Kosdon Plugged Fwd Closure

Actually, I bought an animal works 38mm plugged fwd closure after being told it would work with Kosdon hardware. Trouble is, the amw plugged closure is much shorter than the kosdon fwd closure with delay well. This leaves a significant gap between the last propellant grain and the fwd plugged closure. This seems dangerous or at least destined not to work.

I'm just wondering if I can use my existing Kosdon fwd closure and instead of using the pipe nipple, instead using a 1/4" bolt to plug the opening to affect a plugged fwd closure.

Unless they changed them; it more like a 1/2" bolt or 1/4 NTP pipe nipple.
Can you stack 2 to take up the difference?

JD

JDcluster said:

Unless they changed them; it more like a 1/2" bolt or 1/4 NTP pipe nipple.
Can you stack 2 to take up the difference?

JD

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I'll have to measure to see if two amw closures would work. You're right, 1/4" npt nipple, but would a bolt screwed in or even a 1/2" npt cap on the nipple suit my purposes for making the open closure a plugged closure? Would be cheaper than buying a second amw plugged closure, if the measurements even worked out.

Are the Kosdon loads still certified, or are they strictly Rx fodder?

My dsl connection is acting up today. Half the places I try to go are offline, or my provider is having some kind of breakdown.

Yes, you could use a cap or plug ( they make both).
I use to use a nickel backed up by some O-rings inside the delay well and filled with Super Lube.

JD

hball55 said:

I'll have to measure to see if two amw closures would work. You're right, 1/4" npt nipple, but would a bolt screwed in or even a 1/2" npt cap on the nipple suit my purposes for making the open closure a plugged closure? Would be cheaper than buying a second amw plugged closure, if the measurements even worked out.

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JDcluster said:

Yes, you could use a cap or plug ( they make both).
I use to use a nickel backed up by some O-rings inside the delay well and filled with Super Lube.

JD

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Great news, thanks. This also solves my problem with 8 reloads I recently purchased from a vendor that shipped with delays but no delay liners.

I think I plugged one that was threaded for the pipe with a bolt. Bad idea - it failed and resulted in a cato.

I have several research ones filled with epoxy. I think some I filled the pipe threaded in with JB Weld and an eye bolt.

Just watch for loose / mismatched threads.

hball55 said:

Great news, thanks. This also solves my problem with 8 reloads I recently purchased from a vendor that shipped with delays but no delay liners.

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But that still doesn't solve the issue of the forward closure being different lengths. Kosdon closures are much longer than AMW closure. I would recommend getting a Kosdon closure from either Ken at Performance hobbies or Dave at red arrow hobbies.

Yes Kosdon loads are still certified for use.

ECayemberg said:

But that still doesn't solve the issue of the forward closure being different lengths. Kosdon closures are much longer than AMW closure. I would recommend getting a Kosdon closure from either Ken at Performance hobbies or Dave at red arrow hobbies.

Yes Kosdon loads are still certified for use.

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I have the original open closure that I was thinking of using a pipe plug to close and the AMW plugged forward closure that is definitely shorter in length, thus creating my problem; however, I contacted Robert DeHate asking about the forward closure I purchased from him and asked about the shorter length. In reply (very quick reply I might add) I received notification of a shipment. Now I call that excellent . . . I was just inquiring and apparently he saw my problem and proceeded to correct it within an hour. So, when the package arrives, hopefully my problem will be corrected in the best possible manner.

As for Ken (Performance Hobbies), we aren't what you would call on friendly terms.

Real Kosdon loads had: the delay element then, you had these delay washers which you alternated with o-rings in the stack around the delay element.

JD

hball55 said:

Great news, thanks. This also solves my problem with 8 reloads I recently purchased from a vendor that shipped with delays but no delay liners.

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JDcluster said:

Real Kosdon loads had: the delay element then, you had these delay washers which you alternated with o-rings in the stack around the delay element.

JD

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Oh, then all was shipped correctly. So, there's a washer on each end, with o-rings in the middle? These are TRM reloads, not KBA, so what you say makes sense. I wondered why there were so many small o-rings. In any event, since these reloads (I220, I420) don't show up in Rocksim I can't sim them and won't be using motor ejection and thus my trying to figure an easy way to plug my forward closure.

hball55 said:

.

As for Ken (Performance Hobbies), we aren't what you would call on friendly terms.

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op:op:

CoyoteNumber2 said:

Do you know the size of the washers? I lost all mine. I just stack O-rings instead.

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The washer is .75" outer diameter and .484" inner diameter.

CoyoteNumber2 said:

Where does one get them? Are search in all the usual places revealed nothing.

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Good question, I got mine when I bought the case; I do have an extra, so if you PM me your address I will mail it . . . it would be simple enough to do and little enough cost to not break me :lol:

I'm not sure why Frank incorporated those spacers; I use them on occasion, but more often then not simply add enough #208 o-rings to cover the length.

For what it's worth, the 208 orings work with Aerotech RDK delays; the RDK-16+ kit is the longest at .781" long. If I burn a research or Kosdon load in Kosdon 38mm hardware, if I plug it, I'll just stick some dog barf in the threaded ejection well and add tape to the top. One could certainly plug the hole with an appropriately threaded bolt or sealed fitting.

Enjoy!

-Eric-

The OD of Kosdon delay elements is 0.625". Buy the following and you'll be all set:

Delay tube: https://www.mcmaster.com/#8527K136
O-Rings: https://www.mcmaster.com/#9452K187

1" of delay with 5 o-rings stacked on the outside will work fine. Either fill the delay with your favorite smoke concoction (40/40) or fill with epoxy for a plug.

Looking at a copy of assembly instructions that tfish sent me, the use of the o-rings before Aerotech started supplying a delay liner, the instructions show the delay spacer in the forward end of the delay cavity, followed by the delay with three o-rings surrounding the aft end of the delay. This shows the forward end of the delay bare, though the aft end is sealed with the 3 o-rings.

Just offering what the instructions say, as I'm sure the previous comments by experienced users work perfectly well. Up to this point, the only Kosdon reloads I have burned have had the delay liner. Only recently have I procured Kosdon reloads, as opposed to Kosdon KBA reloads.

When plugged, I was planning on using Dow Corning 111 grease in the threaded end of the ejection well before installing a NPT pipe plug. Any comments on the merits or negatives of this method? Dan, the liner material you cite from McMaster-Carr, do you recommend using it over the use of multiple o-rings?

Also, I noticed when practicing assembling the delay using the multiple o-rings, that if the metal delay washer is placed in the forward end of the delay cavity, the delay spacer is easily centered and then the delay can be inserted with the three o-rings at the aft end of the delay and the whole assembly is flush in the delay well. I wondered if this is why there is the metal delay washer and why it wouldn't be needed once Aerotech started supplying delay liners.

ECayemberg said:

I'm not sure why Frank incorporated those spacers; I use them on occasion, but more often then not simply add enough #208 o-rings to cover the length.

For what it's worth, the 208 orings work with Aerotech RDK delays; the RDK-16+ kit is the longest at .781" long. If I burn a research or Kosdon load in Kosdon 38mm hardware, if I plug it, I'll just stick some dog barf in the threaded ejection well and add tape to the top. One could certainly plug the hole with an appropriately threaded bolt or sealed fitting.

Enjoy!

-Eric-

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I got a blow by using-208s and Rdks, just not quite tight enough with manufacturing tolerances. RCS sells 22.5 mm o rings that are perfect for RDKs. I Use 208s and one of the Rcs orings all the fwd.

All I do is stack 5 greased o-rings, press the delay element through all 5 o-rings at once, then push the bulkhead over the outside of the o-rings. Lastly, I take a flat blade screwdriver and make sure that the o-rings are all bottomed out against the fore end of the bulkhead. Easy peasy. And yes, DOW 111 is what I use for every motor I assemble.

patelldp said:

And yes, DOW 111 is what I use for every motor I assemble.

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As Frank intended

Here's a question, why do some Kosdon reloads have liners while others don't? My I310 38/640 reloads don't use liners and I know this is correct as the instructions and the kit parts list don't mention or show a liner. Same with my 38/510 I420 & I220 reloads; though these reloads didn't come in sealed bags nor did they come with assembly instructions. They came with the grains, in bulk, in bags, while the o-rings and delays came in another bag - not being critical, just descriptive.

All the rest of my Kosdon reloads, both 38mm and 54mm, sealed and with assembly instructions, have liners.

BTW- At today's launch, my I420 CATO'd, blowing the nozzle out and obliterated, as I found no pieces. I did find the nozzle washer and aft snap ring, twisted and mangled horribly. They were stuck on the launch tripod assembly. My only guess is that perhaps I had the wrong nozzle. Now I'm going through all my nozzles and checking the throat diameters. Luckily, there's no apparent damage to the case. Though closer inspection will be needed.

All REAL Kosdon loads had no liner except for his C-slot loads for obvious reasons ( heat soak).
I've flown numerous Real deal Kosdon Loads: I 255 DH, J 450 aka: I500, J630F, I 385, H360DH.
The 29's had a liner none of the 38's though.

Nozzle mix up could very well have been the culprit.
When I bought the hardware from a vendor it also had the wrong nozzle.

JD

hball55 said:

Here's a question, why do some Kosdon reloads have liners while others don't? My I310 38/640 reloads don't use liners and I know this is correct as the instructions and the kit parts list don't mention or show a liner. Same with my 38/510 I420 & I220 reloads; though these reloads didn't come in sealed bags nor did they come with assembly instructions. They came with the grains, in bulk, in bags, while the o-rings and delays came in another bag - not being critical, just descriptive.

All the rest of my Kosdon reloads, both 38mm and 54mm, sealed and with assembly instructions, have liners.

BTW- At today's launch, my I420 CATO'd, blowing the nozzle out and obliterated, as I found no pieces. I did find the nozzle washer and aft snap ring, twisted and mangled horribly. They were stuck on the launch tripod assembly. My only guess is that perhaps I had the wrong nozzle. Now I'm going through all my nozzles and checking the throat diameters. Luckily, there's no apparent damage to the case. Though closer inspection will be needed.

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I wonder if anyone would be interested in these. I welded an eye bolt to a 1/4 inch nipple to use as a Kosdon plug/ recovery attachment point.