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I made a dutch tool chest out of extremely soft pine.

I was wondering if there is some penetrating finish that will harden up the outside a little bit. Obviously it won't be dent proof but maybe something that penetrates and hardens, like general finishes water based poly (high performance).

I also wanted to paint the chest. Would I paint before or after the water based poly, if the main purpose of the poly is to harden the wood a little bit?

  • a weird idea might be to either just accept the dents as patina. you could also pre-harden/burnish/compress the surface by whacking it all over with a hammer. Done well, this will result in a stippled surface texture, but the wood on the surface will actually be case hardened and subsequently harder to dent from your tools. – aaron Apr 27 '18 at 11:48
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There is a product called "Clear Penetrating Epoxy Sealant", or CPES for short. It is basically a very thin 2-part epoxy. It is typically used for stabilizing rotten wood, but it can also be used as a sealant.

I would imagine that it would harden the wood more than any other normal finish, since it is literally epoxy.

It also takes paint very well.

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I was wondering if there is some penetrating finish that will harden up the outside a little bit.

"Danish oil" and other mixed oil-and-varnish blends will do this, but you'll only get a modest improvement. One source claims it makes the surface of wood 25 or 30% harder but that has to be either a figure directly from a manufacturer or an estimate of the author. In either case expect this to vary because "Danish oil" varies significantly from brand to brand (some have more varnish in the mix and those will be harder).

Varnish will toughen the surface too in a different way because it sits on top and doesn't penetrate as much*. Thinning the varnish heavily will aid penetration only a small amount (much less than one would think) except on end grain, but it is reasonably common practice to dilute the first one or two coats and then go to straight varnish or varnish thinned only a small amount for the finishing coats so if this might help penetration even slightly there's little reason not to try. If wiping the varnish on instead of applying by brush or roller the above will occur naturally anyway.

general finishes water based poly (high performance).

That's not a penetrating finish. One of the reasons for the classic lighter colour and less enhancement of figure imparted by waterbased polys is they penetrate the surface of the wood less than their oil-based counterparts (they're said to 'wet' the wood less effectively).

Even though finishes of this type are not at all like oil-based varnish they will still harden the surface in a similar way, although usually not as much.

I also wanted to paint the chest. Would I paint before or after the water based poly, if the main purpose of the poly is to harden the wood a little bit?

Generally if you're going to paint and varnish the varnish would go on after the paint. This isn't a hard-and-fast rule though and there's no technical reason you couldn't paint over wood that has had waterbased poly applied (particularly if it's just one thin coat) and then apply one or more subsequent coats to add a protective coating to the paint.

A full, glossy varnish film would present an adhesion problem for paints in exactly the same way that they'd have difficulty sticking to glossy plastic (because that's exactly what hardened waterbased poly is, a type of plastic). But a thin coating on wood presents a surface with abundant texture, from microscopic to macroscopic, which paint should have no problems adhering to. If in doubt though, very lightly scuff or sand before painting.


*Wood in general doesn't want to allow things to penetrate, it's not really in its nature. This is why after staining it's so easy to accidentally sand through to bare wood, and that's with stains specifically made to "penetrate deeply" as the manufacturers all love to tell us! So, on face grain, the difference in penetration between a penetrating finish and oil-based varnish would actually be very small in fact, a difference of only a couple of thousandths (hundredths of a mm) at best.

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  • Thanks. I wonder if a couple layers of diluted wood glue could help harden the surface a bit? I didn't realize how ridiculously soft this pine was when I bought it but at its present level it will get deeply dented and bashed just by putting planes in. – jbord39 May 1 '17 at 16:15
  • Diluted glue has been used on wood for various purposes for a long time (called 'size' traditionally). You'll have to test to see if it'll do more than other options as far as increasing dent-resistance. Going another way entirely, would it be feasible to line the surfaces the planes will rest on with something? My first thought was hardboard, but plastic laminates (melamine or phenolic) would be even tougher and they're a lot thinner, so you'll lose less internal volume. – Graphus May 2 '17 at 7:34
  • That is a good idea. I was thinking maybe leather since I have some left over from lining the vise jaws. I also lined the edges with 3/8" thick maple so it doesn't get so beat up. – jbord39 May 2 '17 at 16:01
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Go for extra pure Tung Oil. It penetrates the pores and hardens. First coat should be thined in order to penetrate more, subsequent not thined. BR.

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  • Thinned with what? The choice is likely to be critical to the performance – Chris H May 11 '18 at 14:03

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