> I'm wondering what gram strength glue other builders out there are > using.
there are other traditional glues beyond hide glue, fish glue and rabbit glue are sometimes mentioned. fish glue is similar, but not identical; rabbit glue is a particular quality of hide glue. toolsforworkingwood.com has it down pretty well. Mpst joints in lutherie have a small surface area and many are under some stress; strength is not a bad goal; but experience will tell you that a failed joint can not be a strong one, so use the glue that allows a joint to happen. Joints that are 'closed', eg dovetails, mortice & tenon are where there is the most concern for open-time; these must be fitted tightly, but they will swell and bind when wet by a water-based glue, takes some experience to judge what is a good slip-fit, and when you also have pegs to draw it together, maybe the glue can be omitted. Small assemblies with critical angles and awkward clamp setups are next (peg boxes perhaps). It is often worth the trouble and time to screw a frame to the bench so wedges can be used rather than wrestle with clamps. What is not often mentioned is the need for deliberate and thorough preparation before any glue up work. All tools, jigs, clamps and supplies should be standing close to hand. Warm water and a roll of paper towels (or rags) ready for spills and clean up. Put the bloody phone on the machine. Be rude and firm with unexpected visitors, "Sorry, glue up in progress, cant stop now; if you must stay, would you mind putting on that apron and lending a hand? ..." Prefer the strongest glue your assembly skills will allow, and practice dry until you are skilled at setting up the clamps and whatever is involved. Make sure your brushes will hold enough glue to wet the surfaces involved. Dark backs might show a light glue just as light tops will show a dark one; the back can be given narrow strips of contrasting dyed wood/heavy paper to hide that in a 'detail'; if the thin bits are soft enough you can improve the fit of the joint thru a gasketing effect. > * The 192 gram strength is a good general purpose glue, and it's the > least expensive hide glue around. That's why it's the most common. > Its real application is veneering, although you can use it for > regular gluing in a pinch. A lot of people consider it the best > all-around glue for general woodworking (including veneering), > because it also has the longest open time. If you are new to hide > glue, this is the grade you should get. well, that last is not the advice I would give to a luthier. Veneer has its place in some instruments, the back of many necks is veneered. Most other joints are open and more easily assembled - veneer is often cut from highly figured wood, burls and other squirely wood grain will react to water like drying wash; one must work it with an iron so that it tacks down to the substrate, the heat smooths out the glue and trapped air. Excess glue lubricates the surface. One works from the center towards the edges, and some expectation of creep must be made. > * The 315 gram strength is a special purpose glue for very high > stress applications. It is favored primarily by instrument makers > for situations where a joint will be under constant force. Of the > glues the 315 has the shortest open time. > So, is 192 not strong enough for lutherie, as implied by the > description of the 315? ok for the label inside, maybe for the parchment liners, if its already in the pot. Ideal for the veneer on the neck. I bought one each from them and have been experimenting. Have had some lamination joints fail using the high-clarity (on beech), and didnt think it was worth the trouble as the jointline was still easily seen. I find 10 oz jelly jars handy to keep small premixed amounts in, easily labeled with marker for date and strength; keep in the fridge inside a large zip-lock bag - but if you share that fridge, be sure all know it is not food (except to mold). -- Dana Emery To get on or off this list see list information at http://www.cs.dartmouth.edu/~wbc/lute-admin/index.html
