Col Posted October 3, 2014 Posted October 3, 2014 No worries dag, the biggest virgin kraft sheets i can find over here are around 4.5ft wide x 6ft long, no indication of the grain direction. Cant imagine glueing a sheet of that up with a brush and trying to handroll it.
stix Posted October 4, 2014 Posted October 4, 2014 No worries dag, the biggest virgin kraft sheets i can find over here are around 4.5ft wide x 6ft long, no indication of the grain direction. Cant imagine glueing a sheet of that up with a brush and trying to handroll it. Wow Col, that's a huge piece of paper!! - Why can't you hand-roll it? - What weight is it? In general, the grain runs parallel with the longest edge. There are various ways to confirm this as you would know.
Col Posted October 4, 2014 Posted October 4, 2014 Its 90gsm, but weight isnt the issue, you`d struggle to tuck in the 1st turn and it`d be near impossible to keep everything dead straight and evenly tensioned.
stix Posted October 5, 2014 Posted October 5, 2014 (edited) Its 90gsm, but weight isnt the issue, you`d struggle to tuck in the 1st turn and it`d be near impossible to keep everything dead straight and evenly tensioned. I don't get it - why wouldn't you just cut it into more manageable strips instead of trying to roll the whole sheet? eg. 1ft wide x 4 1/2 ft long strips x 6 of them. (1 strip should give you a wall thickness of approx. 2.5 - 3mm not including glue, when wound on a 1/2" mandrel) Anyway, what paper weight are most people using? Edited October 5, 2014 by stix
MrB Posted October 5, 2014 Posted October 5, 2014 I don't get it - why wouldn't you just cut it into more manageable strips instead of trying to roll the whole sheet?Since they are talking about buying, and rolling sheet sizes. Thats why. If you wanted thinner strips of the large sheet, just by smaller sheets, or rolls.B!
dagabu Posted October 5, 2014 Posted October 5, 2014 I don't get it - why wouldn't you just cut it into more manageable strips instead of trying to roll the whole sheet? eg. 1ft wide x 4 1/2 ft long strips x 6 of them. (1 strip should give you a wall thickness of approx. 2.5 - 3mm not including glue, when wound on a 1/2" mandrel) Anyway, what paper weight are most people using? I would hate that, it's all in one or nothing for me.
stix Posted October 5, 2014 Posted October 5, 2014 (edited) Since they are talking about buying, and rolling sheet sizes. Thats why. If you wanted thinner strips of the large sheet, just by smaller sheets, or rolls.B! Smaller sheets would be a PITA - they wouldn't be wide enough if rolling with the grain, which is what is required for a stronger a less distorted tube. It's also the reason why it's best not rolling straight off a roll of paper as the grain direction will likely be wrong.http://www.skylighter.com/fireworks/making-fireworks-projects/kraft-paper.asp I would hate that, it's all in one or nothing for me. Fair enough, not easy though. Edited October 5, 2014 by stix
Col Posted October 5, 2014 Posted October 5, 2014 If they could make virgin kraft with the grain running across the width we`d all be laughing. We`d just buy a 1000ft roll of whatever width would fit the rolling machine and run it straight off the roll. Pity it doesnt exist
stix Posted October 5, 2014 Posted October 5, 2014 (edited) If they could make virgin kraft with the grain running across the width we`d all be laughing. We`d just buy a 1000ft roll of whatever width would fit the rolling machine and run it straight off the roll. Pity it doesnt exist Yeah true, shame it can't be done. What can be done however is if you got friendly with your local paper manufacturer and asked them to slice some off the mill roll across the grain. Some of those rolls are up to a couple of meters wide . Edited October 5, 2014 by stix
MrB Posted October 5, 2014 Posted October 5, 2014 Smaller sheets would be a PITA - they wouldn't be wide enough if rolling with the grain, which is what is required for a stronger a less distorted tube. It's also the reason why it's best not rolling straight off a roll of paper as the grain direction will likely be wrong.I was on the other hand imagining something like the 150cm rolls where you simply cut the same sheets your suggesting above...B!
Col Posted October 5, 2014 Posted October 5, 2014 I cut a 4ft wide x 220m roll into (300) 750mm sheets using a cutting table with a rotary knife on 2 guide rails, it took a few hours which seemed like days.My advice is, if you need it cutting pay the supplier to do it
stix Posted October 5, 2014 Posted October 5, 2014 (edited) I was on the other hand imagining something like the 150cm rolls where you simply cut the same sheets your suggesting above...B! Yep - that would do it. The wider the better. I cut a 4ft wide x 220m roll into (300) 750mm sheets using a cutting table with a rotary knife on 2 guide rails, it took a few hours which seemed like days.My advice is, if you need it cutting pay the supplier to do it Sounds good - what size tube ID with strong enough wall thickness are you able to roll with one sheet? Also what paper weight are you guys using - 90gsm (60#) ? Edited October 5, 2014 by stix
a_bab Posted October 5, 2014 Posted October 5, 2014 (edited) A rolling machine with a handle, that would roll a tube very tight onto any mandrel:http://www.youtube.com/watch?v=OhxbTI80MMg A neatly built version, although small and too complicated for my taste:http://www.youtube.com/watch?v=eOhRcbFTCKI Edited October 5, 2014 by a_bab
dagabu Posted October 5, 2014 Posted October 5, 2014 A rolling machine with a handle, that would roll a tube very tight onto any mandrel:http://www.youtube.com/watch?v=OhxbTI80MMg A neatly built version, although small and too complicated for my taste:http://www.youtube.com/watch?v=eOhRcbFTCKI The second one, while complicated and too small, is the design I like with the exception of the hand crank, delrin mandrel and puller block.
Col Posted October 5, 2014 Posted October 5, 2014 (edited) The first one would damage the paper as the mandrel is driven solely by friction on the paper. the second one relies on weight again, not paper tension.Think of the mandrel in terms of a winch drum and the paper as the winch cable, winches dont use a weight to tightly press the cable onto the drum Heres an example of a simple layout, the mandrel is fixed between bearings (not floating), 3 non-weighted rollers (2 shown) to guide the 1st wrap and control mandrel deflection. 2 rubber covered weighted pinch rollers located a short distance from the mandrel to create two independant tension zones. High tension zone (T1) between the pinch rollers and mandrel, lower tension zone (T2) between the pinch rollers and the glue machine. The pinch rollers can be used to drive the paper edge into the mandrel (no glue on your fingers). When using connected sheets, the pinch rollers will hold the next section firmly in place and in alignment while you disconnect the tail end of the piece thats just been wound. Here`s a rough idea for a modded roller layout so they can be moved out of the way of the mandrel.The bolts (in red) attached either side of the top hinged assembly provide adjustment. You can attach a rod or cable to the bottom roller lever frame so it can be raised independantly (via a foot pedal maybe) and still be clamped by the top roller frame. The roller frames will automatically adjust as the wall thickness increases. Edited October 5, 2014 by Col 1
Col Posted October 5, 2014 Posted October 5, 2014 Sounds good - what size tube ID with strong enough wall thickness are you able to roll with one sheet? Single sheet 1/2" x 3mm wall, 2 sheets 3/4" x 4mm, 3 sheets 1" x 4.5mm and 1.25" x 3.8mm, 4 sheets 1.5" x 4.5mm
stix Posted October 6, 2014 Posted October 6, 2014 (edited) A rolling machine with a handle, that would roll a tube very tight onto any mandrel:http://www.youtube.com/watch?v=OhxbTI80MMg A neatly built version, although small and too complicated for my taste:http://www.youtube.com/watch?v=eOhRcbFTCKI Nah, I don't like the first machine at all - the end result was way too dodgy looking for pyro tubes. The second machine is better, but in agreement looks far too complicated and also very limited in width.Also the music was crap and I didn't like the colour of the paper he was using This machine is similar to the 2nd one. Less complicated, no music and the right colour paper - a far more professional setup .This is a similar setup to your design mockup Col which I like. https://www.youtube.com/watch?v=p1hb7bfEUk4 The thing I like is that it's wide enough (could be made wider) and easily adapted to different diameter mandrels. I think you could use a winding handle instead of the motor although it might be difficult to wind, glue and keep tension on the paper with your right hand as he does. Single sheet 1/2" x 3mm wall, 2 sheets 3/4" x 4mm, 3 sheets 1" x 4.5mm and 1.25" x 3.8mm, 4 sheets 1.5" x 4.5mm Thanks Col, about what I thought if you're using around 90gsm (60#)??? You forgot to verify that part - I've only asked that question on this post twice! [EDIT] I 'linked' the video this time - It was embedded before which is a bit of a no no, yes? Cheers. Edited October 6, 2014 by stix
Col Posted October 6, 2014 Posted October 6, 2014 (edited) yep, its 90gsm. I havent seen that vid before. He was really generous with the glue but at first glance its not that bad. Not sure how consistant the tubes would be with variable tension using his hand pressure. The gluing method and doing the first turn manually "off machine" add a few more variables and you already know how i feel about floating mandrels There are quite a few differences in this machine to the mock up, The fixed mandrel allows the top and bottom roller(s) to be operated independantly. This gives you a means of clamping the paper firmly between the mandrel and the bottom roller(s) which is necessary if you want to automate the first wrap. If you can move the rollers out of the way of the mandrel you can include a simple tube ejector.I guess the extras could add 20% to the cost along with a little more work but not a great deal considering you wouldnt need to touch the paper, mandrel or the tube.. until it falls on the floor. Edited October 6, 2014 by Col
stix Posted October 6, 2014 Posted October 6, 2014 (edited) yep, its 90gsm. I havent seen that vid before. He was really generous with the glue but at first glance its not that bad. Not sure how consistant the tubes would be with variable tension using his hand pressure. The gluing method and doing the first turn manually "off machine" add a few more variables and you already know how i feel about floating mandrels Yeh, but probably more consistent than rolling by hand - otherwise why else do we have this thread? The OP has displayed his machine and also started the discussion about glues (casein I believe), which is more important than the machine that rolls tubes using it Surely we can roll tubes by hand and test glues without resorting to contraptions, don't get me wrong, I love contraptions and have been responsible for many in the past but this thread needs to re-focus (I get easily side-tracked). Perhaps the OP can step in to re-guide us with his original vision. btw. I find floating mandrels rather pesky at times myself Cheers. Edited October 6, 2014 by stix
MrB Posted October 6, 2014 Posted October 6, 2014 I wonder how much pressure you need on something like a cutting wheel for cutting pipes to cut the paper to size. I'm thinking you could cut the tubes on the mandrel before the tube gets removed (while it's still reasonably soft from what ever glue one went with) but you wouldn't want to damage the mandrel it self. I'm also not sure about if the cutting wheel from a pipe cutter is the best idea but it's what popped in to my mind right away.B!
dagabu Posted October 6, 2014 Posted October 6, 2014 (edited) I wonder how much pressure you need on something like a cutting wheel for cutting pipes to cut the paper to size. I'm thinking you could cut the tubes on the mandrel before the tube gets removed (while it's still reasonably soft from what ever glue one went with) but you wouldn't want to damage the mandrel it self. I'm also not sure about if the cutting wheel from a pipe cutter is the best idea but it's what popped in to my mind right away.B! Not much, I have a motorized tube cutter with a manual rotary knife and on a 6" handle it takes ounces of force to cut through the tubes (thick) in seconds. I use Delrin for the cutting mandrel but it is still, not rotating so the knife makes very little damage, a stop at the place where it penetrates the tube keeps the knife from scoring deeply. Edited October 6, 2014 by dagabu
Bobosan Posted October 6, 2014 Posted October 6, 2014 So it's a viable way to do things. Thanks.B! Sure is. Check out this tube roller machine.
MrB Posted October 6, 2014 Posted October 6, 2014 They are working on a slightly different scale. I was seeing something more like spring-loaded pizza cutters, preferably with a dept-guide so they don't cut in to the mandrel. Only problem i see is, just like they do in the clip, you really need to remove them when the tube is spun to size. With a floating mandrel, your adding the "drive" from the outside, so you should be able to leave them in place. I think you get better tubes with the mandrel being the source of the motion, but then you really need to remove the cutting tools while making the tube, or risk a segment of the tube (between 2 cuts) not rotating as fast as the rest of the segments, creating issues.Anyway, at this point it's just fancy pipedreams, i'm still talking to a guy about getting meter long mandrels, in the sizes i use... If i'm making something, i want it to be able to make all my sizes.B!
Col Posted October 6, 2014 Posted October 6, 2014 (edited) Uou can make a mini version using 28mm rotary cutter blades (carbide), 2x 5mm bearings to support the sides of the disc and a 5mm hardened steel dowel for the axle. You``ll need to press the dowel into the bearings, nothing too powerful needed.. a drill press with a piece of round stock in the chuck is enough. The mounts can be made from nylon sheet, aluminium or steel flat. The 28mm cutter + bearings will allow for an actual cutting depth of 8mm. Mr BIf you have a non floating mandrel and independant rollers you just move the top roller(s) and pivot the cutters over to cut into the top of tube. Tip, if you use nylon or non conducting material for the mounts you can use a multimeter/continuity test to set up the blades. Connect a probe to an axle and one to the mandrel, adjust the stop point until it beeps and then back it off a smidge. The blades will score grooves in your mandrel if they cut too deep. Edited October 6, 2014 by Col
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