In the author’s channel and the chat that joined it, users constantly pop up asking for a link to instructions on how to independently assemble the usual three-layer pharmacy mask. Despite the fact that we have already discussed a thousand times, wherever possible, that the “pharmacy mask is ONLY FOR THE DISEASED,” people still appear who are conducting strange propaganda (including from the state media) and are looking for these unfortunate pieces spunbond. It is also warmed up by the fact that in different groups / house chats such a simple mask (bought a couple of weeks ago not even for a cent, but for a fraction of a cent) today in Belarus costs from a dollar to two (2-4 BYN). In state pharmacies, prices are stilllagging behind, but not by much. How much does such a mask really cost - you can figure it out by reading the article to the end ... Under the cut - a technique for creating a homemade surgical mask.In addition to the “wild, frantic” price increase, the channel of the well-known “blogger” Nexta (such as the “unofficial media of Belarus”), which seems to be in opposition to the government and should have provided adequate information, made me go for spanbond. But he’s not in a hurry to do this, preferring to spread rumors and jokes like “but we made masks for Instagram.” I wrote to him, offered to use a user resource (I read mostly Belarus) and drop links to two of my articles on the hub with a description of the right remedies, at least for someone who really needs protection. But he didn’t receive any adequate answer, the Belarusian “truth-minded bloggers” consider it right to copy-paste the news about coronavirus to China.In general, it turns out that there’s a lot of hysteria with accessories that are useless for protecting healthy people. Although, frankly speaking, such masks are still needed, they are definitely needed by all “walkers to work with malaise”, “they do not give me sick leave”, etc. to people. I understand that they don’t give a damn about themselves, but maybe at least for a second they should think how many people such an individual would really help if he just stayed at home, as the doctors advise ...For those who have previous articles ( first and second ) I didn’t read it, or I read it inattentively, under the spoiler I’ll remind you why it makes no sense to wear surgical masks if you are not sick (= wear a respirator).About the effectiveness of surgical masks(, ..) - , «» , . « » , , , . , « », , ( ) ( , ), «», . - . . , 34,0%, – 95,0%. - , 20–40 . «» 58,0 %, , , 100,0 % [1]… , , . «» .
[1] .. .. // «VI »: . . ., , 2007 . – ., 2009. .291-306.
So, we meet (= "dedicated to all outbits" :)) - a guide for assembling a makeshift mask.Step 1. Finding the Right Material
A three-layer pharmacy medical mask is called because it consists of three layers of the so-called nonwoven fabric .Non-woven textile materials - materials made of fibers or threads, interconnected without the use of weaving methods.
The outer layers are familiar and familiar to many spunbond from polypropylene, with a density of 17 g / m 2. The central layer - should be the so-called Meltblown, i.e. the same non-woven material, but due to the technology of hot spraying, the formation of fibers of a smaller size than in the case of spunbond (about 1 to 5 microns). Meltblown is a more even laying of fibers and high waterproofness. It is from such material that the so-called "Pocket filters" and often filters for vacuum bags. Naturally, far from HEPA. Why “it should be”, but because having disassembled the mask for spare parts (see below), I did not notice any difference (other than color) in the structure of the fibers of the fabrics used. Therefore, I decided to take an ordinary spanbond and not get hung up on it, all the same, after all, about some kind of tightness and “the absence of air leakage under the mask” (as in the case with respirators), it does not even occur to me in this case.Mask for filtering a large droplet aerosol fraction during sneezing / coughing. What to take from her (as well as from a cotton-gauze bandage).I didn’t have to look for Spanbond for a long time, this material can be bought without problems right in the center of Minsk, directly from a roll. Any length (but a multiple of 1 meter). Moreover, in rolls, something similar to the so-called. sleeve. Those. if you buy one meter running - in the end you get a piece of 1 m by 3 meters (or even 4, depending on the density of the fabric). Price - from $ 0.5 to a dollar per meter. This material is also sold in any stores related to gardening, horticulture, “goods for summer residents”, etc. I think maybe in fabric stores, like some kind of lining fabric.As I already mentioned, in the vast majority of selling pharmacy masks, the thinnest, cheapest spanbond is used, density 17 g / m 2 . In our case, it is in the middle roll with the inscription SUF-17. A little more than half a dollar for a piece of 1 m by 4.2 m.I got the pieces with the inscriptions. At least I didn't have to sign anything myself. True, he also took a piece of fabric more tightly in reserve (to pack if necessary, etc.)It looks like this non-woven material is close. Looks like a well-known spider web repair fabric.Stage 2. We measure / study a factory mask
The first thing I measured the size (you need to get attached to something). Although no one bothers to make small dressings for children or large dressings for adults with a giant face. You never know what. In the photo - the length of a typical dressing from a pharmacy.And the width of a typical dressing from a pharmacy:We slowly disassemble, cutting off the thermally welded ends. Some rubber-like polymer threads are thermally welded to the side faces.In the upper part there is a “nose clip” for a more accurate fit / fixation to the face. In fact, it’s an ordinary wire, like a half of telephone noodles. And with a similar thing in Minsk (and in Belarus) they clamp packets with bread / loaf, twist computer wires in stores, etc.We have decided on the fittings, now we disassemble the mask itself. Indeed, the manufacturer did not lie - three layers. So we will be attached to this figure (although no one bothers to make ourselves a custom, “supermask” of 5 layers or the like). I draw your attention to the fact that how many layers you don’t do - all the same, these pieces will be worse than a respirator made of filtering fibrous material. But this has already been discussed repeatedly before (see my previous articles).After layer-by-layer dismantling - I measured distances for bends. Of course, everything here is by sight, but I wanted to attach to something for a start. Well, the dimensions of the workpiece in the unfolded state. I took a width of 165 mm.And the length is 175 mmNow we mark our spanbond into pieces of the same type 165x175 mm in size. Since we are copying a three-layer mask, we need three pieces. It is better to carry out this operation together - one tissue pulls, and the second - draws.Then carefully cut the pieces and put them in a stack.Between the layers we put our improvised "nose clip":Stage 3. Assembly
Reassembly is the need to fuse the edge of the fabric (it can, by the way, be glued together, but I wanted to quickly). How this can be done depends on your financial and “hardware” capabilities. I had a plastic bag sealer on hand, so I used it. True, initially spanbond after melting pestered the heating elements of the device. I had to lay a layer of ordinary polyethylene. This did not affect the quality of the seam - the spunbond alloys perfectly with polyethylene into a monolithic seam. For those who do not have a sealing machine for bags - you can try to cook spanbond with an iron through a sealant-diffuser from a newspaper. In childhood, I glued covers for non-standard books, though made of polyethylene.Note for needlewomen: instead of looking for a sealing machine or stuffing your hand with an iron sealer, you can simply sew the sheets of spunbond around the edges. To make the seam airtight, you can:a) use something like “elastic for the seam on the swimsuit,” which you need to put in the seam a little stretch. Such an elastic band immediately gives both the necessary tension and sealing. Theoretically, any thin rubber, even a doubly folded balloon, will be used as such an elastic band (note mine: the best option is long cylindrical balloons from which various figures are knitted).or you canb) coat each layer of spunbond with any building silicone along the edge (thin layer), lay on top of each other and then flash it. silicone will polymerise and seal the joint along with the seam,or you canc) carry out a procedure similar to “gluing the seam of a tent” - see a good article on this topic. The main function of this procedure is the use of sealant that seeps into the needle holes, creating a waterproof barrier. For this purpose, the so-called “Suture tape” (ask at travel shops and homemade goods stores):The suture (sealing) tape is a thin polyurethane tape that rolls over the seams to block the needle holes through which moisture can leak.
Well, for those who, like me, have a sealing machine, we begin to solder our polypropylene spanbond.Having made one seam, then I began to form folds on the material, focusing on the example of a factory pharmacy mask. True, the spanbond slides and strives to take its former shape - so we had to use weighting materials first. Then I just rolled along a folded fold of material with a heavy object (screwdriver handle) and the fold was fixed.After successful “folding”, the dressing was scalded from the three remaining sides according to the method described above. As a result, we got such a thing:After the mask frame is ready, it remains to attach attachments to it. Any gum will do (even out of cowards). I had a fishing, round section. First measured a piece of the same length as the factory:And then just attached these gum to the mask with staples from the stapler. The elastic bands are deformed under pressure from the brackets and do not slip out even with a sufficiently strong, excessive tensionThat's all! By its properties, the homemade product does not differ in any way from what they are selling in Belarus now for a price of up to $ 2 / piece. What is the cost of my mask - I don’t even want to think, because we don’t find money of such a face value :)By the way, the samopal sits just fine (see KDPV)!That's all, I say hello to all resellers ! And the rest, traditionally, I advise you to quickly subscribe to my scientific and technical channel and join the discussion!Acknowledgments : the author thanks his volunteer assistant Ilya and volunteer assistant Justina! Dzjakuy for your uzel!Important! If the information from the article came in handy in your life, then:Become a sponsor and support the channel / author (= "on reagents")!
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