lordsorril
freely admits to licking rocks
Member since April 2020
Posts: 866
|
Post by lordsorril on Sept 25, 2020 19:04:25 GMT -5
Anyone here tried brown aluminum oxide in a vibe tumbler? If so, what were your results? Does it function the same as white?
My specific question: Can it be used as a pre-polish step in a vibe? I'm due to restock my 500 grit and I can get 100lbs. of brown AO for $190 (shipped).
|
|
|
Post by Mel on Sept 26, 2020 15:46:23 GMT -5
I *believe* it has something to do with the heat tolerance of white (2100F) vs brown (1850F) but unfortunately I don't know more than that. Doesn't seem like any method of polish application would get that hot. Some sites say you can use what you prefer but haven't found anything that says the difference between them.
I'd say try it, as long as the grit sizes match what's the worst that could happen?
Sorry for the unuseful information, but that's all I ever found about it when I was looking.
|
|
EricD
Cave Dweller
High in the Mountains
Member since November 2019
Posts: 1,142
|
Post by EricD on Sept 26, 2020 16:03:07 GMT -5
"Perhaps one of the most commonly used abrasives for sandblasting, surface prep, carving and etching. Aluminum Oxide (brown or white) is tough and will give you many repeated impacts. Brown aluminum oxide is not friable, it does not break apart easily and keeps its shape and cutting edge. As it wears it slowly rounds itself out. White, on the other hand, is friable, as it wears it slowly shears apart, which has the effect of creating new cutting edges."
Edit: I should add that as white AO shears apart and creates new cutting edges, the edges are continually smaller and smaller, effectively creating new, smaller grit, until it eventually becomes so small that it is finer than new AO polish. However, rounded brown AO will also impart a polish as it is essentially becoming a rounded, polished stone it's self.
The question is, will the brown AO remove all the scratches as efficiently as the white AO, before it loses all of it's cutting edges?
|
|
lordsorril
freely admits to licking rocks
Member since April 2020
Posts: 866
|
Post by lordsorril on Sept 26, 2020 19:37:35 GMT -5
Thank you Mel and EricD for the info. It does not seem like Brown Aluminum Oxide is very popular. I suspect there is a reason. I ordered 5lbs. as a test material and will post my results. I normally buy my 500 grit white AO in 40lb. bags from The Abrasive Armory, but, my friend tells me that they do not have any in stock and they are considering no longer carrying it (as it is not a popular item). I have quote requests out to different blast media companies, but, I doubt they will be able to match the price I was paying originally.
|
|
EricD
Cave Dweller
High in the Mountains
Member since November 2019
Posts: 1,142
|
Post by EricD on Sept 26, 2020 21:58:30 GMT -5
I snatched that quote from him (the abrasive armory). I'm pretty sure he will stock anything you want to order if you ask him to. He can always order it in, I'm sure. Otherwise a slightly coarser grit can do the same damage to your rocks in the long run, meanwhile, since it will eventually break down into polish.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
|
Post by jamesp on Oct 2, 2020 5:32:41 GMT -5
This article solved my questions about aluminum oxide - www.azom.com/article.aspx?ArticleID=1389Fused aluminum oxide is the form used for abrasives: "Fused alumina is made in electric arc furnaces by passing a current between vertical carbon electrodes. The heat generated melts the alumina. The furnace consists of a water cooled steel shell and 3-20 tonne batches of material are fused at any one time. The fused alumina has a high density, low porosity, low permeability and high refractoriness. As a result these characteristics, it is used in the manufacture of abrasives and refractories." Other types of aluminum oxide include smelter grade, calcined, low soda, reactive, tabular and high purity. These formulations are used for applications other than abrasives. Pick your favorite color, fused AO. I have used grey brown white black and can't tell any difference.: Fused aluminum oxide grinding wheels in many colors. Bonding agents and additives and particle shape come into play relating to performance. Particularly particle shape and it is short lived in a rock tumbler. Good luck finding pink and ruby. ofieldindustrialsupply.com/index.php?main_page=index&cPath=5&zenid=58mgvbr08epp1cs7kmlareuk91Good descriptions by Alchemy. For rock tumbling we won't likely see a difference. It is just fused AO with various additives adding to toughness and hardness on a small scale. alchemymineral.com/brown-aluminum-oxide
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,561
|
Post by jamesp on Oct 2, 2020 6:22:03 GMT -5
|
|
lordsorril
freely admits to licking rocks
Member since April 2020
Posts: 866
|
Post by lordsorril on Oct 11, 2020 10:58:25 GMT -5
|
|