LDCs for PCPs

[Warburrito]

Another material worth checking out is Melamine.  Its the foam like material used in magic erasers.  That's what I line the moderators I've made in and it seems to work great.  Once my PP750 arrives I plan on using some in the shroud as well, maybe in between some 3D printed baffles.

If you're shopping for regular foam be sure to purchase open cell foam.  Closed cell foam has a lot of good uses in home and automotive applications, but won't allow air and sound to get absorbed properly in an airgun.  You want it to be able to travel inside the foam to get the best effect.  Closed cell foam is better for sealing and completely blocking out airflow, not absorbing it.

[mrbulk]

Thanks for the tip on foam type Dave.

Meanwhile, you can now buy LDCs for around ~$25 using their discount code provided here:

https://www.gatewaytoairguns.org/GTA/index.php?topic=178228.msg156020510#msg156020510

[rkr]

Foam is not good material for silencers as air can not penetrate it. In practice foam just compresses a bit and you loose volume inside, this can be verified by measurements. Dense felt has worked well for me as dampening material.

[Mole2017]

Another material worth checking out is Melamine.  Its the foam like material used in magic erasers.  ...

Magic erasers are cheap--don't use up your wife's supply! Personally, for cleaning I like the heavy duty version, which is somewhat denser than the regular ones my wife buys anyway. (I'll have to try this idea on that fuel filter, but that might take a whole box of them!)

[Rallyshark]

I have both 30 and 40 mm humas.  The 40 is substantially heavier.  While the 30 is still extremely effective.

The most balanced config for effectiveness/length/weight on the 30mm moderator is 3 40mm long modules and 1 20mm.  6.4" and 4 oz on the dot.  When hunting I only use 2 modules for 2.8oz, and 3.9" length.

For those looking for STO mods... https://www.silentthunderordnance.com/secret-menu

I couldn't find anywhere on that site to actually purchase the STO though.  All I could find was the blog about them.  Maybe I missed something?

[Long_Gun_Dallas]

I have both 30 and 40 mm humas.  The 40 is substantially heavier.  While the 30 is still extremely effective.

The most balanced config for effectiveness/length/weight on the 30mm moderator is 3 40mm long modules and 1 20mm.  6.4" and 4 oz on the dot.  When hunting I only use 2 modules for 2.8oz, and 3.9" length.

For those looking for STO mods... https://www.silentthunderordnance.com/secret-menu

I couldn't find anywhere on that site to actually purchase the STO though.  All I could find was the blog about them.  Maybe I missed something?

Did you follow the link?

[Rallyshark]

I'm a dummy,lol!  I was thinking those were just pictures from his blog post that I had looked at earlier    I'm going to go hide by myself now 

[Rallyshark]

I sent them a message via the site to inquire about which version they would recommend on my guns.  They have a "flow factor" calculator on their page to determine which versions of their LDCs to use.  By their calculator, my guns fall between moderate and high flow factors...  The pricing doesn't seem that bad, I may get one to try out, depending on the response.

Oh and another LDC related thing...  I got the chance to hear a Ramus Technologies Trident today on a 60 fpe Daystate Renegade in .25.  It seemed to work quite well for the size, fyi.  I can't be completely sure how well though, since I don't have much experience with what that gun sounds like with a different LDC, so take that with a grain of salt.

[mrbulk]

I sent them a message via the site to inquire about which version they would recommend on my guns.  They have a "flow factor" calculator on their page to determine which versions of their LDCs to use.  By their calculator, my guns fall between moderate and high flow factors...  The pricing doesn't seem that bad, I may get one to try out, depending on the response.

Oh and another LDC related thing...  I got the chance to hear a Ramus Technologies Trident today on a 60 fpe Daystate Renegade in .25.  It seemed to work quite well for the size, fyi.  I can't be completely sure how well though, since I don't have much experience with what that gun sounds like with a different LDC, so take that with a grain of salt.

Donny I would have liked to hear that Daystate bare barreled first, so I that could experience just how much quieter the LDC made it afterwards. Did you get a chance?

[Long_Gun_Dallas]

I'm a dummy,lol!  I was thinking those were just pictures from his blog post that I had looked at earlier    I'm going to go hide by myself now 

Haha, no worries.  Everyone has their hiccups

[Rallyshark]

I sent them a message via the site to inquire about which version they would recommend on my guns.  They have a "flow factor" calculator on their page to determine which versions of their LDCs to use.  By their calculator, my guns fall between moderate and high flow factors...  The pricing doesn't seem that bad, I may get one to try out, depending on the response.

Oh and another LDC related thing...  I got the chance to hear a Ramus Technologies Trident today on a 60 fpe Daystate Renegade in .25.  It seemed to work quite well for the size, fyi.  I can't be completely sure how well though, since I don't have much experience with what that gun sounds like with a different LDC, so take that with a grain of salt.

Donny I would have liked to hear that Daystate bare barreled first, so I that could experience just how much quieter the LDC made it afterwards. Did you get a chance?

I did hear it without the Trident, and it was noticeably louder for sure.  However, we were shooting in open space with a bit of wind as well.  If I get the chance next time, I will see if I can get the owner to let my stick that trident on my gun and compare it to the long Huma I have.  I think that will give me a definitive answer on how well it performs, since I know my gun very well, and it is making about the same power with a shroud that serves no function in other than stiffness. 

I'm a dummy,lol!  I was thinking those were just pictures from his blog post that I had looked at earlier    I'm going to go hide by myself now 

Haha, no worries.  Everyone has their hiccups

What happened was...  I had looked at their site before, but not the "secret menu" part, and assumed those pictures were nothing more than pictures, rather than actually paying attention.  My bad there for sure. 

Speaking of shrouds and LDCs, I've read a lot more of STO's info and testing on their LDCs.  At first reading the blog, they kept stating that the large volume LDC was a waste of space.  Upon further reading(regarding their "flow factor"), it would seem that isn't entirely true.  The best I can determine, that was only true with guns using a functional shroud that air was venting to.  That shroud was taking up a lot of air volume during the shot cycle.  When you go further down the rabbit hole of their very extensive explanations, that large volume LDC rule seems to have gone out the window.  When designing an LDC for the high flow factor guns(guns without a shroud), everything changed.  What did they end up with for an unshrouded gun making decent power?  A 10" by 1.6" LDC! 

I'm not trying to dump on STO, but there sure was a lot of talk about the uselessness of large volume LDCs.  Boy, that all changed when they started playing with unshrouded guns.  I still think there is some serious coolness to their LDC design though, and I'm certainly not saying they don't work.  I'm just pointing out a minor gripe, about how conventional wisdom of LDC volume was seemingly made fun of, prior to the shroudless airgun testing .  I'd still be very willing to give one their LDCs a try, and still may.  You guys should really dig into all the info on their site about them.  It is all very interesting to say the least.  I think there is a lot of merit to the whole gas diode design he has been working with.  I still come away with the idea of you can't tame the bark of a powerful gun without some volume to handle all that air though.

[mrbulk]

I sent them a message via the site to inquire about which version they would recommend on my guns.  They have a "flow factor" calculator on their page to determine which versions of their LDCs to use.  By their calculator, my guns fall between moderate and high flow factors...  The pricing doesn't seem that bad, I may get one to try out, depending on the response.

Oh and another LDC related thing...  I got the chance to hear a Ramus Technologies Trident today on a 60 fpe Daystate Renegade in .25.  It seemed to work quite well for the size, fyi.  I can't be completely sure how well though, since I don't have much experience with what that gun sounds like with a different LDC, so take that with a grain of salt.

Donny I would have liked to hear that Daystate bare barreled first, so I that could experience just how much quieter the LDC made it afterwards. Did you get a chance?

I did hear it without the Trident, and it was noticeably louder for sure.  However, we were shooting in open space with a bit of wind as well.  If I get the chance next time, I will see if I can get the owner to let my stick that trident on my gun and compare it to the long Huma I have.  I think that will give me a definitive answer on how well it performs, since I know my gun very well, and it is making about the same power with a shroud that serves no function in other than stiffness. 

I'm a dummy,lol!  I was thinking those were just pictures from his blog post that I had looked at earlier    I'm going to go hide by myself now 

Haha, no worries.  Everyone has their hiccups

What happened was...  I had looked at their site before, but not the "secret menu" part, and assumed those pictures were nothing more than pictures, rather than actually paying attention.  My bad there for sure. 

Speaking of shrouds and LDCs, I've read a lot more of STO's info and testing on their LDCs.  At first reading the blog, they kept stating that the large volume LDC was a waste of space.  Upon further reading(regarding their "flow factor"), it would seem that isn't entirely true.  The best I can determine, that was only true with guns using a functional shroud that air was venting to.  That shroud was taking up a lot of air volume during the shot cycle.  When you go further down the rabbit hole of their very extensive explanations, that large volume LDC rule seems to have gone out the window.  When designing an LDC for the high flow factor guns(guns without a shroud), everything changed.  What did they end up with for an unshrouded gun making decent power?  A 10" by 1.6" LDC! 

I'm not trying to dump on STO, but there sure was a lot of talk about the uselessness of large volume LDCs.  Boy, that all changed when they started playing with unshrouded guns.  I still think there is some serious coolness to their LDC design though, and I'm certainly not saying they don't work.  I'm just pointing out a minor gripe, about how conventional wisdom of LDC volume was seemingly made fun of, prior to the shroudless airgun testing .  I'd still be very willing to give one their LDCs a try, and still may.  You guys should really dig into all the info on their site about them.  It is all very interesting to say the least.  I think there is a lot of merit to the whole gas diode design he has been working with.  I still come away with the idea of you can't tame the bark of a powerful gun without some volume to handle all that air though.

Hey man, what a highly astute and well thought out overview of it all. It hit the nail on the head because actually my own Akela is easy to quiet down with just a small LDC because it's already shrouded. And not only that, the shroud itself also holds a short series of conical spring loaded baffles. No wonder it was so quiet at medium and even 3/4 power, I thought at first. You would just require a middling good moderator if shot at full power in the backyard.

[Nomadic Pirate]

If you don't have a reflexed Neil Clague yet you're doing a huge disservice to yourself.

[mrbulk]

If you don't have a reflexed Neil Clague yet you're doing a huge disservice to yourself.

I agree. I just need to manage some funding on my end first.

[Long_Gun_Dallas]

If you don't have a reflexed Neil Clague yet you're doing a huge disservice to yourself.

Yep, I dont have a suitable setup on any gun to run one.  Absolutely the most effective design, though.  I'm doing something similar with my FX Crown this week.  Going to place a very tight (6.2mm) baffle inside the shroud.  Rather than the gaping (9.5mm) outlet endcap on superlight barrels, I should be able to contain a huge amount of pressure in the shroud, versus how it is now.

[Rallyshark]

I just ordered a high flow version of the STO Falx LDC to test out on my guns.  I should be able to report back on the effectiveness of this very unique design soon.  I'm hoping it works well.  I have two different NC LDCs, and a large Huma to compare it with.  I think the .22 slug gun will give it the biggest challenge, followed by the .177 slug gun, and a lower powered .177 pellet shooter.  The latter is back yard friendly with a Huggett Belita, so I don't really see much need of testing it on that gun...

[Long_Gun_Dallas]

 

Looking forward to results.  I've been eying the same model as well.

[soupyyy]

Although I don't have any fancy LDCs to compare for you folks.  I was inspired enough to do some noise recording of some popular airgun that I own.  I know I know...it is impossible to measure dB accurately with a cheap sound meter.  Just think of this as cheap entertaining OK?

Thing around the house.


Some popular airguns.


Some good dB info https://pulsarinstruments.com/en/post/understanding-decibels-decibel-scale-and-noise-measurement-units

[mrbulk]

If you don't have a reflexed Neil Clague yet you're doing a huge disservice to yourself.

Yep, I dont have a suitable setup on any gun to run one.  Absolutely the most effective design, though.  I'm doing something similar with my FX Crown this week.  Going to place a very tight (6.2mm) baffle inside the shroud.  Rather than the gaping (9.5mm) outlet endcap on superlight barrels, I should be able to contain a huge amount of pressure in the shroud, versus how it is now.

Let us know how this turns out Dallas, I am curious about the super tight 6.2mm baffle - so is this the thickness of the baffle as measured from barrel's outer wall to shroud's inner wall?

[mrbulk]

I just ordered a high flow version of the STO Falx LDC to test out on my guns.  I should be able to report back on the effectiveness of this very unique design soon.  I'm hoping it works well.  I have two different NC LDCs, and a large Huma to compare it with.  I think the .22 slug gun will give it the biggest challenge, followed by the .177 slug gun, and a lower powered .177 pellet shooter.  The latter is back yard friendly with a Huggett Belita, so I don't really see much need of testing it on that gun...

Donny so you did order the STO? Cool, I am super interested in how that works for you. With everybody buying stuff we should have a meetup and test these things out live!