Ye Olde Rocket Forum

Go Back   Ye Olde Rocket Forum > Work Bench > Building Techniques
User Name
Password
Auctions Register FAQ Members List Calendar Today's Posts Search Mark Forums Read


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 07-03-2007, 02:33 PM
spacefan spacefan is offline
Junior Rocketeer
 
Join Date: Jul 2007
Posts: 3
Default Rolling Your OWn Body Tubes

Does anyone know of a quick and efficient way to build or roll your on body tubes for constructing engine mounts? I seem to recall reading or hearing somewhere that you can build an engine mount tube by rolling paper or cardboard around an engine casing (18mm, 24mm, etc. depending on what size you want). I recently bought an Estes Outlander kit and want to upgrade it from 18mm to 24mm . I've heard from other rocketeers that the Outlander is dangerously underpowered if flown in stock form on 18mm engines.
Reply With Quote
  #2  
Old 07-03-2007, 03:20 PM
Zeus-cat Zeus-cat is offline
Intermediate Rocketeer
 
Join Date: Jun 2006
Location: Enon, Ohio
Posts: 98
Default

It should be possible, but rocket parts are easy to buy. I use Semroc for parts and their minimum order is only $20 and they don't charge for shipping.
Reply With Quote
  #3  
Old 07-03-2007, 04:13 PM
JRThro's Avatar
JRThro JRThro is offline
BAR Wannabee
 
Join Date: Mar 2005
Location: NW Houston, TX
Posts: 1,304
Send a message via MSN to JRThro Send a message via Yahoo to JRThro
Default

I vote for Semroc as well. In my experience, their minimum order is $10 and they don't charge for shipping.

Also, they absolutely have everything you could possibly need. Like the 24 mm motor tubes I bought from them, one of which I'll probably use in my Outlander when I build it.

Or if there's someplace local that sells inexpensive Estes rockets with BT-50 body tubes (inner diameter 0.950" or 24.1 mm), you could use a section of BT-50 as the 24 mm motor tube in your upgraded Outlander.

Or yes, you can absolutely roll your own 24 mm motor tube for your Outlander. Get a 24 mm motor, wrap it in waxed paper, then wrap it with cardstock. Once the cardstock begins to overlap, glue it to itself with a thin layer of yellow wood glue. Probably two or three layers of cardstock would be robust enough to use for a motor tube.
__________________
John Thro, NAR #84553 SR
I was too old when I started! Now I'll *never* become a BAR!
Reply With Quote
  #4  
Old 07-03-2007, 05:55 PM
Zeus-cat Zeus-cat is offline
Intermediate Rocketeer
 
Join Date: Jun 2006
Location: Enon, Ohio
Posts: 98
Default

JRThro is correct on the $10 minimum order at Semroc. Where did I get $20 from?
Reply With Quote
  #5  
Old 07-03-2007, 06:05 PM
maricopasem's Avatar
maricopasem maricopasem is offline
Craftsman
 
Join Date: Aug 2006
Posts: 141
Default

I always roll my on tubes, especially for MMT's. I use regular index cards and a glue stick (or sometimes white or yellow glue). I used to roll them around spent casings but had some that shrunk too small as the glue dried. I now use .75 and 1 inch dowels as mandrels. Masking tape is required for a good friction fit but they work like a charm.
__________________
Trash Can Rocketry
Reply With Quote
  #6  
Old 07-04-2007, 01:57 PM
handeman's Avatar
handeman handeman is offline
Intermediate Rocketeer
 
Join Date: Mar 2007
Location: Northern Virginia
Posts: 56
Default

I've been rolling my own too. I have a large roll of the brown craft paper. Spray adhesive works well too.
__________________
Handeman

TRA #09903
Reply With Quote
  #7  
Old 05-19-2010, 12:20 AM
GlueyFingers GlueyFingers is offline
Intermediate Rocketeer
 
Join Date: May 2010
Posts: 31
Default

I've been having some success spiral winding tubes, and recently solved one problem that had been really frustrating.

Due to the spiral winds, some glue inevitably leaks through onto the mandrel, so it's necessary to either have a teflon coated mandrel (I wish) or cover it with something. Wax paper was the obvious choice. But contrary to 1001 plan instructions, white glue does stick to wax paper to some degree. Pulling the tube and wax paper off the mandrel was no problem, but getting the waxed paper out of the tube was. Well, I just solved that.

Step 1 - as soon as the glue has set up to hold the wraps down (and before any ironing), slide it off the mandrel, almost certainly bringing the waxed paper along

Step 2 - fish a piece of string through the wax paper tube inside the newly formed body tube

Step 3 - twist the far end of the wax paper around the string and tie the string to the outside of the twist.

Step 4 - now pull it out the other end with the string. Since it's being pulled from inside, the waxed paper is being separated in only a small circumferential area at a time, so the tension isn't enough to tear it.

As for materials, I started with poster board, which is workable, then did some with a roll of craft paper which is more tricky, as it swells when it gets glue on it. Cutting it into absolutely straight strips helps minimize the spiral effect - I use a rotary fabric cutter. Any edge imperfections could lead to overlaps and exaggerated spirals. Leaving a tiny gap between the spirals on the lower layer helps especially with paper that tends to swell.

But a much better material for larger tubes (and I can't take credit as I've seen it mentioned before) is paper sheetrock joint tape. This has a very clean edge so its easy to conceal the spirals, and it glues up like a dream with no evidence of unglued sections as was common on the poster board. Try to pick a roll with less of a ridge down the center, though since I'm ironing the tubes on the mandrel as they dry this hasn't been much of a problem.

Just whipped up several slightly over BT55 (1.4" OD) tubes on PVC conduit mandrels. My two wrap tubes are about 16 mills wall and seem like they will hold together but have to be handled with care. I put a third wrap on one that had dried for a half hour or so and it is now 25 mills and much stronger.

Now I just have to see if I can split it accurately enough to wrap smaller mandrels, as the tape is a hair over 2" wide.
Reply With Quote
  #8  
Old 05-19-2010, 08:01 AM
gpoehlein's Avatar
gpoehlein gpoehlein is online now
Paper Rocketeer
 
Join Date: Mar 2005
Location: Evansville, Indiana
Posts: 1,181
Default

I've both rolled my own and used cardstock for tubes. 110# cardstock (you buy a whole pack at Walmart for a bit over $5) works fine - just roll a piece about a quarter inch larger than you need around a motor (or better yet, use a piece of coupler stock as a mandrel) and glue the tab. It will be plenty strong.

Second method was to create a mandrel with a piece of brass tubing just smaller than the tube needed and build up the rest with wax paper (use digital calipers to get the diameter right). I bought a package of cash register tape at the office store and use that - you can cut nice long lengths of it. Cut it about 1/2 inch wide and wrap it around the mandrel in the spiral with the edges touching but not overlapping and tape down both ends. I then test wrap a second piece going in the opposite direction and tape down one end. I thin a bit of white glue and paint it on the new strip about 10 inches at a time and work it around the tube, again careful not to overlap or get gaps between the spirals. Once that layer is done, I put on a third layer in the direction of the first. After the third layer is on, cut the tape ends off and carefully slide it off the mandrel to dry. Once dry, square up both ends and you've got a nice tube.

BTW, I also use cardstock for body tubes in general and I have also used the coupler stock mandrels for vellum tubes.

Greg
Reply With Quote
  #9  
Old 05-19-2010, 11:34 AM
luke strawwalker's Avatar
luke strawwalker luke strawwalker is offline
BAR
 
Join Date: Dec 2007
Location: Needville and Shiner, TX
Posts: 5,824
Default

Quote:
Originally Posted by spacefan
Does anyone know of a quick and efficient way to build or roll your on body tubes for constructing engine mounts? I seem to recall reading or hearing somewhere that you can build an engine mount tube by rolling paper or cardboard around an engine casing (18mm, 24mm, etc. depending on what size you want). I recently bought an Estes Outlander kit and want to upgrade it from 18mm to 24mm . I've heard from other rocketeers that the Outlander is dangerously underpowered if flown in stock form on 18mm engines.



Quick and easy motor tubes (where the appearance doesn't particularly matter) I've used toilet paper tubes... put a vertical line axially down the tube with the angle or doorjamb method, carefully cut along the line (scissors are fine) then wrap it around an engine til it overlaps tightly, draw a line down the cut edge to mark the overlap, cut along the line to cut the overlap off, then using white glue, glue the overlap piece to the edge of the tube with half the overlap piece sticking out over the edge, let it dry fairly good (not all the way is best, though) then put some glue on the other edge and glue the other half of the overlap to that edge, forming a tube with a butt joint underneath the overlap, which strengthens the joint...

Same basic method some folks use to reduce a tube diameter by cutting a strip out of the tube, but the overlapping 'glue tab' part goes to the outside.

Works like a champ, it's quick, easy, and they're just as strong or stronger than regular motor tubing...

If you want quick and easy (if a bit more expensive) just use some BT-50; Semroc sells them for a couple bucks per 18-24 inch tube, or most local hobby shops that sell Estes rocket stuff usually have SOME of the parts collections on the shelf (bagged tubes, nosecones, engine mounts, launch lugs, parachutes, etc.) The tubes and nosecones usually aren't too bad a buy-- stay away from the launch lugs, motor mount kits, and parachutes-- they're usually GROSSLY OVERPRICED in the hobby shops!

Look at Hobby Lobby in the clearance aisle for cheapy/dinged BT-50 rocket kits for parts, too... usually a fairly good deal...

Later! OL JR
__________________
The X-87B Cruise Basselope-- THE Ultimate Weapon in the arsenal of Homeland Security and only $52 million per round!
Reply With Quote
  #10  
Old 05-19-2010, 11:21 PM
Mark II's Avatar
Mark II Mark II is offline
Forest Sprite
 
Join Date: Dec 2006
Location: Back Up in the Woods
Posts: 3,657
Default

Take it from an experienced card modeler: for the best strength:weight ratio for the money in the size that you are talking about, it is really hard to beat commercially-made spiral-wound model rocket tubes. You can make your own (as I have done, many times) but it will not be as light, and with the Outlander, weight is the critical issue, isn't it? You can make one that matches the weight of a spiral tube, but it won't be as strong. Model rocket body tubing is quite inexpensive, too, and centering rings are designed to fit standard tubing. DIY tubing really only makes sense when you need a really oddball size, usually for scale purposes. Otherwise, it is more trouble than it's worth. I can't speak for everyone, but my hobby time is limited; as a consequence, I prefer to work smarter, not harder.

MK
__________________
Mark S. Kulka NAR #86134 L1,_ASTRE #471_Adirondack Mountains, NY
Opinions Unfettered by Logic Advice Unsullied by Erudition Rocketry Without Pity
+09281962-TAK-08272007+
SAM # 0011
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT -5. The time now is 06:50 AM.


Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Ye Olde Rocket Shoppe 1998-2018