Bench Top Lamination Question

Re: Bench Top Lamination Question

Scott Post

>There's nothing wrong with face gluing to get the thickness you want but there's no good way to clamp the two layers to get intimate contact without something like a veneer press. The only reasonable way to face glue the boards would be to do it one plank at a time then edge join those to get the width.

Personally, I'd rip the boards to the thickness you want for the bench top and turn them on edge. I'm guessing that the majority of your boards are flatsawn so turning them on edge puts the quartersawn edge up and will be a bit more stable. Yes, that will leave you with a lot of glue ups but it's really not as bad as you're thinking. Do it in 4 sections of 6" each first. This way you're only dealing with 6 boards per glue up. Next combine them into two 1' sections. This will allow you to pass them through a lunchbox planer to do some cleanup before the final glue up if you're so inclined.

Two hints. Use a cheap foam roller to spread the glue. This will significantly speed things up. Also, like any panel glue up I always take a couple hand plane swipes on the show face and mark which direction you can plane most easily without tearout. When you glue boards together make sure your marks are all going in the same direction. It wouldn't be much fun leveling a benchtop with the grain changing direction every inch.

Re: Bench Top Lamination Question

Jack from Maine

>I totally agree with Scott. I built mine with 1 1/2" wide laminations so it was a little easier than yours. It was intimidating at first but not really difficult in practice. Use alot of clamps and alternate them one over and one under.Wally world sells a cheap throwaway 3" roller with a built-in plastic tray. I used that for mine and it worked great.I didn't pay too close attention to grain direction and I'm very sorry for it. My benchtop has become a test field for plane tearout.Have fun.---Crackerjack

Great advice (plus some gluing stuff)

Adam Cherubini, NJ

>I too agree with Scott. I glued up one board a night for a month to build my bench. I didn't feel this was unreasonable. Here's why:

Franklin, the manufacturer of Tite Bond II recommends at least 150 psi of clamp pressure to develop bond strength. That's a lot of pressure. So I think you want a lot of clamps. I used 8 over 6' and I concentrated them at the ends where I felt I most needed bond strength. I was worried about controlling where the pressure was going (and alignment). That's why I did one board at a time. Really saved on planing too.

For face gluing, I don't think you'd ever get that pressure (150psi). Traditional veneer presses or veneer operations weren't designed to do what you are doing since hide glue requires no pressure to develop bond strength. In fact, you want the opposite with hide glue- a reasonably thick and guaranteed bondline thickness (thus the old belief that rough surfaces adhere better- the rough sawn cheeks of a tenon, for example, maintained the bondline thickness.

The ramifications of this go pretty deep, BTW. In general, woodworkers seem to be using the wrong glues for the wrong jobs. You should never use PVA where you can't produce excessive amounts of clamp pressure (M&T, dovetails). You should never use hide glue when you want an imperceptible bondline or you have a really tight fit.

Re: Bench Top Lamination Question

Chuck Taylor

>I see you are in British Columbia. Starting with one Douglas Fir 4x12 by 12 feet, make one crosscut and one glue joint and you have a 24" by 6' top, 4" thick. Save your maple for skirts and end caps. I've noticed in the local lumberyards that for Douglas Fir, the larger the timber, the better quality the wood (from bigger trees).

Chuck Taylor

Everett, WA, USA

Re: Great advice (plus some gluing stuff)

Adam Cherubini, NJ

>My subject line "great advice" referred to Scott's advice. I just wrote to agree with Scott when I hijacked my own post with that glue stuff. Didn't mean to suggest I was providing "great advice".

Sorry if I looked self absorbed there.

Adam

Re: Great advice (plus some gluing stuff)

Mike L. in SoCal

>150psi? I never imagined that much pressure was optimal. That equals 50,400 pounds total pressure for gluing up my tuba-four benchtop. Yowza! I suspect I didn't provide quite that much. What about glue squeeze out at that pressure? Isn't that a concern?

Cheers,

Mike

Great post, Adam (and Scott too)

Wiley Horne--Glendora CA

>Really appreciate it. Both on the 150 psi for PVA, and low pressure/defined bond line for hide glue. Gonna switch to hide glue for tenons, due to this post.

Wiley

Re: Great advice (plus some gluing stuff)

paul womack

>You should never use hide glue when you want an imperceptible bondline

But... AFAIK luthiers doing matched plates for guitars always used hide glue, and aimed for invisible glue lines.

On a second note, is it better to add one board at a time to a growing benchtop, or to build by doubling, e.g. glue 2 boards into 1 beam, 1 beams into 1 mini-top, and so in?

And how to you avoid building in a wind?

BugBear

(who laminated a curve into his triple ply benchtop, and wishes he hadn't)

Re: warp

paul womack

>Starting with one Douglas Fir 4x12 by 12 feet, make one crosscut and one glue joint and you have a 24" by 6' top, 4" thick.

One of the reasons for lainating a benchtop is to allow the individual pieces to be alternated, curve-up, curve-down. The resulting benchtop can then only develop minor "ripples" under humidity changes, as opposed to the supposed ultimate one-piece slab top, which can warp like a pretzel.

BugBear

Tnks, all. Good advice. Progress reports as & when

Garrett in Victoria BC CA

>

Don't do it

Russell Seaton

>I built a red oak bench by gluing 31 strips of 4/4 S4S material together. About 2.5" thick. I don't recall how many I glued together at a time and how much clamp pressure I used. But I had lots of clamps and probably used most of them. Particularly the big C clamps and Pony pipe clamps and Record style C clamps. I think I ruined a few of the Records by putting too much force on the clamps and twisting the steel. In the last 8 or 9 years the top has not come unglued so I must have used sufficient pressure.

I used yellow glue. Don't recall exactly how I spread the glue. Probably with a scrap board. I do recall gluing them into 3 8" wide sections. Running them through the lunchbox planer to get them sort of flat or something. Then gluing them together into one slab. Then using a jack plane and belt sander to flatten it but I really didn't flatten it. And just recently using a jack and jointer and card scraper to really flatten it.

I also used a double row of biscuits between each board. Ostensibly for alignment of the top edge.

After all that work, I'd suggest just buying a quality benchtop from Woodcraft or Lee Valley or Grizzly or someone else and then attaching your vises to this slab and building a nice base.

Re: roller aside (almost a hijack)

William Duffield on the Cohansey

>A really cheap 9" foam roller and a bandsaw (or your WMD of choice) results in really really cheap 3" rollers. The thinner the foam, the better they work, because you waste less glue gluing a roller to itself. For PVA, I find that thinning the glue with a little water helps when applying with a roller. I put the glue in a bread pan and mist it with a spray bottle. At the end of the session, the roller gets thrown in the bucket along with the glue rag and the acid brush. Sometimes, I can reuse the roller.

great tip

Jack from Maine

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