[gaiusmarius]

thanks Chamba for sending me this chart. i also think this info needs to be a sticky. this way it's easy to find. anyone that wants to add info about which size screens they use for which kind of jobs or any other related info, please do so.

Mesh to Micron Conversion Chart




had to add this quote from Chamba...

Originally Posted by Chamba

A 124LPI would be a 70 US Mesh or a 210u. Not suitable for the vacuum


That's incorrect, 124 lines per inch (LPI) = 124 Mesh, 100 Mesh = 100 lines per inch mesh. US Mesh are based on how many lines per inch.

70 mesh has 70 LPI

Some USA "100 Mesh" (or 100 lines or threads per linear inch mesh) screens are similar to 160 micron (microns measure the distance between the mesh openings and so are more accurate for our application), some have 150 microns openings....and it also depends on how thick the threads are when basing comparisons by using US Mesh sizing.

Check out the mesh comparison chart that is "sticky-ed" on the top of this "Hashish" forum...but that's just one chart, other charts that you will notice online will and can be slightly different (as they are based on meshes with different thread thicknesses,...a mesh with really thick threads will have smaller openings than a mesh of the same lines per inch count that has thin threads, so one 100 Mesh might have openings of 160 microns and another will have openings that are 140 microns)...but since almost all meshes commonly available today are synthetic (mostly Nylon) and are mono-filament threads (not silk, which is like rope and each thread is a combination of many finer threads twirled together to form one thread), and the threads are not that different, so you can use the attached chart to get a fairly accurate comparison

another way to check out the Mesh size (or how many lines per inch the screen is) is to get yourself a thread counter, which is a magnifying glass that is mounted on a fold out metal frame, there are 3 sides which are hinged together, these are about 2 inches x 2 inches and have fractional inch and also often metric markings on them. Fold out the device so it locks in place to form a cube, hold the glass section close to your eye and press the opposite side hard against the mesh as you hold it up to light (a window or low watt lamp) and count how threads there are in a quarter inch section, then multiply that number x 4 to get the lines per inch count. It's easy to count 80, 100 and even 125 Mesh screens with this, but finer meshes, eg 200 Mesh, are difficult to count with a thread counter, so it's easier to count a smaller section then multiply (that's if you have really good eye sight)...for fine meshes, use a microscope (USB if you have it) with a ruler on the mesh.

[Psuper]

I really like that you made this a sticky brother GM!

One distinction in the rated size among different screens is an absolute or nominal rating. Here is a link to an article that explains the difference between absolute rating vs. nominal rating for filters:

https://www.lenntech.com/library/fine...al-filters.htm

....so basically which size of particle is allowed to pass through the screen or is left on top of it.

Different mesh material is going to be either multifilament or monofilament. Here's an article explaining the distinction:

https://www.shfilters.com/corporate-b...ting-mesh.html

As the article linked above in this post points out, most of the "silkscreen" and printing cloths you find online and at craft stores is going to be multifilament. It isn't that this multifilament won't work, it is that the monofilament mesh holes will retain there rated size much better and that the filament itself is more durable (the multifilament will fray over time).

Multifilament mesh has a rating with "xx" (example: 10xx) in its rating while monofilament does not. Monofilament mesh will list the micron or millimeter size of the filament used.

The material of the mesh is polyester (that usually means polyethylene) or nylon. Folks use both for dry sieving. For ice-water resin collection you want polyester monofilament (I learned this last bit from Vorsprung, in this forum) as nylon is hygroscopic and will absorb moisture while the polyester won't.



In above pic is a 12'"x12" and a 24"x12" mesh sheet.

I use a 120μ and a 27μ polyester monofilament mesh sheet for filtering small QWISO (quick-wash isopropyl hash-oil) runs which is better than a coffee filter. Jar of QWISO is poured first through a stainless steel wire mesh colander than through the 120μ and finally through the 27μ mesh.

[gaiusmarius]

thanks Psuper, that's what i'm talking about

[Gray Wolf]

Good points all and good idea stickying this post!

Add that while general charts are good for determining micron size, they are just a rule of thumb, because different manufacturers use different thread sizes in their mesh.

When they use a larger thread, the same mesh or thread count, produces a smaller space between threads.

If you don't have your manufacturers own charts, you can calculate it as follows:

Thread or mesh times (X) thread diameter= closed area per unit.

1- (minus) the closed area= open area

Open area divided by (thread or mesh count minus one)= individual opening size.

If the dimensions are in inches, divide the answer in inches by .00003937 to get microns. A micron is 1,000,000th (one millionth) of a meter, which is 39.37 inches.

[Kushed_]

I use this chart a lot. I have about 30 screens, all of the bags use micron, and all of the others use mesh. Thanks!

[gaiusmarius]

i noticed my local silk screen supplier is not using microns, instead he has a T after the number. anyone know what that measuring unit stands for and how it compares to microns.

https://www.siebdruck-versand.de/Sieb...8046d65d8e18aa

[Psuper]

Originally Posted by gaiusmarius

i noticed my local silk screen supplier is not using microns, instead he has a T after the number. anyone know what that measuring unit stands for and how it compares to microns.

https://www.siebdruck-versand.de/Sieb...8046d65d8e18aa

GM, this is referring to "threads per centimetre" instead of "lines per inch". Here's some info and link to a conversion table:

There is a rule of taking the US number (inches) and divide by 2.5 to get the UK thread count conversion.

For example:

110 divided by 2.5 equals 44. This is closest to a 43T English or “European” measurement. The T is the Swiss method of telling you the thread diameter of your mesh. Usually, mills make mesh in 3 thicknesses with 3 thread diameters.

S = small thread diameter
T = medium thread diameter
HD = heavy thread diameter

The Italian, Japanese and French don't all use the same letters. The following is a general reference chart for these conversions. Please note these charts do not take into consideration American thread diameter measurements:
https://www.catspitproductionsllc.com...nversions.html

[gaiusmarius]

in the end i went on german wiki and found out about it, was just about to mention it. but thanks a lot for the response, it's such a great thing to be part of a site like this where no questions stay unanswered for long.

seems like they have all the sizes i will need for my future hash making projects. would you say the medium diameter is about right? it's what they are selling for silk screen printing.

so if i'm looking for a 61 lpi screen, i divide by 2.5 which gets me 24T? doesn't seem right, maybe you mean multiply, that would make the 61 lpi into 215T? some one already posted earlier that 61 lpi is 205, lol.

or maybe i should look for places that sell the screens made with small thread diameter?

[Psuper]

Originally Posted by gaiusmarius

seems like they have all the sizes i will need for my future hash making projects. would you say the medium diameter is about right? it's what they are selling for silk screen printing.

or maybe i should look for places that sell the screens made with small thread diameter?

Without knowing the actual thread diameter of the monofilament it is hard to say but the medium thread or heavy thread is probably the best choice. Thinner thread diameter= weaker mesh, so stay away from that.

My 85µ polyester monofilament has a 43µ thread diameter. My 27µ, also good quality, has a thread diameter of 42µ .

Originally Posted by gaiusmarius

so if i'm looking for a 61 lpi screen, i divide by 2.5 which gets me 24T? doesn't seem right, maybe you mean multiply, that would make the 61 lpi into 215T? some one already posted earlier that 61 lpi is 205, lol.

Check out the conversion table I linked, I couldn't get it to copy-and-paste properly but yes, 61LPI=24T.

[gaiusmarius]

i'm still confused it seems. my bubble bag 25u is the smallest bag, it lets nothing through except the water, lol. does it mean the bubble bag sizes from bubble man are using another measuring system? i mean the biggest screen holes are in the 220 bag, the best collects on the 72. so how can 61 lpi be used for the initial sifting, if it's 25microns? if i look at the mesh on the chart above, it says 60 is 250micron, if i look at 59 inches it says 160micron. LOL i have to get this before i can order the correct screens lol. i'm guessing lpi is the same as inches in the chart above?