Official Luthiers Forum!

No not those cracks....

Here is a video that Dave Collins just put together showing the magic of closing a nasty top crack. Although the method is not shown the results speak for themselves.

Enjoy!

PS: If anyone knows how to post YouTube videos with the screen shot showing in the OLF post please enlighten me? TIA!

https://youtu.be/ZKe1VcU_Yts

phpBB software, which the olf is built on, doesn't automatically support a lot of youtube stuff without modifications. Video addresses have to be in the form http://www.youtube.com/watch?v=xxxxxxxxxxx for them to work... the shorter youtu.be/xxx links don't work. Also note the address has to start with http:// not https:// for some stupid reason. It's a real pain in the butt and point of frustration for normal users but there it is.

Looks like some kind of trick photography to me.

So that was the bag method? And do you, and if, at what point go you give a squirt of glue in there. Thinned hide glue?

Thanks David and Hesh. One to dazzle the layman with.

No trick photography but it is time lapse. Closing the crack took likely 30 minutes or so and what's happening and not shown is a calibrated, variable temp heat gun with a diffuser is positioned in the sound hole and warming the area under the crack. Since the camera was taking a pic at a rate of about once a minute in the in between time we were putting a few drops of water on the cracked area and where the pick guard was. The idea is to let that area get wet, dry out, get wet, dry out exploiting the differential expansion rates of wood when hydrated and not.

Once closed the crack is glued shut level and then cleated from the underside.

This is a very common crack on Martins and others and is caused by the differential expansion rates of the pick guard material and the top wood. These guards shrink over time too which plays into this as well.

So no magic just physics and science and a day in the life of Ivan Luthierovich.....

Thanks for looking

Great post -- I like that method far better than one I saw for the very same type of crack where chunks of wood were used and then a much larger pick guard was installed. That video was a pro too.

As for the YouTube posts -- there is something a bit different with the OLF phpbb setup, my forum AGCF is phpbb based as well with the default attachment preferences and all you need to do is insert the code after the = between the ][

_________________
Ken Cierp

http://www.kennethmichaelguitars.com/

Thanks Ken - we do a lot of Martin work and Martin warranty work too and pick guard cracks and pick guard replacement is standard fare for some of these older instruments.

Lutherie IMO suffers from the idea that many Luthiers practice our craft in relative isolation and as such may not be exposed to the ideas of others be they something new and better or what ever. IME it's pretty common for five Luthiers to have five approaches to the same task and there is nothing wrong with this either but I do think that all would benefit from more of a group think.

Forums help with this somewhat but pros are reluctant to participate on forums because we have skin in the game and some snot nosed punk who flames us on a public Internet forum does not....

Martin requires that when pick guards are replaced that finish is applied under the guard. It's a good practice and idea and we do it too of course. This has changed over the years as well. It used to be lacquer and waiting, leveling, waiting, burning in, waiting.....

These days various Luthiers will again have various approaches. We've used e*poxy with great results, very thin e*poxy the kind used to encase bugs in a cube. More recently we are using The Glue Boost CA products again with great results and of course no waiting to finish the job beyond hours not days with lacquer.

Times change folks come up with different approaches. One of the most interesting newer approaches that I am aware for fixing open cracks that won't close is ep*xy matched for color, cleated on the inside, etc. When I first heard about I was appalled at the idea of adding ep*xy to a guitar top but when I saw the results and understood the idea better it's a great solution.

Our shop, all of it, is specifically set-up for shooting pics and videos. We have a major investment in lighting, cameras, video editing software and computers. It helps keep the wok interesting and our YouTube channel a2guitars gets lots of hits and we get lots of emails with comments.

Dave is not interested in just doing the same old work day in and day out. He is on a mission to advance the craft, innovate, provide greater value to clients and safer, cleaner, more effective approaches for those of us who do the work too. It's a trip for me to work with him day in and day out and I have to tell you that I feel like I am in the midst of someone who will likely be the next Frank Ford or Dan Erlewine.

I'm a very fortunate guy and know it too!