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Posted 24 May 2016 - 02:00 AM
Edited by Mixer, 24 May 2016 - 07:08 AM.
Posted 26 May 2016 - 12:48 AM
Thank you for the tutorial.
What would you think about rolling with thicker kraft? (70# or even thicker?) Would it be more physically demanding?
The commercial tubes are all made with very thick kraft, the length of the unrolled paper would usually be under 1 meter.
Posted 26 May 2016 - 01:10 AM
No more demanding - in effect I am rolling with 70# Kraft simply by laminating 2 layers together (and drying) before I start.
The main reason for this is because I couldn`t get 70# to start with.
Done properly more laminations = stronger tubes.
Posted 05 June 2016 - 04:55 PM
If you stack 2 identical sheets of dry paper and roll them on a former, you`ll find they dont finish at the same point. The top sheet has to travel further than the bottom sheet and its cumulative with each turn
If you glue the 2 sheets together and allow them to dry, the two sheets cant move in relation to each other. The top sheet will have to stretch to make up the shortfall. The resulting tension will either cause the glue line or the paper to fail
If you plan to laminate 2 or more sheets, you have to do it while they are wet and you have to keep the sheets seperated until they meet the mandrel. Another benefit of this approach is the sheets will be completely interleaved so there are no weak points. With series wound sheets you have what is effectively a set of tubes glued together by one turn. If the glue joints fail you`ll be able to push the individual tubes out like a telescope
Edited by Col, 05 June 2016 - 05:03 PM.
Posted 05 June 2016 - 05:00 PM
I've been playing with tube rolling and have found that your adhesive needs to be slick rather than tacky to allow those sheets slide on each other or all the problems you just mentioned happen.
Posted 05 June 2016 - 05:37 PM
Keeping the ultra tacky, non-slick, non-soggy sheets seperated until they reach the mandrel will give you a much better tube. You want the glue film thickness to be minimal and as uniform as possible. The more glue you slap on the paper, the higher the risk of tube deformation and voids appearing between the turns as it dries. Ideally, you want the tube to be almost dry as it comes off the mandrel
Posted 05 June 2016 - 05:56 PM
I've been rolling mine with the sheets staggered only by 1 tube circumference difference
in spacing with a mixture of Elmer's and water that gives me good adhesion yet allows for the sheets to slide upon each other. So far so good!
Posted 05 June 2016 - 09:41 PM
I've never rolled a good tube in my life. But I have taken a few apart. NEPT tubes (the old ones at least) have layers glued together before rolling. It seemed to me that the adhesive used to glue the layers together was different than the stuff used to roll up the tube. The layers did not soak apart in water. The long strip of layered papers that the tube was rolled from easily unwound itself when soaked in water.
Posted 05 June 2016 - 09:49 PM
I've got end pieces of thick wall NEPT tubes lying about outside where I'd cut them earlier and after a rain they de-laminated and just like you described, they seemed to be held together by two different adhesives.
Posted 06 June 2016 - 02:21 AM
If you stack 2 identical sheets of dry paper and roll them on a former, you`ll find they dont finish at the same point. The top sheet has to travel further than the bottom sheet and its cumulative with each turn
If you glue the 2 sheets together and allow them to dry, the two sheets cant move in relation to each other. The top sheet will have to stretch to make up the shortfall. The resulting tension will either cause the glue line or the paper to fail
This will only happen if you use inferior adhesive. Provided the two sheets are firmly bonded and previously dried they will become and behave as one single layer. This is no different than rolling with a single layer of thicker paper, here the outer fibres will be under a little more tension than the inner fibres, but its of no real consequence.
If you plan to laminate 2 or more sheets, you have to do it while they are wet and you have to keep the sheets seperated until they meet the mandrel. Another benefit of this approach is the sheets will be completely interleaved so there are no weak points. With series wound sheets you have what is effectively a set of tubes glued together by one turn. If the glue joints fail you`ll be able to push the individual tubes out like a telescope
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A moot point here as the whole purpose of the exercise is to not let the glue joints fail, simply by using the correct adhesive - this will obviate all of the above theory.
There are various ways of rolling tubes, this is my way, and I think it works very well as the burst strengths suggest.
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Posted 06 June 2016 - 04:46 AM
I've never rolled a good tube in my life. But I have taken a few apart. NEPT tubes (the old ones at least) have layers glued together before rolling. It seemed to me that the adhesive used to glue the layers together was different than the stuff used to roll up the tube. The layers did not soak apart in water. The long strip of layered papers that the tube was rolled from easily unwound itself when soaked in water.
Yes, if I remember correctly approximately one third of the tube was scrub tapered thicker laminated layers, with as you say a continuous thinner outer winding. I found the inner layers did de-laminate after a prolonged soaking.
Edited by Mixer, 06 June 2016 - 04:47 AM.
Posted 06 June 2016 - 06:00 AM
I`d like to see your method of laminating 2 big sheets of paper so they look and behave like a single thicker sheet
Applying a perfectly even film of glue to the whole sheet in a few seconds is tricky. Without a calender roll to apply heat and pressure to consolidate and dry the layers you`ll end up with sheet that isnt flat with air bubbles and wrinkles
Try soaking an nept in a alkaline solution, it`ll come apart pretty quick.
Posted 06 June 2016 - 06:41 AM
You are correct, it would be virtually impossible BUT mention was never made on `laminating 2 big sheets of paper `
My method is clearly explained in detail in the Tutorial.
"Cut the required lengths and coat them all both sides with a thin coat of paste and set them aside for a few minutes to dry and expand close to their limit, then re-coat one side of a length and line up another length over that (inset a 1/4") and then working from the centre outwards press them firmly together using a spatula or flexible metal dough scraper expelling any surplus paste and ensuring there are no air bubbles left trapped".
Posted 06 June 2016 - 11:53 AM
The issue with gluing and stacking the sheets prior to rolling is they cant move in relation to each other as you roll the tube
If you keep them seperated they will automatically correct for diametrical differences when they combine at the mandrel.
For example, if you are rolling a 1lb x 3/16 wall tube using 7x 2ft long strips of 35lb kraft, the combined thickness of the stack will be over 0.5mm which doesnt sound that thick until you try to roll it around a 3/4" mandrel. On the first turn, the top strip will need to gain around 1/8" in length in comparison to the bottom strip because its effectively winding onto a mandrel thats about 1mm larger in diameter. If the glue in the stack holds, the extra length will have to come from stretching the paper and it has to be found within each turns length because every turn has to stretch
The stretch will create excessive paper tension which builds a huge crushing force into the tube causing it to deform as it dries.
You can get an idea of the forces by wrapping turns of paper or masking tape around your finger under tension
Edited by Col, 06 June 2016 - 11:53 AM.
Posted 08 June 2016 - 11:58 AM
The issue with gluing and stacking the sheets prior to rolling is they cant move in relation to each other as you roll the tube
If you keep them seperated they will automatically correct for diametrical differences when they combine at the mandrel.
For example, if you are rolling a 1lb x 3/16 wall tube using 7x 2ft long strips of 35lb kraft, the combined thickness of the stack will be over 0.5mm which doesnt sound that thick until you try to roll it around a 3/4" mandrel. On the first turn, the top strip will need to gain around 1/8" in length in comparison to the bottom strip because its effectively winding onto a mandrel thats about 1mm larger in diameter. If the glue in the stack holds, the extra length will have to come from stretching the paper and it has to be found within each turns length because every turn has to stretch
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The stretch will create excessive paper tension which builds a huge crushing force into the tube causing it to deform as it dries.
You can get an idea of the forces by wrapping turns of paper or masking tape around your finger under tension
Col, again I agree with everything you are saying, BUT none of this applies as that is NOT what I am doing! I am rolling with one laminated length at a time. Please read my Tutorial carefully ( including previous posts) and you should fully understand exactly the process I am using.
This process does not give me any problems at all, they roll nice and the tubes come off in perfect shape, they are extremely tough and as you can see from the pressure testing - way more than adequate.
Respectfully, if you had read the Tutorial carefully at the start we could have avoided all this typing
Edited by Mixer, 08 June 2016 - 12:00 PM.
Posted 09 June 2016 - 05:37 AM
You can get an idea of the forces by wrapping turns of paper or masking tape around your finger under tension
Then you insert a pin in the finger tip ?
Can someone measure the calendered paper thickess NEPT uses? Or, cut a 10x10cm square and weight it?
I think it will be around 300 gsm (180 pound) ?
Some people are just good at paper rolling...
Posted 09 June 2016 - 06:51 AM
NEPT doesn't use paper that heavy! They laminate several layers of thinner paper into one piece of 'rolling stock'.
I've used hundreds of thousands of NEPT tubes, and probably unrolled two or three hundred over the last 15 years. It's pretty apparent how they're made once one gets damp and starts unraveling on its own.
LLoyd
"Pyro for Fun and Profit for More Than Fifty Years"
Posted 09 June 2016 - 09:41 AM
Lloyd, NEPT supposedly gets that "rolling stock" from a paper supplier which in turn manufactures it by calendering the regular kraft if I'm not wrong.
Either way, if one can get hold of very heavy kraft he can roll good tubes without the regular issues such as paper being too damp, shrinkage etc.
In fact, some old tutorials I've seen recommended Manila paper which is really thick.
Posted 09 June 2016 - 10:15 AM
Manilla paper isn`t as strong as virgin Kraft.
A tube rolled from thick Manilla wouldn`t be very strong (if that is the aim)
Generally, the thicker the paper the weaker the tube.
Edited by Mixer, 09 June 2016 - 10:24 AM.
Posted 09 June 2016 - 03:36 PM
Lloyd, NEPT supposedly gets that "rolling stock" from a paper supplier which in turn manufactures it by calendering the regular kraft if I'm not wrong.
Either way, if one can get hold of very heavy kraft he can roll good tubes without the regular issues such as paper being too damp, shrinkage etc.
In fact, some old tutorials I've seen recommended Manila paper which is really thick.
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ALL finished papers are "calendered". That has nothing to do with the discussion. I have unrolled hundreds of NEPT tubes. They're not made from "180lb" kraft! Period.
LLoyd
"Pyro for Fun and Profit for More Than Fifty Years"
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