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Who sells BT50H?

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neil_w

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I've mostly switched over to BT50H for my scratchbuilds. I buy it from BMS.

The other day I was curious, and to my great surprise I could not find it listed at any other vendor. Well, eRockets has "foil-lined" BT50H, but I don't know what that is exactly, or whether I'd want it. The foil lining is probably good for protecting the tube against ejection charges, but I'd be concerned trying to glue anything into it. Turns out when I went back and looked, BMS sells foil-lined as well as the normal stuff I usually buy.

Does *anyone* else sell the regular stuff? Who's using BT50H out there? Do you use the foil-lined, or regular? What's the deal?
 

neil_w

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teepot

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The "H" from BMS stands for heavy walled. I get all my tubes except for 4" from them.
 

Sooner Boomer

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I've used it in a couple of rockets that have ejection baffles. I think in this case it will hold up better.

 

kuririn

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IIRC it was explained to me once a few years ago that the foil lined BT-50 was to protect the motor tube from the high heat of composite motors. The casings can get pretty hot. As I found out the first time I tried to pull out a casing immediately after recovery. 😁
 

BABAR

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IIRC it was explained to me once a few years ago that the foil lined BT-50 was to protect the motor tube from the high heat of composite motors. The casings can get pretty hot. As I found out the first time I tried to pull out a casing immediately after recovery. 😁
That’s what I call “self critiquing”. Nobody needs to tell you not to do that again.
 

neil_w

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Buy an ST-9 tube from erockets.
Almost twice the thickness of a BT-50 tube but fits 24mm motors.
Ah, there it is. That's even thicker-walled than BMS BT50H, probably close enough to be interchangeable, at least for internal tubes.
I've used it in a couple of rockets that have ejection baffles. I think in this case it will hold up better.
Interesting, I'd never seen that in use before.

Outer diameters (according to vendor):
Regular BT50: .976"
BMS T50H: .990"
BMS T50MF (foil): 1.000"
eRockets BTH-50 (foil): .992"
eRockets ST-9: .998"


A little more standardization would be nice, but whatcha gonna do.
 

jqavins

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What about centering rings? The BMS T50H is .014 larger than the standard BT-50 on the OD, so you need to remove .007 on the radius of a normal CR, which I assume is no big deal to sand out. It goes up from there. Would you be concerned, or noticeably inconvenienced by any of those?

Intresting to note, the next row down on the BMS chart is their T104 (Centuri ST-10) which has a 1.00 ID, so it would make a viable sliding sleeve for the eRockets ST-9 (I assume a Centuri clone) or slightly smaller. Think of the design possibilities...

I didn't read any answer about gluing to the foil inside on the T50MF. Sure, epoxy should hold to the metal, but is the metal bonded well enough to the cardboard for a sound joint? Has anybody done this, like for inserting an engine block or a BT-20 stuffer tube?
 

neil_w

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What about centering rings? The BMS T50H is .014 larger than the standard BT-50 on the OD, so you need to remove .007 on the radius of a normal CR, which I assume is no big deal to sand out. It goes up from there. Would you be concerned, or noticeably inconvenienced by any of those?
I am already in the habit of only purchasing rings for BT50, and sanding out the insides to fit. I find the BMS 50H rings are often a bit loose. Easier to remove material (especially with my beloved sanding sticks) than to add it.
I didn't read any answer about gluing to the foil inside on the T50MF. Sure, epoxy should hold to the metal, but is the metal bonded well enough to the cardboard for a sound joint? Has anybody done this, like for inserting an engine block or a BT-20 stuffer tube?
I would think that the foil would be compressed between the ring and the body tube, so it really has nowhere to go. I would tend to trust it, although not necessarily to the same degree as I would a standard cardboard tube. I too am still interested in anyone's actual experience with this.
 

Bill S

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In one of my last builds, it was using a BT-55 tube, with a 24mm motor mount. I was concerned about the hibachi effect on the tube, so I took 4" of BT-55 tube, cut it length-wise, removed a small slice so it would slide into the main body tube. I then took some actual aluminum duct tape with adhesive and lined the inside of the tube. I then epoxied it in the main tube ahead of the motor mount. I don't think its going anywhere. Maybe this is a viable option instead of fooling with BT-50H foil tube?
 

tsmith1315

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Outer diameters (according to vendor):
Regular BT50: .976"
BMS T50H: .990"
BMS T50MF (foil): 1.000"
eRockets BTH-50 (foil): .992"
eRockets ST-9: .998"
LOC 24mm tubing, in 12" lengths: 0.99"/0.95"
They also have 6" and 18" MMT in 24mm, I found no mention of OD

weight and cost aside, Mach1 BT 50 fiberglass tube is 0.98"/0.94"
 

neil_w

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LOC 24mm tubing, in 12" lengths: 0.99"/0.95"
They also have 6" and 18" MMT in 24mm, I found no mention of OD
Excellent find. I shot them an inquiry regarding the OD of their 24mm motor mount. I would guess it's the same as their other 24mm tubing, but would like to hear them confirm. Does anyone else resell their tubing?
 

tsmith1315

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Does anyone else resell their tubing?
Good question, I've been looking at various sizes of airframe tubing for a couple of planned projects. Too confusing, now I can't remember who sells what.

Chris at CSRocketry does sell LOC parts, but he drop ships tubes- none in stock.

The motor tube in Aerotech's 29mm/24mm motor adapter measures 0.99"/0.95", but I don't see that they sell it separately in any length.

Would you let us know if you get a response from LOC? I'll add that to my spreadsheet.
 
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