Sieves and screens

[Swede]

As usual, when faced with an acquisition, I bought first, researched later, and found I could have done better. I bought a set of five stainless steel screens from Skylighter, then made 5 frames from poplar, heavily polyurethaned. They will work fine, but they are not as easy to clean as a true lab sieve like this one:

 

http://vwrlabshop.com/images/200/W0220.jpg

 

Lab sieves are expensive because they are precise. Just like the scale thread, a genuinely accurate lab-grade instrument simply cost$ a lot of money. But again, this isn't medical research. The accuracy isn't that critical.

 

I found the pottery people onc again have some cool stuff; not just chemicals, they also use sieves for glazes like these:

 

Sieves used for glazes

 

http://aardvarkclay.com/catalog_pics/sieves/cole_sieves.jpg

 

If you google "sieves glaze" you will get many hits, and some pretty interesting gadgets like this thing:

 

http://aardvarkclay.com/catalog_pics/sieves/Talisman.jpg

 

Anyway, I am wondering if anyone has made use of these plastic bowl sieves. The prices seem pretty decent, and maintaining them would be cake - just hose them down when you are done. I'm wondering if the plastic though will be resistant to acetone and other binders.

 

If you were going to have 3 or 4 meshes, what mesh sizes would you guys recommend? Are the finer-meshed screens, above 400, really all that useful? Thanks.

[lnstantkarma]

Good find, I've been thinking about getting a set of screens and I've never thought any other hobby used them for me to buy cheaper.

[Richtee]

Good find, I've been thinking about getting a set of screens and I've never thought any other hobby used them for me to buy cheaper.

Myself as well.... good post thanks!

[tentacles]

If you're willing to make your own they are much cheaper - just buy square feet of mesh from mcmaster-carr.com and make screening buckets. They even nest so you can mesh out all your sizes at once. Plus, you can put the bucket lid on the top screen to keep the dust in.

 

I've gotta at least make myself a mill media sieve soon.

[TheSidewinder]

That's what I did.

 

I went to Menards and picked up a bunch of the Polyethylene Rubbermaid storage containers that were the correct size and shape for me, then cut the bottoms out, cut my screen to cover the hole, then carefully hot-glued them in place. You MUST use the highest-temp glue sticks you can find, and have a high-temp gun. If you do, it actually melts the poly enough to "blend" with the glue.

 

If you don't get it hot enough, the glue simply peels off. Took me a couple tries to figure this out, then had to go back to Menarsd for the right glue sticks.

[al93535]

Or melt the plastic right into the screen as I did. This makes a very good bond, mine have never shown any sign of coming apart. I made a rather detailed post about making them in the thread here:

 

http://www.apcforum.net/forums/index.php?s...5&hl=mesh\

 

 

Its the 6th post.

[TheSidewinder]

Excellent tutorial with pics, Al.

 

That's exactly what I started to do, too, only I destroyed a couple containers because I didn't have a small enough torch. The gluegun idea was born out of that discovery.

 

Thanks for posting the link again. The pics show the result clearly. That should help a few people.

[tentacles]

A heatgun would seemingly be the perfect tool for making bucket/tub screens. I need to make up a set of screens soon myself, I just shudder to think of what those shitty buckets they sell at <insert hardware store here> go for.

[Mumbles]

If you notice, Al's screens are 6x12". I happen to have the other 6"x12" pieces which I did a similar thing with. I also only put the ones up to 58 mesh in the tubs. I made the mistake of using a full on blow torch, which is a bad choice for fine meshes. A pencil torch is really a must. I must say, Al's turn out significantly prettier than mine. One of mine did come loose. The "soldered" bead is fine, but I use them so much, I cracked the plastic in one of the corners.

 

If I had to pick 3 or 4 meshes I would go with 4, 16, 30 and 60. That should give you good overall functionality. You will be able to grade your BP into roughly 2FA, 4FA, and meal D. The 16, 30, and 60 will be quite useful in screening compositions as well. I use my coarse screen(I have 6 mesh) like the 4 mesh to screen my media out of the mill load.

[Swede]

That's good info, Mumbles, thank you. Those bowls that most guys seem to be using (paint buckets too) are polyethylene, and I'm pretty sure you can "plastic weld" these, meaning you take some scrap plastic, and with scissors cut it into sticks. These will be filler rods. Then with a hot air gun focused pretty tightly, or maybe a butane torch very low, get the plastic/mesh interface barely molten, then add the filler to form a plastic weld bead that should seal the mesh in place nicely. I've done limited plastic welding, and it's not too tough, but it can be difficult to make a neat job of it. It often ends up looking like a blobby mess.

 

Do meshes smaller than 100 or so really see much use in pyro? The only thing I can imagine it used for would be screening metallic powders.

[FrankRizzo]

Those recycled blue and green ones I bought from Menards were ~$2.50/ea so they're only a bit more expensive than Rubbermaid shoe boxes. I'm sure the local grocery/deli would have some to sell (or give) you even cheaper. As a plus, the 12"x12" sheets you can buy from McMaster are perfectly sized to fit across a cut 5gal bucket with just a bit of overlap to trim off.

 

It's also a good idea to pre-stretch the screens over an open wood frame, then drop the frame over the cut bucket before trying to melt/attach the screen to the edge.

[pudidotdk]

I have a 10, 20, 40, 60, 80, 120, 200 and 300 mesh bucket screen made from 20 liter buckets. I scratched my head wondering why I couldn't get it pretty, but the problem was also using too big a flame. Right now I havn't cut off the excess, so I sometimes hurt my fingers when I accidentaly touch the edges of screen.

I will probably also make a 4 mesh screen to make coarser BP.

 

The fine I use to screen chemicals that need to be very fine, like benzoate or metals.

[lnstantkarma]

On mcmaster I'm not used to all the options, like they say all of their mesh sizes like 30x30 mesh, Is that 30 mesh or what does it mean? Also what wire diameter do I want?

[Mumbles]

Yes 30x30 is 30 mesh. It means 30 mesh wide by 30 mesh long. The ones where the numbers are not the same are going to be rectangular. As far as wire diameter, normally I go with whatever is cheapest. If the prices are comparable, go with the thicker one. It will last a big longer and be a bit more resilient. The use of 100% exact particle sizes isn't as critical in pyro as in other applications.

 

Also, you should make sure to get stainless steel.

[al93535]

Swede,

 

The only thing I use my finer mesh screen for is to screen my perchlorate after it gets milled, and thats a 200 mesh. Other then that the 200 and 325 don't ever get used anymore now that I don't size out my own metal powders.

 

I bought the fine ones simply for fine mgal powder.

 

However, you don't ever know when something might come in handy. Order the screens all in one order, save shipping, make them all at once and have them ready.

 

Nothing, other then good pure chemicals, is as important in pyro as good screens, for mixing and sizing. Don't skimp, make them the best you can if you cannot buy them ready made. Take your time, You don't want to do it more then once

[jacob]

I need to make a set of screens as well, John Svinicki runs a site that sells premade bucket-screens here,

http://www.bucketscreen.com/

If you need a finer mesh then he has on his site apparently you can ask him to make custom ones, I don't know much more about it though.

[Swede]

I need to make a set of screens as well, John Svinicki runs a site that sells premade bucket-screens here,

http://www.bucketscreen.com/

If you need a finer mesh then he has on his site apparently you can ask him to make custom ones, I don't know much more about it though.

John's bucket screens look like they are very well made, and the price is not bad considering the work involved on each one. I'd buy those before the pottery types, and we'd be supporting a Pyro guy to boot!

[justanotherpyro]

I finally broke down and ordered a set of 60, 125, 200, and 325 mesh screens 12X12 a piece from McMaster. I found that a soldering iron works very well for gluing the screen into my tupperware containers. Very nice SS screens from McMaster too.

[Mumbles]

You know, I've really found no use for anything smaller than 100 mesh yet.

[FrankRizzo]

They're good from grading mangalium if you make/crush your own.

[Swede]

I'm thinking like you, Mumbles. I like 10, 20, 25, 30, 50, and 60. About the only thing I've used finer screens for is screening perchlorate and nitrate after milling, to get those annoying larger chunks that somehow avoid the mill process. I can definitely see it being used for magnalium.

 

The very first screen I made, an aluminum window screen in a frame, was too weak to do any real work, but it's handy for drying stars.