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I was originally going to use spray lacquer for my speaker cabinets which are essentially large cubes. However, I've switched to brush on Poly. Is it possible for me to apply the poly on the vertical surfaces? If not, when will the poly be dry enough for me to turn the box so the poly surface will be vertical.

Example: Perhaps 1 side wait 30 minutes, turn and do another side? At some point with that method, I'll need to rest the box on a poly'd side, how long would that side need to cure before resting the box on it's side while the newly poly'd side dries?

  • You don't need to finish all six sides, so you don't need to mess with painter's pyramids or anything of that kind — these are largely intended for surfaces that aren't critical (e.g. the underside of a shelf) which is very much not the case here. All you need to do is sit the box on its base (raised on blocks if needed) and start varnishing. As usual my recommendation is to convert your varnish to wiping varnish by thinning, see this previous Answer for a complete intro. – Graphus Aug 27 '18 at 18:25
  • agreed. I'm finishing 5 sides. But I would need to apply it vertically and I'm wondering if the water based brush poly will allow for that. Perhaps thin coats? – tjcinnamon Aug 27 '18 at 18:37
  • Yes of course you can apply the waterbased poly on a vertical surface — otherwise it couldn't be used on table legs, the side of a bookshelf etc. ;-) BTW if you're asking any more Questions where you refer to a finish please be more specific, "brush on poly" doesn't tell us the exact product and I (and I'm sure a few others) assumed you meant oil-based polyurethane varnish as this is what we generically refer to as 'poly', and the two types of finish aren't commonly applied the same ways. – Graphus Aug 28 '18 at 15:15
  • Makes sense. This is going over Danish oil. – tjcinnamon Aug 28 '18 at 15:39
  • Are you adding a film finish over the oiled wood primarily to increase the gloss or to add protection? "Danish oil" alone is a perfectly acceptable finish for many things, including side tables, certain boxes and decorative items that see light handling.... I would imagine the typical home speaker would fall into the same category. – Graphus Aug 28 '18 at 15:50
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Is it possible for me to apply the poly on the vertical surfaces?

Yes, that shouldn't be a problem as long as the finish is thin enough. You can use various thinners with polyurethane, such as mineral spirits. But you shouldn't need to worry about that if you use a product that's meant for wiping or brushing.

when will the poly be dry enough

Drying time will depend on the particular product, the temperature, whether you've added any thinner, and maybe other factors too. As an example, I've got a can of Watco wipe-on poly that says the product will be dry to the touch after two hours.

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  • The vert poly is working. Although it’s coming up blotchy! This is devastating! I went with Miniwax Wipe-On satin oil poly and for some reason there’s white clouds in it, even after I coat with a fresh coat. – tjcinnamon Sep 4 '18 at 3:31
  • @tjcinnamon, there is a matting agent in any varnish product that isn't high gloss and they need to be evenly distributed by thorough mixing or shaking prior to use. This sort of issue is one of the things that testing on scrap wood is intended to highlight prior to working on the finished product.... Edit: also, aren't you intending to rub out? If so you should be using a gloss varnish to begin with. – Graphus Sep 4 '18 at 9:32
  • @Graphus I think I should be. How can I undo this blotching? I shook it pretty good on the first coat but forgot to shake it on the next. If since put on a 3rd. On one of my boxes, I’ve attempted to hand sand it with 220 and recoat with a well shaken amount. – tjcinnamon Sep 4 '18 at 9:57
  • @tjcinnamon, generally the way to fix this — you know what I'm going to say here — is to strip and start again. If you can salvage it by lightly sanding then you can, that's great, but often that's not possible. – Graphus Sep 4 '18 at 13:04
  • @Graphus this is paper backed veneer. Do I just sand it? – tjcinnamon Sep 4 '18 at 13:25
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My answer for this (Spray on Lacquer for Vertical Surface) still holds. However, if you find yourself in a hurry for the finish to dry, I would recommend an alcohol based shellac. Most retail available shellacs are alcohol based.

Advantages for this application (where you're not going to be messing with the thing) include:

  1. It's very easy to apply (you can use a rag)
  2. It dries very quickly (depending on your conditions, as quickly as 15 minutes)
  3. It looks good
  4. You can apply another finish on top if you need something harder

Now, what you're going to want to do is apply a coat and let it dry. Lightly sand it with fine sandpaper (1200 grit). Apply a light coat. Rinse, lather, repeat. With the last coat, I'd polish with very fine steel wool before you apply the very last one.

Don't discount shellac as a viable finish. It's been used for millennia and for strictly indoor applications it still works quite well.

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  • Would wipe-on poly work as well? I could use those paint triangles you mentioned. With someone on a vertical surface application, I could just leave it on its feet – tjcinnamon Aug 27 '18 at 17:14
  • You could but wipe on poly takes longer to dry. I would use a system like is pointed out in your previous question regardless of your finish. – CharlieHorse Aug 27 '18 at 17:17
  • Perfect! How long until I can swap sides to make it a “non-horizontal” surface on the triangles? – tjcinnamon Aug 27 '18 at 17:19
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    @tjcinnamon be careful using the painters' pyramids. If your finish is still curing or the piece is heavy they can leave small indentations in your finish (or even the underlying wood). I try to limit them to non-show or "secondary" show surfaces only. – SaSSafraS1232 Aug 27 '18 at 18:04
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    OP, while I'm a fan of shellac myself it's a hard finish to get used to for the uninitiated (even following good, clear instructions), wiping varnish on the other hand is very much more user-friendly, and can give a superior finish in almost all respects even for the first-time user. – Graphus Aug 27 '18 at 18:22

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