New equipment-media questions-pro help please!

[LabRatKing]

Well gang, a month or so and 1500$ USD later, I have upgraded/replaced, and modernized my prep lab. (pictures to follow once the new flooring and dust collector is delivered and installed) Between all the prep I need to do for my hobbies, my job, my degree, and many many vintage VW parts, plus an overall need for new toys when the budget allows... Well, that and my dissertation is coming up next year and I have to get my display ready for that...

 

I managed to finagle some really good deals on scratch and dent, factory returns, and industrial auctions so I got about 5+ grand worth of equipment really, really cheap. (All those years slaving away in factories fixing other people's junk finally paid off!)

 

Anyway, I purchased a slightly used bench top Cyclone Manufacturing media blast cabinet (retail around 300, got it for 50 as the hinges and lid seal were shot and the air inlet valve needed replaced so put 25$ into it).

 

Looking for suggestions for appropriate media to use in with fossil/artifact prep. I'm used to only working with metals for welding repairs and such, not sure if there is a specific media type for rock and stone. Winter is coming and I have years worth of specimens to play with while the weather is awful! If you have a preferred media, nozzle, outlet size, please let me know, I'd like to try it out!

 

To go with it, I installed an Ingersol-Rand 80 gallon 240 volt compressor with a "blown" motor (200$ at auction, 15$ for replacement brushes and a new rotor bearing and a 2$ replacement relay- retails new for around 2 grand) in my garage and then plumbed a feed line and manifold up to my work room. Now I can run my all of my Volkswagen tools in the garage and art and fossil prep stuff upstairs without having to wait for the tank to recharge every 15 minutes.

At the same auction, I got them to throw in an Extract-All variable speed collector for free, which I modified to work as both a bench top collector and some rather clever if I do say so myself adapter system for my various woodworking and fossil prep tools. They retail for around 2 grand. Found that the set screws on the squirrel cage were stripped, so retapped them and and did some fill and polish on the shaft to get it working. Set up an old shop-vac as an intermediate for the bigger chunks and flakes.

 

I already owned a number of different air tools, but added a used Fossil Shack air scribe from a certain auction site to my so-old-I-cant-get parts and so-battered-they-do-more-harm-than-good Chicagos. I haven't tried it out yet, but the claim of no more cold fingers lured me in. I suspect I may finally get my Cowboy Pass finds suitable for display...

 

I was also able to get a used dental drill rig with all the goodies from a scientific/medical auction, so I am going to be teaching my self the techniques for really fine control of that toy. That was the most expensive part of all the deals and a knee-jerk purchase at 450$, but I figure it will come in handy for some of the stuff I have to prep in the harder matrixes. I am also converting the water cooling jets over to compressed air cooling venturis as I'm pretty sure the "patients" aren't feeling anything...

 

I was also able to get a new motor for my vacuum pump, and a modern table vibrator for under 200$ as I have dozens of display/teaching casts to make for the Uni (I am also a sculptor/model builder and can finally do limited edition repops of the stuff that sells real well...Warhammer 40k Chaos tanks and weird biologically textured display stuff the art folks are willing to pay far too much for).

 

 

[Kane]

A search on this subforum should provide you quite ample information.

 

It very much depends on what kind of rock one is working with, and the Mohs scale of the media in relation to it. For instance, I would not use anything with a higher Mohs scale than baking soda on soft shales, but would use dolomite (or a dolomite-baking soda mix) on some limestones. 

 

Of the more common fossil prep blast media, there is:

 

Baking soda

Dolomite (~40 micron)

Iron powder (more used in Europe). 

 

Nozzle size is also contingent upon what one is doing. A larger nozzle size is suitable for matrix landscaping, but something like an 18 gauge dispensing needle is a must for detail work on a fossil.

[LabRatKing]

3 minutes ago, Kane said:

A search on this subforum should provide you quite ample information.

 

It very much depends on what kind of rock one is working with, and the Mohs scale of the media in relation to it. For instance, I would not use anything with a higher Mohs scale than baking soda on soft shales, but would use dolomite (or a dolomite-baking soda mix) on some limestones. 

 

Of the more common fossil prep blast media, there is:

 

Baking soda

Dolomite (~40 micron)

Iron powder (more used in Europe). 

 

Nozzle size is also contingent upon what one is doing. A larger nozzle size is suitable for matrix landscaping, but something like an 18 gauge dispensing needle is a must for detail work on a fossil.

Thanks! I dug around in the forums for quite some time, but with access to industrial grade stuff, I just wanted to make sure! <orders large sack of dolomite and a larger sack of sodium bicarbonate> At the prep lab I interned in, they liked to use gypsum, of all things, but I suspect that was only because the lab manager's family owned a gypsum board factory!

 

As an added question, anti-caking additives or is it better to keep the relative humidity low to prevent the issue? About half the year around here the humidity is extremely high.

[Kane]

You definitely want to "keep your powder dry"! Any clumping will just clog the line or tip of your abrader, so a few steps are recommended here:

 

1. Bake your media. I mean it! Place it on a baking sheet and put it in your oven at about 200F for 20 minutes. This will get rid of any lingering moisture in the medium. 

2. Sift, and sift again! If you have a sifter with a very fine mesh, you ensure none of the bigger particles will end up gumming up your works. As I don't have a mesh sieve, I give it stir with a fork.  

3. Get some water traps and place those on the line between the compressor and the abrader. This should take out any of the moisture in the air that gets sucked into your compressor.

4. When not in use, all blast media should be stored in airtight containers.

[LabRatKing]

1 hour ago, Kane said:

You definitely want to "keep your powder dry"! Any clumping will just clog the line or tip of your abrader, so a few steps are recommended here:

 

1. Bake your media. I mean it! Place it on a baking sheet and put it in your oven at about 200F for 20 minutes. This will get rid of any lingering moisture in the medium. 

2. Sift, and sift again! If you have a sifter with a very fine mesh, you ensure none of the bigger particles will end up gumming up your works. As I don't have a mesh sieve, I give it stir with a fork.  

3. Get some water traps and place those on the line between the compressor and the abrader. This should take out any of the moisture in the air that gets sucked into your compressor.

4. When not in use, all blast media should be stored in airtight containers.

Baking is a darned fine idea! I have a curing oven I use for my resin work. It has a range of 35-to 250C so it should do the trick.

I have the full gamut of mesh and sieves, but again, this is just the sort of tip I need!

As an old maintenance tech, I have in line desiccant and oil separators before the tank, and a triple sep on the supply line (oil/water/dust). Mostly because the only thing worse than a cold air tool is a cold drippy air tool!

I have a bunch of old 20mm ammo cans from my active duty days, you think those with an added desiccant pack would do the trick?

 

this is why I come here for info more and more often, you folks remember so many things I have forgotten in the last few decades.

 

Keep 'em coming!

[Kane]

Sounds like you have the gear! 

In terms of storage, a simple one of those plastic tubs used to store leftovers should do the trick. 

When I buy the big bags, I open those up and store those in the plastic paint buckets (with lid) you can get from the home reno stores.

[LabRatKing]

5 minutes ago, Kane said:

Sounds like you have the gear! 

In terms of storage, a simple one of those plastic tubs used to store leftovers should do the trick. 

When I buy the big bags, I open those up and store those in the plastic paint buckets (with lid) you can get from the home reno stores.

As I am not used to sodium bicarbonate as a media, do you one shot and done, or do you recycle it after sieving a few cycles?  I ask as with aluminum oxide media, it is usually only good for a single pass particularly with glass etching applications. Am I safe to assume dolomite is similar?

[Kane]

1 hour ago, LabRatKing said:

As I am not used to sodium bicarbonate as a media, do you one shot and done, or do you recycle it after sieving a few cycles?  I ask as with aluminum oxide media, it is usually only good for a single pass particularly with glass etching applications. Am I safe to assume dolomite is similar?

i know some people who save and sieve it, but it's so dirt cheap I just buy another bag. I try not to use dolomite too much if I can get away with it since it is like flour and hangs like a cloud (I must have a Fisher-Price shop vac or something, lol). 

[jpc]

2 hours ago, Kane said:

You definitely want to "keep your powder dry"! Any clumping will just clog the line or tip of your abrader, so a few steps are recommended here:

 

1. Bake your media. I mean it! Place it on a baking sheet and put it in your oven at about 200F for 20 minutes. This will get rid of any lingering moisture in the medium. 

2. Sift, and sift again! If you have a sifter with a very fine mesh, you ensure none of the bigger particles will end up gumming up your works. As I don't have a mesh sieve, I give it stir with a fork.  

3. Get some water traps and place those on the line between the compressor and the abrader. This should take out any of the moisture in the air that gets sucked into your compressor.

4. When not in use, all blast media should be stored in airtight containers.

I was planning to mention all four of these but Kane beat me to it.  

I'm not sure what size nozzle you have on this type of machine, but the smaller you can get, the better.  (I am assuming it is pretty big; I worked in a VW shop decades ago for a summer and I spent much time glass beading old parts with a rather large nozzle compared to what I now use on fossils). 

 

Wait... did you say old VWs?  I htink we need a photo or two.  

[LabRatKing]

29 minutes ago, Kane said:

i know some people who save and sieve it, but it's so dirt cheap I just buy another bag. I try not to use dolomite too much if I can get away with it since it is like flour and hangs like a cloud (I must have a Fisher-Price shop vac or something, lol). 

Panty-hose and Smith's Filter Spray! This was the trick I used with the various etching units back in my window glass factory days. In a pinch you can use plain old silicone spray, like what one would put on a snowblower rotor, but purpose designed filter treatments are the way to go, particularly when one can get nylons at the dollar store in bulk. We used cerium oxide as the abrasive and it behaved much as you describe dolomite. Best part is nylon stockings are much cheaper than Shop-vac and Collector filters. You can get it for around 15$ a can at most places that sell HVAC supplies, and online too. That 15$ will save you hundreds on washable and disposable filters and seriously control the fine dust without sacrificing air flow. The HEPA filters on those glass sytems were 300$ each and had to be replaced weekly. A pre filter and spray and it became quarterly...plus there was next to zero dust escaping the machines.

[Phevo]

19 hours ago, LabRatKing said:

Baking is a darned fine idea! I have a curing oven I use for my resin work. It has a range of 35-to 250C so it should do the trick.

I have the full gamut of mesh and sieves, but again, this is just the sort of tip I need!

As an old maintenance tech, I have in line desiccant and oil separators before the tank, and a triple sep on the supply line (oil/water/dust). Mostly because the only thing worse than a cold air tool is a cold drippy air tool!

I have a bunch of old 20mm ammo cans from my active duty days, you think those with an added desiccant pack would do the trick?

 

this is why I come here for info more and more often, you folks remember so many things I have forgotten in the last few decades.

 

Keep 'em coming!

 

I had issues with humidity during the summer and ended up making a cooling coil out of copper pipes between the compressor and tools, warmish air from the compressor gets cooled down in the coil and condenses. 

 

In an ideal world I would have put it between the motor and tank similar to your setup, but the cooling coil could be a last resort if all else fails, that said I do think you have a drool worthy setup with your compressor