Types of glue
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- This topic has 7 replies, 4 voices, and was last updated 4 months ago by Matt Sims.
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Folks,
I’m running a little low on glue… So I’ve gone online to look for some. I’ve been thinking about using hide glue for a while as I assume it’s more environmentally friendly than the “normal” stuff I’ve always used, which is plain old PVA, (i.e. plastic)…
However I notice that many “ordinary” wood glues available her in UK, such as evostick, are now described as “resin”
Does this mean that they are not plastic? I think of resin as being a product from trees.
Am I being naive? Is this just some new “spin” and it is PVA still?Thanks in advance,
MattI always think of things like Evostick as more in the epoxy world.
They are not natural glues, like hide glue etc.
Personally I match the glue to the job:
PVA / Tight Bond – general woodworking
Hide Glue – restorations, veneer repairs, antiques, etc
Epoxy – jobs that need a long open time, things that don’t have good wood to wood contact, repairing splits in wood, etc. never for joinery.
Not sure that answers your question, but hope it helps
Cheers
Darren.
The precise definition of a resin is a chemistry thing, and I do not know any chemistry. I do know resins can be natural. They can be derived from plants. Think of amber for example. You can collect your own from pine — I think you can find instructions on the web to make glue from pine resin. It can also be derived from animals. Shellac is a resin derived from insects. Frankincense is a resin too. I do not know where it comes from, but do know I do not like the smell. Resins are now often artificial. Asphaltite is a resin, this time derived from petroleum bitumens. To get a modern glue from them you generally have to do a lot of stuff to them. For example, epoxy resin needs to be mixed with stuff (the second tube) to serve as a glue. Lots of glues involve one sort of resin or another derived from some modified natural thing or wholly artificial.
I have seen discussions (you can look them up) that say yellow carpenters glue is a resin (aliphatic resin I think) while white PVA glue is not. That has something to do with the different characteristics of white and yellow glue. Not sure any of that helps.
Yah, no one answered that. Hard to know who in a woodworking website would know. But here is a thought from someone who is completely ignorant of the topic. If you are talking about the manufacturing of the glue, I bet hide glue is easier on the environment. Modern glues are made using modern chemistry in modern factories and involve various man made chemicals. That sort of production always has environmental impact, though I have no idea how much in this case. As I understand it, hide glue is made from otherwise not very useful bits of hide bought from tanneries. These hide fragments are treated with lime and then some sort of mild acid. Not much in the way of complex, man made chemicals there. And since the glue is made from otherwise not very useful bits of hide, its not as if animals are raised, slaughtered etc (all environmentally costly) to create the glue. So maybe it is more environmentally friendly process than the manufacture of modern glues. Though that is not certain to me.
On the other hand, I bet if you lived near a hide glue factory, the smell would be very environmentally unfriendly!
I spent a fair bit of my career doing something called lifecycle analysis, which is a method to assess and compare the environmental consequences of various processes. To explain, let’s suppose one is interested in energy use and greenhouse gas production. If one simply evaluates the energy used by and emissions from Factory #1 and then again for Factory #2 and compared them, the results would be meaningless. This is so because both require raw materials and those materials must themselves be produced. Also, the type of energy matters. So, if Factory #1 uses half the energy (total joules) as #2, but it is electricity rather than natural gas, it isn’t doing any better and may be doing worse than #2 because we need to combust about 2-3 joules of gas to make a joule of electricity.
If you want to worry about glues, you will need a careful analysis of the upstream portions and will likely need to know about embodied emissions associated with plant construction and end of life emissions from disposal. This is really, really hard to get right, especially for industrial chemical processes because of how often unrelated chemicals and products are co-produced or share energy through process heat integration.
Moreover, need to consider many aspects here. Energy use and GHGs is just one thing, but eutrophication, criteria pollutants, and a hoard of other emissions and environmental changes are possible.
In the present context, the energy use and petroleum consumption for the production of chemicals to make PVA glues sounds bad, as perhaps might the disposal of “plastic,” but hide glue will be associated with animal husbandry which inevitably is associated with methane emissions, one of our big challenges. Animal husbandry couples to farming, which is a large driver for fertilizers and chemicals. Using hide glue likely is associated with plastic consumption upstream, but I have no idea how much.
I applaud your diligence and concern. We all should make choices in our personal behaviors rather than waiting for some global or governmental solution. Unfortunately, there are times when it is just too hard to know which thing to choose! People like me aren’t doing their jobs to get the required info. But another way to look at this is that using wood glues for woodworking and maybe even for all industrial operations, is quite likely to be a small effect compared to plastics use in the food industry, packaging industry, and so forth.
I use hide glue, but not for environmental reasons. I use it for woodworking reasons.
Hope this wasn’t too long, too far afield, or (most likely) way too boring. Again, I applaud your considerations, but suspect you shouldn’t drive yourself nuts over it. Probably the most important choice is to use a method that reduces waste of whatever you choose including waste associated with product lifetime.
Thanks Ed…
I understand all you have written.
The “total cost of ownership” though process I completely understand…
In the absence of all the information, (and the lack of mental capacity and ability to process all of the information if I had it!), I have to make a decision that I suspect falls somewhere in the right zone.I’m still pondering… but in the meantime I’ve bought some more evostick wood glue!
Regards,
Matt -
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