Primitive Archer
Main Discussion Area => Bows => Topic started by: toomanyknots on October 14, 2010, 04:52:27 pm
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I use smooth-on for some of my laminations and titebond III for others. If I am gluing in reflex I go with smooth-on. If I am gluing two straight pieces together, I go with TB III. Can't go wrong with either for your purposes. TBIII is just a little less of a hassle than mixing up the smooth-on IMO.
Eric
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A lot will depend on how you plan to join the siyahs. Traditionally sinew and hide glue were used.
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Pat, you know if them injuns turned to guns and steel heads, they woulda used TB III or another modern glue as well....
Just jerkin ya chain.
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ive glued on a few siyahs, and i used titebond II on some and then titebond III on the latest. i made a a shortie red oak, 48 inches with small siyahs. just used a bit of wrap on the small ends, it pulled to about 45lbs before i pulled it too far.
what problems are you having?
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Toughest Glue that I know of is Hide Glue....will pull splinters out of a piece of plate glass when it dries... TiteBond won't do that...and neither will epoxy....but if you ain't going traditional....then it really don't matter any of the above-mentioned glues....along with many others will work just fine....jmo
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I've used both TBIII and Urac. No problems with either. Only had one break, and it was the grain in the siyah that failed, not the glue joint. :)
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Well I used tb2 for some siyahs and they lifted a bit, they're wrapped insanely well and is the only reason I believe they have not come off. I never really thought of using hide glue, I will definitely try that. Pulling splinters out of glass?!!! Man! I've used sinew glue and read that they are similar in strength. Is tb3 significantly stronger than tb2? I always thought that was just a marketing scheem, :). There was only 2" of glued area on the siyahs, they were glued right on top, not spliced in. What is the best way to secure a strong glue up? I use clamps but only to press em just a little, just enough to not push all the glue out,...
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well, i remember seeing yours. your next try, make the base a bit bigger. my siyahs had, if i remember, at least a 3 inch base. and then i wrapped them. also, it sounds like you might not have kept enough pressure on it. i pressed mine pretty tight, watch for sliding! and i left my clamps on for 24 hourse. you can buy hide glue on ebay..
can anyone tell anything about this stuff? they claim 450gram strength, i thought it went only to 300 something in gram strength?http://cgi.ebay.com/hide-glue-1-lb-pipe-organ-luthier-woodworking-piano-/160436431360?pt=LH_DefaultDomain_0&hash=item255ac1aa00 (http://cgi.ebay.com/hide-glue-1-lb-pipe-organ-luthier-woodworking-piano-/160436431360?pt=LH_DefaultDomain_0&hash=item255ac1aa00)
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Here is a bit of Information on Hides Glue, it's different Grades, and the Properties of Hide Glue
Hide Glue is graded on a basis of its gel strength, a measure of how many grams of force it requires to depress a 1/2” plunger 4mm. into a 12.5% protein solution of the glue at 10° C. Glue is manufactured in standard grades from 32 to 512 grams. 192 gram strength is the most commonly used for woodworking; 251 is the highest normally used for instrument building; 135 is the lowest used for general woodwork.
The higher the gram strength, the stronger the cured glue, and the shorter the working or gel time. The lowest grades are considered strong enough for woodworking: “stronger than the wood itself.” (Personally, I don’t think any glue deserves that sort of comment. It may be that strong only for certain tests; it is not the same as the wood itself.) It is never a good idea to dilute too strong a glue to obtain lower viscosity or longer working time when it is possible to use a lower grade of glue. Glues of different gram strengths may be mixed to get an intermediate. I like 192 gram “high clarity” because it’s transparent and doesn't gel too fast.
Now, here's an important note. The higher gram strength glues have higher molecular weight, which (I'm guessing here) may have slightly lower electrochemical adhesion, i.e., they may not stick as well. Because the very high gram strength glues require up to twice the water to reach workable consistency, there will be less glue actually in the joint after it is clamped and the water evaporates. This may be why the very high strength glues (300g. to 500g.) are often described in the literature as "too strong for woodworking." Additionally, they gel too fast for many applications.
Commercial liquid hide glues have gel suppressants & remain liquid at room temperature. They are not quite as useful for most work: slightly greater tendency for the joint to “creep,” lower moisture & heat resistance, short shelf life, no initial tack. Many Bowyers use liquid hide glue, but they are (or should be) careful to test each batch, in addition to watching the expiration date printed on the bottle.
When a hide glue joint is clamped, thick liquid glue should squeeze out all around. If the squeeze-out is “crumbly” when rubbed with a finger, or has the texture of cottage cheese, the joint may not have been clamped in time. Excess glue should be washed off finished surfaces to avoid chipping the finish as the glue dries and shrinks.
Hide glue cures entirely by evaporation. Hide glue is about 2/3 water, and it is important to pay attention to the amount of water absorbed into the work piece. Maple necks can take on quite a “back bow” as a result of water absorption. Joints will swell when glued and must be allowed to dry completely before leveling to avoid “sunken” areas around the glue joint. Old hide glue joints can be restored by adding more hot hide glue. The heat and moisture will reactivate the old glue on the joint surfaces, and the new joint may be nearly as strong as the original.
Hide glue sticks to surfaces by electrochemical attraction, or specific adhesion. Mechanical bonds, like little “fingers,” may help modern adhesives such as epoxy because of their very high cohesive strength, but with hide glue’s low cohesive strength, roughening joint surfaces will not help adhesion. It is better to be concerned about the electrochemical properties of the wood.
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oh, i didnt realize they went that high. so, you use the 192 stuff? i personally havent seen the gram strength stuff till about a month ago, and i did a bit of research on it, but i didnt know how it went with bow making. thank you for the wonderful write up though!
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I recommend the medium strength (315 gram strength) glue. All strengths of hide glue are capable of making a joint stronger than the wood. The major differences in the glue is the working time. The strong glue (380 gram) tacks faster, and the weaker glue (195 gram) gives more working time. In my opinion, the 315 gram gives the best of both worlds, and IS rated stronger than the weak one.
just add the www. violins.ca/supplies/hide_glue.html