Mixer Posted December 16, 2018 Share Posted December 16, 2018 Ok we`re trying to help you here. They say you can lead a horse to water but.... well you know the rest! Link to comment Share on other sites More sharing options...
Col Posted December 16, 2018 Share Posted December 16, 2018 I would expect the 90% glue to have stronger adhesion even though its less spreadable If the method used is identical for the roman and the pva and the outcome is different it points to the glue as thats the only difference Here`s the hand calendered 3 layer sheet of kraft, cut lengthwise and partially removed from the 60mm former, with both sides opened out its about188mm wide and 3ft long. Link to comment Share on other sites More sharing options...
dagabu Posted December 16, 2018 Share Posted December 16, 2018 Ok we`re trying to help you here. They say you can lead a horse to water but.... well you know the rest! But you can't make it think! C'mon, you can put aside your bias and make this work, I KNOW you can! Link to comment Share on other sites More sharing options...
dagabu Posted December 16, 2018 Share Posted December 16, 2018 I would expect the 90% glue to have stronger adhesion even though its less spreadable If the method used is identical for the roman and the pva and the outcome is different it points to the glue as thats the only difference Here`s the hand calendered 3 layer sheet of kraft, cut lengthwise and partially removed from the 60mm former, with both sides opened out its about188mm wide and 3ft long. 3 turns on 60mm former.JPG Yes, Burst strength was suggested to be higher with the paste but it makes tubes much larger than PVA because of the gelatin like consistency? It should slip better allowing for tighter tubes but it does not. Link to comment Share on other sites More sharing options...
dagabu Posted December 16, 2018 Share Posted December 16, 2018 (edited) I have the tubes cut and ready for testing. I am not looking for burst in this test, just survivability at #4535 and #6500 LPI. These are the significant numbers for me since I need to press black powder rockets at #6500 with no fissures or cracks, no wrinkling or crushing. What I found in these tests surprised me a lot. Tests were conducted with exactly 10g of medium sized DR. ELSEY'S Precious Cat ULTRA Cat Litter. The base is a 1" stand off providing 1.5 times the ID of empty tube so that the end of the tube does not contribute to wall failure. Two tests were conducted with no tube support of any kind, the paper itself was the only medium resisting bursting. An analog of 9000 LPI was used to ensure that there was no mechanical or pressure errors, knowing that NEPT tubes show a nominal burst strength of 8800 LPI. A 6" aluminum rammer was mounted on top of the 10g of clay and two pressings were conducted, both were short cycles where as soon as the full pressure shown on the dial, it was backed off to zero and reapplied. There was no dwell time. PVA is the clear winner in this case and 6 more tubes will undergo full hydraulic compression up to 9000 LPI or until failure occurs. Video of the dial will give a nominal idea of the pressure at which burst occurs. Edited December 16, 2018 by dagabu Link to comment Share on other sites More sharing options...
Col Posted December 17, 2018 Share Posted December 17, 2018 If the romans are only doing 880 i would check they`re completely dry. This ready mix is a fair bit wetter than my usual glue, i cant find any manufacturers spec on the solids % but i have a test underway so i`ll find out in a day or two. Link to comment Share on other sites More sharing options...
dagabu Posted December 17, 2018 Share Posted December 17, 2018 (edited) 38% solids. They are dry and strong, stronger than NEPT. Edited December 17, 2018 by dagabu Link to comment Share on other sites More sharing options...
Col Posted December 17, 2018 Share Posted December 17, 2018 what does the 880 signify? Link to comment Share on other sites More sharing options...
dagabu Posted December 17, 2018 Share Posted December 17, 2018 A number.... Nothing, It is "ROMAN Pro-880 Professional Wallpaper Paste" Link to comment Share on other sites More sharing options...
Col Posted December 17, 2018 Share Posted December 17, 2018 (edited) that explains it, over here wallpaper paste doesnt usually come with any numbers When i test tubes i just put masking tape over the bottom and drop the clay in so the end of the tube is included in the test. The roman may be 38% solids but its the solids of this wickes ready mixed i`m after, Mixer says its 40% but looking at the water loss so far i`ll be surprised if its that high. Edited December 17, 2018 by Col Link to comment Share on other sites More sharing options...
Mixer Posted December 17, 2018 Share Posted December 17, 2018 It was measured on a very expensive fully calibrated industrial scale Col. It`s important that the paste is thoroughly stirred as water does seem to rise to the top after extended standing periods. Link to comment Share on other sites More sharing options...
Mixer Posted December 17, 2018 Share Posted December 17, 2018 (edited) "When i test tubes i just put masking tape over the bottom and drop the clay in so the end of the tube is included in the test." This is the way I do it too. The same as Ned does it to get a true comparison. Edited December 17, 2018 by Mixer Link to comment Share on other sites More sharing options...
Col Posted December 17, 2018 Share Posted December 17, 2018 I gave it a good old stir before taking the sample. I use the same method to test different glues so the results are comparable, My yardstick is neat evo-stik waterproof pva (blue bottle) which is 50%. Solids content doesnt tell you much about the adhesive properties because inert fillers will count as solids It does tell you how much water is in the glue and its the water that ends up in the paper. The wickes ready mix spreads better than some other wallpaper pastes i`ve tried, it has a decent amount of tack and good adhesion (peel test). Applying it by brush works well on small sheets (2ft x 9") which stay relatively flat with no wrinkling but its a different story with a larger sheet (3ft x 2ft), i guess a roller may be a better option there. The structural rigidity of the tube straight from the mandrel is definitely a lot less, it wouldnt take much to accidently deform the tube when removing it. The tube is damper than i`m used to, i dont think i could use them the next day without forced drying. Link to comment Share on other sites More sharing options...
Mixer Posted December 17, 2018 Share Posted December 17, 2018 "The structural rigidity of the tube straight from the mandrel is definitely a lot less, it wouldnt take much to accidently deform the tube when removing it. The tube is damper than i`m used to, i dont think i could use them the next day without forced drying". Yes, I found this to be the only drawback. I have several formers so now after each wind they get 5-10 minutes ( with former attached) in a fan oven at 50c before rolling the next strip, and that alleviates the problem. When finished I leave them in the oven for any amount of time at that temp and they come out in perfect shape. I`ve torn down a few and found no faults whatsoever, so now that will be my procedure in future. Link to comment Share on other sites More sharing options...
dagabu Posted December 17, 2018 Share Posted December 17, 2018 (edited) New England paper tubes were tested in the factory for burst strength the same way I am testing them, 10 gram of nozzle mix 1 1/2 IDs away from the base + 2 pressings, one to settle the clay the 2nd to test the strength of the walls. Ned just tested the way he envisioned it, but it does not test the actual burst strength of the paper, only the ability of the end of the tube to not deform and tear. I can shoot Steve a email to verify this technique but I believe it is still accurate. Edited December 17, 2018 by dagabu 1 Link to comment Share on other sites More sharing options...
Mixer Posted December 17, 2018 Share Posted December 17, 2018 (edited) Col,if you ever do a side by side comparison with the Wallrock and the Wickes I would be interested in your views.Although the Wickes is more than adequate for my needs I think I preferred the Wallrock and I also used Polycell ready mixed (heavy duty) which was excellent and seemed to have less water in it. I only changed from those to Wickes because I was a tight arse and Wickes cost less! Now I`m a millionaire and light my cigars with £20 notes I don`t have to worry. Actually those new notes might roll into a nice tough tube Edited December 17, 2018 by Mixer Link to comment Share on other sites More sharing options...
Col Posted December 17, 2018 Share Posted December 17, 2018 Dag, i`m not questioning the method As long as you use the same method with different tubes you can compare the results directly. If Ned`s method provides a lower burst strength number than with the nept method you`ll`have the peace of mind there`s always a bit more in the tank Link to comment Share on other sites More sharing options...
Col Posted December 17, 2018 Share Posted December 17, 2018 The wallrock supposedly has resin in it which is prolly why it sticks like wotsit to a blanket. I know it dries to a light tan/yellowish colour, i dont know what colour the wickes stuff dries to but i guess clearish white. The thing i did notice was the wickes stuff has a different smell to most wallpaper pastes, a tapioca or a spud based starch maybe Link to comment Share on other sites More sharing options...
dagabu Posted December 17, 2018 Share Posted December 17, 2018 Ned's method is not a good analog at all. It's almost universally applied to all aspects of fabrication to never use a mounting hole less than 1-1/2 times the distance to the edge of the material. With wood it is even larger due to splintering. Engineering on that is sound, putting clay in the end is only measuring tear pressure, not burst strength. Ned does that because he does not have a lathe or a way to make a rammer to take up 1-1/2 the ID to get a true burst measurement. Ned does mention this in his experiments, it is only his method and not engineered in any way, it's a redneck, seat of the pants analog. Link to comment Share on other sites More sharing options...
dagabu Posted December 17, 2018 Share Posted December 17, 2018 "The structural rigidity of the tube straight from the mandrel is definitely a lot less, it wouldnt take much to accidently deform the tube when removing it. The tube is damper than i`m used to, i dont think i could use them the next day without forced drying". Yes, I found this to be the only drawback. I have several formers so now after each wind they get 5-10 minutes ( with former attached) in a fan oven at 50c before rolling the next strip, and that alleviates the problem. When finished I leave them in the oven for any amount of time at that temp and they come out in perfect shape. I`ve torn down a few and found no faults whatsoever, so now that will be my procedure in future. I look for the total weight when dry so that i know that the excess water has evaporated and the tube is dry. Each sheet is rolled up one at a time on the mandrel (mandrel was tared first) and the weight of all three sheets (all are cut on an industrial guillotine) is written down. A tube is rolled up with adhesive and each layer is allowed to dry completely with zero weight loss for 24 hours. That total weight is also recorded. To measure the dry weight in comparison with the wet weight is simple, simply put the tube on the scale and see if the tube has lost the water weight. We do the same with stars, comets and black powder to determine water content. This is also why when I pump stars, I use all the comp and finish off with a single pump and use everything left on the paper. An example of this is is making a batch with a total dry weight of 1000g, water is added, stars are pumped and the batch is weighed. Just for clarity, say the batch weighs 1100g wet, I know they are dry inside and out when the batch once again returns to 1000g. The same applies to a tube, just weigh them to know if they are still damp. Link to comment Share on other sites More sharing options...
Mixer Posted December 17, 2018 Share Posted December 17, 2018 (edited) Col,Out of sheer curiosity I`ve just picked up a tub of Polycell Ready Mixed (heavy duty) paste from a mate who hangs heavyweight vinyl wallpaper in banks.It is very different to the Wickes paste. Turning the tub on its side the paste doesn`t move - yet when brushing on it needs just a little more work to spread out - open time is better as there is less water penetrating the paper - everything is how I remember it. I have some evaporating at the moment to see what the solids content is - i`m guessing at 50-60% Edited December 17, 2018 by Mixer Link to comment Share on other sites More sharing options...
dagabu Posted December 17, 2018 Share Posted December 17, 2018 Will that work with the rolling machine? Link to comment Share on other sites More sharing options...
Col Posted December 17, 2018 Share Posted December 17, 2018 Ned's method is not a good analog at all. It's almost universally applied to all aspects of fabrication to never use a mounting hole less than 1-1/2 times the distance to the edge of the material. With wood it is even larger due to splintering. Engineering on that is sound, putting clay in the end is only measuring tear pressure, not burst strength. Ned does that because he does not have a lathe or a way to make a rammer to take up 1-1/2 the ID to get a true burst measurement. Ned does mention this in his experiments, it is only his method and not engineered in any way, it's a redneck, seat of the pants analog. I`ll have to test one both ways to see if theres a difference between tear strength and burst strength Link to comment Share on other sites More sharing options...
Col Posted December 17, 2018 Share Posted December 17, 2018 (edited) Will that work with the rolling machine? That depends on the viscosity, not the solids content Viscosity comparison, neat evo-stik pva on the right (50% solids), gravy on the left (58% solids). Both glues were in the shed so they are cold but the same temperature. The pva didnt want to leave the bottle without a fight Edited December 17, 2018 by Col Link to comment Share on other sites More sharing options...
Mixer Posted December 17, 2018 Share Posted December 17, 2018 Ok, the Polycell is 40% solids - so I must have made the wrong calculation for the Wickes Link to comment Share on other sites More sharing options...
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