PDA

View Full Version : Dry Sand



alsinaj
05-29-2014, 06:00 PM
It's rust removing time again, and once again, no sand for my blaster. Curiously, although I live within spitting distance of the Ausable River ("Sandy River"), it's impossible to find clean, dry sand here. The play sand at the hardware store is wet and has to be sifted. Anyone have a method for quickly drying and cleaning sand say, 100 lbs at a crack?

kendall
05-29-2014, 06:10 PM
I used to keep a light bulb in the bottom of my sand bucket to keep it dry. If it's already wet it may cake up.
When I collected sand from behind my house, I'd use three screens to sift, chicken wire, hardware cloth then window screen, all set in frames that stacked on a rocker like the old prospectors used.

Careful collecting from a beach, many places it can mean jail time. If you mean the Michigan Ausable River, it is definitely illegal, I've seen some heavy fines for people collecting rocks there. No idea about the one in New York.

Willy
05-29-2014, 06:16 PM
Anyone have a method for quickly drying and cleaning sand say, 100 lbs at a crack?

A clean smooth concrete surface and the sun. Spread it out and sweep it up a few hours later.
I've tried this before and it does dry the sand quickly.
The only problem I had vs. store bought sand meant for sand blasters was that my particular source contained too many fines. Lots of dust, and due to the grain size being too small and rounded in shape, the cleaning ability of the sand was compromised. Ideally the sand particles should have a sharp fractured shape.
Under a magnifying glass it was like comparing crushed rock to rocks from a stream where the rocks have been rounded off due to the water.
Run a small batch first to ascertain if it will meet your expectations.

mike4
05-29-2014, 07:00 PM
I have found that for rust removal , crusher dust works well is cheap and readily available , just need to sieve the fine dust out first.

For those who dont know what crusher dust is , it is the leftovers from blue metal crushing after the desired sizes are removed by screening .

Any quarry company will supply it by the truckload, good for driveways, under slabs of concrete etc.

Michael

brian Rupnow
05-29-2014, 07:00 PM
Beach sand and alluvial sand (as found in the bottom of river beds) all have the corners rounded off of the grains from the action imposed on it by the movement of the water. Good sandblasting sand is made by crushing and grinding stone. All of the grains have really sharp cutting edges, and will do the job in about 1/3 of the time it takes using beach or river sand.

Black_Moons
05-29-2014, 09:09 PM
Not to mention death by silicosis.

Have you tried looking for crushed glass? Its low dust, the grains don't cut you like you would expect glass to (Just feels like annoying sand if they get into your sock/whatever), and its cheap since its just recycled random glass. Low dust and low health hazard AFAIK. (Still use a mask)

Being glass, its likely inert enough to sweep into the lawn too.

Other alternatives: Knotted wire wheel on angle grinder (radial works MUCH better then cup), electrolysis.

brian Rupnow
05-29-2014, 09:21 PM
Black_moons---I could be wrong on this---but--Glass is made from silica sand. I'm pretty sure you can get silicosis from crushed or powdered glass same as you can from sand.

JRouche
05-30-2014, 01:58 AM
Beach sand and alluvial sand (as found in the bottom of river beds) all have the corners rounded off of the grains from the action imposed on it by the movement of the water. Good sandblasting sand is made by crushing and grinding stone. All of the grains have really sharp cutting edges, and will do the job in about 1/3 of the time it takes using beach or river sand.

Agree!! I live right next to a dry river bed. Its ALL sand, all year. But its "rolled" sand. Meaning its round. I might grab a hand of it and some quarry sand to do an under the microscope pics.

And then the biological "stuff" in river or beach sand! WoW. Ya think silicosis (problem with ALL sand) is a problem. Think about some other issues also. Really makes you strap on the mask JR

Black Forest
05-30-2014, 02:33 AM
Where are you located?

boslab
05-30-2014, 03:11 AM
Builders merchants sell bags of sand that is sieved and dry for jointing up concrete paviours and paving.
Watch your lungs though!, as BF said glass is good, grit is my stuff till i run out, most of the structural steel blasters i know were more concerned about lead paints common on steelwork than silicosis
Mark

Black_Moons
05-30-2014, 06:41 AM
Black_moons---I could be wrong on this---but--Glass is made from silica sand. I'm pretty sure you can get silicosis from crushed or powdered glass same as you can from sand.

"Materials that don’t expose workers to crystalline silica include the following: ... Glass Beads ..."
http://www.cbs.state.or.us/osha/pdf/pubs/3301.pdf
" What can employers do to protect workers from silica dust? Change the material - Substitute crushed glass, olivine, or other material for silica sand in abrasive blasting."
http://www2.worksafebc.com/i/posters/2009/WS%2009_04.html

"Recycled crushed glass eliminates the Silicosis hazard because it is a completely inert media that contains no free silica (less than 1%) or heavy metals and produces less dust than OSHA limits. Recycled glass dust is classified by OSHA/NIOSH as a “nuisance” dust. "
http://www.turtleclanglobal.com/turtleglass.html

Seems that glass is safe, I assume because its silica is in a different state.
Glass manufacture may expose you to silica however.

alsinaj
05-30-2014, 12:03 PM
Thanks for the tips concerning safety, etc., but I do have respirators. What I don't have is dry sand. Willy made a practical suggestion: spread the sand out on a clean concrete surface and sun dry it. I live in a temperate rain forest (Adirondack mountains in northern New York State, not far from Canada. Think coastal Oregon.) We have sunny days here from time to time, but not often. Any other suggestions?

LKeithR
05-30-2014, 12:38 PM
This may seem redundant but I'm curious why you don't just find a supplier and buy a few bags of proper blasting sand? As others have said, river sand is the last thing you want; it's edges are dull and rounded which makes any job very slow and the results are not as good. Around here another product that's very popular is black nickel slag--it's very sharp and works really well...

cameron
05-30-2014, 12:51 PM
Thanks for the tips concerning safety, etc., but I do have respirators. What I don't have is dry sand. Willy made a practical suggestion: spread the sand out on a clean concrete surface and sun dry it. I live in a temperate rain forest (Adirondack mountains in northern New York State, not far from Canada. Think coastal Oregon.) We have sunny days here from time to time, but not often. Any other suggestions?

Prop a steel plate up on rocks, build a wood fire underneath.

wierdscience
05-30-2014, 01:05 PM
I live and work in an area where sand blast sand is mined and processed by train loads daily,a lot of my customers at work are in the processing business and I have designed,built and serviced a lot of their equipment.It's all river sand and it does an excellent job of blasting,most sand in NA is a mixture of silica and quartz.Blasting with sand is a spalling process,meaning the sand shatters and reduces in size upon contact with the metal.

Silicosis is a concern,but no more than any other dust.Bottom line is nothing is supposed to be in your lungs other than air period,so mask up.

Now that we have that out of the way,since your in a humid area your going to have to dry it.The way my customers do that is in a rotary kiln,picture a large diameter steel drum revolving on some rollers and a flame directed down the center.Wet sand goes in one end,dry comes out the other.

If you have a small concrete mixer available that has a metal drum,just dump the sand in,turn the mixer on and direct the heat from a heat gun or propane weed burner into the drum while it's turning.It won't take much to do a 100lbs at a time.You could do 15lbs at a time in a metal pot on your cook stove assuming the wife is out shopping.

Weekend_Scientist
05-30-2014, 02:15 PM
I've never liked the term "silica" because it has always been somewhat ambiguous to me when it is used in normal conversation.

When someone says "silica" are they referring only to the crystalline form of SiO2? And if so, why not just say "quartz" or "crystalline SiO2"?

The other abrasives: glass, garnet, and olivine all contain a large amount of silicon and oxygen. There are differences of course, glass is amorphous and (usually) contains a lot of sodium, potassium, iron, and other metals. Garnet and olivine also have a lot more metals. But there are also similarities, at the molecular level they are largely built up of silica tetrahedrons (four oxygen atoms surrounding one silicon atom) and any other metals or other elements tend to go along for the ride in between the silica tetrahedrons.

I'm not a doctor and I can't evaluate the potential of the other abrasives to harm your lungs but I'd want to wear a mask when using any of them.

I can say that particle size and shape (without regard for composition) can be enough to cause harm. All of those blasting media will shatter into smaller bits when used for blasting.

mike4
05-30-2014, 06:12 PM
As others have said , mask up with the appropriate equipment , not hard to get a breathing air setup and have a slightly positive pressure in your mask , certainly better than coughing you lungs up in a few years time and not really expensive compared to medical bills.

I find that there are always people who will push the "safety " issues of any product or process without fully exploring the methods of eliminating health risks to operators with the appropriate gear.

We are nearly all capable of making most of the equipment required , just have to purchase the filters.

Michael

wierdscience
05-30-2014, 06:56 PM
I've never liked the term "silica" because it has always been somewhat ambiguous to me when it is used in normal conversation.

When someone says "silica" are they referring only to the crystalline form of SiO2? And if so, why not just say "quartz" or "crystalline SiO2"?

The other abrasives: glass, garnet, and olivine all contain a large amount of silicon and oxygen. There are differences of course, glass is amorphous and (usually) contains a lot of sodium, potassium, iron, and other metals. Garnet and olivine also have a lot more metals. But there are also similarities, at the molecular level they are largely built up of silica tetrahedrons (four oxygen atoms surrounding one silicon atom) and any other metals or other elements tend to go along for the ride in between the silica tetrahedrons.

I'm not a doctor and I can't evaluate the potential of the other abrasives to harm your lungs but I'd want to wear a mask when using any of them.

I can say that particle size and shape (without regard for composition) can be enough to cause harm. All of those blasting media will shatter into smaller bits when used for blasting.

Well,around here in the sand and gravel biz the term "silica" refers to a softer white grain and "quartz" refers to a translucent nearly clear grain.What if anything it has to do with the chemistry I don't know.

The health risks of silica dust have been known since at least the 1890's.It became more popular recently due to some ambitious Tort lawyers trying to make a class action or two stick.All forms of inorganic dust are harmful,people hear about silica,the lawyers and media talk it up and before you know it the public acts like it's Plutonium:rolleyes:

MrSleepy
05-30-2014, 07:24 PM
Builders sand also colours the item being blasted.

Scangrit ,local to me in the uk sell "glassia" .. which is made from recycled glass. It works really well in my small chinese desktop cabinet. http://www.scangrit.co.uk/?page_id=73

Rob

RussZHC
05-30-2014, 10:05 PM
The way my customers do that is in a rotary kiln,picture a large diameter steel drum revolving on some rollers and a flame directed down the center.Wet sand goes in one end,dry comes out the other.

If you have a small concrete mixer available that has a metal drum,just dump the sand in,turn the mixer on and direct the heat from a heat gun or propane weed burner into the drum while it's turning.It won't take much to do a 100lbs at a time.You could do 15lbs at a time in a metal pot on your cook stove assuming the wife is out shopping.

wierdscience: I was thinking along the lines of a trommel, so close I guess :D...its on the project to do list so maybe I should consider one that had solid inserts (rather than just a series of screens) as I could see extra use for sand but also maybe "sterilizing" soil.
Do you think such a rotary device with enough empty space, relative to sand volume, would be somewhat successful even without an external heat source?

RichR
05-30-2014, 10:22 PM
... would be somewhat successful even without an external heat source?
That would probably depend on the relative humidity. Assuming the ambient air is dry enough, it would take longer, and you would still need a blower to replace
moister air with dryer air.

dp
05-31-2014, 03:20 AM
I have a couple hundred pounds of garnet - some is first generation and some is second generation from previous blasting. I keep it in orange buckets i get from Home Depot. The garnet comes from a local blasting firm and they're happy I cart it away. It flows like Morton salt and dry as a cracker.

fixerdave
05-31-2014, 03:35 AM
For what it's worth, somehow water found its way into my sandblasting cabinet and left quite a mess when I found out. I propped the door open and stuck a fan in it for a week. Came back, tossed the sand about some, and let it go for a few more days. It worked fine. There were still a few clumps here and there when I went to use it, but they all dried out in the process. In other words, airflow over time dries fairly well, at least a few inches deep.

David..

wierdscience
05-31-2014, 09:35 AM
wierdscience: I was thinking along the lines of a trommel, so close I guess :D...its on the project to do list so maybe I should consider one that had solid inserts (rather than just a series of screens) as I could see extra use for sand but also maybe "sterilizing" soil.
Do you think such a rotary device with enough empty space, relative to sand volume, would be somewhat successful even without an external heat source?

Kinda doubt it,these kilns have flights on the inside made to an angle specific to the material being processed.The ones for sand start out at about a 3* helix angle which is almost parallel to to the kilns axis.Then they transition to 15-20* in the last few feet so the sand falls across the open center of the kiln in a curtain for final drying.

The kilns I work on are natural gas and waste oil fired,they can be run hot enough to burn off chemical and petroleum contamination and also fracture sand and gravel.Those have to be ran with material in the drum constantly to keep the drum cool.I worked on one a couple years ago where the operator didn't notice his feed belt had stopped feeding material in.Imagine a steel drum 60' long and 10' in diameter that's glowing red:eek::eek:

I have seen a couple kilns for sterilizing soil,they dry the soil first,then screen it through a couple screen sections.You would probably have to build something and experiment with it to get it working right.The bad part is if you change the soil type,you will probably have to change the kiln too.

RussZHC
06-01-2014, 04:31 PM
Thanks for the info...there is always more science and maths than I imagine.