Gluing Indian Rosewood

[ozziebluesman]

Last weekend I joined using the tape, tent method two Indian Rosewood book matched plates. The wood spent two weeks in the drying box previous and was glued up in the workshop at 45% using the aircon and the back was placed back in the drying box all last week. Today I decided to thickness it down and I got to 3mm and gave it a good flex and the glue joint let go! I thought the edges where prepared correctly but obviously not. On close inspection the glue didn't take in some parts like it was oily in spots. Should I use epoxy instead of original Titebond?

Has anyone else had this happen?

Cheers

Alan

[ProfChris]

When a rosewood bridge popped off I was advised that the magic trick for rosewood is to scrape the gluing surface immediately before gluing. Minutes at most. I think the idea is that any surface contamination can make adhesion harder (including oils rising to the new surface).

This seemed to do the trick - the bridge is still in place and shows no signs of lifting.

Not sure you'd want to scrape the edges of plates, but a tiny plane shaving on both surfaces should do the job.

I used HHG, but I believe the same advice is for Titebond.

[ozziebluesman]

Thanks Chris that makes good sense. I have built three acoustics using Indian Rosewood and have never had this problem before. I am going to have another go at gluing it up tomorrow so will try running the plane over the edge just befor gluing.

Cheers

Alan

[Trevor Gore]

Shoot the edges then glue immediately. Titebond works fine.

[ozziebluesman]

Thanks Trevor,

I realise what I did wrong now a the edges where prepared the week before and glued a week later.

Cheers

Alan

[liam_fnq]

Slightly off topic but I always shoot then glue immediately because I had joints that move enough after a day that you can see light through the gaps.

Alan, is it possible the joint moved enough that the glue didn't have anything to bond to?

[ozziebluesman]

G'day Liam,

The edges where prepared the weekend before joining and it was carried out with the aircon on in the workshop to control the humidity, let dry for an hour and then placed in the drying box for the week. It may have been a bit too dry in the workshop as it is always 47% rh in the drying box so good point, it may have moved.

Cheers

Al

[Lutherie Gervais]

In my personal experience, I use Naphta right before gluing. A quick light passes of naphta then gluing.
Same with cocobolo, ebene and i'd say most of my gluing.
It assure clean, dust free, oil free gluing surface.
Naphta is your friend.

and for Indian R/W, and most of my glue joint, MY choice is fish glue

there you go, you got some of my secrets

[ozziebluesman]

Thanks Mr Gervais, your ideas and advice makes good sense to me.

This is a guitar build I am mentoring with a student so it could have been a poor join too. It looked good to me though! I usually do it all in one session building my own guitars using the shooting board and a joiner plane and finish with a sandpaper glued on a square block. I immediately glue it up too. Leaving it a week in the drying was the problem for sure. I have build three acoustics myself using Indian Rosewood and joining with HHG without a problem.

Cheers

Alan

[kiwigeo]

Ive never had problems gluing up IRW back sets with Titebond. Like others say shoot the wood and then glue up immediately. If you're worried about oil affecting the joint then give the glue surfaces a wipe with meths but IMHO it isn't really necessary.

BTW I glue up my top and back sets in a wedge/torniquet style jig.

[jeffhigh]

This is a controversial topic Alan.
You get two camps

One advocates solvent wiping

The other just glues straight after planning, scraping or sanding and considers that solvent wiping can mobilize the oils, making the glue joint worse.

I just joint and glue right away myself and have had no problems on the 3 Rosewood backs I have done.

[simonm]

Shoot the edges then glue immediately. Titebond works fine.

Same here. I never sand after the planing. I think planing gives a better surface. I have never used a solvent either. But I've never had back and sides that I thought were very oily.

Usually I get a few sets ready, then over the day I am actually glueing up, I give each set a few cuts with the plane to get a fresh surface, glue and clamp for a few hours (on the bench using the bench vice), then repeat. Last time I did 3 sets in an evening. Once the tightbond had been clamped for about two hours I move to the next one. I believe 20-30 mins is enough but I am not in a hurry.