Laminating Rockers

Advise on sawing, prep, lay-up, and glue-up for laminated chair rockers. January 13, 2006

I made a non-critical mistake on the last rocker I made. A solid wood rocker skid was taken too thin at the back and the tip broke off on assembly. I was able to recover and finish. It brought up questions on going to laminating the rockers and the means of doing it. I know I need to make the clamping forms, etc. but I need experienced information on equipment, etc.

1. I have a Jet 18" bandsaw. What blades do I choose to go from cut to glue up without a pass through the planer?

2. How thin do I need to cut the lams to make rockers with 42" and 40" outer and inner radii?

3. I use Titebond glue. Is this okay for this application or do I go to Titebond II or III or some other glue? I would prefer a single part glue.

Forum Responses
(Furniture Making Forum)
From contributor D:
For cold bent lamination, I have always sanded coming off the band saw. I am naturally lazy, so find it easier to sand than to change blades on the saw. The sanding also helps fine-tune the total thickness, as well as give clean, tight joints. If the stock permits, you can preserve the grain by marking before sawing.

I then use either a rigid glue (Unibond 800 or Weldwood urea resin) or urethane glue. The reason is that on our work (handrails), yellow glue expands out of the joints - days or weeks later - and can be felt. Most folks probably think this is the grain, which is okay, but it bugs me. Sand it off and it'll come back, so we avoid by using other than yellow glue.

From contributor P:
We do the rails of our Arts & Crafts rocker from 1/10" cherry and 3" wide. We use Titebond extended in a vacuum press. Titebond extend is the only Titebond that you want to use for bent lams. Do not use the Titebond II or the outdoor type or you will get seam creep over a period of time. This info was from the techs at Franklin. For prepping your rockers, I don't know what width or thickness you want to get, so there are many ways to prep your stock. Please post what the sizes are of those rockers.

From the original questioner:
Rocker width is 1 3/4" to 2" and 2" thick with inner radius of 40" and outer of 42". Length is 40" to 45".

From contributor P:
I would stay with something around 1/6" thick. What we have found is the thinner the lams are, the less tension you have when it comes out of the press. Vacuum presses, I think, are the way to go - even pressure and they have many uses. For prepping the stock, I would just take 8/4 stock and use a glue line rip blade and do the rips. If you have a feeder, that would work better. Then see how the surface is out of the saw and do your glue up. A lot of people try to joint the edges of glue ups, but you need something for that glue to grab to and jointed edges come out way too smooth sometimes, depending on the wood you are using.

From contributor S:
Your bandsaw will work fine. I use a silica carbide re-sawing blade. The blades I have were special order from Japan from a buddy, but any good quality carbide re-sawing blade will work.

I widebelt after sawing. I don't own a widebelt, so I rent time at another shop. It usually takes me 15-30 min and costs me $30-60 to widebelt, but the pieces are all perfectly equal thicknesses with no tearout. I mark the end of each piece before widebelting so that the grain matches up when laminating. The thickness of your pieces will depend on the species that you are laminating. Typically, 1/8" - 3/32" works fine for most species. I have found I have less problems If I err on the side of too thin rather than too thick. Yellow glue will creep over time in laminations, so I use Smith's Laminating Epoxy. It works great and is very thin but is expensive (about $200 for 2 gallons - which will last forever if you're just doing rockers).

A vacuum press is my preferred method, but if you don't have one, then a top and bottom form works well on pieces this size. We always oversize our laminations in width, then join them after they are set up. We have a 16" jointer so we can do rather large curves, but a small jointer will work for the sizes you are talking about. The jointer just cleans up the edge nicely, then we thickness the pieces through the planer. The epoxy can be a bit messy, so I'd suggest doing some tests beforehand.