Hairline Crack upper Rib

Treyzer · #1 11-16-2010, 09:14 PM

My bass developed a hairline crack about 4 inches long in the upper bout along the rib side opposite the side I stand/sit. Probably happened in transit to a gig. It doesn't appear to have impacted tone or playability. Since there are no qualified luthiers on Kauai (maybe not in the islands) Do any of you luthier types (Jake, Arnold, Mathew, Dallas Strings et al,) have any suggestions as to how this might be repaired?

Treyzer · #2 11-16-2010, 11:24 PM

Thought I'd bump this so it stays up long enough to get a response. Thanks in advance to those who have other questions.

Treyzer · #3 11-17-2010, 01:08 AM

One more bump. Hopefully others can leave this thread up long enough to get a few responses form our respected luthiers. It sort of feels like cutting in line or something. It seems rude.

vejesse · #4 11-17-2010, 05:59 AM

Here's a quick fix that will probably last a long time if the area is not under a lot of tension.

Glue the edges of the crack together, aligning things with wedges, etc. When the glue dries, then work through the F holes and glue a linen backing strip behind the crack. Don't make then linen strip too wide or the ribs tend to get distorted as the glue dries.

Treyzer · #5 11-17-2010, 06:47 AM

Vejesse, can you explain what you mean by aligning things with wedges.

Uncletoad · #6 11-17-2010, 06:48 AM

Can you post a little picture? Close up as you can.

vejesse · #7 11-17-2010, 07:17 AM

I just meant that when you clamp the crack closed, if one side of the crack is sticking up higher than the other you use wedges between the clamp and the sides to push the edges flush.

One more thing: Does the crack run right along the inside or outside lining? This is tougher to fix from the outside.

Jake deVilliers · #8 11-17-2010, 09:10 AM

Hey Trey, Jesse's program sounds about like what I would do.

Be sure to crack is level - its a good idea to try the repair 'dry' a couple of times before you slip the hide glue in there so you get an idea of where things go and when!

Make sure to clean up the excess glue as soon as everything's clamped up nicely - hide glue really contracts as it dries and it will pull the finish off your bass.

Or you could send me a plane ticket and I'll come and fix it for free!

Treyzer · #9 11-17-2010, 10:06 AM

First off, thanks for the great responses. Jesse, thanks for clearing up the clamping, it was really helpful. Phil I tried to take a pic but the camera really doesn't show the damage. It is a very fine hairline crack almost in the center of the side of the upper bout. Jake, thanks for letting me know what hide glue will do to the finish. Does it start eating the finish right away or do you have a bit of time? Finally, how long could I let this little problem go before it gets worse?

Treyzer · #10 11-17-2010, 01:26 PM

Got to bump for mo info!

1st Bass · #11 11-17-2010, 01:50 PM

The glue does not "eat" the finish-- it may, however, as Jake has warned, pull the finish off as the glue shrinks. In my experience, usually hot hide glue will not stick to violin varnishes, but it will pull the face off plate-glass, so, if it will stick to your varnish, it will certainly pull it off.

Uncletoad · #12 11-17-2010, 02:16 PM

Depending on where the crack is doing the linen thing from the back might be pretty tough for those not used to doing things like that. Moreover if it's not on there right it could do more damage than good as it dries and settles.

The important thing is to view this as something that will need redone again sometime in the future. As such whatever you do should be able to be undone.

I'd suggest using bottled hide glue from Franklin. It will come apart reasonably well when the time comes. Avoid Titebond or superglue or Gorilla Glue. If the only glue you can get around you is Elmers white you can use that and not cause problems.

Try to clamp from the top and bottom plates if you can get it to pull together cleanly and flat. Any wedges you use to help you near where the glue is need a release agent on them like some wax paper or saran wrap between those blocks and the glued crack area or you'll glue the block to the side of the bass. When you have everything reasonably clamped up use hot water on a cotton rag to clean up as much as possible so you don't have it dry up where you don't want it.

Be sure to work relatively fast, I'm not sure how long of an open time you get with that bottled stuff but I'd guess more than Hot Hide Glue and less than Titebond.

Have fun.

1st Bass · #13 11-17-2010, 03:28 PM

One thing about the bottled stuff: it is VERY sensitive to moisture--read humidity. I have had some luck with it, but I know a guy who had the experience of watching five instruments self-destruct in semi-unison slow motion, at a gig where he had hoped to sell them. Fair warning...

Uncletoad · #14 11-17-2010, 05:28 PM

Quote:

Originally Posted by 1st Bass

One thing about the bottled stuff: it is VERY sensitive to moisture--read humidity. I have had some luck with it, but I know a guy who had the experience of watching five instruments self-destruct in semi-unison slow motion, at a gig where he had hoped to sell them. Fair warning...

Yes it is not a great glue. I said pretty clearly it's not supposed to be a permanent fix.

I'm assuming Trey doesn't wanna mess with hot hide glue, the best adhesive for a crack repair. It makes little sense to use Hot Hide glue for one little crack by a fellow without any repair chops or desire to develop them. It just has to hold until it can be repaired better later. That Franklin Hide won't complicate the proper repair done in the future like some other adhesives would.

Treyzer · #15 11-17-2010, 05:40 PM

Quote:

Originally Posted by Uncletoad

I'm assuming Trey doesn't wanna mess with hot hide glue, the best adhesive for a crack repair. It makes little sense to use Hot Hide glue for one little crack by a fellow without any repair chops or desire to develop them. It just has to hold until it can be repaired better later. That Franklin Hide won't complicate the proper repair done in the future like some other adhesives would.

Phil,
You know me pretty well regarding this kind of stuff. Me and power tools; tools in general are not a great fit. I play instruments but I try to leave the repairing to far more capable individuals than myself. Thanks for the info and the type of repair I can possibly do that will suffice until I get back to the mainland and a good luthier this coming summer.

1st Bass · #16 11-17-2010, 07:20 PM

No problem Uncle! :-) Wasn't criticizing you...I just wanted the caveat to accompany the temporary fix.

I did my whole first instrument (small viola) with it and thought it was great-- but that instrument has never travelled to Pascagoula, or anywhere similar. So it is still in one piece.

Sam Compton related how a bass FB (or maybe it was a cello-- I can't recall, and he is beyond asking) came off during a concert. It got stickier and stickier, and he looked down and could see the glue oozing out like syrup from a biscuit. :-) (Oh joy!) It was another maker who told about the five fiddles self-destructing.

Now I only use that glue for the wedge in re-hairs. Works great.

Chet

Uncletoad · #17 11-17-2010, 10:06 PM

For anyone else who is reading this I don't like that stuff and don't use it in my shop. We only use Hot Hide glue for those kinds of jobs.

Jake deVilliers · #18 11-17-2010, 10:28 PM

Quote:

Originally Posted by Uncletoad

For anyone else who is reading this I don't like that stuff and don't use it in my shop. We only use Hot Hide glue for those kinds of jobs.

Not to worry Phil - I didn't think for a second that you'd use that stuff inappropriately. You're just trying to keep TASER from ****ing up his bass.
I use either liquid hide or fish glue to glue labels and nuts - that's all its really good for...

Besides, you can sniff that stuff all day and not even get a headache!

Mike Conner · #19 11-18-2010, 09:16 AM

How about Knox gelatin used as a substitute for the hide glue? I've done some tests with it to gain experience using a home-rigged glue pot (hot plate, glass jar in a heavy pot). My test pieces are still firmly glued after a couple months. Knox is pretty cheap at Walmart, and not so hard to try it out on some scrap pieces of wood before commiting to the crack repair. I'm guessing this would be much better than rolling the dice with the Franklin glue. Won't be building a bass with it, but for a one-off repair it might be a good alternative?

Uncletoad · #20 11-18-2010, 09:25 AM

Quote:

Originally Posted by Mike Conner

How about Knox gelatin used as a substitute for the hide glue? I've done some tests with it to gain experience using a home-rigged glue pot (hot plate, glass jar in a heavy pot). My test pieces are still firmly glued after a couple months. Knox is pretty cheap at Walmart, and not so hard to try it out on some scrap pieces of wood before commiting to the crack repair. I'm guessing this would be much better than rolling the dice with the Franklin glue. Won't be building a bass with it, but for a one-off repair it might be a good alternative?

I don't have an opinion about that. Jake?