Schey, J.A., Venner, T.R., Takomana, S.L.: Shape changes in the upsetting of slender cylinders. J. Eng. Ind. Trans. ASME 104(1), 79–83 (1982) Narayanasamy R, Pandey KS (1997) Phenomenon of barreling in Al solid cylinders during cold upset-forging. J Mater Proc Tech 70:17–27 The barreling compound, it’s important, not so much for the jewelry pieces itself, as many might thinking, but mostly to keep the steel shots lubricated and keep the dirt and oxidized dark matter off from the pieces, into the barreling liquid suspension. Polishing – produces a semi bright finish on many metals, reduces work on polishing wheels and does not damage delicate items. It’s the dies that separate open die forging from closed die forging. With “open” dies, the part of the die that compresses the metal is typically flat, or slightly contoured so that the metal is compressed between the two surfaces. Other variations of open die forging, the dies can be curved, or even V-shaped, but the metal is never fully encased within the dies. Open die forging process

But the amazing mix from Metal Clay, contains balls and pins and planetoids, so small, 1mm, 2mm that can enter in any nooks and crannies of even most intricate and fine jewelry imaginable. Of course, there are also larger size shots, 3, 4 and 5, but the majority is of those finest dimension. Banerjee, J.K.: Barreling of solid cylinders under axial-compression. J. Eng. Mater. Trans. ASME 107(2), 138–144 (1985) To summarize, open die forging differs in its process from closed die forging (impression forging) by the shape of the dies used. Typically, open dies are flat, possibly concave or v shaped, but always open. Closed die forging on the other hand uses dies that completely encase the metal, allowing it to fill up the space between the dies. Li, Y.P., Onodera, E., Chiba, A.: Evaluation of friction coefficient by simulation in bulk metal forming process. Metall. Mater. Trans. A 41A(1), 224–232 (2010) The majority of abrasive operations are carried out with wood pegs, since corn cob grit and walnut shell grit are too light to create sufficient friction. All carrying agents should be of a size which makes part separation easy and which will not lodge in any holes or crevices. Therefore, carrying agents come in a variety of sizes. Media

Technical Details

Centrifugal barrel tumbling uses a tumbling barrel at the end of a rotating arm to add centrifugal forces to the barreling process. This can accelerate the process 25 to 50 times. [5] I have used it on sterling silver & it did give a nice soft polish (with barrelling compound) but not the lovely shiny mirror finish I am used to. When used on ArtClay Copper it didn't smooth the finish as much as my previous shot did - it was almost pitted in some places. The main benefit of using a tumbler is the amount of time you will save compared to polishing by hand. You can make a batch of jewellery and tumble polish it all together, this not only saves you time but it frees you up to get on with the next task -which is particularly important if you are making your work to sell.

Im so pleased with my mini tumbler, the instructions are very clear and easy to follow and the results are fabulous, this is going to save so much time. Narayanasamy, R., Sathiyanarayanan, S., Ponalagusamy, R.: A study on barrelling in magnesium alloy solid cylinders during cold upset forming. J. Mater. Process. Tech. 101(1–3), 64–69 (2000) Dadras, P.: A semi-empirical solution to upset forging. J. Eng. Ind. Trans. ASME 103(4), 478–483 (1981) Stroud, P.D., Sydoriak, S.J., Riese, J.M., Smith, J.P., Mniszewski, S.M., Romero, P.R.: Semi-empirical power-law scaling of new infection rate to model epidemic dynamics with inhomogeneous mixing. Math. Biosci. 203(2), 301–318 (2006) The kit provided by Kernowcraft includes an electric motor base, one 3lb plastic vaned (paddled) barrel, 500g of mixed shape, rust-resistant stainless steel shot, 500g of barrelling compound (barrelbrite), easy to follow instructions and a 1 year motor guarantee.

Resources, guides & advice from the jewellery making experts

Open the barrel (if I'm using the plastic barrel I put the lid-end in HOT water first to soften it), drain out most of the old water which my shot has been sitting in. If you put too much, the extra foaming in the barrel could cause the lid to pop off during tumbling, the liquid pouring into the tumbler etc. Now, I experimented with this compound; if you use lesser than necessary, you will get the dark matter spread onto all the pieces inside, is much worse than not cleaned :-(

Yao, Z., Kim, G.-Y., Wang, Z., Faidley, L., Zou, Q., Mei, D., Chen, Z.: Acoustic softening and residual hardening in aluminum: modeling and experiments. Int. J. Plast. 39, 75–87 (2012) It is a lot smaller with many of the pieces being the size of poppy seeds....poppy seeds which ping and bounce everywhere when I am decanting the shot after tumbling. Malayappan S, Narayanasamy R (2003) Some aspects of barreling in aluminium solid cylinders during cold upset forging using die with a constraint. J Mater Process Technol 135:18–29

Origin of barrel

Another major reason for consideration is that the concentrated compression enables manufacturers to form net- or near-net-shape components (whereas with conventional forging, you’d likely pay high prices only to machine up to 95% of it away as waste). Rotary Forging Applications