Looking for insight on options for finishing wood veneer speaker cabinets.
I used to use Gloss, Satin polyurethane cut with 25-50% mineral spirits. I am located in Canada, where straight Mineral spirits were banned in 2024, and the only alternatives available are mineral spirit substitutes; the same applies to paint thinners. I tested these formulas, but they leave streaks and film residues on the finish.
I actually bought wipe-on poly for the first time; it's quite expensive compared to simply cutting straight poly with the aforementioned materials. The issue with wipe-on poly is that it's too thin and runs on the vertical surfaces. It dries/sets quicker, which was also a bit tricky when I was doing thin coats with it; it was almost as if I was wiping it right off. As soon as I try to apply it slightly thicker, it runs, and well, shit hits the fan.
Located in Ontario, Canada.
What's this? A question on ASR that I am actually qualified to answer? Pinch me, I must be dreaming.
Hello, fellow Ontarian woodworker here. I have a lot of experience with fine-finishing, and it's always a challenge. Perhaps the hardest part is that everyone you ask has their own opinion, and no two opinions seem to overlap, in terms of what products to use, and which products look the best.
The truth of the matter, in regards to which finish looks the best, is, ironically enough, very similar to asking the question on ASR "which headphones sound the best?". There's no objective answer, and in reality, most of the visual differences that people claim exist between finishes, are all but imperceptible to 99.9% of people. When done properly you can make any coating look like any other coating. Well, maybe except for French polish.
Now first things first, waterborne finishes outperform oil-based finishes, and have for about 15 to 20 years now. The only people who still hold on to oil-based coatings are the old heads who refuse to admit that water-based products are better. That's not to say that every water-based product is great, only that the quality ones are better than what you can buy in terms of oil-based coatings now.
Note that I said oil-based though. These are separate from "hot solvent" products, such as true Nitrocellulose Lacquer, and catalyzed conversion varnishes, or anything with isocyanates. Hot solvent coatings are still the best, but they are nasty to work with, highly toxic, and generally not for beginners, or even intermediate woodworkers.
So, for you, you have two broad categories of finishes to choose from. Film-forming finishes, and non-film-forming finishes. Finishes which build a film , such as polyurethane, are much more durable and protective, but much harder to apply. They also typically cannot be repaired without having to sand and recoat the entire piece. Coatings which do not build a film include things like waxes , hard oils, drying oils ( tung oil , and boiled linseed oil)
If you want to use a polyurethane, and want to apply it by hand, I would use an oil-based wipe on poly, simply for its ease of application. You should not be experiencing any runs down the side of your speaker, even with a wipe on poly. That's still a sign that you're applying it too heavy. You can also cut back on the dilution ratio, aiming for something like 25% dilution or 33% dilution instead of the 50% cut that is common. You can still buy mineral spirits from industrial vendors and more specialized paint stores.
If you're willing to spray, however, then you should use a water-based polyurethane instead, as they are higher-performing. A finish like Saman, Old Masters, General Finishes, or Renner, would all be great, and you can buy a quality little hvlp sprayer for about $150 bucks.
If it were up to me, though, I would be using Renners Hydro oil product. M305. It's an incredible product , because it can truly be brushed on , with no dilution, and nothing else mixed in, and yet will lay out perfectly flat, achieving a finish completely indistinguishable from spraying. It also does not require intercoat sanding, and can be touched up and repaired seamlessly. It's not as durable as a full polyurethane, but it is a hybrid finish , and is still much tougher than a non film forming finish.
All that being said, it's important to remember that this is just audio equipment, not a dining table. Realistically speaking, it doesn't actually need protection from anything , beyond what can be afforded by non film forming finishes. You would be totally fine to use something as simple as tung oil, which always comes out beautifully and is super easy to apply and reapply, or something like a hard wax product from osmo. So long as we're talking about the clears, they're stupid easy to apply.
I hope this all helps, let me know if you have any questions. And don't worry about the looks, all of these Coatings will come out looking more or less the same, depending on what sheen you choose.
