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You might try scraping the BRW surface just prior to gluing. The chemically activated surface can only help with adhesion.

Also...are you sure you're getting the surfaces together before the glue gels.

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JJ
Napa, CA
http://www.DonohueGuitars.com

Gee Filippo

Sorry this happening to you...but you know what they say "Shift happens"



blessings
the
Padma

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Audiences and dispensations on Thursdays ~ by appointment only.


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You could try titebond or you probably have scraps left over. Try some test samples with the same materials and different glues or techniques. I have not dared try to work with hide glue. There are so many new things to learn in lutheri I stayed with glues that I have a lot of experience with. So far I have haad great luck with epoxy titebond 1 and superglue. I have really enjoyed your photos as my first guitar was made using this plan and David Schramms on line apprentice. That is still my go to book when putting things together although he never did get too specific on glue techique. Good luck

If I recall correctly, Laurent mentioned in a recent post that for linings he mixes HHG with Franklin liquid hide glue @ a 1:1 ratio to extend open time. Might be worth a try for the solid linings, not so much so for the tentallones since they have to be held in place until the glue gels.

Not really sure about whether or not flooding with CA would cause HHG adhesion problems but I wouldn't think so, so long as the excess has been removed and you have a fresh glue surface which it seems you do.

You might try heating both the lining and the side rpior to glue-up (especially if your shop is a little on the cool side). Apart from hair dryer/heat gun, a heat lamp can be helpful here.

Also, not sure if this is plausible but, 320 is a little finer than I usually go on the inside of the sides before gluing linings. It may be possible (though I wouldn't think likely) that you could be building heat/slightly burnishing the wood which might create an inferior glue surface. Again, not too likely but a thought.

I have a strong feeling that 90 seconds is your problem...especially if the surface temp is room temperature. I try to shoot for 45-60 seconds. Keep the surfaces warmer and your open time will extend accordingly.

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JJ
Napa, CA
http://www.DonohueGuitars.com

My advice, don't get too caught up with all the info which has propagated around the internet stating how critical it is that HHG be this temperature, that viscosity and only ever mixed with deionized water from green glass bottle by Tibetan monks wearing crochet mankinies or you will miss out on one of the biggest advantages of this fantastic product. That is it's adaptability. Think about the basic of what the stuff does, it is crystallized cologne which we then devolve in water. We paint it on whilst hot and it then cools becoming sticky. The water then dries leaving the cologne to re-crystallize forming a secure bond, and that is about all there is to it.

How much water do you need to mix with it? Well within reason that would depends on how much viscosity you need for the job at hand, how long you have to wait around and leave it clamped before you need to move on, and how strong you 'need' the bond to be. Therefore viscosity allows some variation of the open time, work flow, bond strength and penetration. Same deal with heat, variation allows control, more heat = more open time. I think you will find that the 140f to 150f 'rule' is actually only a generalisation, a basic best practice guide that has been hijacked and taken far too seriously in our critical, analytical and pedantic times. Think for a moment how the glue is made? You get a really, really, big pot and half fill it with water. Then you throw in the bits of dead animals we did not eat until the pot is full. Then you simmer and stir until the pot is half full again. Then you drain, filter and dry the liquid and then you grind it up so it will absorb water more easily when required...that is about it. Yep part of the process was to bring the stuff to a very high heat and hold it there for hours on end. But doesn't that weaken the glue? Obviously not. Extra heat for a short period will not harm hide glue, just don't boil the crap out of it and it will be fine.

To your problem, i would suggest that you wet the lining and heat them before you apply the glue, i would even 'damp' the BRW along the edge a little as well because the moisture will allow the wood to retain heat a bit longer. How? Because it makes the wood more dense, but don't go silly here, I am not suggesting that you flood the bloody guitar. Moisture will also help the glue wick into the wood a little better and improve the bond. Pre-injection with 'hot' water is a trick used when gluing neck breaks with HHG. It also helps to thin the glue a little with water so it runs like warm honey. As mentioned turn up your glue pot a little for this task, don't 'boil' the gutz out of the glue, but it 'is' OK to get it quite hot for a little while but make sure you keep an eye on the viscosity as a hotter mix will reduce quite fast. Last of all i think you will need to work a bit quicker because i highly suspect from what you describe that you are not getting the joint closed in time and the glue is skinning before you get the clamps on. The measures i describe should give you enough time but if you need help, get someone to work behind you with a hair dryer, (paint stripping gun on low and held at a distance so it covers more area is better. If your concerned about apposing glue joints, insulate them with a rolled up towel) as you place the linings and clamp every couple of inches just to get things where they need to be and then you follow them clamping between the gaps till your done.

Cheers

Kim

Filippo,

I understand your frustration, I think we have all had moments like that. When you heat with the hair dryer do you heat only from the outside and is the inside of the side hot to the touch when you finish heating? It should be. It takes some work to get that glue warm if it has cooled way down. I can only see two things you are doing differently: The CA which must be TOTALLY scraped off and then the heating after gluing which I do with a hot air gun. I assume you are applying the glue to the linings and not the sides. That is important too. As far as I know hide glue will show this behaviour for only a few reasons. 1. The surfaces have some traces of glue, grease, etc. 2. The glue is too cold. 3. The glue has deteriorated in the pot. 4. The joint has space in it. Are you getting a bit of squeeze-out on the bottom of the linings? Another question, when you took the linings off did you get good adhesion along the lower edge of the lining? That is the only place it really needs to stick as long as your bindings are later set well into the sides and glued to the lining itself. If you can afford to you should set this guitar aside and start on some new sides for a second guitar. No CA this time. Check your linings for a flat surface on the gluing face too beforehand. Also try to get some moisture in there after glue up. I do that as I clean up the squeeze out with a brush and hot water.

hang in there,

John Ray
Granada

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John Ray
Granada, Spain
blog: http://www.granadaexpert.com/johnray/

I have nothing to offer here, but as I read the process, I wondered if the flooding with CA of the BRW sides is causing the issue. CA is basically plastic, and it's like gluing wood to plastic. Not really the case, but it would seem that the CA in the BRW would reduce the surface glue area where it was present. Maybe my thinking is all wrong, but it was the first thing I though of. I just wonder if the CA is acting as a deterrent to the HHG sticking to the BRW?

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

hide glue sticks pretty well to cured CA... and it is pretty easy to do a quick experiment to convince yourself of that.

I think your problem is the time you are taking is allowing the glue to cool before clamping. Best use of your hair dryer is to heat the sides before applying glue, or after re-warming after wetting the sides with glue before placing the linings. try working with shorter sections of lining 4-6" at a time to assure you get the clamps on before the glue gels.

you should be able to instect the failed joints to see how think the glue layer is - if you have a significant thinkness of glue stuck to your linings, you were likely too cool when you clamped. glue layer after curing should be like a thin layer of varnish, any more any you are asking for failure.

are you applying glue to both surfaces, or just to the lining ?

-jd

I have found that I have to replace the water that evaporates during heating. After 8-10 reheats the glue might be too thick to bond well. I feel the glue is happiest when it drops off a stir stick in individual droplets. The golden rule is try everything on scrap pieces when you are getting unexpected results. Good luck Mikey

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The Biggest Little City, Nevada
www.hammondguitars.com
I love building guitars!

snip


"Cologne"? Where do you get your glue? Mine doesn't smell like cologne!

I think you mean "cologen", but I like the "cologne" idea.

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Hank Mauel

I'm with JD here. You can feed the glue in sections using a pallete knife, although it will take much more clean up. Failing that switch to Fish glue - gives lots of time to get the clamps on.

Cologne glue is a mix of both Hide and Bone glue. At least that's my understanding of the term.

Filippo -

Here's my two cents worth - take it for what it's worth - I'm a novice, and have worked with HHG on the last 3 guitars.

I've had touble with HHG on two occasions - once when the materials beingglued were'nt hot enough. When I applied the glue, even though it was 145 upon application, it gelled very quickly. I use a paint stripper - gets the wood pretty hot prior to applying the glue - your hair dryer may not be robust enough, especiallly if you work in an envirionment like mine - basement shop - ambient temp at about 60 degrees in winter.

Second, if you've not been pretty careful to rehydrate the glue, 8 - 10 reheats could have resulted in thicker glue - I had the same issue, and the glue gelled much faster when thicker. Don't know what your gluepot, glue bottle is, but might be worhtwhile to mix upa fresh batch.

Good luck!

Good

I don't use hide glue so i am no expert on the subject but a friend uses it and he turns the heat in the shop up to 90 a before he starts and while gluing to let the wood warm up and the slow the glue setting process. He also works fast and clamps even faster as he's going along. This is why i don't use hide. My working speed is very casual.

Not sure how else to help you with your hide glue issues, but fish glue seems like it might be a good alternative with those difficult to glue pieces.

Cheers,

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Gwaltney Guitars

Filippo. I'm not quite understanding your problem with the tentellones. It takes around 10 seconds (at the most) to get glue on an individual block. Even in a cold(ish) shop the glue shouldn't gel and that's without pre heating it. Once the glue on your tentellones is thoroughly dry they should not pop with heat alone - that's why you can glue binding/purfling strips with Hide and then bend them on a very hot bending iron without them delaminating. The glue must be thoroughly dry though.
Your continuous lining is a different proposition but I'm pretty sure I could glue them by feeding glue in one section at a time, even in a cold workshop. It's just a matter of technique.

yeah, just to try and embarrass me...well it doesn't work Hank! I'm too old to get embarrassed anymore too!

how about you keep an eye on u'r post counter and i'll stick with my cologne glue

Besides, i call it cologne glue for a very good reason Hank. It's because i always put a dab behind each ear to hold my glasses on before i start work.

Darn spell checker

Cheers

Kim

I first thought the CA might be part of the problem, but I believe what Todd and others have said about it. I think the 60 degree shop, and 90 second open time are what's causing troubles. I add a pinch of salt to 1 ounce of HHG to extend open time when closing the box, but I take less than 90 seconds. I have a small fan forced heater blowing on the body for a while before closing the box. I heat the edge of the top (or back) with a heat gun. (I glue my (kerfed) linings in small sections so my process for glueing them wouldn't help your situation)

My suggestions.
A pinch of salt in your glue, but try on scrap first. My "pinch" and yours may measure differently.
Heat the shop up to at least 75 degrees.
I'd heat the sides, but not to 140. A fan forced heater or heat lamp should be able to heat the entire area/assembly to 110 or so, instead of heating a small area hotter. Same with the linings.
I see no need to put glue on both surfaces. This takes alot of time. I'd put the glue on the linings from a bottle. It would take 10 seconds or less to run a bead from end to end. You could mist the sides with warm water while heating them if you think it's necessary.

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I didn't mean to say it, but I meant what I said.
http://www.brackettinstruments.com/

Filippo, perhaps you could use foil or something to cover the tentelones to protect them from the hot air from the gun while you warm the solid lining.

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Steve Smith
"Music is what feelings sound like"

Some good experience and good advice here. Great thread. One thing that I did was travel E-bay a bit and pick up a couple of food warming trays. I place braces and smaller parts on them and warm them prior to the glue up. They can also be found in thrift shops.

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Jim Howell
Charlotte, NC

60* is really flirting with danger and almost an impossible situation given your method, Fillipo. Here's what I do when I glue liners:

1) Clamp the mold with the sides in a vise
2) Lay down a bead of HHG only on 1/3 the length of the side where the liner will be glued...horizontal surfaces hold beads better than vertical surfaces.
3) Slap on the liner and clamp it quickly
4) Lay down another bead on the second 1/3 and clamp
5) Lay down the final bead, clamp and clean squeezeout after 15 minutes.

This has worked for me for years. The key is laying down the bead on a horizontal surface IMO. But continue to use warm surfaces and get the room much warmer...or do it in a warm kitchen or bathroom when SWMBO is out shopping. Also...45 seconds is the target you should shoot for in getting the joint closed. I do it all the time for tops and backs...so you can do it too. Just practice with dry runs...it's so worth it. Good luck!

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JJ
Napa, CA
http://www.DonohueGuitars.com

I had no problems with gluing tentellones on any of the three guitars I have built. I do not pre-heat the sides or the top, or the tentellone. What I do do, is to use lots of glue, then clean up. Lots of glue helps hold the heat. I don't even think of keeping it neat. I hold my tentellones for about 30 seconds. Longer than some have recommended. Actually, in the lower bout, I hold for about 45 seconds each, as there is some tension on that joint, due to the recurve in my doming process. It takes time, but not that much. Couple of hours to glue in a top.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

"do it in a warm kitchen or bathroom when SWMBO is out shopping. "

the smell of HHG in the kitchen does not seem consistent with domestic harmony.

...pre-warming the linings in the oven at ~180F can help a lot and leaves the kitchen smelling a lot nicer.

-jd

Buy your Sweetie's favorite cookie dough in a tube and bake them afterward. It'll cover the scent of HHG and, unless there a dietary situation to avoid, score you brownie points. If it is unwise for you to bake all of them at once, bake just a couple small ones. It will still smell like cookies. You will have been thoughtful enough not to sabotage the diet but still giving a treat. Or you could bake them all and take the rest to work with you, but get them out of sight before Sweetie gets home.

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Aoibeann