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Education / Training How to make a leather piston seal

How to make a leather piston seal

by B.B. Pelletier

Before we begin, I have to tell you that next week is going to be exciting. I will fulfill two promises you guys have been waiting for, plus there are some other nifty things going on in this blog. So, next week is not a time to skip reading. I promise…you will see some neat stuff. On to today’s post.

Here’s a good tip you can use to resuscitate many older spring-piston airguns. And, not just rifles, because plenty of old air pistols have leather seals, too. Dyb asked for this, and I’ve been meaning to do it for several years.

First, you need a supply of leather. I save old belts and shoes for this purpose. The leather needs to be about 1/8″ thick, but don’t obsess over that. It should also be on the stiff side, though it does have to be at least a little pliable for the forming you’ll do.

Step 1. Measure the seal
If there’s an old seal in the gun, measure it. A dial caliper is an easy way to measure, just try to forget those measurements on the dial smaller than 1/10″. With leather, they’re meaningless. Leather expands and compresses to fill the compression chamber. If there isn’t an old seal, measure the diameter of the compression tube. That’s the size of your seal.

Step 2. Make the form
Making a form for a leather piston seal is easy. Just drill a hole in a 1″ plank and you’re done. Drill the hole larger than the diameter of the piston seal, for reasons you’ll see shortly. The only challenge is finding the right size drill bit, and I have a tip for that. If possible, use an adjustable drill bit. Drill the hole all the way through the board but don’t obsess about the smoothness of the edges.


An adjustable drill bit makes it easy to drill a hole just the right size.

Step 3. Prepare the leather
Cut a square piece of leather wide enough to cover the piston with enough left over to make a sidewall at least 1/4″ high. I like to make the sidewall higher than that, but don’t get hung up on how high to make it. Keep it in the 1/4″ range. Soak the leather in water for 24-48 hours. Add a drop of dishwashing detergent to the water to break the surface tension and make the water easier to be absorbed into the leather.

Step 4. Form the seal
Take the wet leather and center it over the hole in the board. Use the appropriate size wrench socket to drive the wet leather into the hole. Drive it in as deep as you want the sidewalls to be high. Set the board aside to dry for 2-3 days.


A wrench socket drives the wet leather into the hole in the board.


Set aside for several days to dry.

Step 5. Trim the seal
When the seal’s dry, trim the edges while it’s still in the board. I find a razor knife does this best. There may be wrinkles in the seal near the top, but disregard them. They’ll go away when the seal’s used.


Trim the dry seal while it’s still in the board.

Step 6. Drill the screw hole
Invariably, leather seals are held to the piston head by a flathead screw countersunk into the steel piston. There has to be a hole for this screw to pass through, and drilling it while the seal is still in the board is easiest.


Drill the hole for the seal retention screw.

Step 7. Remove the seal and soak it in oil
If you’re going to use the seal right away, soak it in petroleum oil for about 24 hours. If you have a magnum air rifle such as the Diana 45 or the BSF 55, use silicone oil. If you don’t plan to use the seal soon, store it where it will get air.

This method produces seals with rounded bottoms. That bothered me before I bought a factory leather seal and saw that it looked the same. Shooting will flatten it out.

author avatar
Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

90 thoughts on “How to make a leather piston seal”

  1. BB
    Haven’t even had time to read this yet, but I can already see this might save my bacon. THIS is the kind of stuff that makes your blog top-notch. Thanks for the info. JP

  2. B.B. –
    I would love to use this tip to re-build my old Daisy 99 for my grandson. It’s the gun that I learned how to shoot with when I was his age, and is still in very good condition except for the seal. Any chance of a blog describing dissassembly and reassembly for one of these? I can’t imagine that I’m the only one needing help restoring a bb gun with family history.
    – Jim in Kansas

  3. B.B., my question is not really related to this subject and I think someone may have already asked before. Anyway, I would like to know that if the scope stop pin is smaller than the scope stop hole on the rifle, shall I push the mount forward (so that the pin makes contact with the front edge of the hole) or backward or it doesn’t really matter? Thanks.


  4. B.B.

    On the subject of leather accessories, slings seem like a great idea that is not mentioned often. I was wondering if you could recommend a set of sling swivels for air rifles. I’m guessing that the stock screws are better than the ones that attach directly to the barrel. Is that right?

    Can you recommend a good set? This Beeman model seems to have a common design.


    What tools do you need to get the screws into the stock? Is there a danger of messing up the rifle by putting them in the wrong place? Are there other guidelines for positioning them? And do these screws, or others, work for synthetic stocks? Thanks.


  5. B.B.

    Thanks for getting back to me. Okay, so maybe there’s a reason why one doesn’t hear too much about airgun slings.

    While I’m here, any suggestions about using AGE impact putty to reinforce the back of my Crosman 850 trap which has had its interior pretty much blasted out? Will the stuff stick on its own? Is there a recommended adhesive?


  6. BB,

    This comment belongs with yesterdays blog comments, but I didn’t read it until today.

    Thanks for the explanation of the regulator! That made it clear to me. I also found a visual representation at http://www.warpig.com/paintball/technical/regulators/howtheywork/index.shtml. Also thanks for blogs like todays with valuable information on DIY maintenance!

    The Walther Dominator finally came out! WOW, that is a HUGE price difference from the 850 AirMagnum!!! I could understand if they were using a Walther barrel, but just for air instead of CO2? That seems ridiculous (especially considering people on the web that have converted their 850s to PCP with power similar to the 1250). And $100 more for the .22 – what is that about?

    .22 multi-shot

  7. Matt,

    If the interior is blasted out of your Crosman 850 target trap, you are using guns that are too powerful for it. My 850 has about 10,000 rounds and it’s in great shape. But I don’t shoot at it with guns over 450 f.p.s. That’s the secret.

    I think you are ready to move up to a metal trap. The Pyramyd trap is invulnerable to all smallbore air rifles. My similar trap has over 100,000 rounds from guns as powerful as a Fire 201 air shotgun (250 foot-pounds) and it’s still like new. Such a trap costs a lot of money, but that’s the last time you will even think about it. Mine is 15 years old.


  8. B.B.,
    Please address the 4 questions regarding your successful use of lead balls [From Wednesday’s blog, 1st comment, last paragraph]in the Drozd bb rifle. Thank you very much.
    – Dr. G.

  9. Dr. G.,

    I use Gamo round balls and Beeman Perfect Rounds. I have never had a jam in a Drozd, and that’s after shooting five different guns over a period of four years. But I seldom shoot burst-fire. As I am more interested in accuracy, I tend to shoot semiauto most of the time.

    I believe all round balls are essentially the same, though H&N copper-plated balls migfht be good for automatic fire. I just havn’t tried them.


  10. B.B.

    Thanks for the comments on the trap. Actually, I don’t think my guns could have much less power. The IZH 61 I’ve heard chronographed at around 450 fps. The Walther CP Sport is supposed to be around 360 fps and with the Walther Nighthawk gear around 400 fps. Perhaps the Crosman 1077 is the culprit at around 600 fps although in the two months it was working it couldn’t have done that much damage. Maybe range is the problem since I only have 20 feet for my apartment shooting. (You lucky dogs with 10 meter ranges and bench rests don’t know how good you have it.)

    Anyway, since I will be apartment shooting, the trap needs to be quiet and since ballistic curtains are not the answer, it looks like impact putty is the only way to go. Can the putty be plastered onto the back of the heavy duty metal trap or is the official quiet trap strong enough for my equipment?

    Another equipment question. The flashlight for my Walther Nighthawk has a very annoying dark spot right at the point of aim (it’s plenty bright enough otherwise). The spot interferes with marksmanship and my “freeze and drop your weapons” scenarios. Are all Walther flashlights built this way or is it worthwhile trying the replacement bulb from Pyramidair?


  11. Matt,
    B.B. can surely answer your questions better. I just have one suggestion – go to Home Depot, go to the Electrical section and buy this materal called Duct Seal made by Garden Bender (it feels like oil clay). You’ll have the best homemade quiet pellet trap. When I shoot my 300 – 400fps pistols, pellets can only stick on the surface. When I shoot my .22 TX200 (~17fpe) at 10-yard, pellets only go in about 1/2 inch.

  12. B.B.

    This question is completely unrelated to today’s post. I am looking for a mid level hunting PCP (primarily for squirrels, crowes, and pigeons) I was originally looking at air force rifles. Keeping noise to a minimum is important so a shroud would be a must. In that vein I stumbled across the FX whisper and although it is priced a bit higher it seems attractive. What are your thoughts on the whisper vs. the airforce system and are there any other rifles you recomend I look into? Thanks in advance from a long time lurker.


  13. Zak,

    The Talon SS really isn’t all that quiet. Compared to the Air Arms S410, the Talon SS is down right loud. I own both so my comments are based on personal experience.

    I don’t own an FX Whisper but I would expect it to be quieter than than either of the others based on the shroud diameter. Don’t overlook the fact adjustable power is not available on the FX T-12 Whisper.

  14. B.B.,
    Thanks for another great how-to. You didn’t say, but the smooth side of the leather is supposed to end up against the cylinder? Any reason a leather piston seal couldn’t be used in a gun that originally had a synthetic seal? Some performance degradation and no magnums, I guess? Plus figuring out how to attach it.

  15. Zak,

    I was considering a fx revolution and after a month of thought and research found that fx were not so great. I would take a air force over them.

    i agree. the best thing would be an air arms. Think about .22 for squirrels, and also if you want a repeater (i would).


  16. Pestbgone,

    Yes, the smooth side of the leather goes against the cylinder, however, if you reverse it, it will polish out in a few hundred shots.

    Converting a gun that had a synthetic seal to a leather seal can be very problematic, because the synthetic seals use the return-to-form nature of the synthetic material to hold themselves to the piston crown. I’ve only seen one that had a screw retainer, and that may have been die to a transition from an earlier leather seal.


  17. Zak,

    Sumo answered you well, as far as he went. However, he didn’t touch on the frame extender that Airhog now sells for all three AirForce rifles. I have tested it on the Condor only and it is quieter than the S410 sidelever. I have heard quieter air rifles, BUT NEVER AT THE POWER LEVER THE CONDOR PUTS OUT! When the Condor is dialed back to 19 foot-pounds, it sounds like a nickel being dropped on a cement floor.

    Did you read my report on that device? It REALLY works. You could have 30 foot-pounds that is so quiet you closest neighbor would never know what you are doing. I live in a housing development where the homes are less that 20 feet apart, and I know what this thing can do.


  18. Matt,

    I took too long to answer and you got a great answer about duct seal. Yes it will stick to the back of your trap, but that’s a messy way to do it. Make a box-type trap and don’t forget to back the putty with a thin steel plate. I used a cookie sheet for mine – a fact my wife still hasn’t forgotten.


  19. 14 in Fla.

    A bipod on a pistol!!!

    Son, you are watching too much television! The whole reason handguns were invented was for portability. Yes, I know there are people with benchrest pistols who probably do use bipods, but a 1377 isn’t a 300-yard gun!

    Homework assignment: Find out what the Creedmore shooting position is for handguns, and tell me who is considered to be the greatest proponent of long-range handgunning.

    Hint: He killed an elk at greater than 400 yards.

    The rest of you readers lay off answering this question. This is for the kid.


    • I believe you are referring to Elmer Kieth. And he did that using iron sights and Kentucky windage for both the holdover and windage. Like many long range shotters he seldom speaks to the number of “ranging shots” it took to master the technique.

  20. B.B.
    I’m new to scopes. And, I don’t know what scope to get for my 1377. Do you know any good scopes that can be sighted in at 10 yards and is in the $40-$65 range?


  21. Re: pellet traps. I cut two 5# blocks of duct seal to fit in my Crosman trap. I just stand them in the front edge of the trap and they stay there. It has stopped several thousand .22 pellets from my B40 @ 730 fps average and none have made it through. Called around to electic supply houses and purchased two blocks for $15.75.

  22. Hi BB,

    The leather seal that came out of my TF99 was really thick, like 5/16- 3/8″ and looked like it had been cut out by a kid with a dull cookie cutter (as I described in my review of it on another site). I think if they had originally used this method that you described for the seal, it would have never been an issue, and I would have had a full power gun to begin with (discounting all the other things I fixed on it, which has made it a nice shooting gun now). But, at least now I know how to make leather seals for the future. Maybe some future restorations. Thanks for the great info!


  23. BB, Off topic, a .22 pellet query please. Are jsb exacts the same pellet as AA fields, also in theory should a 5.51 work better than 5.52 in a 11.5 lbs TX200 mk3, Regards Ged.

  24. Jeremy,

    An air pistol scope isn’t cheap and the 1377 is a multi-pump, which makes it very difficult to pump without touching the scope.

    To mount a scope on a 1377, you will have to use Crosman’s intermount and scope rings on the 11mm dovetail the intermount gives you.

    The only pistol scopes Pyramyd carries have a 50 yard fixed parallax setting – no focusing to 10 yards.


  25. Ged,

    There is no theory about pellet fit. You have to try each size in the actual rifle. There is no way to guess what will work best.

    Regarding AA Field pellets, Bill Saunders, the Air Arms managing directpr, tells me his pellets are better than JSBs, which is one way of saying they are not the same. That is all I know about it, as the Air Arms pellets are not being shipped here, yet.


  26. Creedmore: lying flat on back, knees drawn up, weapon rested on right leg. Elmer Keith, Model 29 S&W.

    I asked the question of multi-pump bipods(though I had thrown in the 1377c, I’ll admit that) because springers can’t be left cocked, and the critters who eat fruit here simply hide when I come out, then continue eating. I was thinking of the pneumatic type-airguns because of their ability to hold a charge for longer and their inherent consistency.

    14 in Fla

  27. B.B.
    My 1377 has the Crosman Steel Breech and a shoulder stock so a pistola scope is not needed. I just looking for a scope that has the ability to be used at 10-35 yards. I have been looking at the bug busters.

  28. bb,

    i like my condors loud. It ads to the effect. LOL (yes i have been taken to court). i was accused of shooting my neighbors dog but then found innocent as it was not> Ummm? Dead. LOL

    i own 3 dogs myself and they have the choice to run away and they don’t. So i don’t think i would be one to shoot anyones dog. You know that. Don’t you. LOL

    All i said was that i would choose an airforce over a fx. and that the best thing to get would be an air arms. i was not thinking about noise too much. More about that I THINK the air arms is a superior gun.


  29. B.B.,
    I have a brand new TX200 MKIII from Pyramyd. I notice that sometimes after cocking the gun, the safety pin does not pop out, which means the safety is off, the gun is loaded and is ready to fire at any moment without being realized. This is outright dangerous. Does this sound normal to you since you know TX200 much more than anyone here? If this is a defect, what should I do?

  30. TX200,

    What you should do is pull the cocking lever a little harder. The condition you describe is common to all guns with the Rekord trigger and safety, going back to the 1950s. The safety is spring-loaded and waits until there is clearance in the trigger before it springs out. Your rifle either has too much lubrication (most likely) a piece of dirt or a burr (highly unlikely, since the safety works some of the time) or you are just not pulling the cocking lever hard enough to set the safety.

    I even play a game with guns having the Rekord trigger. I cock them as slowly as possible, trying to cock the sear without setting the safety. I can do it on some guns every time, but on well-used guns I have trouble doing it even once.

    There is nothing wrong with your rifle, but knowing that the safety sometimes doesn’t set should make you cautious of where you point the muzzle. And isn’t that the first rule of gun-handling safety?


  31. 14 in Fla,

    Good for you! I read Elmer Kieth when I was your age and then when I was old enough to own my own firearms I put his writings to the test. I have hit man-sized rocks with regularity with an 1860 Colt Army cap and ball replica gun and I have hit and destroyed football-sized dirt clods at 80 yards with a .38 Special Colt Agent snubnosed revolver. This was all from the Creedmore position, though the Colt Agent was fired from the modified Creedmore in which you have your back against a tree.

    The point is, you can be far more accurate with your handgun or rifle than most people would believe if you just take the time to get into a good resting position.

    Now, as to your question, which was really is it possible to mount a bipod on the multi-pump, the answer is yes, if you own a sidelever multi-pump like a Daystate Sportsman or a Sharp Ace Target. With an underlever, no bipod made will work.


  32. Hello there. Been reading yout great stuff for awhile and decided you will decide what rifle I want to buy.
    I want a spring .177 to shoot as far as it can accurately, at tin cans and such, no hunting.
    My choices are either the TX200 MkIII or the Diana 350 Magnum (just for the open sights really.
    Could you tell me what your choice would be (even if not one of the 2 above)?
    Thank you

  33. Choices,

    I think the caliber has made your choice for me. Because you choose the .177 and have the money for the TX 200 MKIII, that’s the gun I pick.

    Had you said .22 caliber, I would have thrown an RWS Diana 54 into the mix, but in .177, the TX200 is king.

    However, if open sights are that important to you, I’m going to make a suggestion you didn’t mention. The RWS Diana 52. It does require technique to shoot well, but not as much as a breakbarrel like the 350 Magnum.


  34. I was just looking over your “How wet weather affects airgun” blog, and I realized you didn’t mention any countermeasures to water messing up a wood stock. Is a waterproofing treatment possible, or is it just something that can’t be prevented? I remember seeing a Birchwood Casey gun stock treatment on this site, perhaps that is the solution?

    14 in Fla

  35. 14 in Fla,

    I remember a field target match held in the fringes of a hurricane. Living in Florida you should be familiar with the misty rain that never lets up. Well, ALL the stocks of all the rifles that participated that day were affected. They swelled and lost zero. Four of them cracked!

    You can treat the outside of the wood well enough, but nobody ever thinks to treat the inside where the action is bedded. In really wet weather, that’s where the water gets into the wood.


  36. BB and all,

    Being a woodworker, I can attest to the importance of finishing wood ON ALL SURFACES. The reasoning behind it is that moisture will be absorbed at different rates when one or more surfaces of ANY wood is left untreated. The untreated surfaces will absorb moisture faster than those surfaces not treated and will swell, warp and in some cases as you have described, crack. If any of you have attempted to make your own wood grips without finishing front AND back, your grips will cup and eventually crack.

    BB is right. Treat inside and out of your wood stocks and grips.

    Michael in Florida

  37. B.B.,
    You da’ man!
    When I read this blog I had forgotten about the Chinese B3(?) that I bought on an impulse for $15 at a Cummins Tool sale. Bought it to protect the bird feeders from marauders. It got to the point where it wouldn’t shoot thru a piece of cardboard. So I ordered an Industry repair kit and of course it came with a plastic seal of the wrong size. Plus the failed seal was leather. Chucked the B3 into the garage attic and forgot about it. Then I bought the Gamo and beyond, LOL.
    So I read your blog about leather seals Friday and I’m looking for Christmas lights in the garage attic and what do you know? Son-of-a-gun. There’s that B3.
    Made a seal from a thick leather coaster per your instructions.
    After only 25 shots its holding between 480 and 500fps with CPs.
    This is fun!

  38. Hello. Thank you for your quick response above. I have another question. About iron sights.
    For example, Diana 48/52 has that plastic front sight glued (i guess?) to the barrell and the Diana 34 has the front metalsight. Does it matter that much? What i mean is will the plastic type front sight become unglued or something? I remember seing a tester Gamo CFX and the front plastic sight was all messed up (maybe because it was abused by thousands of people in the store). Under normal usage, should I have a problem with the Diana 52?
    Thank you

  39. Glued sights,

    The front sight of any Diana RWS rifle should last a lifetime with normal care. The “glue” used to hold the sight is epoxy and after seeing thousands of rifles over 15 years I have never seen or hear of one coming loose.

    I have had at least 20 model 48/52 rifles to test and they all performed well in this respect.


  40. Tom,
    A great big thank you for this column about leather cup replacement. Armed with this information I replaced the leather cup on my 30-year old 2-gallon stainless steel Sears sprayer that I use to spray my apple trees. Your method of forming the cup shape worked like a charm.
    Thanks, Dan from Detroit


  42. Tom –
    Early in the process you say to “Drill the hole larger than the diameter of the piston seal, for reasons you’ll see shortly.” I didn’t see any mention made of that later on in the post. Shouldn’t the diameter of the hole match the outside diameter of the old seal? If not, do you have a formula for how much larger to make the hole in the wood form?

  43. When the leather is compressed in the hole it folds up. You trim a lot of that away, but you want what remains to be tight in the compression chamber. I didn’t explain that at all in the text. One-eighth inch large is a bit too much oversized. Maybe a sixteenth?


  44. Hi all,

    When you make the mold you make the plunger (core to a caster)the size you want. Soaking the leather lets it stretchw/o cracking breaking. You could just wrap the leather around a stick/tube and rubber band it. By using the plank you keep the toolerances tighter and the walls flatter.

    You need the thing wider then the hole wider then the diameter cause if not it will EXACTLY FIT and not seal, the slight largeness of it is what makes it SEAL, (well that and the oil/vaseline/bacon fat (not recommended).
    Over the drying time in the form, the leather will stretch and stay pulled, (like a spring in a pen that you pulled apart as a kid and then it doesn’t go back in the pen). But the stretch is at the wall/bottom edge and drying it gives it an edge. You could make the cup more pronounced by taking a vee gouge and after it dries trim the inside of the cup at the now embedded circle, then re wet it and re form it. Or , you could after drying carefull sand away a bit of the outer edge in the same place. then rewet and reform, (if you are going to do this don’t do final trim until AFTER the seconding forming.

    When you then soak the gasget/seal/cup it relaxes the leather, but since it is stretch and such it can neve be flat , so it conforms to the space.

    doing this makes tigher seals BUT IT WEAKENS THEM, SO make 4

    Additionally you can take a soft parrafine type wax, or bees wax melt it, THEN while OFF THE FLAME , stir in an oil fit for a gun, enough to keep t it barely liquid, rub this into the cup. Since I do not own a gun I can’t tell you what side to put the mix on. I would guess the inside, the waxes will harden a bit over time and the use will push the waxes into the body of the leather and make them stiffer. You could also try a harder wax, (like jelly jar wax), these produce harder walled items. The oil you add degrades the stiffness enough to make the seal.

    The techniques of putting leather in liquid wax is for making leather armour, as in medievil ancient, Roman/Greek/Egyption leather war gear.

    I carve wood (hobby), and used to do leather work, soaking stretching and drying over forms is how I made cases or square boxes.

    I found this place looking for a how to on the gasket. I was curious to see if one existed.

    last , if you didn’t stretch and oil it, it would over time shrink more and more. When leather is tanned (ever do a hide?), you must stretch it wet and scrape it then you smoke it or rub non stinking tannins/fillers into it. This STOPS the skin from shrinking up, and curing into a ball, (well sorta). Later oiling or waxing leather keeps the tannins in and lubricates the leather so it wears better, and making it water resistent, helps retain the tannins.

    I do appologise for lenght of post. This was agreat how to! This site is awesome, and I may even purchase an air rifle for my kid 😉 wink wink nod nod.


  45. sparkie,

    Thank you for all that info! How would you like to wriote a guest blog for us on the same subject. You post would be most of it, with perhaps a few pictures.

    And, Sparkie, is your wife Ellen Griswold and did you guys have a disastrous Christmas vacation a few years back?


  46. Hi B.B.

    Thanks fer the invite, but currently I must decline. (was griswolds’s name sparkie? i never saw the movie, I was blown off a 5, ooo amp3 phase electrical panel once though, a minor tingle but scared me good. But a tiny squirt of 277 volts across my index finger put the fear of a higher power in me for a month. Felt like a hammer strike. Then there were the screw drivers now used as ice picks,chisels and pry bars. One year it was so bad I almost bough welders goggles! woof)

    There is another product that shoemakers and seal makers use that is ground leather with a binder. Seals made from it look like bottle caps, and will absorb oil and swell up ensuring good tight seals. I thought that coleman used this for a while back in the 70’s. Maybe I changed one seal in all the years I camped. You used to find this stuff in cheaper all leather shoes and belts, oor as the stifferners in the heel cup and toes section of the lasts, (the lart of the shoe that goes over the top of your foot). If there is a phone number somewhere on your site BB I will call you.

    Oh , err after the grizwold question it makes me wont to ask is the b.b. for ammo or B.B. busting, chuckle, yikes

    but go here this is more likely my life, not as bad, but there are times….



  47. I are be a newbie wit no guns, but I have a question.

    Does an air gun (mit a spring) work like the following.

    You cock the gun, as you do it pulls out a piston (leather cup at the end), which holds the piston out of cylander. Upon pulling trigger it releases the spring behind the plunger,(piston). When cocking the air can easily go around the cup , but on releasing the piston the cup expands and forces the air out the action end.

    Kinda like a bellows flap assembly?

    zowie and gadzoooks.

    And BTW where in am hill IS midtown tx , is that Midtown tx LA or Midtown TX Australia?

  48. Sparkie,

    Leathger seals have mostly gone away. This is the synthetic age. You might like to look inside a spring gun:


    The bellow gun (yes, there was such a gun) existed in the 1700s and before. The spring piston is simpler than you describe. I will blog it for you tomorrow, because I suspect a lot of guys want to know the same thing.


  49. Hi B.B.>I am in the process of making some piston seals and i am currently approaching the 24 hour mark of soaking some old italian calfskin leather that used to be an old cup for shaking dice in.
    I just rinsed the first soak and added new water because it was leeching dark color into the water and turned the water almost black.
    Would i be best to wait another week till i feel like actually making these or would that be to long for the leater to soak??
    Also the leather started out pretty stiff but has softened pretty good,I did not see any cracks so i am assuming it's ok to use.

  50. Robert,

    The goal is to get the leather as pliable as you can. It sounds like you are there. Remember to form the leather while still wet for this procedure to work.

    I don’t think leaving the leather in the water an extra week will be a problem.


  51. Thanks BB,
    I’ll keep it soaking it has expanded to fit the entire width inside my 2 liter pepsi bottle,will make several different sized seals this weekend…fun stuff.
    Best Regards,

  52. THANKS for this – I missed the article when it came out, and used the wrong search to find it until tonight.
    Thank you so much for following through on your promise.
    The cheap chinese springer will be done over the next month, and the pump in the kero torch as well.
    Thanks again,

  53. hello BB,

    Thanx for the article. worth reading..

    I have something to share and need your and others advice..

    I have a Philippine Footpump airgun called 'Eskopeta'. I did bought one of its leather seal in their booth but after placing it in the petroleum oil for 24 hours and then replace the old one,it didn't pump air efficiently.

    I mean, the air usually leaked in the pump cylinder.why?can you advice?

    You know, maybe i think it needs to be in the oil for 2-7 days, to make it pliable, or maybe something i didn't figure out which is which..Please advice.

    Good day..

  54. Eskopeta,

    I would do what you have suggested — leave the seal in oil for several days. It that doesn't work, perhaps there is another problem with your pump, other than the seal? If dirt got into the pump the wall of the compression cylinder might be scratched, which would allow air to blow past the seal during compression.


  55. If you have a rubber seal that has shrunk on your air gun, then you can take it out and soak it in brake fluid for a day or so. This makes it swell. After it is the right size again, you can wipe the BF off, oil it, and re-assemble the gun. Hope this helps someone…

  56. Thank you 🙂 I've just used the techniques described here to resuscitate my old El Gamo Expo. Had a couple of practice tries, fiddling around finding which of the leathers available to me worked best, but finally produced something usable which together with a new spring and a little TLC has rejuvenated the old girl. Can't help but think that replacing a synthetic seal wouldn't be half as rewarding…
    Neil, from UK.

  57. Neal,

    I'm glad this report helped you. It is rewarding to make a leather piston seal from raw leather. And if you keep it lubricated the new seal should outlast you!


  58. I recently had to replace a seal in a Xisico BAM B3-1 and the seal I bought was too small and I resized it using this method, having never seen this post. Now I find it after I figured it out. LOL I didn’t know if the leather would just shrink back, but it worked. I am glad these old posts are still available even if I didn’t see it in time. I have some leather pieces I saved and didn’t know what I would do with them, now I do.
    Thank you! Dan

  59. Hello BB

    Yes thanks, such a great resource. It still works now.
    I needed one for my diana and here is the answer. All the time i look for something and its in the pyramidair library.
    Is there a trick to fill a deep breech seal? The old one was done, and i tried stacking leather rings but keep sqeezing them flat. Should it be all filled with thick leather? I did see a guy on youtube see smack it gently, i tried that too to get more mass in. But i still flat it out after couple of dozen shots. I haven’t found a thick enough piece of leather so i can make one in one piece.

    Greet from the Netherlands

    • Dennis,

      I have not done it, but familiar with the deep seals like what you mention. (from reading here) What about taking something like lead solder wire and putting that in there first? Not melt it, just wind it in and tamp it tight. That way, you raise the bed and can use something more traditional in thickness.

      Just an idea,….. Chris

      • Thanks Chris!

        I’m gonna try this. I’m sure i can manage this with the stuff i have at home. The groups keep opening up with the flattening of the seal. I’ ll post the results later, greets from the Netherlands and take care

        • Dennis,

          I see from comments that you are still on the fence as to what to do. I recall the very tall seal being synthetic. I could see problems with a very tall stack of leather washers. The solder idea seemed like an easy to do compromise,.. until you can get the proper seal.

          Keep us posted as to what you do and the results.


          • Hai Chris

            Well the first test shoot seems good, but it got dark today. Result for now, best grouping so far in 9 pellets touching eachother, not a perfect group but very acceptable.
            I looked into your idea, but my wire was thin and the breech its not only deep but wide too.
            So i figured mybelt looked like the right size, so my girl made from 4 mm thick leather a solid one. And first tests were looking good. But i keep it in mind, i tried rubber and leather but that only worked couple of shots. A solid base and 2 rings does it in one of our other rifles fine. Thanks for the motivation, it was just what i needed
            More coming cos it sqeeks a bit so i figured the inside needs a good cleaning and polish. And i’m a newby so learning here all the time.

      • Hello BB

        The problem is, my groups open quite a bit with theflattening of the seal.
        I,ve had several 5 shot groups touching eachother. But then after 60/70 shots the seal flattens (i think) and the groups spread out till 12 cm across and it was like 3/4cm
        I use thin leather rings and if i take an old one out and put a slightly thicker in, they close again to smallergroups.
        I triedrubber rings but they start to chip after the same nmbr of shots.
        The breech is a bit worn on the underside i noticed.
        And the shotgroup is quite open but with the touching shots, i think the powerplant is okish? But i’m gonna open it as soon as i have my compressor to check.
        Thanks for the help, its very appriciated. And helps keeps some oldies shooting and in condition.

        Greets from the Netherlands


  60. Hello BB

    I guess its the lockdown, too much time in the house. And just one rifle that’s inconsistent.
    Maybe you’re right, and i should just shoot some tins trough it to see how it settles.

    Thanks and take care


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