Col Posted January 25, 2018 Posted January 25, 2018 (edited) Here`s the newest addition to my collection of strange contraptions. This time its a 12" top-coating glue roller with stainless metering roller supplied by a peristaltic pump. A digital one-shot timer controls the pump run time/interval via a momentary push button on the handle (footswitch could be used). The timer is set to supply the right amount of glue for the size of sheet being glued. The unit could be table mounted, for example, hinged above another stainless roller set into the table. This arrangement, where the paper runs between the table roller and the glue roller. could be used to apply glue to a continuous paper roll.. as long as its no more than 12" wide The paper could be pulled through manually or under power. Total cost, incl timer, was around £70 / $100 US. 1st pic is a diagram showing the principle of a top coating glue roller, 2nd pic is the roller and pump. Edited January 25, 2018 by Col 1
Col Posted January 25, 2018 Author Posted January 25, 2018 (edited) Hi Mason,what do you need to know? There`s not much to it. The glue is pumped up the tube by the peristaltic and delivered into the nip point of the two rollers by a tee shaped manifold (rigid nylon tubing) with holes drilled in it. As the roller is pulled (not pushed),both rollers rotate downwards forcing the glue down into the nip where it is squeezed by the rollers, like a mangle. The striped roller takes a thin coating through the nip which is transferred to the paper and the excess glue stays behind in the nip which acts as a small glue reservoir. When the gluing is all done, the glue in the tube is pumped back into the glue container by the pump. The tubing and manifold get flushed through with warm water, again using the pump. The rollers come apart for cleaning without any tools. The stainless roller is designed to handle washdown. It has fully sealed bearings and spring loaded pins see attached pic. The main roller is solvent resistant with a short knap, its easily cleaned in warm water. In the event it ever needs replacing, a new one wont break the bank at £3 / $4. The manifold fittings are all pushfit so its very easy to disassemble/replace those bits if its required. The pump can deliver 1.7 us gph at 18psi so it has no trouble pushing thickish glue. The only thing that will wear out eventually is the tubing inside the pump, replacement cost is £4 / $5.60 Edited January 25, 2018 by Col
Maserface Posted January 26, 2018 Posted January 26, 2018 It helps to automate tube rolling, and makes the results far more consistent.
Col Posted January 26, 2018 Author Posted January 26, 2018 (edited) You dont need a roller for watered down pva or anything that stays wet and workable for ages Try using a high solids glue that tacks to the same grab as gaffa tape in a minute or less Its not as forgiving, especially when working with large sheets of kraft. A metered roller only takes a few seconds to apply a thin uniform film of glue to the entire sheet. Its saves time and does a much better job. The finished tube is relatively dry as it comes off the mandrel so your not waiting days before you can use it. I`ll never roll another tube with pva but each to their own Edited January 26, 2018 by Col
Col Posted February 3, 2018 Author Posted February 3, 2018 (edited) Did some testing yesterday with the roller/glue combo. Looks like it applies an average 3.6g of water per m2 of paper. A wet, freshly rolled 1lb x 3/16" wall rocket tube contains about 2.46g of water, about half a teaspoon. The more water that goes into the paper, the longer the tube takes to dry.I spent a few hours converting a slitting saw blade into a tube cutting blade, only $4 per blade but it does take a while with a drill press Edited February 3, 2018 by Col 1
Arthur Posted February 4, 2018 Posted February 4, 2018 In the UK used conveyor rollers are available cheaply on ebay in 2"dia by most lengths. A metal roller may be more easily cleaned.
Col Posted February 4, 2018 Author Posted February 4, 2018 Conveyor rollers wont have the precision needed If you use a metal roller for the coating roll you`ll need very tight tolerances on both of the rollers and zero play in the bearings. The metering roller will have to be finely adjustable so you can control the gap width to the nth degree. With top coating, the gap between the rollers sets the glue film thickness and acts as a glue reservoir so the gap width is critical. With the short pile roller and stainless metering roller the tolerances arent as critical.I have a commercially made bottom coating glue machine, it uses a solid 70mm diameter anodised alloy roller which sits in the glue reservoir. As the glue is picked up by the coating roller, the adjustable doctor bar sets the glue thickness and the excess is returned to the reservoir. I have a big homemade bottom coater very similar in design, it uses a 4" diameter chain driven polyprop roller. https://youtu.be/dC6zCvUFOY0
Col Posted March 1, 2018 Author Posted March 1, 2018 Repurposed a few heavy duty steel conveyor rollers that were surplus to requirements.
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