Glue Choices for Curved Railing Glue-Ups
A discussion of suitable adhesives for curved stair railing laminations. Long open time and minimal spring-back are the issues. December 6, 2008
Question
I am going to be gluing up a curved rail and a curved nosing (balcony rail installation). An article in the Knowledge Base suggests National Casein glue. I have run across a Titebond product (Liquid Hide Glue) that sounds like a similar product but without the mixing.
1) Has anyone tried this glue?
2) Titebond claims "long assembly time" but then the specs say 10 minutes. This doesn't seem all that long. Are there glues with 30 minute or more open time?
3) If I use a glue with a shorter open time, I was thinking about doing three or four laminations at a time (i.e. half of the rail), letting it dry for a few days and then completing the remaining laminations. Has anyone ever tried this or seen anything wrong with this approach?
Forum Responses
(Adhesive Forum)
From contributor H:
How long do you think it's going to take you to bend rail around a form? It takes maybe 5 minutes with a helper (you need one) to get a few main clamps in place to hold everything while you go back and clamp in between. We glue rail/stringers/nosings just about weekly. Use Titebond 2 or Titebond Extend. Do not do part of it. Do it all at once or you'll have a problem. Leave the rail on the form for at least 2, preferably 3, days. It may be dry on the outside but in the middle it's still soft.
From contributor J:
Although it is a little messy, National Casein's DR regular powder resin glue works great for laminating. That is all we use on radius laminations. It cures very hard, which helps keep the springback to a minimum. We apply the glue with a roller, then stretch wrap the pieces on the ends and middle before bending around the form. Curing time for us is 12 to 16 hours, but that is in Florida. Leaving it on the form longer can't hurt.
From contributor T:
As contributor J states above, stick to two part urea and you will never have a failure. We just completed a huge 15' diameter spiral and all the rail sections were done with urea. By varying the catalyst ratio, you can adjust the working time to the part at hand. We never had any problem gluing 8 laminations at a time. In clamp time was approximately 16 hours and we had no perceptible springback at all. We manufactured some of the rail sections months prior to the stairs being completed and the rails fit the form just as if they had been laminated the day before.
From contributor A:
Since I am sold on West System glue, I would recommend using it. I work by myself most of the time so I need a glue that will allow as much as a half hour for assembly time. On a tight bend I may use over a dozen strips. I use a very small roller and I can apply the glue easily in that time. I have tried most of the glues mentioned and have had issues with all but West System. I have had glue failures with all on occasion. The cost of the glue is a very small part of the project so I see it as a false economy to use others. I am much more relaxed when not working under the pressure of a ticking clock. Also to set the kick time back, I mix the glue in a tuna can which is set in cold water with crushed ice. I have experimented with setting the leftover glue in the freezer and used the next day and had no ill effects. On exterior projects I use the glue mixed with acetone to seal the wood. It works great. I sealed exterior hand rails out of four layers of three quarter treated pine. There were a lot of dropped goose necks and swans and 8 years later they look as good as when they were first made.
