Bent Laminations cutting....?

Stuart Ablett

Member
Messages
15,917
Location
Tokyo Japan
I'm planing a bent lamination project, I have Big Blue to cut up the laminations, they will be about 1/8" thick, or slightly less, how smooth do the pieces have to be to be glued together?
I understand that the smoother they are, the tighter a glue joint I'll get, but do they have to be silky surface smooth, or will a nice smooth cut off Big Blue do the job?

I'm looking about 8 to 10 laminations all about 6" wide and maybe 24" long?

Also, will regular white or yellow be good for this? Radius will be about 6" or less over the 24".

Cheers!
 
Stu,

I recommend a clean surfacing after you cut them on the BS. With a 3mm thickness you will find that a thickness planer will chew them up even if you use a backer board. The best solution for this is to put them through a drum sander. Also the 6" radius sounds a bit tight for a 24" piece @ 3mm. You may have to experiment to find the best thickness at that bend. Make sure you have clear wood as knots and such will hinder the bend in that area.

If you need you can takyubin the items down to me and I can put them through my DS.
 
Thanks Alex, I figured that the thickness planer would blow them to bits, and I also figured the DS would be the way to go, but I do not have one :rolleyes:

Thanks for the offer of help, but I do not think I'll have the time.....:huh:

Cheers!
 
whatcha buildin` stu? 1/8" thick around a 6" radius is really pushin` it!
you could get some species to bend that tight by prebending with steam, drying in the form and then gluing.....the rougher the cut the more pronounced the glueline......i just bent some 1/8" mahogany 8" wide around a starting step and it took 3 tries in the bag:eek: and i kinda know what i`m doin`?
the more laminations you have the stiffer the resulting glue-up will be, so if you`re doing over 5 plys yellow glue will not spring back much....plastic resin or epoxy won`t creap but the cells in the wood will flex still introducing springback.....for a lamination that you need to hold a predetermined radius try to introduce as much glue into the finished product as you can(more plys)......tod
 
whatcha buildin` stu?
Can't say right now ;)

1/8" thick around a 6" radius is really pushin` it!
you could get some species to bend that tight by prebending with steam, drying in the form and then gluing.....the rougher the cut the more pronounced the glueline......i just bent some 1/8" mahogany 8" wide around a starting step and it took 3 trys in the bag:eek: and i kinda know what i`m doin`?
the more laminations you have the stiffer the resulting glue-up will be, so if you`re doing over 5 plys yellow glue will not spring back much....plastic resin or epoxy won`t creap but the cells in the wood will flex still introducing springback.....for a lamination that you need to hold a predetermined radius try to introduce as much glue into the finished product as you can(more plys)......tod

OK, maybe I'll go down to less than 1/8", I can easily do 2mm on Big blue, maybe I'll try that..........? :huh:

If I get a really nice smooth cut, maybe just a little hand sanding???

I'd LOVE to buy a Drum sander, but that is not in the works right now.....

Cheers!
 
okay........next question.....how are you going to apply pressure for clamping? vacuum or male-female forms?
 
The 6" width isn't going to lend itself real well to this but you might be able to flip it over and accomplish it in two passes. But if you put the tallest sanding drum you can find in your DP then hook a single point fence to the DP table you can smooth out the lams that way. An Osc. Spindle Sander would be even better. Just run it through between the fence and spinning drum. I did some 6" radii bends with cherry on a project and experimented until deciding that 1/16" was about as thick as I could go for a bend that tight. Even then I soaked the whole lam stack in real hot water for about 1/2 hr, then pulled them out, dried them off, and clamped between the 2 form halfs for a week for some pre-bending. Glue up was done with some modified Urea Formaldehyde glue which worked nice - no creep, fairly long open time, and the color was a dark reddish brown so didn't show up against the cherry much at all.
 
Well, I don't have even a DP mounted sander either :eek:

What I'm looking at would be something like this.........

bent_lam.jpg

Two separate pieces, so I do not know the exact curves, yet. The bottom piece, before it is bent, would be about 24".

It will be a stand for my kid's flower arrangement vases to go on.....?

Dunno, I might have to do it differently.... :huh:
 
stu, bend it! just veneer the laminated sides after bending;) .....it`s a freeform art kinda thingy not a jamb extention that must fit an existing curve.....play with it and have fun! bending may be more addictive than turning:eek:
 
Well, I got my saw blades back today, so I can cut my own veneer! :thumb: :D

Not bad 9,000 yen ($75?) I got Big Blue's blade sharp, and the metal cutting blade (that thing must have 80 teeth on it) two 10" TS blades, fine and ripping cut, two SCMS blades, both fine cut, and one Festool saw blade, including shipping back to me, all for $75, not bad!

Now I can get started on the bendy stuff.....:D

Cheers!
 
With a carbide tipped blade I can get incredibly consistent lams/veneers that require no sanding or fine dimensioning after the bandsaw, straight to the form and glue. For pieces smaller than 24" long hand feeding is fine, but as the pieces get longer I hook up my power feeder to the bandsaw and the pieces look like they just came out of my planer.
 
Well Sam, I just got my good blade back from the sharp shop so I should be able to pull off some nice crisp thin pieces, I'll see how it goes!

Cheers!
 
Top