When filtering waste vegetable oil or waste motor oil, we all typically use filters that are rated in micron ratings. But, what do those ratings really mean? And how big is the hole? If you haven’t seen or touched an actual micron screen, it’s difficult to get a relative size in mind of just what a particular mesh might look like.
So, we decided to take some pictures of different micron rated stainless steel mesh so you could get a feel for things.
Before we start with the pictures it’s important to understand what the micron rating actually represents.
Microns is a metric measurement that refers to how big the hole is in the weave of wire. It ties to a millimeter square hole. For example, a 1000 micron mesh means that each hole is 1 mm. A 400 micron weave means that each hole is 0.400 millimeters. A 100 micron weave means that each hole is 0.100 millimeters. So the smaller the number, the smaller the hole.
Also, before starting, here’s the full specs on the mesh we’ll be taking pictures of.
Nominal means “average particle size” allowed through the filter
Absolute means “largest particle size” allowed through the filter
Plain Dutch and Twill Dutch carry both a nominal and an absolute micron ratings.
The Straight Weave mesh only carries a nominal micron rating.
And here’s what the weave styles mean.
So, with that in mind, let’s show some pictures….
These are our standard hole meshes. Nice & sturdy with a wide range of hole sizes. 1000 is extremely sturdy and gets used as a backer to our smaller meshes quite often. 800 feels similar to 1000, but isn’t quite so hard to bend. 600, 500, 400, and 300 are pretty robust and are by far the most popular sizes.
These meshes are the smallest of our standard weave meshes. 234 is commonly used in the marijuana production industry while the other sizes are used in just about every production industry we work with.
These are our tightest meshes. The 100 and 74 meshes feature a nice, tight plain dutch weave while the 15 and 5 feature an extremely tight twill dutch weave mesh. The 5 micron is extremely thin and flexible and requires a backer when used as a filter.
The 177 and 149 micron are semi-transparent. The 100 micron is much tighter. The 74 micron reminds me of a t-shirt weave. The 43 Micron is like a high thread-count bed-sheet. It has an extremely tight weave but as you feel it, you can still somewhat feel the wire threads. The 15 and 5 micron sheets look and feel just like a sheet of glossy paper. They’re extremely malleable and will easily conform to just about anything they’re pressed into–especially the 5 micron! However, this also means that they can have a tendency to tear fairly easily.
Also, here’s a video of some of the mesh samples as well
We also shot a video of water flowing through 74, 43, 15, and 5 micron stainless mesh in the form of our Stainless Bucket Filters. It helps give you an idea of what the flow rate of water through the screens would be.
Ok, more pictures!
For these I took close up shots of each piece with a penny on them to give you a relative size of the mesh holes. As you look at the pictures, look at the L in the word LIBERTY on the penny. It will act as a good gauge to compare against any screen you may have that you’re trying to match.
This reminds me rabbit cage wire. It has 1/4″ holes and is fairly rigid. It makes an excellent strainer for getting really large chunks. We build a bucket strainer out of this material that is well liked by restaurants.
This material has hole sizes half the size of the above sample at 1/8″. We’ve used it for a variety of custom filters for filtering large particles out of liquids or even powders. Because the holes are closer together, the material is stronger than the 1/4″ above. It makes a great filter!
600 micron is very similar to the rigidity of the 800 micron above but with a smaller hole size. This size is very popular as the first filter for waste vegetable oil or waste motor oil. In fact, we even use it as the preferred filter with our locking drum lids.
400 micron is a step down in hole size from the 600 micron and is by far our most popular size for filtering vegetable oil before reacting it into biodiesel. In fact, it’s the size I personally use when filtering my oil before putting it into my BioPro 190 Automated Biodiesel Processor
If you’re looking for a great universal size for vegetable oil filtering, this is the size I always recommend.
300 micron is just a hair smaller than 400 micron is and is by far the most popular size among beer brewers! In fact, it’s the #1 size we sell in our brewing filters.
234 micron is a special size we brought in for customers in states where marijuana production is legal. It’s the largest size they typically use to filter out the plant media. It’s a fairly robust mesh and can be used in just about any application needed.
177 micron has always been popular among our customers filtering waste engine oil and waste vegetable oil to be used straight in a diesel engine. It’s weave is fairly tight and it does a good job of getting a lot of the gunk out. If your liquid your filtering is thick, it can take a while to go through 177, so plan accordingly, but it does a great job of filtering!
149 micron is the closest we have to 150 micron. We’ve had several customers that need to get as close to 150 as possible and we’ve used it for a variety of custom filter applications. It was even one of the sizes we offered in our drum filters when we first released them. It’s not a terribly rigid material and isn’t the greatest for bearing a lot of weight, but if you absolutely need something close to 150, this is it!
100 micron is awesome! It’s our go-to size for methoxide filters. The hole size is perfect for keeping sodium or potassium hydroxide in the filter until the methanol can dissolve it. It has a really tight weave and it’s one of the toughest stainless mesh sizes we offer. It’s extremely rigid and holds it’s shape exceptionally well. In fact, because it’s so strong, we’re able to build bigger filters out of it without having to add supports.
74 micron is our smallest size we offer in our standard filters. It’s extremely popular among those filtering waste vegetable oil and motor oil. It’s very good at getting the really small stuff out and is usually the last stainless filter our customers use before switching over to our bag filters for smaller sizes. It does take longer than the larger sizes for liquids to filter through it, but it’s a good, heavy duty mesh that holds up well over time. This is by far our most preferred size for cold brew coffee brewers. It’s been extremely popular with them and holds up well.
43 micron is one of our custom sizes that we offer. It’s weave is exceptionally small (tighter than a t-shirt weave) and can be difficult to filter vegetable oil or motor oil through without putting it under some pressure. Also, the material is extremely malleable and can tear fairly easily. For this reason, we always back this material with other stainless mesh when we build filters out of it.
15 micron is really close to the smallest stainless steel mesh we have access to. Because of the twill dutch weave, it acts like a 5 micron nominal filter too. It requires a backing when used in any of our filters too. If you need to go small though, this is a great option.
5 micron is the smallest micron size stainless mesh we offer. It will act like a 2 nominal micron filter. It’s extremely fine, feels like aluminum foil, bends extremely easy, and is easy to cut and tear. We don’t use it very much because it’s so fine and requires a backer.
We also took some pictures at high magnification to show the mesh even closer.
This animation is at 12.5 x magnification (1000 micron to 5 micron).
Here’s an animation of mesh at 30x magnification (100 micron to 5 micron)
For the next set of pictures, I set up a light below a glass plate and set the mesh onto the plate one by one to see what the transparency through the mesh looks like.
I was able to easily see through everything down to 120 micron. 100 micron started to get harder to see through. 74 micron got even tougher, I could make out the faint glow of the bulb, and at different angles I could even make out the outline of the bulb, but it was still pretty opaque. The 43 micron hid the bulb even more and at 15 micron, I wasn’t able to see the bulb at all but could tell something behind it was glowing. 5 micron made it even more difficult to see the light behind it. You could faintly tell that there was a light behind it, but couldn’t make out what it was at all.
Now the million dollar question…which one should you use? Well, that depends on your application.
If you’re filtering waste vegetable oil for biodiesel production, I recommend either 600 or 400 micron screens. If you have really thick, nasty oil, 800 would be great to use to get the big chunks out. 400 micron is what I personally use in my own oil filtering setup when I’m planning to make Biodiesel.
If you’re filtering Straight Vegetable Oil or Motor Oil, the 177 and 100 micron are clearly the most popular. The 74 micron will still work, but you may be hanging around a while waiting for the oil to flow through the mesh. The 40 & 15 micron are good for filtering Biodiesel and waste water, but SVO will definitely take a while to go through them.
Also, when we build our filters, anything lower than 74 micron requires us to line the filter with a backer mesh to keep the shape of the filter. Typically, we’ll use a 400 micron filter and then inlay and weld the finer mesh requested. This provides a very rigid filter while still allowing for the finer filtration micron rating.
So, go with the larger microns for filtering waste veggie to get the chunks out & go smaller for filtering biodiesel or waste water. In stainless, much smaller than 74 micron though & svo will usually take forever to go through it. If you need to filter down to that level, our poly bag filters would be better suited.
Also, you may have run across people rating stainless weave in mesh ratings. It’s quite a bit different, but there is a relation. To help you out with this, here’s a handy conversion chart between mesh & micron.
So, there you have it, a quick demo on the different sizes of stainless screens!
If you’d like to test out a few different sizes for your application, we sell stainless sample sheets in 6″ x 6″ and 12″ x 12″ in every micron size we stock.
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