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Biscuits, cauls or both?

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Forum topic by Andybb posted 11-18-2020 01:34 AM 778 views 0 times favorited 17 replies Add to Favorites Watch
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Andybb

3164 posts in 1612 days


11-18-2020 01:34 AM

Topic tags/keywords: walnut joining modern

Gonna be doing a 72×44 table glue-up with five 8/4 Walnut boards. I was planning on using biscuits for alignment with the top side down so they are guaranteed to darn near be flush. I also saw a Stumpy vid where he made some curved cauls but he wasn’t using biscuits. So.. overkill?...cauls, biscuits, or both.

When using cauls do you taper the caul for just the top or both sides? If need be I’ll take the whole thing to the mill to have it planed/sanded but I’d like to see just how close I can get it.

As always, thanks in advance.

-- Andy - Seattle USA


17 replies so far

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Loren

11019 posts in 4657 days


#1 posted 11-18-2020 01:40 AM

Overkill, imo. But you have to make or buy the cauls.

I find dowels more reliable than biscuits for flush alignment but more of a pain to drill correctly. I would use the thickest biscuits for alignment, skipping the glue if they fit tight without. You can hydrate or dehydrate biscuits with a sponge or toaster over, etc.

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CWWoodworking

1497 posts in 1188 days


#2 posted 11-18-2020 01:48 AM

I don’t use cauls or biscuits, top up. Like to start in the middle and work my way out.

With a top like that, I’d take it to my supplier for sanding.

If I had to sand it in house, I would glue it up, cut in half, sand, glue back together.

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Foghorn

1036 posts in 395 days


#3 posted 11-18-2020 01:59 AM

I have a Porter Cable biscuit jointer I bought back in the Norm days. I think I’ve used it once. Relegated to a back shelf as I really don’t see the value in it for much. Anyone want to buy it cheap? :)

-- Darrel

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Madmark2

2300 posts in 1597 days


#4 posted 11-18-2020 02:00 AM

Both. Biscuits help keep things from slipping too much – more than about 1/16”. For a tighter alignment cauls can reduce the level shift to essentially zero.

Biscuits are great for preventing the entire join from slipping if you over tighten the edges.

Cauls should always be used for three or more piece glue ups. I use them on simple two piece glue ups as well.

-- The hump with the stump and the pump!

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Andybb

3164 posts in 1612 days


#5 posted 11-18-2020 03:02 AM

Ding ding ding…..Loren, .Madmark2 & CW. All easy to do with 0 cost. I have probably the same biscuit joiner that foghorn has that I’ve used once I think in 20 years. I have some scrap 4’ 2×6 that can easily be ripped into cauls.

With a top like that, I’d take it to my supplier for sanding.

If I had to sand it in house, I would glue it up, cut in half, sand, glue back together.

- CWWoodworking

+1 on taking it to the mill for sanding. If I get this to glue up well, ain’t no way I’m gonna cut it in half! :-)


Overkill, imo. But you have to make or buy the cauls.

I find dowels more reliable than biscuits for flush alignment but more of a pain to drill correctly. I would use the thickest biscuits for alignment, skipping the glue if they fit tight without. You can hydrate or dehydrate biscuits with a sponge or toaster over, etc.

- Loren

Not so much overkill but safety factor/insurance policy. Good point about the dowels. They can be tricky but I just remembered that I do have a Beadlock dowel jig that I use once every 5 years that would be perfect for this!.

-- Andy - Seattle USA

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Rich

6531 posts in 1598 days


#6 posted 11-18-2020 03:53 AM

First of all, the idea behind biscuits is that the glue swells them. My first biscuit joiner was the Porter Cable 555—probably the same one you and Foghorn are talking about—that I bought probably back in the late ‘80s or early ‘90s. I sold it years ago when the 557 came out.

The notion of wetting them with a sponge is unheard of. But hey, I’ve only been using one for 30+ years, so what do I know?

Glue your biscuits. The only thing cauls would do for you is flatten the piece if your edge angles don’t add up to 180º. To prevent that, I always run my boards over the jointer with one face towards the fence, and the other away. That way, if your jointer is off, say 89º, then the mating board will be 91º and it will come together perfectly flat.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

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CWWoodworking

1497 posts in 1188 days


#7 posted 11-18-2020 03:56 AM

At 44” it’s wider than my sander. Wider than a lot of people’s sanders. That’s why I would cut it in half.

In my opinion, you get to the ultimate goal of 44” easier this way. It’s easier to get 2 halves(that were once one board) to line up, than 5 boards.

Of course the best option is to run it through a 3 head 52” wide belt.

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CWWoodworking

1497 posts in 1188 days


#8 posted 11-18-2020 04:01 AM



First of all, the idea behind biscuits is that the glue swells them. My first biscuit joiner was the Porter Cable 555—probably the same one you and Foghorn are talking about—that I bought probably back in the late 80s or early 90s. I sold it years ago when the 557 came out.

The notion of wetting them with a sponge is unheard of. But hey, I ve only been using one for 30+ years, so what do I know?

Glue your biscuits. The only thing cauls would do for you is flatten the piece if your edge angles don t add up to 180º. To prevent that, I always run my boards over the jointer with one face towards the fence, and the other away. That way, if your jointer is off, say 89º, then the mating board will be 91º and it will come together perfectly flat.

- Rich

I agree. Why set my glue bottle down to wet the biscuit with a sponge when I could just use glue as intended? It doesn’t make sense. I wouldn’t bother with the biscuits in the first place though. Get flatter boards.

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pottz

14824 posts in 1993 days


#9 posted 11-18-2020 04:34 AM



First of all, the idea behind biscuits is that the glue swells them. My first biscuit joiner was the Porter Cable 555—probably the same one you and Foghorn are talking about—that I bought probably back in the late 80s or early 90s. I sold it years ago when the 557 came out.

The notion of wetting them with a sponge is unheard of. But hey, I ve only been using one for 30+ years, so what do I know?

Glue your biscuits. The only thing cauls would do for you is flatten the piece if your edge angles don t add up to 180º. To prevent that, I always run my boards over the jointer with one face towards the fence, and the other away. That way, if your jointer is off, say 89º, then the mating board will be 91º and it will come together perfectly flat.

- Rich


+1 this is exactly what i do,i love the bisquit joiner and use it often,just never understood why so many put it down.

-- working with my hands is a joy,it gives me a sense of fulfillment,somthing so many seek and so few find.-SAM MALOOF.

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Andybb

3164 posts in 1612 days


#10 posted 11-18-2020 06:47 AM

Well, for me, if that’s what Rich and the Beagle do then that’s what I’m doin’.

OK. As always, thanks for sobering me up. Overbuild = Overkill. Gotta stop doing that.

Yes. Biscuits swell. That’s how they work. As Rich said, no need for cauls, ESPECIALLY since I plan on taking it to the mill for surfacing. Although, I am anxious to see how my Bosch dual-mode sander does on it before I take it in.

Have watched quite a few ways to do glue-ups that I hadn’t seen before.

-- Andy - Seattle USA

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AlaskaGuy

6398 posts in 3318 days


#11 posted 11-18-2020 08:41 AM

I’m surprised you old time biscuit users aren’t aware of the “Lamello Clamping Plates K20”. I haven’t used any in quite a while now because I bought a domino.

The Lamello Clamping Plates K20 are plastic biscuits that are thicker than the standard compressed biscuits. They fit the biscuit slot fairly snugly. They have little directional checkering on them so once inserted into the slot they are fairly hard to pullout(no glue required). These would be good for alignment because the fit the slots snugly. They will be as accurate and the slots you can make with you biscuit jointer.

I have a few of these out in the shop somewhere. I’ll go out to the shop tomorrow and a photo.

https://youtu.be/Y1MzEw3xY4s

Good stock prep with be your best friend. Flat straight square stock.

All that being said. I don’t normally use anything for alignment on my panel glues ups. But then I don’t usually make glue up that large. I’d probably glue that up in 3 sections and the glue the sections together.

-- Alaskan's for Global warming!

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Robert

4440 posts in 2489 days


#12 posted 11-18-2020 12:21 PM

Good stock prep with be your best friend. Flat straight square stock

Way more important than anything else especially 8/4 boards.

-- Everything is a prototype thats why its one of a kind!!

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Jim Jakosh

25924 posts in 4114 days


#13 posted 11-18-2020 01:37 PM

Hi Andy,
It has probably been taken for granted here but the first thing is to be sure the edges are dead straight and the faces are square or at the same angle and flipped to have them mate fully when clamped. On pieces that big you would never pull out a gap with a clamp.

I use biscuits and I glue them in but when we had a seminar from Franklin Glue, Bob Benneke said you did not need to glue them in, they just hold alignment when the boards are pulled together. Cauls are extra but I have never needed them with biscuits

Without biscuits, I would for sure use cauls or they will slip up and down when they are wet with glue

I read you post again and said that Stumpy used curved cauls and NO biscuits. I see the logic in that because when clamping the curved caul on the sides you insure pressure in the center when the clamp won’t reach

I agree to take that top to a wide belt sander to make it right after gluing.

Cheers, Jim

-- Jim Jakosh.....Practical Wood Products...........Learn something new every day!! Variety is the Spice of Life!!

View pottz's profile

pottz

14824 posts in 1993 days


#14 posted 11-18-2020 02:35 PM



Well, for me, if that s what Rich and the Beagle do then that s what I m doin .

OK. As always, thanks for sobering me up. Overbuild = Overkill. Gotta stop doing that.

Yes. Biscuits swell. That s how they work. As Rich said, no need for cauls, ESPECIALLY since I plan on taking it to the mill for surfacing. Although, I am anxious to see how my Bosch dual-mode sander does on it before I take it in.

Have watched quite a few ways to do glue-ups that I hadn t seen before.

- Andybb


i havn’t really had much time using that sander yet but the tests i did with it,it kicked ass.

-- working with my hands is a joy,it gives me a sense of fulfillment,somthing so many seek and so few find.-SAM MALOOF.

View pottz's profile

pottz

14824 posts in 1993 days


#15 posted 11-18-2020 02:40 PM



I m surprised you old time biscuit users aren t aware of the “Lamello Clamping Plates K20”. I haven t used any in quite a while now because I bought a domino.

The Lamello Clamping Plates K20 are plastic biscuits that are thicker than the standard compressed biscuits. They fit the biscuit slot fairly snugly. They have little directional checkering on them so once inserted into the slot they are fairly hard to pullout(no glue required). These would be good for alignment because the fit the slots snugly. They will be as accurate and the slots you can make with you biscuit jointer.

I have a few of these out in the shop somewhere. I ll go out to the shop tomorrow and a photo.

https://youtu.be/Y1MzEw3xY4s

Good stock prep with be your best friend. Flat straight square stock.

All that being said. I don t normally use anything for alignment on my panel glues ups. But then I don t usually make glue up that large. I d probably glue that up in 3 sections and the glue the sections together.

- AlaskaGuy


I m surprised you old time biscuit users aren t aware of the “Lamello Clamping Plates K20”. I haven t used any in quite a while now because I bought a domino.

The Lamello Clamping Plates K20 are plastic biscuits that are thicker than the standard compressed biscuits. They fit the biscuit slot fairly snugly. They have little directional checkering on them so once inserted into the slot they are fairly hard to pullout(no glue required). These would be good for alignment because the fit the slots snugly. They will be as accurate and the slots you can make with you biscuit jointer.

I have a few of these out in the shop somewhere. I ll go out to the shop tomorrow and a photo.

https://youtu.be/Y1MzEw3xY4s

Good stock prep with be your best friend. Flat straight square stock.

All that being said. I don t normally use anything for alignment on my panel glues ups. But then I don t usually make glue up that large. I d probably glue that up in 3 sections and the glue the sections together.

- AlaskaGuy


i have seen those before and always wanted to try some,would be great for hard to clamp situations.

-- working with my hands is a joy,it gives me a sense of fulfillment,somthing so many seek and so few find.-SAM MALOOF.

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