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I'm planning on making a heavy bench top by using six 4"x4"x6' posts, and gluing the faces together with Elmer brand carpenters glue and several large bar/trigger clamps. Afterwards, I'll just manually plane the top and bottom of the board to smooth it out and remove the excess glue.

For the support posts and the bench top, is there a specific type of sealer I should apply that won't compromise the glue's bond? I am installing this in the garage in a humid area, so I'm using a 1" raised post base to keep it off the ground in case of spills:

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And then I will be connecting the top half of the support 4x4 posts to the bench top with adjustable deck support brackets so that I can perfectly level the desk in case the top is flat but at an angle, or if the posts aren't cut to the same lengths:

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I am also concerned about the sealer causing an interaction with or oxidation of the metal parts.

How should I proceed choosing a sealant/stain? For what it's worth, would tung oil be a good choice?

Thank you.

  • Personally, I would screw a couple of layers of heavy duty plywood together instead of using 4x4 posts for a worktop. I would take 2 layers of 3/4" CDX plywood (outdoor rated) and glue them together with construction adhesive, and screw them with coated deck screws. Then I would take one more sheet of top grade plywood that has a veneered surface and glue that to the top of the base. In the end, you will have a bench surface that is strong enough to support a small car. It would definitely be stronger than gluing posts together. – Jason Hutchinson Nov 25 '15 at 15:12
  • @JasonHutchinson Are there any glues that would work specifically with cedar posts? I want to have a very thick workbench surface as I'll be attacking a drill press and CNC machine. I'd imagine that with the two-layer plywood solution you noted, it wouldn't be thick enough to prevent "wobble". Also, I want to avoid putting screws in the bench all over the place. – Cloud Nov 25 '15 at 15:44
  • I actually had 3 layers of plywood in my solution. 2 layers of thick plywood for the core, and then an additional top layer. The top layer would just be glued on, and the base layers will be glued and screwed together. You can stiffen the whole thing even further by adding 2/4 bracing around the perimeter on the bottom, and also a few cross members in the middle. When you put the bracing in, you want to lay the boards on the flat side instead of being vertical. Then you would use lag screws to bolt on the legs. If you follow that plan, the top will be around 3 1/2" thick. – Jason Hutchinson Nov 25 '15 at 16:05
  • @JasonHutchinson One detail I forgot to mention: I am planning on installing a woodworking vise, and I am concern that installing screws into the sides of plywood wouldn't have enough support. Would the plywood be adequate for this task? – Cloud Nov 25 '15 at 16:51
  • You could use a tail vise like this: lumberjocks.com/assets/pictures/projects/… Here is a tutorial on how to build one: paulsellers.com/2012/06/making-the-workbench-16 Notice how there are holes in the top of the work bench. Those are to accommodate pegs called bench dogs. Bench dogs are used to clamp pieces of wood so you can plane them, etc. without the vise getting in the way. An example of this is in action is here: ps-5e0.kxcdn.com/wp-content/uploads/sites/2/2012/06/… – Jason Hutchinson Nov 25 '15 at 17:48
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I'd go to the manufacturer of the wood glue you want to use before you get too far along. Titebond is popular and I've had great luck with it, in their FAQ they have specific instructions for gluing up cedar, before you finish it, due to the oil in cedar.

I think most of them are pretty oil resistant once they cure, especially polyurethane, which is pretty much impervious to everything, which is why it's awful to get on your hands. Cleans off like a tattoo. But polyurethane is a mess to work with, and where it gets on the work surface, you're going to have to sand it off, and it may soak in a ways. No stain or sealer will get past the polyurethane.

Tung oil is very good stuff. I worked for a contractor years ago that did a lot of cedar decks. He liked a mix of turpentine and boiled linseed oil, which was considered old school even back then. Tung oil seems to harden a lot better than linseed oil. I'd prefer it over polyurethane for a work bench. I wouldn't stain a work bench.

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application for your bench is the driver here. topcoats like urethanes or latexes work great as sealers from water, but they are soft and flexible. probably good since cedar is so soft and will deform under load. they do mechanically protect the substrate by acting as a sacrificial element. penetrating sealers like thompsons water seal or tung oil work by getting deep into the wood and staying put even if there is deformation of the substrate. they offer no mechanical advantage as a coating and generally need to be re-applied annually. lacquers, epoxies and enamels are the hardest, but they fracture under deformation, thus admitting more moisture or other materials. I think that since you are using cedar, which is naturally very porous, and will become more so over time as it micro-tears with expansion and contraction, you want something easy to recoat. use thompsons. its a far better sealer than tung oil. tung oil went out of style long ago because it sucks. its just very hipster to think its a good choice. don't fall for the marketing.

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