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Duncan.Byers

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I'm new so I'm sure I'm missing maybe two thousand years of discussions about card stock and centering rings. But...whereinhell do I get card stock like Estes/Apogee uses for centering rings? Other than paying too much for it and shipping at Apogee. I know bunches of people use mat board but that stuff is lousy and separates ridiculously easy. I could use balsa, I know, but I do like using the card stock. Anyone have any idea where I can get it by the sheet? And not some little 4" by 3" sheet.
 

bjphoenix

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I'm new so I'm sure I'm missing maybe two thousand years of discussions about card stock and centering rings. But...whereinhell do I get card stock like Estes/Apogee uses for centering rings? Other than paying too much for it and shipping at Apogee. I know bunches of people use mat board but that stuff is lousy and separates ridiculously easy. I could use balsa, I know, but I do like using the card stock. Anyone have any idea where I can get it by the sheet? And not some little 4" by 3" sheet.
Do you already have some cardstock? You can laminate multiple layers to get the thickness that you want. You can also check all of the various packaging you throw away. I've noticed that occasionally I find a product that comes packaged in quality feeling cardboard. If you are making your own rings I wouldn't be afraid of making them thicker than the rings you get in kits. It can be hard to cut out a real thick ring, you can cut the rings out of the thinner pieces of cardboard and then glue them together. The next step if you don't want to make your own from random cardboard is to laminate 2 pieces of thin balsa with the grain of one running perpendicular to the grain of the other and then cut rings out of that.
 

Duncan.Byers

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Do you already have some cardstock? You can laminate multiple layers to get the thickness that you want. You can also check all of the various packaging you throw away. I've noticed that occasionally I find a product that comes packaged in quality feeling cardboard. If you are making your own rings I wouldn't be afraid of making them thicker than the rings you get in kits. It can be hard to cut out a real thick ring, you can cut the rings out of the thinner pieces of cardboard and then glue them together. The next step if you don't want to make your own from random cardboard is to laminate 2 pieces of thin balsa with the grain of one running perpendicular to the grain of the other and then cut rings out of that.
Thanks for the reply; I appreciate it. One of the cool things about this crowd is that everyone is constantly innovating. One of the bad things about this crowd is that everyone is constantly innovating. ;) I've got all of those options - I'm just looking to cut corners because I'm lazy that way. And I also know that I can us CA on the mat board to solve some of the problem....but then I'm using up CA for something that I just feel has a better solution. Like a bulk source for the card stock! If I do find a bulk source I'll get a bunch as sell sheets cheap, I swear.

Again, thank you for the reply. In all seriousness I really appreciate how responsive and open everyone here seems to be with ideas, designs, solutions, etc.
 

PDawg

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I'm not sure exactly what cardstock is but I found Posterboard to be more than strong enough for centering rings and it works for fins as well. I have 3 launches on a C powered rocket with posterboard fins. The fins are soo stiff and thin I may never use Balsa or basswood again. I have an E engine rocket with them I'll send up shortly to see if they can handle that engine. No finishing or filling is a big plus, they are smooth as can be.
 
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No finishing or filling is a big plus, they are smooth as can be.
+1
Duncan, you might find this thread interesting:
 

GlenP

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Do you have any cardboard boxes in your recycling bin? I usually print the template from PayloadBay.com and glue stick it to whatever cardboard I have in the bin. Cereal boxes can work but you might have to peel off the glossy layer and then glue it up two layers thick. You can layer a few sheets of 110# cardstock to make them yourself also.
 

Sooner Boomer

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I bought pre-cut packages of matte board from Hobby Lobby in 3x5 and 5x7. It works fine for fins and centering rings for low/mid power stuff. I also use it to make fin templates that are then cut from balsa/ply. The matte board works well with yellow/white glue because it soaks into the paper. I think because of this, these glues are better than epoxy, which doesn't soak in.
 

bjphoenix

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I bought pre-cut packages of matte board from Hobby Lobby in 3x5 and 5x7. It works fine for fins and centering rings for low/mid power stuff. I also use it to make fin templates that are then cut from balsa/ply. The matte board works well with yellow/white glue because it soaks into the paper. I think because of this, these glues are better than epoxy, which doesn't soak in.
I agree- I think wood glues are better for paper/cardboard. All of my LPR uses wood glue and I've occasionally used wood glue in my larger LOC kits. Certainly for LPR the bond of the glue is stronger than the strength of the paper/cardboard so stronger glues don't gain anything. The problem with wood glue in larger rockets is it is hard to build up much thickness because so much of the glue goes away when it dries. (And it takes it a long time to dry if you put a lot in there.) I can build up reasonable fillets for LPR but I could never build up a decent fillet with Titebond II. (I haven't tried any of the thicker forms of Titebond.)
 

Duncan.Byers

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I'm now running an experiment. I went to an art supply store (https://www.jerrysartarama.com) instead of a hobby store and got a few iterations of thick board material - presentation board and the like. I am going to try all and post the results here. And because they are all paper products there should be no problems with wood glue. But as I said I'm going to report.......
 

Duncan.Byers

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I bought three different types of dense paper/card stock and wrote the prices on each. And comparing them to each other and to standard mat board.

20220519_220325.jpg 20220519_220332.jpg 20220519_220317.jpg

In the Illustration Artboards there are ten sheets in the pack that are 8"x10" for twenty bucks. So it's 800 in^2 for 2.5cents per square inch. The marker boards and lettering boards are three sheets per pack of 11"x14" for thirteen bucks. That's 462 in^2 at 2.8 cents per square inch. For comparison, Apogee sells centering ring card stock for $2.72 for an 8.5"x11" sheet. That's 2.9 cents per square inch. The shipping will add at least another ten bucks or more to your order though. All the material I bought is also available on Amazon so if you're a prime member there's no shipping of course. And you'll get the stuff faster if you need it.

I started with Illustration Artboards. If you're doing the math, the 800 in^2 is 2,032 cm^2. So if you're cutting rings for, say, a bunch of bt-50 tubes, they're roughly 4.52cm^2 in area with a 24mm diameter, so you are using 5.76cm^2 worth of material (I'm accounting for waste around the ring by using squares rather than circles for the area) so you get somewhere around 300-350 rings out of the ten boards. Or if you cut rings with as much waste as I do maybe 150. So your rings are costing you 13 cents each to get 150 of them. Or half that if you're a true craftsman unlike me. Apogee charges 54 cents apiece for bt-50 centering rings. Plus shipping of course.

It is denser than mat board. These are the weights of the same size piece:

20220519_222824.jpg

I didn't bother to calculate the weight per inch or cm but based upon the feel the illustration board is likely close to what centering rings are cut out of by Estes/etc.

I bent them to see about delamination (which mat board does very easily). The illustration board is far more resistant to it than the mat board:

20220519_223131.jpg

I rough cut rings intentionally being sloppy to damage the edges as much as possible. As you would expect the illustration board is tougher to cut but again is far more resilient than the mat board.

20220519_224208.jpg 20220519_224313.jpg

Bending the larger sheets did cause sharper cracks in the illustration board than the mat board but that's kind of what I expected when I brutalized them. The illustration board does have branding on one side but I don't care about that. Maybe you do.

20220519_223153.jpg

I will do the other boards when I get a chance, as well as gluing. Thus far, however, the illustration board seems like it's good stuff.

More to come.
 

Duncan.Byers

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So the lettering and the marker board are the same just with different top finishes. They are thinner than the illustration board:
20220521_180553.jpg

Easier to cut and fairly stiff. Similar density to the illustration board and with the same other characteristics. They do delaminate a little bit:

20220521_182144.jpg

But nowhere close to the delamination of matte board (and yes I know I was misspelling it earlier....don't know why). I think they are all good choices but I think I'll stick with the marker and lettering boards simply because I think they've got the strength and density to do the job and are easier to cut than the illustration board. Also will reduce the almighty weight just a little. But I would say you can't go wrong with any of them.

I think my next review should involve bourbon.
 

bjphoenix

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Could you measure the thicknesses of these various materials in thousandths of an inch and tell us? I'm curious how they compare to cardstock and to some of the various packaging materials I've collected.
 

Duncan.Byers

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Could you measure the thicknesses of these various materials in thousandths of an inch and tell us? I'm curious how they compare to cardstock and to some of the various packaging materials I've collected.
I'm still unpacking from a move and so I'm not sure where my caliper is hiding at the moment. Best I can tell you is that thinner material looks to be 1.25mm and the thicker illustration board 2mm. So 0.049in and 0.0787in. Rounding gives you 50 thousandths and 80 thousandths. Close enough for government work I would think.
 

bjphoenix

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I'm still unpacking from a move and so I'm not sure where my caliper is hiding at the moment. Best I can tell you is that thinner material looks to be 1.25mm and the thicker illustration board 2mm. So 0.049in and 0.0787in. Rounding gives you 50 thousandths and 80 thousandths. Close enough for government work I would think.
The various stuff I've collected ranges from 0.009" to 0.028". If I was making centering rings I would laminate several layers together.

I've done some experiments with spools for shock cords. At first I glued several layers together and then cut out what looked like a small centering ring. Cutting all the way through the thickness was hard and it damaged the edges at the same time. The last one I built I cut out the rings first and then glued the pieces together, that way I don't have to mess with the edges of the pieces after laminating. And its a lot easier to make one clean cut through 2 separate pieces than to make one cut through a thicker piece.
 

Duncan.Byers

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The various stuff I've collected ranges from 0.009" to 0.028". If I was making centering rings I would laminate several layers together.

I've done some experiments with spools for shock cords. At first I glued several layers together and then cut out what looked like a small centering ring. Cutting all the way through the thickness was hard and it damaged the edges at the same time. The last one I built I cut out the rings first and then glued the pieces together, that way I don't have to mess with the edges of the pieces after laminating. And its a lot easier to make one clean cut through 2 separate pieces than to make one cut through a thicker piece.
I get the cut then laminate but I'm not sure what you mean by using spools for shock cords. Can you elaborate?
 

grafgulch

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A long time ago I found some cardboard that looks exactly like the stuff Estes uses for there centering rings. It was sold at a comic book shop as backing boards. The back boards went into a plastic sleeve along with your prized comic book to keep it in good shape. Paul
 

Duncan.Byers

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A long time ago I found some cardboard that looks exactly like the stuff Estes uses for there centering rings. It was sold at a comic book shop as backing boards. The back boards went into a plastic sleeve along with your prized comic book to keep it in good shape. Paul
I used to collect comics so yeah I'm very familiar. They are not as thick as I would prefer however.
 

lakeroadster

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Hmm? I thought this testing was going to be: Building several motor mounts using different materials for the centering rings.

Then the body tube would be restrained and a load would be applied to the motor tube until the centering rings failed.

Thus determining the best centering ring material to be used, based on the actual thrust of the motor.
 

Duncan.Byers

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Hmm? I thought this testing was going to be: Building several motor mounts using different materials for the centering rings.

Then the body tube would be restrained and a load would be applied to the motor tube until the centering rings failed.

Thus determining the best centering ring material to be used, based on the actual thrust of the motor.
I'm not exactly sure where you got that idea. Besides, I'm not slapping P motors in tubes at this point. All that seems to be overkill for me slapping together LP rockets, right? I could do that but I'd rather build 'em and fly 'em. Maybe when I'm shooting for 100,000 ft of altitude I'll worry about it a bit more.
 

lakeroadster

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I'm not exactly sure where you got that idea. Besides, I'm not slapping P motors in tubes at this point. All that seems to be overkill for me slapping together LP rockets, right? I could do that but I'd rather build 'em and fly 'em. Maybe when I'm shooting for 100,000 ft of altitude I'll worry about it a bit more.

Not at all. Sizing components based on motor size works for everything from 1/4A3 motors up.

Form - Follows - Function.
 

Duncan.Byers

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Not at all. Sizing components based on motor size works for everything from 1/4A3 motors up.

Form - Follows - Function.
Yeah sure. But that's overkill for me. Not for others, maybe. So far using the cardstock I've got is pretty much same-same as the Estes and Apogee cardstock so I don't see much reason to go to that extent. If I was trying a completely new-fangled very thin material maybe I'd worry about it some more. Or if I was entering into some competition.
 
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