Cauls or vacuum press?

[Mark Gibney]

I want to glue two 3/4" thick glue-ups together to make a table top (36" x 86" each).

Can I use a lot of cauls and get a good tight glue line or do I need a vacuum press?

[Mike Ontko]

p.s. - I should have started this reply with the disclaimer: I'm no expert, but...

The point of the vacuum press is to apply even pressure over the entire surface area so there are no voids left beneath the material being glued. I think the issue of not having any voids beneath the material is only critical when that material is thin--like a veneer--and susceptible to lifting away from the substrate, creating obvious bubbles, wrinkles, or instabilities in the surface. If the top layer that you're gluing on to your substrate material is thick (3/4" in this case), then using multiple cauls should be sufficient to get an even and well distributed pressure across the majority of the surface area. And, because your material is thicker, it will be able to distribute some of the force applied directly from the cauls to other areas that are not directly beneath the cauls. There may be some real math heads who could calculate an optimum caul size and spacing, but I'd go with the same reasoning as clamping--the more you can get on there the better!

[Mark Gibney]

Thanks Mike, it's tempting to just clamp it with cauls. I have everything I need and could just go do it, always nice.

[Mike Henderson]

Cauls should work fine. A vacuum bag is nice and will do a great job but getting your work into the bag can be difficult without a helper.

I would certainly not buy a vacuum bag and pump just for that project.

Mike

[Gerry Grzadzinski]

I would first glue your 3/4" boards together into 1-1/2" boards, and then glue them together for your table top. Much easier.

[Bill Orbine]

Have you thought about using 8/4 lumber? Otherwise, clamps and cauls will work fine if you haven't invested in a vacuum press.

[Chris Padilla]

Here is the fun part about getting a vacuum press: Using cool exotic veneers!!!! So if you need an excuse, there ya go!! It really does open up a whole world of cool projects!

But if that doesn't interest you so much, clamps and cauls galore will get the job done fine. Get a helper. Use a large paint roller with a super low nap to get the glue spread on both pieces FAST. TB-III has the longest open time of the 3 TB glues. Get the clamping strategy down before you open the glue! Once the glue is poured on, you have to move pretty decently.

[Mark Gibney]

Thanks everyone. I'm about to do the first glue up using the cauls I have.

If it turns out badly - I know who you are...

To Chris Padilla - I like to use Gorilla Glue for this kind of glue up where I need a long open time.

To Gerry and Bill - I had all the 4/4 lumber, and I've already made the two "layers" of this table, so I'm ready to go. I will bevel the underneath of the table from the glue line of the two layers, so that disguises that fact. I also feel it makes a stronger, more stable table top over using 10/4 or 8/4 lumber, as any weakness are spread around. More work, so that's what I'm telling myself.

[Chris Padilla]

Nice...poly glue works well and I agree. I hadn't thought about it having a long open time but you are correct!

You can still spread it with a roller but plan to toss the roller or clean it with acetone when done. Wear gloves or your hands will be a dark brown everywhere...but you likely know all this.

As to finding us...I don't see YOUR location...sneaky sneaky.... LOL! :D