Yes if sh... happens it should be like this. Very neat and clean cut.That looks like a real clean break and it looks to be some rosewood coloration on the bridge area of the top. Do you suppose there was some oily residue in the rosewood?Marshall Dixon wrote:
Euan, what are the epoxies you have used. I have found Araldite best of those that available in local stores, never used it to joining though.Euan Hannah wrote:
such as acetone will cause havoc with the surrounding finish unless extreme care is taken. Personally I would carefully scrape both surfaces clean without any chemicals or moisture and I would reglue with slow setting exrta strong epoxy.
My next bridge will be glued with HHG.Michael.N. wrote:
Learn to use hide.
Here is some info that @simonm posted as a reference in another recent post about glues.
Alan Carruth wrote: ↑Sun Oct 31, 2010 2:25 amTitebond, and that ilk, will break down chemically if you apply acetic acid. It seems to work faster where the glue line is thicker. I once got a very fragile upright bass top off using hot photographer's stop bath (28% acetic, iirc) mixed with methyl cellulose (to form a gel). The top had been thinned down (with a disk sander) to 3mm or less all around the edge, and then glued with Titebond. It took five hours to remove, but suffered no further damage. Be warned that the use of a plain steel knife or spatula to do this will permanently stain the wood black: you will need a stainless steel knife.
The person who gave me the methyl cellulose got it from the restoration department at the Museum of Fine Arts in Boston, where they ues it all the time in a similar manner. She said that they begin every day with two anathemas: one on people who 'repair' antiques with wood screws, and another on those who do the same with Titebond. Once you have Titebond in the joint, the only way to remove it all and get a good joint is the scrape off wood, and that's verboten in antiques restoration. With HHG all you need is warm water.
I do use Ttiebond in new construction, but less and less as time goes by. I too have repaired my share of instruments that were put together with HHG and subsequently came apart. In general, I find these objects were not properly stored: HHG is perfectly durable so long as it remains dry. High humidity and heat are always factors when I see the sort of 'crystalization' of the glue line that leads to total failure. I usually see it as a mercy: the glue line fails rather than the wood, and reassembly is generally possible, althoujgh not always easy.
Sorry to disappoint you, but it is solid german spruce top - I made it.singularity wrote: Based only on the above picture it looks to me like this is a laminated top with spruce veneer partially removed for bridge to inset and fit into the top.
Titebond I used was fresh I have glued bridges on similar way in my earlier builds also using Titebond with no problems.SteveL123 wrote: Vesa, Why do you think the bridge failed? Was it due to the glue used (Titebond), surface prep not adequate, or something else?
Thanks MD, I might also do a small scale testing of different acids, solvents etc. that I have left over from my motor bike renovations.Marshall Dixon wrote: Here is some info that @simonm posted as a reference in another recent post about glues.
We'll newer know, but I have a feeling that it would have held because,SteveL123 wrote: I wonder if you had used HHG on the same bridge would it have held?
I agree that it does look laminated not solid. Why does it appear that the grain under the bridge is ninety degrees from the grain of the spruce. And...why are there traces, prsumably of spruce, on both the bridge and the top?singularity wrote: ↑Thu Dec 21, 2017 2:51 pmVesa, here's my $2*10^-2 with a huge grain of salt. Based only on the above picture it looks to me like this is a laminated top with spruce veneer partially removed for bridge to inset and fit into the top. This may be reason why your paper test returns false positive. Few spruce fiber leftovers are probably not allowing the bridge to fit tightly to the top as it shows in your picture. OTOH, not seeing it in person I may be completely wrong, but either way, to fix it I would make sure that the top/ bridge area is completely flat and clean before gluing bridge to the top.