Tough Exterior Finish For Plywood?

[lupinsea]

Are there any recommendations for a good exterior finish for plywood?

Preferably clear-coat.
And something that doesn't show scratches easily.

I'm building a chuck box out of some good quality 1/2" ACX fir plywood and would like to possibly clear coat it. However, I'd love to get a pretty tough finish on it. I've tried some SPAR varnish on a past project. And I've used some Sikken's Window and Door finish. Both of which give a nice coloration and finish but they are also somewhat "soft" and can scratch easily.

The chuck box will be stored in an unheated garage / shed. And of course it'll be set up at the camp site. I don't anticipate letting it get dumped on out in the rain but if it's left set up overnight and it gets a bit of dew on it or there's an over-night rain storm it'll need to hold up to that.

Someone suggested some Penofin or some kind of penetrating oil instead of a varnish finish.

Any thoughts on this?

 

[RHINO]

yeah prolly an oil is best, that way the wood is sealed and treated and you can reapply as needed with out stripping the old finish off, just a light sanding. if you use an oil any will work, even olive oil, i use boiled linseed.

the other option would be a clear epoxy, its tougher than the other clear finishes but all of them will scratch.

 

[4xdog]

There was a longish thread on exactly this a year or so ago. My search **** is not strong. I can't run it down. Maybe someone else will remember.

Don

 

[PaulJensen]

Resin Research Epoxy...

Non Yellowing...

Easy to use compared with every other epoxy...

 

[lupinsea]

Sweet. There is a Rockler not far from my office. I might drop in and see what they have.

Also, it sounds like the oil might be the way to go . . . or the oil / poly mix. I like the idea of the oil but it would be nice to find something that would toughen up the wood with out having a large amount of build up of a semi-soft coating like a varnish. I realize there is only so much I can do with a soft wood fir ply construction.

Thanks guys.

I'll look into the resin, too.

 

[lupinsea]

Ok.

Poking around the Rockler website I'm seeing things such as butcher block oil and a "salad bowl oil" not to mention other things such as wood floor finishes.

These also sound intriguing. Especially the salad bowl finish, in part since it's non-toxi. . . not that I'll be smearing food all over the chuck box.

Oh, and this may be silly but . . . should I worry about any of the penetrating oil causing any problems with the Titebond III glue I've used to build the chuck box?

And . . . I'm considering backing up the piano hinge screws with a bit of gorilla glue. Would there be any problem with the penetrating oils affecting the glue bonds? Note, I figure I'd glue / bond everything first, then put whatever finish I wanted on second since I assume glue won't bond to an oiled / finish surface.

 

[Haggis]

Great post Squatchout! Tung oil would be my choice too, just remember to add touch up coats when the shine starts to fade or if water stops beading on the finish.

Don't use linseed oil. It turns black with age and UV exposure.

I hate linseed oil and heavy linseed oil stains. They do just as you say and turn black over time and provide no UV protection at all. As a log home restorer I can tell you that the homes with the most damage are those that have a linseed oil coating. Plus linseed oil never truly cures, stays gummy in the coatings interior and is a bear to remove. Here's a shot of a linseed coated home that was only 6 years old, you can see the difference from the corn cob blasted section as I was removing that nasty stuff.

 

[lupinsea]

Wow, Squatchout, the table looks great and I'm digg'n your tool box. It's nicely dinged up, if you don't mind me saying.

My theory is that no matter what finish I put on the chuck box will get dinged, dented, scratched, and dirtied over it's life as it gets used regardless of how tough the finish. I don't want to abuse the thing but it's a piece of camping equipment that'll get hauled in and out of vehicles, stored in my shed, and then set up at campsites which will probably mean it'll get set on the ground. So given that, I'd rather have a finish that doesn't show said scratches and blemishes as well and is then also easy to "repair".

The tung oil sounds like a good way to go, too.

And don't worry, I'll post up pix when I'm finish with the chuck box. Probably in it's own thread but I can link to that thread here.

Last night I got everything sanded down. I also got the recesses for the piano hinges routered in (so they'll be flush with the top of the plywood). And a door attached (counter sunk machines screws with t-nut threaded inserts instead of wood screws). It's looking pretty good so far but there is only so much that can be done with ACX plywood. I'm just trying to keep the joints tight and even.

 

[lupinsea]

Cool. Thanks. I've never used tung oil before so I'm very unfamiliar with it.

I have used a Spar varnish on the cargo deck and it didn't last longer than the first item I set on the cargo deck before it scratched up like you wouldn't believe. I sort of wish I had topped the cargo deck with a piece of plastic laminate (like Formica counter top surface) but oh well. I do know I'd like to steer clear of a varnish or other build-up coating that is soft and easily scratchable.

Say, does the tung oil harden the wood fibers at all? Would you suggest I put down a sealer or some other product that would do that before the tung oil?

Oh, and it's hard not to post some preliminary pix of the chuck box. I'm really jazzed about how this is coming together.

The basic chuck box and base is now assembled. Doors are on and the flip top panels are on, too. I still need to source the latches to keep the doors closed and finish the wood. . . I'm leaning towards tung oil unless someone has other suggestions.

I've been salting the forums here with a enough pix and I was not going to post any more pictures until the project is done and I do a write-up but . . . I can't help posting these progress photos:

I was playing around with this after I got it screwed together. It takes about
15 second get it set up and ready for use. Very smooth and easy.

Here it is next to the cargo deck table. As you can see, both the
chuck box and table are the same height.

Not too bad. . . 6 1/2 ft of stable, usable kitchen counter top
space when out camping.

Finally, all folded up and in its position on the cargo deck. Note, the cargo
deck sits between the wheel wells in the back of the Jeep. While this is
perhaps a little bulkier than I would have liked it's not too bad.​

 

[Papa]

That is very clever and nicely executed.

 

[whitewatersully]

That is a great design and excellent work. Where did you find the design or did you come up with the design and if so would you be willing to share?

 

[lupinsea]

Thanks for the extra info on the tung oil, Squatchout.

Whitewatersully: it's my own design. Once I'm finished with the project in a few weeks I'll be putting together a plan set and cut layout documents. There has been enough interest here on ExPo that I think it makes sense.