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Anyone used any of the Pro-Glue products to assemble rods? Their PVA sounds promising. Check it out and let me know what you think. (Tom Key) Looks interesting to me, though I have never used it and can't see switching to a PVA glue. I like the looks of the urea based glue they offer even better. Reminds me of the DAP version of Resorcinol.
I was at Sweetgrass today. Glenn sells PVA glue and the acid catalyst in small quantity for those of you that are interested. (Dave Norling Jr (7/25/2016))
I was using some PVA glue this afternoon on some Krenov style wooden plane bodies and I got to thinking about the thread on the list a few months back about non-cured PVA occasionally found in the centre of rods. I got to thinking about the uncured glue question and I think it doesn't matter at all in the least. The reason for that is that PVA glue cures once its moisture content is reduced below a certain point. I tried to find the exact % but can't, I sort of remember it being 8% but the exact % doesn't matter, it has to be less than it is in the bottle. The glue can reach this moisture content either through evaporation or from being absorbed into the wood or bamboo under clamping pressure. Once the moisture % is reduced to the right degree the glue cures. I'm thinking that if there is trapped liquid glue in the centre of the blank it's likely there because it's become encapsulated in an air tight space by cured glue in the centre before all of the glue gets the chance to cure. If that's the case then it makes no difference that some of the glue hasn't cured because it's not in contact with bamboo and being in the centreline it makes little difference to the strength of the rod anyhow. The Krenov style planes are dead easy to make and work very well BTW. (Tony Young (12/8/2016)) Surface contribution to strengths is no doubt a major factor, but the rod would be stronger if the glue was fully cured, especially if the depth of cure was fairly shallow. Does anyone know of any studies regarding surface contribution of bending strength? I always assumed it was an inverse square of distance from center of cross-section, incremental shell-by-incremental shell, multiplied by a modulus and a shape factor. It could be that the outside shell contributes far more than that. Any ideas? (Casey) If the rod was hollow there wouldn't be any glue/bamboo contact along the axis which is why I don't think it matters. (Tony Young)
Here is an article from the Titebond site. Readers Digest condensed version: Titebond III wins. Gorilla glue PVA WAY last place. (Mike Bryan) Thank you for the link, Roseanne! That study shows what us beekeepers have been saying almost to the last man - that Titebond III is the best. Even though this study did not test after 5 years out in the weather, I can tell you that it is what you'd want. I've bashed heads with people who rely on advertising for their opinions about Gorilla Glue - I have very few uses for the stuff. One person demanded that I repair some boots with it. I immediately said that cobblers use a glue called Barge Cement. She repeated her demand, I cringed and complied. Not one of the soles on the Chinese work boots made it out the door - they ALL fell off right there in the office. I spent several hours removing the Gorilla Glue from the soles and later applied Barge Cement with somewhat better results. I also clashed with an engineer who thought that an anaerobic glue must be used on a tight joint, so he insisted on using Gougeon Brothers' epoxy on white pine for a shipping container. I suggested that wood glue is know to work and give excellent service (this was years before Titebond III was available). The white pine absorbed the epoxy and left the joints dry and almost zero strength. The wood glue was sent to the rescue after the fact. It did not render it's usual strength with the epoxy filling the porosity of the wood, but a few extra staples made up enough difference to ship some model airplanes to Italy in time for a movie shoot. OK, so I'll make up some bamboo panels with bridle joints and try to repeat the tests in the article. I'll need some of the usual glues us canerodders typically use. I'll probably also include an oven cure test or two, as most of the glues I've tested in the past increased strength and stiffness with some kind of oven post-cure, usually in the range of 130 to 250 degrees Fahrenheit. Again, any studies regarding surface contribution? (Casey) Funny you mention beekeepers and Titebond. I have used TBII or plain yellow PVA glue over the years which I possibly should not have but did to see how it went on hives and they're still perfectly good so III would be ideal. Hives have a certain moisture level inside them due to all the bees in them, because you don't paint hives on the inside where they're usually wetter than outside anyhow it's always seemed a waste of time painting them to me so the glue has been exposed to the inside and outside elements all these years and still no problems. The other thing is something that I wrote to Peter McKean on during the recent glue wars thread of a few moths back was that once when I was between jobs I worked milling timber in a retail woodworker's outlet. I ripped and dressed big timber into small and spoke to a lot of people buying this stuff. This was in Australia of course. Australian hardwood is not very oily but it can be really dense and at the time there was a lot of thought that epoxy would be perfect for Aust timbers. After a time though it was found that it wasn't particularly and that plain old yellow aliphatic glue was better. That's when I tried it on the hives. I ended up with over 50 at the time so it was a decent trial. That was in Western Australia which is pretty dry, but I've done the same here in Victoria where it's much wetter with the same results though with fewer hives. Having said that the glue I like most from the point of view of it never ever failing ever, sort of the Optimus 123 Climber stove of the glue set is resorcinol which is a glue engineers all seem to have a visceral hatred of in preference for epoxy for some reason. Until a year back I worked as a draughtsman for an aviation company, known these days by the sexy term aerospace but is still just aeroplanes. There is a thing called a Type Defined Design for a plane that you must adhere too whenever you do design or repair work to so if in the case of a wood constructed A/C if the Type Def says the glue you use for a job was specified as resorcinol then that's what you use even if you think something else is better which it never is from a strength point of view. It never seemed to fail that people would want to use epoxy saying it was better yada yada yada but there are so many tests saying that it isn't that I could never understand why engineers who love to look at specs and charts would argue the supposed benefits of epoxy over resorcinol. A classic case of tilting at windmills really. If you check this link. Resorcinol has a maroon, note maroon NOT purple glue line that I like but others may not. The glue I've been using now I can get it again and I really like for rodmaking is Cascamite. This is a UF glue which I suppose is like the old URAC. Mixes with water and gives a very stiff and hard glueline that easily sands, won’t gum up like PVA can. It's my belief and that's all it is that it is that you can only get the most out of the classic tapers such as the Paynes, Dickersons, Garrisons etc if you use the glue that was used when the rod was designed. In the case of Garrison, he used resorcinol, but I believe most of the rest used UF or even casein. To my way of thinking if Dickerson for eg was using a glue with a particular stiffness such as a UF of some type then the tapers he developed would have been designed with that glue stiffness in mind. Had he used a softer glue like epoxy or PVA then his tapers would be different to get the action he was after. In other words, if you use a softer glue you'll get a different action with the same taper. If anybody still here would be interested in trying Cascamite and you can't find it try this bloke. Cascamite has a pretty short pot life so you need to be organised when you use it and it also has a reasonably short shelf life so the thing to do with it is buy in small qtys so you can throw it away often and always test it. It's cheap to buy. (Tony Young)
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