With a break like this with plenty of surface area, I would just glue it without any additional supports. My glue of choice is hot hide glue, but there will be lots of opinions on that and many option…
I think that's a good move. One thing I might do to kick things of is to hit the area with some ultra thin master glue so it wicks under the area and prevents more chipping from potentially delaminate…
Hi guys, I finally managed to sort the problem out. Seens like was a simple issue that I cant see in that moment. I took the whole bridge apart and did a complete setup from scratch. I read somewhere…
This is precisely why Leo Fender developed the insideless guitar. A compromised neck block is super hard to come back from and when I see something like this, it leads me to believe that it's the tip…
Chris, can I add this for the council of elders show ? Also, we are going to have @member on pretty soon to talk about a job about this dramastic. Here's a link to the live show co…
I'm using hide glue on this 1st build. So far I've glued up the kerfing, back braces, and the top "X" brace. I'm using the 190 grade glue. Working time is short at best. I heated the top "X" brace surfaces (brace & top) with a blow dryer and that seemed to help, a little.
How can I get enough working time to glue the top, and then later the back, without having to rush and creating a real mess in the process?
A drug store heating pad can be placed under plates to warm them up pretty toasty without overheating them. Heating pads take a while to come to temperature in free air and longer when applied to a surface to be heated. I would bank on 30-40 minutes with a plate on top. I use a heating pad when hide gluing plate halves together- removing the pad at glue time.
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Definitely seems like it. It comes across as a pretty relaxed affair. I'm sure having done it many times is part of that. If your ducks are in a row, I suppose? Trying to think of the hitches that might present themselves with a similar approach on an acoustic flat top.
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This is interesting. I've been contemplating the same question, as I just started a flat top build where I will be trying to use hide glue on all or most of the joints. And I ran across this video of a violin maker showing his process.for gluing tops on. I'm curious what others more experienced with hide glue have to say about it.
As a quick summary, he applies glue to both surfaces (sides/linings & back) and rough clamps them together once they gel. So, there are two surfaces with gelled (not dried) glue partially clamped. He then basically reactivates the gelled glue in small sections with a pallet knife heated in water, clamping as he goes. He says he uses a pork based glue which I guess has a slightly longer open time and he thins it more than he does for other joints. Not sure how much affect either of those would have on the process, if it could be done with standard hide glue or not?
It seems like it makes sense as a process, but I can't vouch for it personally. Just passing it along and, like I said, I'm curious what others will have to say about it.
People have been gluing up violins (and cellos, etc.) with hide glue since long before we've had heat lamps and heat guns, so there have to have been other ways. Wood stoves, I suppose? 😀 I hate to think they were frantically slapping glue on and praying for all those hundreds of years. What do you all think? Is there any merit to this?
Just watched the video. Looks like SOP for Mr. Vincent.
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This is all very helpful. My last attempt at regluing a back I removed was off enough that I’m going to have to recut/repurfle/rebind. The possibility that urea modification could allow enough time to be precise for complex glue ups is reassuring. Got the following ChatGPT dump, does it seem accurate?
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I make a "hot hut" out of my go-bar deck by draping a large piece of vapor barrier plastic over it. Use clothes pins, or spring clamps to clamp areas shut around it. I then place a small space heater inside with my glue pot. I literally go inside the plastic to glue up my braces, or to glue tops and backs on. For tops and backs, I usually come back immediately with a heat gun at the glue seam. Don't hold it too long, but you will see the glue melting and oozing out the seam.
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That comparison is awesome. Just think, the method used 100 years ago is still the "goto".
Regards,
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That is interesting. The key I'm taking away is "find a way to keep the temprature up". I wonder how the luthiers back in 1920 were doing it? I wonder if they had two people working the gule up?
Regards,
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I have mixed plain table salt into my glue, following the instructions on the Bjorn Hide glue website, and by experimenting with amounts was able to increase the working time enough to glue tops and backs at normal room temp without heating the parts.
While It is possible to add enough salt (or urea) to keep the glue liquid at room temp, but I found that this dramatically extends the amount of time parts need to stay clamped up or in the Go-Bar deck and I cannot definitively say if it has any effect on the glues strength. Perhaps other folks have some input.
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Hey Fred,
That's an interesting idea. I saw a video where the presenter mentioned urea as an adder to the hot glue.
Regards,
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↪ Private memberGerry:
Either one works. I use hot hide glue when joining tops and backs together and for my linings and braces, so the idea of applying heat to any of those parts to try and keep the glue liquid makes me worry that I might be reactivating some glue joints.
A little salt in the mix extends the open time enough to allow me to join tops and backs to the rims . This is the only operation for which I use the "adulterated" glue.
I use a cheap digital baby bottle heater to heat my glue (in either plastic squeeze bottles, or a small jelly jar depending on the task) and I find that putting a number of glass marbles in the container while heating helps to maintain the glues temperature for much longer after it leaves the heated water bath.
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↪ Private memberOk on the salt. The marbles are a great idea. I've seen, but forgot about, that hack to keep the glue hot. Now I just need to find some marbles!
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I don't love the idea of applying a ton of localized heat to an area and then gluing it. I bought a heat lamp bulb from Amazon and used that.
For me the big step forward was keeping my hide Glue in squeeze bottles and putting those in the water bath. The Glue stays crazy hot in the bottles. There's a 3d print of my Glue pot top on here, I made a new one recently I have to update it.
That said I am doing all my braces with epoxy at this point. Partially because I'm using carbon fiber reinforcent sometimes and partially because it's easier and strong. It is hard to not make it look like shit though
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Paul,
Definitely going to get the squeze bottles set up and also a heat lamp to raise the temp on the parts. Is there a chance that the parts (top and back) expand and not fit the notched sides after they're heated?
The move I like is to make a hot and humid room for glue up. Space heater a humidifier and a small room is all it takes.
One thing about the hair dryer is a cursory blow probably dissipates before you get over to the glue pot and get your glue on. I've microwaved bridges to pretty good effect. On braces what you might do is put sand in a pan on a hotplate and do a deep heat like Collings does with celluloid binding on their mandolins. Just keep the braces in there until it's go time.
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"like Collings does with celluloid binding on their mandolins."
Sounds like the better method to get heat into a larger piece (i.e. top and back) might be with a heat lamp. Do I run the chance that the parts (back and sides) will expand and won't fit after heated?
↪ Private memberYou could put something under that riser there to heat the area where the plate will sit. Probably easier than getting a light in there.
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↪ Ian DavlinKinda like the college dorm room hot plate idea!
Regards
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You have a long process and a short open time. This can't be changed. I have found when working with hot hide glue you have a bit of time as long as the pieces remain in contact. Maybe as long as 90 seconds. Obviously be organized. If you can't get things reasonably clamped in place before the glue sets, do half at a time. If you can't do that do a quarter etc. A hot humid day will help a bit. Don't be afraid of making a mess in places you can access and clean up with a damp cloth after.
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90 seconds, wow! That means I need to come up up a fixture to fit and hold the top and the back in perfect alignment as I place them on the sides. I'm using a gobar deck, outstide mold and the braces will be notched into the sides so I think I can come up with a way to get a repeatable alignment with some additions to the setup. Naturally I'm doing the back and top at separate times, but right now I don't know how I'm going to get the glue applied that quickly. It must be possible. They could do it in 1920.