We are being asked to provide ipe for the use of interior staircase. We will need to be using bending rail and be glued in the field. I have read alot about exterior use and it seems the Titebond III is the best product but has anyone used it for this type of application or am I just looking for trouble?

In my experience, I can say a few things:

Ipe is not a good interior wood. It is a very good exterior wood. People (owners, some designers) seem to think that since it is good as an exterior product, then it should be good as an interior product. It also is not attractive, no matter what you do to it.

Ipe is several different species marketed together as Ipe. Some species appear to glue better than others. Some will not glue, no matter what. I know of a large commercial job in Ipe that failed so miserably, the fabricator closed their doors and walked away from it. 10 years later, and everyone in town has tried to patch it up, and it still looks terrible. Every glue joint failed, even though they used a customized epoxy to bond it all.

TBIII may or may not glue the Ipe, but it certainly does creep. A lot. I have seen a 12' flat radius rail made of 1/8" plies change to a 18' radius in 48 hours. I would not have believed it if I had not seen it. I thought the carpenter that complained was delusional. He was not. As a result, TBIII is never used for bent laminations around here anymore.

I agree with every word that David has said.

Here's the deal as I see it...
Because it's so hard, ipe (ironwood?) is being used to good purpose for floors and decking (no glue-laminating here). Now that it's become popular for that, idiot architects and interior designers are specifying it for just about everything else ("so that everything will match"). We've all seen this before...

Anyway your question was regarding glue and bending rail. T3 is never a good choice for bending and laminating since it remains "flexible by design". The original T1 would be better and plastic resin would be much better (you're looking for glue that dries or crystallizes absolutely hard).

Of course hard glue will not stay stuck when unstable wood decides to move. That's why I suppose, some have suggested the use of T3. (You are as they say, "between a rock and a hard place".)

I've made several curved stair rails from ipe but not bent-laminated. (This would be the last thing I'd want to try). Ipe is very hard and brittle and the glue lines will be clearly visible.

The use of ipe for interior finish woodwork or furniture is a misuse and mistake. I would try tactfully explaining this.

Excellent advise so far.

I would add that ipe seems to have some natural oil that makes it difficult to bond, along with the high density. In fact, the high density means that it will be very unforgiving if things (like flatness) are not perfect, plus the previous machining may have heated the surface (common with dense wood) enough to have dropped the ability for the surface to "wet" and glue well. (The hot knives burnished the surface.)

I too have had my failures with Ipe.
I try my best to stay away from the stuff and especially if the situation calls for gluing it!
Chaim

ooops....I meant advice

We have had good results by wiping the two edges that are being glued togather with denatured alcohol then glueing.

It's pulles the oiles and let's the glue do its work.