when to bandsaw and when to use bent lamination?

[nick brigg]

i'm in the middle of designing a stand with a curved front rail, the curve is 1 inch thick with a span of 14 inches and a 5/8ths inch bow in the middle(i hope that described it:)) according to my calculations i'd need a piece of stock 2 1/4+ inches to bandsaw this curve, but then i was thinking of bend laminations...so the question is, when to laminate and when to bandsaw a curve?

[Lee Schierer]

Cutting a curved piece will expose end grain along the length of the curve. If the curve is not severe and the end grain exposure not objectionable from an appearance point of view then saw the piece.

If you need maximum strength then a lamination is probably stronger. Laminations will also have a plywood look (to a greater or lesser extent depending upon the finish of the surface on each lamination and how closely the wood color matches in each layer to teh next) when viewed from the side.

[Jason King]

It really depends on the effect you're going for. Both techniques will work. It's more of a stylistic question on how you want the finished product to look.

[glenn bradley]

I'm with Lee; lamination for strength and appearance. Sawn piece for speed and ease.

[James Phillips]

Laminations are not easy and care must be taken to avoid glue spots hurting your finish. Do not skimp on the glue, just be prepared to do alot of clean-up. A lamination done properly will be hard to notice even from an edge view. Lamination is cheaper and stonger, but band saw is faster.

[Mike Spanbauer]

Yup, as Lee stated w/ B-lam as long as you don't have a super thick kerf, you will get what appears to be consistent grain along the curve which when paired with a good glue will yield a stronger piece than the other method by far.

Cutting the curve from a single piece of solid stock works too, wastes more material but is significantly faster and weaker.

mike

[nick brigg]

yeah i knew the strength was an issue. i've never done bent laminations and it doesnt hurt to try new things(unless they go wrong:cool:). so now the question is, is it really worth it to use that urea formaldehyde glue, or is there some glue along those lines without all those nasty chemicals?

[Mike Spanbauer]

Hmm... glue technologies. I may be out of my element, but I'll give you what I've used (and works for me).

Urea Resin glues are extremely valuable in this application as there is practically NO glue creep. Once they dry they are HARD as a rock (and will damage your tools thusly if you try and joint or plane it ;)). I've heard of others used weldwood and Gorilla with fair success as well, but each has a different use that it was designed for.

Urac, Unibond 800, and others were designed with this particular use in mind and the military used them (still uses them?) for many, many years for wings. Extremely strong, durable, and effective adhesives.

The key is to mix them outside and use a mask. Once mixed they are fine and I do not believe (could be wrong) they pose nearly as serious a risk. However, the powders used to catalyze into the glue are highly dangerous and nasty stuff.

The part in particular that I find the most appealing with UF glues is the LONG open time. You'll have 45-60 minutes to work with the glue and ensure good glue coverage on every lamination. When you're working with a stack of 8-15 laminations (personal best was 18) you need that time. I would also HIGHLY recommend purchasing a glue roller if you don't have one (office supply stores carry ink rollers, same thing) in a width appropriate for your laminations.

It's really quite simple to work with once you have everything setup.

G'luck!

mike

[James Phillips]

I did some bent lams with titebond 2 and it was plenty strong. For 1 inch thick ou really only need four slices (each 1/4 inch) and some good clamps.

[Bruce Wrenn]

Why not do both? Cut curved, and laminate a sawn veneer to the front and top. Bottom is seldom seen.

[Jim Becker]

Why not do both? Cut curved, and laminate a sawn veneer to the front and top. Bottom is seldom seen.

Yes, I was going to suggest that this is an option that might be practical from time to time, depending on the design, species, etc.

[Mike Wilkins]

Here's my 2 cents worth:
There are several ways to get a curved surface as you know. I like to avoid glue lines for curved surfaces. The quickest way is to laminate some veneer to a curved substrate, with a lesser quality veneer on the backside.
A glued lamination will take some time, a lot of layers, and you will have to deal with springback.
As for glue: Titebond makes a glue called Cold Press for veneering. I have never used it for a curved surface yet, just a flat project. Titebond 3 worked grreat for a 6 foot tall curved bookcase front leg that I glue up. Still holding together, so it must be OK.

[Jim Becker]

Mike, Joe Woodworker sells a cold press glue that works very nicely, too.