dagabu Posted December 28, 2018 Share Posted December 28, 2018 Col, Sounds like you should re-read my past posts. I have 2 mandrels, the one I roll the tube on that is 0.76" and the second that is 0.75". The 0.75" mandrel fits fine on the shrunken tube and if it does get tighter due to the greater down-force, I will turn a new one to 0.76" or even 0.77". I have about 500 feet of stock, brass and aluminum, in my shop from when I made tooling for you all. Link to comment Share on other sites More sharing options...
Col Posted December 28, 2018 Share Posted December 28, 2018 It dawned on me that you must have a mandrel in the tube for all of the strips because the mandrel drives everything Drying between each strip makes things interesting but having a few mandrels slightly smaller or larger od should do the trick. From a traction point of view. it`d be better if the mandrel was a little tight than a little loose The 2 fixed roller + top hinged roller design is simple and effective (i`ve used it myself), its main weakness is having only 3 pounts of contact and free spinning rollers which doesnt provide a lot of control over the paper.When you put the paper in, it creates a bridge over the 2 rollers so you have to drop the mandrel on top, which moves the paper . The free running rollers always seemed to move at that moment, adding to the fun Here`s the underside of my machine, the paper is clamped solidly to the mandrel for almost the full turn. The paper,mandrel and rollers cant move unless the handle is being turned. Link to comment Share on other sites More sharing options...
Nitrotitanite Posted January 3, 2019 Share Posted January 3, 2019 (edited) Has anyone ever tried Titebond type aliphatics?My problem with rocket tubes is the poor stiffness at the base of the nozzle that can not stand the pressure, the negative thing about these glues is the cost. Edited January 3, 2019 by Nitrotitanite Link to comment Share on other sites More sharing options...
Mixer Posted January 3, 2019 Share Posted January 3, 2019 Yes, then discarded it! Link to comment Share on other sites More sharing options...
Nitrotitanite Posted January 3, 2019 Share Posted January 3, 2019 As I thought it was worth buying already made. I think I will do some proof. Link to comment Share on other sites More sharing options...
dagabu Posted January 3, 2019 Share Posted January 3, 2019 Yes! I tried Titebond PVA, Original, ll & lll. The PVA is very pink in color, it has 45% solids but it feels like it has more CMC than PVA since it has lots of slip but it does tack up very nicely. Probably the best of the white glues out there right now. $13.00 a gallon locally. Original woodworking glue (aliphatic resin) feels a lot like the white glue, 46% solids, sets up fast and bonds well but becomes fragile and not flexible like white glue. Not watertight, it will swell but not become a liquid again. It is $16.00 a gallon locally. Titebond ll is a cross-linking polyvinyl acetate, it has a lot more flex than the original but is still brittle. It happens to be my favorite wood glue for woodworking, 48% solids but has the very best grip of any wood glue I have ever used! It has a published wood failure of 72%! It is $18.00 a gallon locally. Titebond lll is still proprietary but its a polymer based glue and does not break down over time with 53% solids. I cannot recommend this or type ll because they both act a lot like PVC when CATO. Especially lll, it breaks apart in sharp shards. $28.00 a gallon locally. Link to comment Share on other sites More sharing options...
dagabu Posted January 3, 2019 Share Posted January 3, 2019 (edited) PVA has plenty of stiffness, remember that we all use a tube supports when pressing and it is a good idea for pounding rockets as well. You want the tube clay to press into the paper, grip it hard! Rocket tooling bases have a straight portion about 1/2 the tube ID so that you have some paper at the end after the nozzle. This is very important, it helps lock in the nozzle. Wood glue in my opinion is best left for wood, a static load, dynamic loads need a flexible glue but with stiffness that will increase the burst strength. This is why I use a combination of PVA and wallpaper paste, it gives stiffness but does not shatter when pushed hard! Here is a picture of an early nozzle I formed many years ago (it's up side down), notice how it bites into the tube wall. http://www.pyrobin.com/files/new%20nozzle%20mix.jpg Has anyone ever tried Titebond type aliphatics?My problem with rocket tubes is the poor stiffness at the base of the nozzle that can not stand the pressure, the negative thing about these glues is the cost. Edited January 3, 2019 by dagabu Link to comment Share on other sites More sharing options...
Nitrotitanite Posted January 3, 2019 Share Posted January 3, 2019 (edited) Thank you for a very comprehensive explanation. With the many tests you have already done, I will leave this type of glue.The solution seems to be the establishment of a rolling mill. Edited January 3, 2019 by Nitrotitanite Link to comment Share on other sites More sharing options...
dagabu Posted January 3, 2019 Share Posted January 3, 2019 Thank you for a very comprehensive explanation. With the many tests you have already done, I will leave this type of glue.The solution seems to be the establishment of a rolling mill. No need! Look at this post, all you need is a couple of cheap tools and a board!! https://www.amateurpyro.com/forums/topic/9090-how-to-roll-pyro-tubes/page-8?do=findComment&comment=181429 Link to comment Share on other sites More sharing options...
Nitrotitanite Posted January 3, 2019 Share Posted January 3, 2019 👍👍 Link to comment Share on other sites More sharing options...
Col Posted January 3, 2019 Share Posted January 3, 2019 I find handrolling tubes mentally tiring because it only takes a small lapse in concentration to ruin the tube Machine rolling a 2ft rube takes the same amount of time as rolling an 8" tube, quicker if you dont have to cut the paper into strips. A 2ft tube gives you 3/4" of wiggle room at each end (3x 7.5" +1.5") with an 8" tube you only have 1/4" each end. Drifting by more than a fraction can make it more tricky to cut the ends off cleanly Link to comment Share on other sites More sharing options...
dagabu Posted January 3, 2019 Share Posted January 3, 2019 One mans tube rolling zen is another mans aggravation. Link to comment Share on other sites More sharing options...
Col Posted January 4, 2019 Share Posted January 4, 2019 To my mind, hand rolling is a mortar and pestle, machine rolling is a ballmill My idea of aggravation would be grinding a kilo of something using a m&p, not a ballmill Link to comment Share on other sites More sharing options...
Mixer Posted January 4, 2019 Share Posted January 4, 2019 One mans tube rolling zen is another mans aggravation. IMO, if done properly - a hand rolled tube will always out-perform a machine rolled tube - simply because you can control every aspect of the operation in fine detail. The satisfaction for me - is knowing I have developed the skill to achieve it, and the fact that I can set up (and clear away) within a minute at any time, and do some rolling. Link to comment Share on other sites More sharing options...
Mixer Posted January 4, 2019 Share Posted January 4, 2019 No need! Look at this post, all you need is a couple of cheap tools and a board!! https://www.amateurpyro.com/forums/topic/9090-how-to-roll-pyro-tubes/page-8?do=findComment&comment=181429 Or this one HAND ROLLING STRONG TUBES. Link to comment Share on other sites More sharing options...
dagabu Posted January 4, 2019 Share Posted January 4, 2019 Or this one HAND ROLLING STRONG TUBES. Absolutely! Link to comment Share on other sites More sharing options...
dagabu Posted January 4, 2019 Share Posted January 4, 2019 (edited) To my mind, hand rolling is a mortar and pestle, machine rolling is a ballmill My idea of aggravation would be grinding a kilo of something using a m&p, not a ballmill But that is not a parallel issue, I can make tubes at an acceptable rate by hand but I cannot grind an acceptable amount of BP by M&P vs ballmill. Convenience and output are two very different things. Also, like making a cylinder shell, hand spiking is part of the art, I don't do pyro for production but for the learning experience and the art of it. "One mans tube rolling zen is another mans aggravation. " Edited January 4, 2019 by dagabu Link to comment Share on other sites More sharing options...
Col Posted January 4, 2019 Share Posted January 4, 2019 I machine roll for consistancy. productivity is just a bonus Folks that buy commercial tubes do it to save time which can be spent on the more creative stuff. Over here, there are no decent tubes so we dont have any choice Imho, controlling every aspect in fine detail is what machines do and once set they can do it consistantly.They dont get tired or distracted so the last tube will be exactly the same as the first. With handrolling, you always get some tubes that dont quite make the grade for ome reason or another. Those can usially be put down to human error because we`re not machines Link to comment Share on other sites More sharing options...
dagabu Posted January 4, 2019 Share Posted January 4, 2019 OK, now that is funny! The world wide benchmark tube is from NEPT, they were the provider of ESTES tubes and continue to make them for Milspec applications and they have an appreciable waste in machine rolling. There is no way the scrap ratio is less then hand rolling. Every tube gets trimmed, be it 8" wide or 80" wide. This Eskimo ain't buying your ice! Link to comment Share on other sites More sharing options...
Col Posted January 5, 2019 Share Posted January 5, 2019 (edited) Every tube gets trimmed, be it 8" wide or 80" wide. Aye but with an 80" tube only one end needs trimming, then you`d measure and cut the 10 individual 7.5" tubes You wouldnt cut the 80" tube into ten 8" lengths and then trim another 1/4" off both ends of each tube With the precut sheets you have only have the 24" width to work with, the price of the paper was right so no worries there. If you were using a 3ft wide (935ft) roll of kraft and a machine you`d get 19 more tubes from the roll with the 23" widths vs 8". You could match it by using 7.66" widths but you`d have zero room for error and still have to trim both ends somehow By that score, you could say hand rolling 8" strips (from a roll) will waste 19 tubes worth of paper, glue and time compared to machine rolling with 23" strips If you could roll 76" tubes you`d get 10 individual tubes from each tube and still only have one end that needs trimming The number of 7.5" tubes you could get from a roll with each width: 8" 467, 23" 486 and 76" 490. A 3ft roll of virgin kraft costs me £27 / $34 so your kraft sheets were a bargain. Edited January 5, 2019 by Col Link to comment Share on other sites More sharing options...
Col Posted January 9, 2019 Share Posted January 9, 2019 I`ve decided to build an upgraded version of my rolling machine. I`ll be adding some silky smooth linear bearings and a (detachable) tiltable infeed table so i can glue up the paper and slide it straight in. The upgraded version will handle any mandrel size from 8-60mm (5/16" - 2.5") with tubes upto 700mm long. I`ll be using basic tools, pillar drill, cordless drill, saw, spanners etc, nothing special. I have plenty of surplus conveyor rollers in the shed so If i can find a couple of big pillow block bearings cheap enough i have a simple 2 roller design i`d like to test out too. Its only good for paper sheets upto~3ft long ~700mm wide but could be built in a couple of hours. Mocked up a quick test for the linear bearings, smooth as silk with 9kg/20lb on them. Not sure what these can handle but likely a lot more than i`ll ever put on them.. Link to comment Share on other sites More sharing options...
Nitrotitanite Posted January 9, 2019 Share Posted January 9, 2019 Nice project simple but useful, I follow you, I will also have to build a mill together with other tools such as ballasts and a press. Link to comment Share on other sites More sharing options...
dagabu Posted January 9, 2019 Share Posted January 9, 2019 What purpose do the linear bearings serve? Link to comment Share on other sites More sharing options...
Col Posted January 9, 2019 Share Posted January 9, 2019 They provide the tracking and ensure even pressure on the tube as its being rolled. The 4 bearings will be tied together with a flat plate so the travel will be perfectly linear with no twist or skew from one side to the other. According to the spec, the static load rating per bearing is 120kgf, dynamic load 78kgf.. I cant envisage needing more than 20-30kg (UDL) on the mandrel so theres plenty of headroom.The rollers are rated 200kg and weigh in at 4kg each, heavy duty 2" od 10g steel tube with solid 15mm steel axles (female threaded M10 at each end). It`ll prolly weigh a fair bit Link to comment Share on other sites More sharing options...
Col Posted January 21, 2019 Share Posted January 21, 2019 (edited) Made some progress on the simple two roller build, still have a bit to do but so far so good. Edited January 21, 2019 by Col Link to comment Share on other sites More sharing options...
Recommended Posts