cvgjnh
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Post by cvgjnh on Jun 23, 2018 14:19:03 GMT -5
Hello all! I'm not sure if this belongs here as this isn't "rock tumbling" but more "metal tumbling" but I guess it's worth a shot! I'm particularly interested in giving my metal fidget spinners a smooth tumbled/stonewashed finish to round off any sharp spots. Can this be done with this tumbler: www.amazon.com/Thumlers-Tumbler-MP-1-Rock/dp/B000BUW5ZM with aquarium gravel as the media? For reference, this is the result I'm trying to achieve. I know that aquarium gravel is not the most optimal media but ceramic media (which is what I've heard is best for metals) is quite expensive and I'd like to be low-budget (at least for now). Would aquarium gravel damage the tumbler? I'd assume not since rocks are normally tumbled there but I'd like to be certain. Also, am I correct in assuming that aquarium gravel would only wear away at metals that are softer than it? Most of what I've read online regarding metal tumbling is about polishing, which is not exactly what I'd like to achieve. However, if I were to polish my spinners, what media would I use? I've heard the mention of steel shots but would that work for stainless steel or harder metals? Would I need to add any liquids such as water to the mixture when tumbling my spinners? Sorry for the question overload! I just couldn't find much information on this topic elsewhere on the internet!
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Post by rmf on Jun 23, 2018 17:09:34 GMT -5
cvgjnh These are all good questions and you will need to take a healthy dose of experimentation. The finish on the spinner pictured looks more like a sandblasted finish. In that image the inner part is polished so are you planning to tumble both parts together. If so the inner part will get the same finish as the outer part unless protected. That thumbler tumbler should work fine. Aquarium gravel might work, play sand from the local HW store might work, Other rough rock pieces (quartz family) might work. Ceramic pieces. Aquarium gravel will not damage that tumbler. what ever you put in the tumbler will ware away at anything you put in the tumbler. parts, sand, gravel... To polish metal I would start with plastic media with abrasive impregnated in it for metal tumbling, Then to polish SS I would try walnut shells and cerium or yellow rough or aluminum oxide. If you just want to deburr SS shot or ceramic media or small rocks should deburr. SS shot works by peening the metal not abraiding the metal. Yes it will work on SS metal as well though may be slower. Normally you would use a burnishing soap. Burnishing is what the SS shot does to the metal. For tumbling with rocks just water and a pinch of soap (any kind will work) unless you are trying to grind then you would add grit of some type. I have tumbled brass pieces, gold jewelry, silver jewelry and wrought iron. The wrought iron was from a house in the 1600's and we were cleaning the metal prior to painting. I just dump the parts in with a batch of rocks in the tumbler with 220 grit an it cleaned them up in an hour or so. (It was a vib tumbler so it worked faster).
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pizzano
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Post by pizzano on Jun 23, 2018 18:05:11 GMT -5
Having some experience with cleaning, polishing and resurfacing metal casings such as brass, nickel plated brass, steel, used for ballistics, I'd recommend purchasing a bowl type vibrating tumbler made just for that purpose........rotary tumblers will not perform as well, can damage casings and take entirely to much time.........and the variety of media used in rotary's will be limited due to the possible damage or un-wanted blemishes it will leave on the subject material.
With vibrating tumblers, like those sold at Harbor Freight, Walmart or Sporting Equipment shops, one can find prices anywhere from $40.00 to $100.00 new. The majority come as "dry" tumbling equipment and use many varieties of ceramic, poly resin cutting abrasives, as well as processed grits, sand, walnut shell, steel shot, stones......you name it........even some of the Lyman brand vibes can be used with "wet media" and make for great stone polishing results.
The "proper tool" for any specific application, will provide less headaches and frustration, in the long run. Saving time and money while achieving the best outcome and results.
Just something to think about....!
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cvgjnh
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Post by cvgjnh on Jun 23, 2018 18:42:41 GMT -5
rmf About the spinner finish, it is a deep stonewash finish created by a vibratory tumbler I believe. I don't need my results to exactly match that as I have some different goals in mind, such as cutting down on the sharp edges. I will keep your media suggestions in mind if I don't achieve what I want with aquarium gravel. I'm not sure how hard aquarium gravel is on the Moh's harness scale; perhaps you know? I'd assume harder is better in my situation. You mentioned that small rocks should deburr - I assume aquarium rocks fall into that category. The materials you mentioned to be used in SS polishing is very interesting... lots of words that are new to me. Would those materials also apply to other metals like brass? And what about tungsten? With a moh's hardness rating of 8, is it even possible to polish or deburr it? Also, how much water should I use? And what exactly is the purpose of soap in tumbling? Edit: What do you mean by "grinding"? Would tumbling my spinners in aquarium gravel be considered "grinding"? pizzano You are saying that I shouldn't use a rotary tumbler mainly because it can damage and alter the shape of my metal, right? Though achieving a nice even finish is nice, my main goal is to deburr my spinners, which requires some "damage" to the body. I have found a great deal on the tumbler I linked so I would either be buying that one or none at all. Also, I live in Canada so I don't have access to many of the low prices those living in the US do. Could you explain what you meant by "the variety of media used in rotary's will be limited due to the possible damage or un-wanted blemishes it will leave on the subject material"? I have not heard of such a difference between rotary and vibratory tumblers.
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pizzano
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Post by pizzano on Jun 23, 2018 20:16:12 GMT -5
" You are saying that I shouldn't use a rotary tumbler mainly because it can damage and alter the shape of my metal, right? Though achieving a nice even finish is nice, my main goal is to deburr my spinners, which requires some "damage" to the body. I have found a great deal on the tumbler I linked so I would either be buying that one or none at all. Also, I live in Canada so I don't have access to many of the low prices those living in the US do.
Could you explain what you meant by "the variety of media used in rotary's will be limited due to the possible damage or un-wanted blemishes it will leave on the subject material"? I have not heard of such a difference between rotary and vibratory tumblers."
Rotary tumbling relies on a more violent friction action (rolling-bouncing)......best applied with wet "slurry" application, which (in combo) with media like grit, increases the "grinding". Vibe, on the other hand, horizontally circulates while also vertically rotating the subjects without the violent bouncing/rolling......at a higher rate of speed and motion.........combined with media (dry or wet), a more consistent and even surface preparation is applied.
Given your desire to "debur" rather than finish or polish the subject material, the use of media that is angular to include ceramics/poly imbedded with abrasives or angular/rounded steel "shot" of the size of 4.5mm to 5.5mm will serve the purpose in a vibe......in a rotary they would have to be applied dry and can pit/fracture/knick the subject material........remember, it's the media doing the "debur-ing" work here. That is why media selection is critical for your application.
I've tried rotary tumbling with my re-load casings as well with other smaller metal items that needed more than just clean-up and rust removal.......a complete waste of time.......Vibe is the way to go......don't let the "subjective/perceived gentle" action vibes provide fool you.........given the "proper" media application and a vibe with horse power, they can reduce a .50 caliber casing to the size of a .22 if not monitored effectively......!
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jamesp
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Post by jamesp on Jun 24, 2018 4:03:41 GMT -5
I tumble metals in a rotary cvgjnh. The vibe may be the better way to go for de-burr and/or finish. However I was most interested in completely rounded edges throughout and the rotary accomplished that best. The rotary shapes edges better. . The jewelry bezels simply to remove burrs as a minimum. To completely round edge as a maximum. The jewelry bezels seem similar to your task. Real simple. thickness is .030 to .070. Soft metals, including a soft version of stainless. 1) gas build up is a problem with metals so I use a 10 pound capacity "slant rotary tumbler" that allows venting. 2) copper, stainless, nickel, brass were main targets. 3) I used 50% to 70% sharp granite pea gravel and SiC 60 WITH WATER for at least a week for burr removal. Longer to get completely rounded edges. 4) Once edges were shaped or burrs removed I hammer finished the scratches from the SiC 60. However if you wanted a smoother finish go to 220 grit or 500 grit. Metal is more stubborn than one would think. Completely rounding the edges could take up to 3 weeks in SiC 60. I had barrel filled to 75%. Never damaged or bent any metal, not even annealed soft thin roofing copper If you choose to use a sealed horizontal rotary then you best check it daily to see if it needs venting. To just remove your burrs you may get by with quartz or granite pea gravel and forget the abrasives. You could try it dry and probably eliminate the gas build up.
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Post by rmf on Jun 24, 2018 7:43:48 GMT -5
cvgjnh Most of the aquarium rgavel I have seen appears to be dyed type rock possibly quartz/agate I have also seen quartz pea gravel used. Grind -- means to remove material by abrasion All tumblers work in this fashion. Rotary tumblers have more of a drop so there is more concussion than in a vib tumbler. The sharper the media the more grinding. The rounder (pea gravel, ss shot) the more peening. As jamesp points out metals are different than rocks. It is way less brittle. It will grind different than rocks. I would say that all metals can be processed in a tumbler. rotary or vib may make a difference in the recipe (abrasives, media, time...) Water acts as a media carrier, soap reduces surface tension and makes thing slippery while keeping mud or metal pieces from sticking. Aslo when tumbling any hole will fill up with what ever you do not want in it. Rotary tumblers tend to round more and vib tumblers tend to keep the original shape the same, just rounnd the edges. Both have their purpose. Vibs are better for flats and concave areas. pizzano makse so great points about the vib tumbler. If you know someone close to you with a tumbler would they let you do some tests before you fork over $$? Tumbling tungsten could be done with abrasives like Al2O3 and SiC they are hardness of 9 and 9.5 respectively.
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cvgjnh
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Post by cvgjnh on Jun 24, 2018 14:38:03 GMT -5
pizzano Since, the only option I have at the moment is a rotary tumbler, could you provide some links to medias that fit my needs? Why do you say that the media will have to be applied dry? That seems quite contradictory to the other advice I seem to be getting. Lastly, why do you say that tumbling your re-load cases with a rotary tumbler was a waste of time? jamesp Thanks for the advice! I would probably be tumbling for short periods of time at a time so gas buildup shouldn't be a problem. Would you consider this to be pea gravel. It's my first time hearing the term so I don't know. Could I skip the SiC entirely? What difference does using it make exactly? I'm not sure I completely understand the concept of abrasives. What exactly are th differences between an abrasive and media? Does gas buildup only occur when using liquids? rmf What exactly is the difference between peening and grinding? Unfortunately I don't know anyone with a tumbler so I would have to buy one to test it. I don't think I'll do any tungsten tumbling if I have to anything special. haha
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Post by rmf on Jun 24, 2018 14:53:08 GMT -5
Peening is to (polish, shape, work harden) by hitting with a ball peen hammer (originally). The ball on the end of the hammer was polished. This is partly why jewelry is tumbled in steel shot. See also: en.wikipedia.org/wiki/Peening
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pizzano
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Post by pizzano on Jun 24, 2018 15:44:31 GMT -5
Here's a link to the types of media I'm referring to......I'm not suggesting you purchase from Kramer....:
www.kramerindustriesonline.com/tumbling-media.htm
Here's another link explaining the process and identifying the type of equipment/media applicable to each application.....:
www.kramerindustriesonline.com/finishing-guides.htm
The links will explain what we've all been attempting to disclose much better.........take the time to digest the information Kramer provides. They are one of the leaders in the industry.....!
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Deleted
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Post by Deleted on Jun 24, 2018 16:20:46 GMT -5
Glass beads are used in blasters to deburr titanium machine parts. Do you know anyone with a sandblaster you could borrow? I share the concerns of some here. Using rocks or grits intended for harder materials is really going to wear down your metal before it gets rid of all the burrs. And even if you use softer material to tumble, you are still going to get some scratching from metal edges hitting smooth surfaces.
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jamesp
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Post by jamesp on Jun 24, 2018 22:08:46 GMT -5
Yes that pea gravel has Mohs 7 quartz would leave a soft matte finish on most steel in a rotary or vibe. You should fill your barrel 60 to 70 percent with that gravel and add some of your parts and give it a roll. I had to crush aluminum oxide grinding wheels into small pieces to frost my wife's lamp parts in a rotary.(almost a coarse sand blasted finish) She runs them for about 4 hours. We run quartz pea gravel for a matte finish. If you try to drill a piece of quartz it will dull the hard steel with ease. Metals are tough, think about a plow disc going thru quartz rich soil. You have both high grinding pressure and abrasive. The main factor with metal is the grinding pressure and the speed, size, sharpness and hardness of the abrasive. An angle grinder spins at 10,000 RPM and grinds metal at a rate in relation to the size sharpness hardness of the abrasive and the pressure. A rotary tumbler has little pressure or speed so it is a most gentle metal removing device. A vibe use high speed direction reversals and has the ability to cut metal quickly. Adjust a large metal vibe to travel a millimeter at 3000/60 = 50 times a second and extreme speeds and forces are involved. Low density ceramic media and proper adjustment is used in a metal vibe to polish or abrade aluminum to avoid damaging it's shape. High density for harder metals that will not get damaged and might be hard to abrade. Ceramic media in most metal operations is an abrasive. Most of ceramic media is Mohs 9. Most of it is for abrading, some is for polishing. It is an abrasive. If we put or agates in a vibe intended for metals it would tear them up. Rock vibes are gentle compared. Information on media as related to metals can be found at Kramer. I think you will find 80 to 120 pounds density ceramic media and polishing to coarse abrading media. I will copy Kramer's general description of ceramic media: Ceramic Tumbling Media Applications Ceramic media is recommended for general purpose polishing, light and heavy deburring, fast and extra fast deburring and ultra aggressive metal removal. Ceramic media is best for heavy cutting and hard metals. When a small media is required (under 3/4"), ceramics offer the best selection. Ceramic media supports very heavy parts better than plastic media. Advantages of Ceramic Tumbling Media Durable, inexpensive and highly versatile, ceramic finishing media is the most common media used in mass finishing. It can be manufactured in a wide variety of precise shapes, which assists in separation and elimination of lodging problems. Ceramic finishing media is made of silica and other minerals and abrasives that are combined, formed and fired at a high temperature, producing a very hard, cement-like product. Most ceramic preformed shapes, such as triangles, stars and ellipses, are extruded and cut to the desired length. The density of ceramic preformed shapes is usually determined by the amount of abrasive incorporated into the mix prior to firing - the more abrasive, the higher the density. This is important because the higher the density, the more "aggressive" the ceramic media will be (faster cutting, rougher surface) and the quicker it will wear. Therefore, dense media is only practical where the objectives cannot be achieved any other way or where the reduction in cycle time brings a greater value than the extra cost in media consumption. The type and quantity of abrasive grain can be varied to accomplish particular tasks, depending on the bond selected. Ceramic media by color code - www.kramerindustriesonline.com/tumbling-media/ceramic-media/ceramic-angle-cut-cylinders.htm
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cvgjnh
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Post by cvgjnh on Jun 25, 2018 11:55:28 GMT -5
pizzano Thanks for the links! Lots of useful information on there but it's a bit of an information overload for me. For a finish like the one I linked in my original post, would you suggest dry tumbling or wet tumbling? Would sand help in finishing areas that are too tight for the gravel to fit into? @rocks2dust Unfortunately I don't know anyone with a sandblaster. What do you mean by "Using rocks or grits intended for harder materials is really going to wear down your metal before it gets rid of all the burrs"? What harder metal could it be intended for? And wouldn't wearing down the metal get rid of burrs at the same time? My thought process is: if it gets enough scratches, it'll eventually even out the finish. jamesp So my original setup would work, right? I don't have enough funds for ceramic media but I might consider them in the future. I would like your opinion on wet vs dry tumbling. In your previous post, you suggested I do wet tumbling. Why is that?
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jamesp
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Post by jamesp on Jun 25, 2018 13:31:03 GMT -5
pizzano Thanks for the links! Lots of useful information on there but it's a bit of an information overload for me. For a finish like the one I linked in my original post, would you suggest dry tumbling or wet tumbling? Would sand help in finishing areas that are too tight for the gravel to fit into? @rocks2dust Unfortunately I don't know anyone with a sandblaster. What do you mean by "Using rocks or grits intended for harder materials is really going to wear down your metal before it gets rid of all the burrs"? What harder metal could it be intended for? And wouldn't wearing down the metal get rid of burrs at the same time? My thought process is: if it gets enough scratches, it'll eventually even out the finish. jamesp So my original setup would work, right? I don't have enough funds for ceramic media but I might consider them in the future. I would like your opinion on wet vs dry tumbling. In your previous post, you suggested I do wet tumbling. Why is that? Consider 60 to 70% barrel fill to start. I actually did 50% barrel fill to increase the aggressiveness. And I only ran them wet, not much water. No good reason for running wet (see end of post, wife answered the water question) The rotary is really too gentle for soft metal. (bronze boat props are extremely resistant to abrasion.) soft rubbery stuff like copper and german silver is slow to abrade. very slow You can tumble a rubber ball for years and it will hardly wear in a rotary. Just put the gravel you pictured in the rotary and stick a couple of steel bolts in there and see what happens. My wife experiments with all kinds of gravel media and agate chips and glass chips and grinding wheel chunks with here lamp parts. They can be stainless brass bronze copper zinc. She is master Most of the time she is trying to remove galvanization(zinc) so the parts will generate a rust patina. ah, she says she runs water to keep it quiet and circulate abrasive, guess that answers that question lol. Sticks abrasive to the parts....important point. 99% of industrial tumblers are vibes because of their shear speed. Not a thing wrong with a rotary for metals. Now holes in you metal are a problem. If her part has 1/4" hole she uses 1/2 inch media so the media won't jam in the holes(heard her cussing that issue) A tumbler can jack hammer media into holes in your target.
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Deleted
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Post by Deleted on Jun 25, 2018 17:04:06 GMT -5
What do you mean by "Using rocks or grits intended for harder materials is really going to wear down your metal before it gets rid of all the burrs"? What harder metal could it be intended for? And wouldn't wearing down the metal get rid of burrs at the same time? My thought process is: if it gets enough scratches, it'll eventually even out the finish. Yes, it may eventually even out the finish, but in order to do that, for each scratch, the media will have to lower the entire surface of the metal part to the depth of the scratch. Same with burrs, it is not just the burr that gets sanded down in a drum, it is the entire piece. That is why for parts where people want to maintain the original shape and size, or just reduce the amount of metal lost, other techniques are used so that it is only the burrs that are attacked (files, glass or dry ice micro-blasting, etc.).
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