How Small Can You Roll?

Discussion in 'Tips, Tutorials & Tools' started by Gil, May 23, 2004.

  1. Gil

    Gil Active Member

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    Hello All,

    I've been experimenting with methods for rolling small diameter paper tubing. This is one area where most modelers decide that mulitmedia is more than just a word an oft for something much easier to deal with. I guess this will be some sort of a gentlemen's contest in an effort to see who can come up with the best or better yet, several methods for rolling your own.

    I'll start out by offering a 76 x 1.3 mm tube. It was rolled using a dapping block groove, an embossing pen and a jeweller's draw plate. The seam was closed with thin cyanoacrylate as it came out of the draw plate hole on the last pass through. I won't go into the details unless it's apparent that this is one of the winning methods. The paper used was .012 inches (100 lb.) thick and was about 4.2 mm wide by 30.54 cm to start with. Yes, all that I ended up with was 7.6 cm of the original 30 but was the first attempt. Using thinner paper might allow for even smaller diameters...,

    Pictures if successful or words explaining otherwise...,

    Best regards, Gil
  2. barry

    barry Active Member

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    Interesting I've just got to this dilemma with Takao so I tried rolling a cigerette paper tube got it down to about 1.1 mm but only had a length of 50 mm, which is not long enough.

    However it may come in useful on 1/400 gun barrels. The method used cut the ciggy paper in half lick half, roll it around a thin wire lick the other half. Some work some don't but it's cheap.

    barry
  3. Gil

    Gil Active Member

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    Barry,

    Very nice method..., have you thought of trying light drawing vellum? One problem with mandrel rolling is getting it started. Wetting to lay it down on the mandrel may lead to similar methods with other paper types. Also,sStarting the roll on a diagonal bias makes starting much easier.

    I've found that the mandrel method doesn't seem to work well with heavier stock when rolling small diameter sizes. Light stock suffers from poor strength. Your use of light stock and multiple layers is a good idea. As usual there's always an appropriate method for the design conditions present. This also points to two major divisions of paper tubes, seam joint and overlap wrap.

    Some time ago I experimented with pulling (or "drawing") tubes through a plastic drill size gauge received in the mail. Each hole was slightly countersunk before pulling appropriately widthed paper through coated in acrylic medium. One problem cbserved was the weakening of the paper as it absorded the acrylic medium..., controlling the amont of medium to just coat the outside minimized this weakening effect. 67# paper was used in these experiments. Might have to repeat them for purposes of demonstration...,




    Best regards, Gil
  4. barry

    barry Active Member

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    Something else I remembered STEAM wrap the heavier weight paper around the mandrel and hold it in the steam from a kettle, trouble with my kettle it keeps switching itself off.

    Strangely I had given up on this one but I picked the tube up again after it had dried and it rolled more tightly than before,

    I will have most trouble sticking the edges I think.

    barry
  5. Gil

    Gil Active Member

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    Barry,

    Tried spiral wound tubes this afternoon. The paper wrapping tape width is related to mandrel diameter. This method requires a minimum of two wrappings wound in opposition to one another and is finished with a white glue rub (sounds like BBQ). Currently waiting for the layup to dry. Keep your fingers crossed that it will slip off the mandrel shaft. One other point is that a little sandpaper was used to reduce the edge curl that forms when wrapping a paper tape around a circular mandrel before the white glue was applied.

    The drawplate method is still the hands down winner for creating small diameter paper tubes but doesn't have the same strength as this method.

    Best regards, Gil
  6. Gil

    Gil Active Member

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    Barry,

    Finished the spiral wound. It was weak structurally coming off the mandrel so it was soaked in wood hardener and left to dry overnight. It's still fairly flexible. The outer layer wasn't properly bonded to the inner layer greatly reducing the tube's rigidity..., the outer wrap needs to be coated with white glue before it is applied.

    The real problem in rolling tubes seams to be "getting it started" properly. This will require further thought..., your method with wetted tobacco paper is a great method for that medium...., forming through a draw plate is yet another. Need to think about sushi roll mats....,

    Best, Gil
  7. barry

    barry Active Member

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    thin rolls

    Hi Gil

    One of the last jobs on Takao is to produce the crane boom, I was quite suprised at my reluctance to use a shaped piece of wood.

    I cut out the spare main mast bits using thin paper 80gsm but I left a long lead in for the mandrel to pick up, having rolled it roughly I then cut off the excess and rerolled it only this time running as a spiral, then removed this from the mandrel and just rolled it between my fingers until it tightened up. As far as I could see the jib is two long cones joined in the middle.

    Having made two cones as above I finally decided to cheat and glued the plastic rod mandrel inside it but it looks more or less right.

    A coat of black marker pen hid the most obvious faults. Still racking my brains for some thinner stiffer paper, I wonder what greaseproof rolls like ?

    Barry
  8. Gil

    Gil Active Member

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    Hi Barry,

    The spiral tightening method works well for tapered booms and spars. I did some of these a while back and was quite satisfied at the outcome. The two were joined by rolling a short tapered barrel that fit inside the big end of both tapered spars. End caps were rolled out of a trinagular piece of paper so that it formed an acorn shape on one end and a tapered end to stick into the end of the small end of the spar. These needed to be coated with a filler material and let dry before final sanding and painting.

    I tried a triangular starting tab today.., it came out OK but it ended up larger in diameter than the draw plate solution. One idea that came up was to grind in half a brass tube with the right inside diameter as desired for the finished rolled tube. Use a suitable diameter piece of piano wire to force the paper into the half shape...., didn't get any further than this in the thought process, but it's a start.

    Best, Gil

    P.S. Rice paper is definitely not good for rolling tubes..., grease proof maybe glue proof...,
  9. Bikerpete

    Bikerpete Member

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    Small cylinders

    I've been following this thread with interest and mulling over in my mind a few possible ways of rolling small cylinders. I finally got my chores finished and tried out a couple. The first, involving multiple scores to assist the curve did not work well, its too hard to keep the scores close enough to be effective.
    The second worked o.k. and is based on the Sushi roll idea posted previously. The trick is to use laminated paper so that the paper itself acts as the sushi roller. I used the card from a cigarette package, the outer surface will peel away from the backing fairly nicely after rolling. The cylinder is then formed by cutting the circumference a bit bigger than needed, applying glue then rolling it over a plastic mandrel. Since the curcumference is cut a bit long the joint will spiral a bit to fit the mandrel.
    The cylinder is about 1 mm OD and .55 mm ID

    All in all I think I'll stick to metal or wood for stuff this small. :eek:

    Bugbrains
  10. bwallaw

    bwallaw Member

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    This is interesting to me since I struggled rolling the masts on the Ambrose. I got some advice from the Rolling Masts thread and studied the Oberusel research Gil did. It helped. From there I did a lot of experimenting and have a method that works well for me.

    I use the thin paper method and begin with brass tubes and progressively thinner diameter wire. I found that for starting narrow tubes, a potato skewer (those stainless steel pins that you stick in potatoes when you bake them) works great. They are quite rigid so the wire doesn't get all bent up like the softer brass wire.

    To get the really tight rolls, I tried using post-it notes. Start the roll on the adhesive end and go from there. It works. You just can't print on them easily, but at this size, what would show anyway?

    My current preferred method is to use Strathmore 300 Series Sketch pad paper, progressively forming tighter rolls with smaller diameter tubes and wire. When I get to the really tight stuff, I roll the paper/wire on a rubber lid remover. They are also marketed for peeling garlic. This keeps the piece from sliding around so you can concentrate on the roll. A touch of glue on the edge keeps it together. It is fairly successful for me.
  11. Gil

    Gil Active Member

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    Bill,

    Amazingly enough, I came to the same conclusion today..., using a latex rubber matt to roll the tube down under 1 mm diameter (0.85 mm) using 20# paper (sushi method). Pinched between thumb and forefinger. This method works incredibly well and doesn't require any skill set other than rubbing your fingers together! The foam rubber mats sold at arts & craft stores might be a good substitute for the latex rubber. The sticky side of the postit notes is also a great way to roll small tubes. Getting the roll started has always been the problem and these are all ways to facilitate that. Believe we're on to a method here..., organized it would make a good article.

    Barry, what do you think?

    Best regards, Gil
  12. barry

    barry Active Member

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    Just tried it works well don't rush down to stores turn your mousepad upside down.

    Barry
  13. Bikerpete

    Bikerpete Member

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    Neat stuff!

    Thanx for the info, :D

    BB
  14. barry

    barry Active Member

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    Gil

    I would like to see a picture of your dapping block please.

    Have you any ideas on rolling from round one end to eliptical the other. Again in small diameters ?


    barry
  15. Gil

    Gil Active Member

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    Barry,

    The following photograph shows from left to right, embossing tool, draw plate and dapping block.

    What the dimensions are for the circular and elliptical cross sections and the length of the subject of your request?

    Best regards, Gil
  16. barry

    barry Active Member

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    Gil
    dimensions length tube 6mm
    circle diam 4mm elipse 4mm x 6mm.

    I did a diagonal roll to get the cone going then rolled the circle end and added a bulkhead then squashed the elipse end inserted another bulkhead. It will stand up to a long view but it's a bit rough really.

    It's actually the engine bulkhead to the end of the pilots cockpit on Takao. (1/250)

    barry
  17. Gil

    Gil Active Member

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    Barry,

    The following is a development or unwraping of a 3D drawing made to your description. It gives a good idea of what the part looks like beore being rolled into the nose section. The section shown is not to scale but when scaled down will still be large enough to roll with a little care. Just remember where the top and bottom are and insert an elliptical former to hold that ends shape. The circular end will form automatically when the elliptical former is inserted.

    Best regards, Gil

    P.S. If you need an exact sized copy just let me know what's compatible with your paint package and I'll send it to you.
  18. barry

    barry Active Member

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    Gil

    Thank you very much jpg would be fine.

    And to start another rolling ball where the design calls for say a aircraft radial engine cowl, which is fabricated by snipping out sections of the roll over front. Do you glue the edges of the cutouts first and roll the part or do you roll the part and then glue the cutots.

    Is this another dapping block job.

    By the way thanks for the photographs.

    barry
  19. Sticky Fingers

    Sticky Fingers Member

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    Gil, this will relate back to links I posted about the shim punch sets from Precision in the Obersol thread. I saw these on ebay while looking at dapping blocks

    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=10323&item=4900085069&rd=1

    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=10323&item=4900085086&rd=1

    I'm not sure how the clearances would work in card stock but I think based on my work experience they would have to have minimal clearance to prevent pulling the material
  20. Gil

    Gil Active Member

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    Barry, Mark,

    First Barry..., I suppose you want the seam on the bottom instead of on the side where it is in the posted photograph. By the way a simple, low cost dapple block can be found in the kitchen in the form of a measuring spoon set. I posted a picture of such a set several months ago.

    On the art of cowl building..., as in any operation requiring continous concentration and dexterity it's best to do this away from interuptions. It's not that difficult just somewhat tedius but the results can be rewarding.

    Start by finishing the fuselage cylinder section on to which the cowl slices will be added. Cut out the cowl slices and paint with slightly diluted lacquer and let dry. Insure that a small amount of extra material exists at the ends (it can be trimmed latter). Lightly sand the edges which will be glued. Sand at an angle to increase the glued surface area. Roll each slice till it assumes the approximate finished shape.

    Begin attaching the first slice by aligning and clamping one end to the body tube with long tweezers preferably with flat clamping surfaces. Using a large needle that's had the eye cut in half with a dremel tool as a glueing tool dab a small amount of medium CA on the back side. Think of these as "tack welds". Move the tweezers a little further along the seam making sure the two edges are closely butted together and that the surface edges are even before applying another CA "tack weld". Continue this sequence along the periphery of the body tube till the end is reached. Careful trimming is required to join to the body tube and the other end without creating unwanted discontinuities. When finished with the first slice check it's front surface to make sure there are no discontinuities that would affect joining the next slice. Use a small spoon shaped tool to "roll" the two seams against a soft but firm surface making both "blend together" at the joint and giving the slice a curved cross section. Sometimes it's better to hold off triming and glueing the ends together until after this operation is performed. Attach the suceeding slices until complete using this method.

    Look around for the right tweezers for this work. I use a 6 inch smooth jawed pair for this type of work. Use the medium viscosity CA and hold the joint until set before releasing and moving on to the next "tack weld". If a seam "pops up" and is unsightly just gently clamp it with the tweezers and CA it down. This is easier than it sounds and the work moves along quickly.

    On some models like the Fokker EIII the use of paint allows the use of artists acrylic modeling paste and microballoon filler (I mix my own but this can be found in most hobby shops). Using this to further fill areas which lay "flat" giving the cowl a more realistic look. Note that before using the filler it's necessary to give the paper a coat of slightly diluted lacquer to protect it from weakening due to the moisture in the acrylic modeling paste. The filled cowl can then be sanded with 220/320 grit sandpaper before applying a primer coat. The primer coat is then lightly sanded and dust removed before applying the final paint. This was bright silver in the case of the EIII.

    Mark, I've seen these units for sale at various sites. The only problem with them is the top is made out of steel making it impossible to see what is being punched. The site that you posted some time ago allowed the punch to be centered on the hole so that an accurate "washer" could be punched (that was what was patented). The top needs to be made of clear plexiglass for easy viewing. This is why I developed the point and cutting edge for the bow compass. But if you're thinking 1/8 scale rotary I guess the need for the washer maker could be justified (just call yourself punch-o-matic because at least 298 washers are required for the Oberursel U1 100 HP engine alone).

    That's all for now folks!!!

    Best regards, Gil