a start.
I have ordered some cerium polish from Aussie Sapphire so when that gets here I'll try the leather strips as well
thanks to everyone who responded.
I am now officially hooked on polishing rocks, not just collecting them

[calxoddity]

Hi,
  Been there, done that.  The 1500 is not fine enough to get more than a satin sheen.  Use plastic pellets or leather strips as the cushioning, and 0.5 micron aluminium oxide polish for shiny things to happen.

Regards,
Calx

[llarson]

  Egad, just as I clicked off I realized my error. Meant to say "dyed", as in colored, not "died". All leather has died.

[As I in does tries!]

Greetings "Graham", i take it that you are following the wasteful American rotary tumbling recipe?!
See my RTH (UK) Sticky #4 for more information.
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[Aussie Sapphire]

Greetings "Graham", i take it that you are following the wasteful American rotary tumbling recipe?!

This is particularly true of polish.  The Lortone instructions say for a 3lb barrel, use 4 tablespoons for grinding and 6 tablespoons for polishing.  This confuses quite a few people who buy this tumbler and read those instructions when we actually put half as much polish in our starter kits as grinding grit.  However, you dont need that much polish and often can use much less than recommended (plus recycling helps too).

I think a good idea though is start with the recommended amount and then see how much you can vary the amounts down.  That way, you get a good feel for how much is enough.

cheers
Leah