# How to finish cross sectional slab of big tree **URL:** \ **Category:** Factual Questions\ **Created:** [August 20, 2016, 9:51pm UTC](https://boards.straightdope.com/t/how-to-finish-cross-sectional-slab-of-big-tree/763450 "2016-08-20T21:51:47Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [August 21, 2016, 4:29pm UTC](https://boards.straightdope.com/t/how-to-finish-cross-sectional-slab-of-big-tree/763450/21 "2016-08-21T16:29:06Z")
BTW, you may want to post this question on a woodworking forum, where you’ll probably find people with a lot more experience in this type of thing than anyone here has, including me. –Mark ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [August 21, 2016, 4:41pm UTC](https://boards.straightdope.com/t/how-to-finish-cross-sectional-slab-of-big-tree/763450/22 "2016-08-21T16:41:52Z")
> [@markn\_1](#): > > Yes you can plane end grain. To be honest I haven’t done it much, but from what I’ve read, the most important thing is to have a very sharp iron in your plane. You may need to resharpen it a few times while you’re working. > > Yes, stain penetrates end grain more. When building furniture this is a frequent problem. I have a coffee table I built long ago where the edges are darker than the top because the stain penetrated more there. But in your case it’s all end grain, so that’s not an issue. And yes, the light grain will darken more than the dark grain, but normally the stain as a whole is darker than any part of the wood (especially true if it’s pine), so the overall effect is to enhance the grain. But again, I would definitely experiment on the back side. Be sure to smooth the area you’re experimenting on to match how the front will look; stain acts very different on smoothed wood vs. rough. > > If sawdust gets in the cracks, you should be able to just vacuum or blow it out, as long as it’s dry (that is, do this before you apply any finish). > > –Mark Block planes are made specifically to address end grain cleanup, but for something like a large slab, you’d spend the rest of your life at it. A very large scrub plane, like a 14" would work, but again, how much energy do you have? If I wanted to take off a lot of material, I’d use a power planer or a belt sander, as mentioned. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 21, 2016, 8:47pm UTC](https://boards.straightdope.com/t/how-to-finish-cross-sectional-slab-of-big-tree/763450/23 "2016-08-21T20:47:30Z")
> [@Quartz](#): > > True, but I was thinking about the finish, which looks so much better than a plasticised or varnished piece of wood. I agree a conspicuous layer of varnish or plastic can look pretty nasty. It’s possible to have the best of both worlds - fill the voids in with epoxy (which can be loaded with really interesting fillers such as small chips of nut shell, or soft minerals), then cut back to a smooth flat surface, and apply oil or wax as a finish on the bare wood and to add a shine to the filled parts. Here’s an example of a turned item employing that sort of effect: [https://www.etsy.com/uk/listing/215469857/spalted-wood-vase-wood-vessel-emerald?ref=related-4](https://www.etsy.com/uk/listing/215469857/spalted-wood-vase-wood-vessel-emerald?ref=related-4) (I think they actually used a wipe-on oil-polyurethane finish for that one, but there’s no reason why a more natural oil/wax/shellac finish couldn’t be used) ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [August 21, 2016, 10:27pm UTC](https://boards.straightdope.com/t/how-to-finish-cross-sectional-slab-of-big-tree/763450/24 "2016-08-21T22:27:06Z")
Ugh, that thing looks like The Green Lantern jizzed on it. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [August 21, 2016, 10:36pm UTC](https://boards.straightdope.com/t/how-to-finish-cross-sectional-slab-of-big-tree/763450/25 "2016-08-21T22:36:29Z")
A product that I used on an end table and am now using on a game table I’m refurbishing is a German product called [Osmo Polyx Hard Wax Oil](https://www.amazon.com/OSMO-Polyx-Hard-Wax-Liter/dp/B003Q9R3RA). It was created for use on floors, but woodworkers have discovered that it provides a very tough, clear finish. The product is a mixture of poly and wax. After applying a couple of coats, it can be buffed to a nice finish without having that shine to it. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [August 22, 2016, 5:06pm UTC](https://boards.straightdope.com/t/how-to-finish-cross-sectional-slab-of-big-tree/763450/26 "2016-08-22T17:06:52Z")
> [@friedo](#): > > Ugh, that thing looks like The Green Lantern jizzed on it. To each his own - the alternatives for that piece of wood are: [ul] [li]Turn something smaller, discarding the voids[/li][li]Try to fill it with something that looks more natural (which often fails due to uncanny valley)[/li][li]Leave holes (which is OK in gallery contexts, but in the home, quickly traps dirt and fluff, then looks horrible)[/li][/ul] I quite like the look - it looks like a vein of malachite in rock, except it’s not rock - a juxtaposition I find quite pleasing. ---
**Author:** ![awldune](https://avatars.discourse-cdn.com/v4/letter/a/c77e96/32.png) [@awldune](https://boards.straightdope.com/u/awldune)\ **Post date:** [August 23, 2016, 3:54pm UTC](https://boards.straightdope.com/t/how-to-finish-cross-sectional-slab-of-big-tree/763450/27 "2016-08-23T15:54:29Z")
Do you care whether the face is flat? The only practical way to get it flat is to use a router sled. If you already own a router it is very easy to make a sled. Used routers can be found for very cheap. Certainly the quick and dirty way to do it is to get a belt sander and work from very coarse to finer grit belts. This is more appealing if you already have a belt sander. If you will keep the piece outside and/or in the sunlight, that makes a difference in what finish you would want to apply. ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [August 23, 2016, 5:49pm UTC](https://boards.straightdope.com/t/how-to-finish-cross-sectional-slab-of-big-tree/763450/28 "2016-08-23T17:49:06Z")
[QUOTE=friedo] Ugh, that thing looks like The Green Lantern jizzed on it. [/QUOTE] So maybe it would look better if they used blue? It’s probably less vivid in real life. I’ve got a few pieces in this style and they’re rather subtle in comparison. Regardless of your preferences, it’s a classic Japanese philosophy of embracing imperfection. Overall, it’s called wabi-sabi, and the technique, perhaps more commonly applied to things that were intact but got broken such as pottery, is kintsukuroi. ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [August 27, 2016, 7:09pm UTC](https://boards.straightdope.com/t/how-to-finish-cross-sectional-slab-of-big-tree/763450/29 "2016-08-27T19:09:21Z")
I don’t care if it’s flat. Though, the comments on this are welcome; we are also writing for the ages, after all. I got a dozen sanding belts in 36 grit, which is about as rough as falling off a motorcycle. These are 3" by 21" for my Craftsman belt sander that I bought about 33 years ago\*. And I just spent a good hour or so sanding away. I’m pleased with the result. I actually got all the individual marks out of the wood, all the tracks and divots and mountain ranges made by the chain saw. The piece is not flat, it’s still dished by around an inch. Since it probably weighs 40 lbs, is around 4" thick, and I’d have to remove a total of about an inch of wood (weighted toward the center on one face and the edge on the other face), I think I would have to sand away about 10 lbs of wood to fix the dishing, whereas I’d say I had about 1 lb of sawdust after my hour, so sanding it flat with a handheld belt sander sounds pretty difficult. The sanding is fairly easy but still takes a bit of effort to control. It seems like the platen is so small relative to how distant the handles are from it, so it’s too easy to lean the thing one way or the other and dig in on an edge. I’m sanding with this slab leaning a few inches from vertical, and the thrust of the sander counteracting its weight. I think it would work better if I got the slab more like 45 degrees, or even closer to horizontal. The main crack is getting bigger. This thing has been cut for about 4 years, but apparently my finished basement (w dehumidification) is different from the previous environment. It’s more like 3/4" now. I don’t much mind. After all this sanding, the smaller checks are less visible and I guess may not have run very deep at all. I guess this is pine. Sanding it makes a smell like sandalwood. Since it supposedly came from only 3 or so miles up the road I may drive over there and try to find the stump or a stand of trees with similar bark, so I can ID it. I made two good efforts to count rings, though the contrast is still poor and I’ve only sanded at 36 grit so far. It looks like 100 rings but I could be off by 10 or even 20. I think it likelier that I missed rings than that I double counted them. I read in the Wiki article on Dendrochronology that some kinds of trees can have more than one ring in the same year, but I don’t know what kinds those would be. \*Any Dopers who want to entice me into ordering a very nice sounding Porter-Cable 4" by 24" belt sander for about $250 on Amazon should probably know I am very close to falling into exactly that trap. [Previous page](https://boards.straightdope.com/t/how-to-finish-cross-sectional-slab-of-big-tree/763450.md?page=1)