Questions answered – Don’t let finishing stump you
For more information on finishes, see our beginner site Common Woodworking.
On finishing a project
Brian wrote to us on woodworkingmasterclasses this week and strangely enough, while I was finishing off the recent tool chest project I was thinking about how woodworkers are intimidated by finishing. I think that his letter reflects the feelings many people have and you can read it for your self:
Hi guys.
Wondering if you can answer a question.
Finishing really has me stumped. Scares me to death.
I am just finishing a pair of walnut shaker night stands and soon it’ll be time to prepare for final sanding and finishing.
My first question is is it necessary to sand “back” to 240? I have glass smooth surfaces after final smooth and now I have to remove that perfect looking finish? It almost hurts to put sandpaper to it.
Second question is does finishing HAVE to be as complicated as magazines and manufacturers make it seem? Paul, did craftsman really jump thru 15 hoops to finish a nice piece of furniture 50 years ago?
Thanks for everything. I love the masterclasses too!
Brian.
Answer 1:
In my view the answer is yes you should sand down or “back” to about 240-grit before applying finish. Try to think of the wood and the finish as two separate surfaces and indeed items. Some finishes such as oils are indeed soaked into the surface of the wood and penetrate deeply. Some oils for instance. Many so called oils are little more than oil-based finishes with other additives added that skin the surfaces of the wood and many of these oil-based finishes will have added polyurethane for instance which forms the skin I speak of. What many woodworkers refer to as a hand rubbed finish is nothing more than say Danish oil applied with a rag in successive coats, wiped off after a few minutes and allowed then to dry between coats. Nothing wrong with that in itself, but they try to suggest that this”hand-rubbed finnish” is comparable to French polishing which is indeed a had rubbed finish, but French polishing is an art and craft in and of itself and takes much skill to master whereas applying oil is dead simple and takes no skill.
I suggest that you apply Danish. Not all Danish oils are the same in that they have different chemistry and content. In the USA I like Deft wood finishes. Deft Danish oil is a high quality oil that works well on just about anything and I used it for two decades when I lived there with no problems ever. I like the fact that you still feel you are touching the wood after you have built up four or five coats. Apply it with a rag, leave it for 20 minutes and then vigorously wipe it off as though you are trying to remove every trace of residue. It can be hard work if the weather is warm, but it is worth it. The rags when wadded up and left untreated can spontaneously combust so take care to discard them safely. A can of water for total immersion works best.
Back to my answer: Sanding the wood gives ‘tooth’ to the surface and it’s this tooth that most finishes grab on too. Many finishes shrink and stretch as they dry, pulling themselves to a taught skin on ‘op’ of the wood. When the surface is to slick, the finish has less to attach itself to. Oils do better than varnishes but as most oil-based finishes will state that they are oils and not oil based, two different things, you may find that you are applying more of a wipe on polyurethane than you are actual oil. Tooth is important and that’s why we rarely sand beyond 250-grit because finer surfaces tend to give poorer adhesion.
Building up sufficient coats means that you apply enough initial coating to sand down without sanding through the initial coats. I usually apply a coat of clear bleached shellac first, which can be used with most top coats (This is not necessary with Danish oil). This is usually the only sanding I do but I am never likely to go for a super high gloss finish as I don;t like the plastic look-through look. There are some excellent water-based high glossy finishes used for guitars that are stunning if that’s what you are looking for. These are best applied with an HVLP sprayer and then sanded out after the coats are built up. Not usually suited to furniture.
As a final point on sanding; try not to round over the detail to end up looking like an American 2×4. Use a padded block if necessary to prevent this.
Answer 2:
There is no doubt that magazines provide content that rarely ever simplifies the issues surrounding woodworking. They are mostly advertising billboards for the giants of the industry and the more then can have you coming back for a dangles carrot the more magazines they sell. Most magazines sell magazines surrounding key areas of concern to woodworkers for the very thing they know woodworkers struggle with the most such as sharpening tools and applying finishes. Just as sharpening is as simple as abrasive, angle and steel, fishing is sanding, build-up and drying.
Conclusion:
I would go for the Danish oil. It looks good, feels good and is easy to repair and recoat in the years to come. Walnut in and of itself has wonderful colour that needs no further colour adding so coating is dead simple. You cannot go wrong with Danish oil. Later, you may want to investigate other finishes and methods too. We are working on a video to that end on woodworkingmasterclasses. Also, I am just finishing up my tool chest with shellac, you might want to watch that too, before you start.
Mr. Sellers, I’ve noticed that Danish oil is sold in a variety of “colors”. I say colors but they are really labeled with names such as golden oak, dark walnut, red oak, and so on. I am referring to the stuff at Home Depot (Watco brand); I’m going to search for Deft.
It gets confusing to a newbie because it’s not entirely clear whether it’s just stain added to mimic that particular species or if we are meant to match the can to the wood species in our project for best results (I tend to believe it’s the former). Should I just use the can labeled “natural” on all woods and call it a day? 🙂 Thank you, and happy holidays.
I don’t recommend Watco oil. It’s not the same Danish oil as Deft Danish oil. In the UK products sold as Danish oil are high in other contents such as varnish. The oil usually offers a low sheen finish and so varnish is added to add hardness and shine. The colouring in these products is usually a stain of some kind and stain as opposed to dyes can cause a more muddy look to the project. Best to go for a natural which is usually clear.
Paul – few thoughts on this post; hope they are helpful. My venture into real woodworking started from the finishing end. Much of the furniture I finished starting 30 years ago was with nitrocellulose lacquer – allows for a very broad range of options, but that was re-finishing and not something I would use now. I can understand the “scary” feeling – there is nothing worse than “ruining” (though you can remove the finish) a piece that was beautifully crafted. I totally agree with you as far as the oil finishes are concerned. And these walnut pieces will look wonderful when complete – and you really cannot mess up that finish. That said, thought I would pass along how I finished my last two pieces using water based dyes, oil stains and shellac:
1) The wood is sanded with #220 and a coat of “shellac wash” (1 part shellac to 4-5 parts alcohol) is applied. The shellac wash is a prep that “freezes” the grain, making it brittle, so the next sanding step “sheers” the fuzz and helps eliminate the risk of blotches. It is something I have done for years and it is very effective.
2) The piece is now sanded with #320 to prep for the dye application. If I was using oil base stain, it would be #220. Since the water base penetrates easily, and the shellac wash is a very thin coat, #320 works very well.
3) Using a rag, I apply the dye evenly over the piece – the combination of the shellac wash and smooth surface allows for control. The dye needs time to dry after this step.
4) Using #320, I very lightly – very lightly, sand the surface to remove the slight roughness from the water. I then apply a very light coat of an oil based stain that helps highlight and pull the overall color together. Again, this is a very light coat.
5) Once that is dry (overnight), I spray clear (not amber) shellac using an HVLP spray gun – I have found that the $30 guns perform just fine (I used #7 Binks knock-offs for years that sprayed wonderfully). Because of the look I want to achieve, I usually apply about 8 coats – the first are very thin. (finishing hint – if you are intending to finish with lacquer, do yourself a favor and start with one coat of shellac – you will never see fish eye due to silicone contamination)
6) Using the same method you demonstrate on the candle box, I use steel wool and wax to achieve a beautifully smooth and elegant finish. It is best to let the piece dry for a time, a shellac is a solvent-released based finish. Like lacquer, it dries on a bit of a bell curve, in my experience.
I have attached two photos – in the small side table on the right you can see a bit of the wax in the corners – the first table has not had the last step done.
Hope this adds some additional value to the post….
Herb- Thank you for the excellent description. I have struggled hand-applying water based dye without getting uneven color and had concluded I had to spray it. Do you think your wash coat would give you enough control to hand-apply water based dye to something as complicated as Paul’s Craftsman style rocker? When you apply the water based dye, do you flood on the dye and go quickly, then wipe back? When you say 1 part shellac to 4-5 parts alcohol, is that 1 pound of shellac to 4-5 gal alcohol or is that weight per weight? If you try to wipe shellac over water based dye (or spray it and get runs!), the shellac can dissolve the water based dye and make a mess. I’m guessing that is why you spray your shellac finish coats and one reason why the first are very thin?
Ed – thanks for the positive feedback. Finishing is still an “experiment” with each new type of project for me. The shellac wash does provide a surface that allows for control – but I still take caution in the approach. The dye is mixed to a lighter shade than the finished color I am after, as unlike a standard “pigment” stain, subsequent applications will darken the color (take care with overlap). I use a rag dipped in the dye that is just wet enough to put the color on – in some ways it reminds me of coloring with a crayon. I never flood, just carefully wipe. The mix for the shellac wash is 1 part (i.e., cup, etc) of ‘off the shelf’ 3 lb cut clear shellac (right from Home Depot, Lowes, etc) to 4-5 parts alcohol. This can be sprayed or brushed – I usually brush. You will want to practice on something before tackling the rocker, and maybe turn it upside down seeing how the bottom goes. Even a flat piece of scrap will give you a feel for the wash and dye. I use an HVLP gun, thinning the shellac slightly and go for multiple thin coats. Spray the “corners” – ex – the legs on the tables are sprayed directly at the very corner – once on an opposing corner – not straight on. Only two corners – each pass gets two sides of the legs. If you spray everything straight on, you can end up with too much overlap and runs. The initial thin coats do tend to “set” the stain to a degree, but keep in mind that shellac, like lacquer, is a solvent release finish. Each coat dissolves those under it to make “one” coat. The last few coats can pose as much danger of runs if you get too aggressive. You want to keep enough distance as well, and dial the gun to spray only the amount you need. One other point on shellac – both of these projects were sprayed in somewhat humid weather. And both “blushed” quite a bit. Unlike lacquer (which requires a thinned coat with some retarder to release the moisture and the blush), the shellac “self healed” – the blushes disappeared on their own. If things go awry, the one good thing about shellac is – it removes fairly easily with a rag soaked in alcohol. Take your time, allow time between coats, keep them thin and the project will come out fine. Hope this helps…
I’ve had the same questions. I found some answers in a book titled Understanding Wood Finishing by Bob Flexner. I highly recommend it to all those who are new to finishing.
Sorry I can’t recall Rustins though I have used it in the past. I think that ot will come down personal preference though. I just don’t like plastic look or feel finishes.
I know warming the oil helps the initial coat penetrate and seal off the wood, but there are safety issues with heating the oil not the least of which is combustion. The end result is quicker build up and easier rub down because you can apply it more evenly and remove the excess more easily too.
Ron Bowser
Paul, I have a question regarding the cure time of using Shellac on wood. When I apply the second coat of clear Shellac, I let the wood sit for 24 hours to dry, however when I handle the wood to sand, or re-coat, the heat from my hand leaves my finger prints in the Shellac. Any suggestion or thoughts on why this happens, and how I can prevent this issue, thanks.
It might be the shelf life of the shellac, usually around six months if you make your own and about the same for most proprietary brands too. You should need to leave it only a couple of hours max. I inly leave it 30 minutes or so and no warm thumbprint should happen at all.
Paul, Thank you for your information. I will look at the shelf life of the product I purchased since I opened it for use.
Sincerely,
Ron Bowser
First of all, thank you for your willingness to pass on your knowledge and experience. Forgive my ignorance but I have no experience with dyes or shellac and I’m wondering what dyes do you recommend for shellace, what manufacturer (here in the states), and where can I get them?
Paul, I need help. I live in Louisiana. Used Danish oil on my log looking bare wood, look great. Rub more oil again. Then comes the mold and my pretty natural wood, does not look good. I bleach it and it look better. So I tried a sealer this time. The mold comes back again. I tried some more bleach and the wood looks better. This time my sealer starts to off. I just wanted my log looking furniture to look natural with out paint. It has become a nightmare. The paint store does not know what to do. My furniture is outside on my covered back porch. Please help!
Hire a contractor. You will have to “enjoy” the mess you are just about to do, for many years to come. For every person that manages to achieve great results, 100 fail. If you are very good at DIY jobs, then go for it. But if you are more in to reading news online, don`t take on a floor sanding project
I get rich from repairing the mess people leave behind. A job that could have been done for 250-400, ends up costing 1500 to repair. Sanding floors well is an art. Avoid doing it if you can. My advice.
Paul,
I couldn’t find Deft Danish Oil anywhere in EU or even online. Is Liberon’s a good substitute? What do you use in the UK?
Best wishes,
Serge
All Danish oils are nothing to do with Denmark but they are simply a mix of components with solvents and oils or polyurethane varnishes mixed together. If I created my own finish I can call it the Paul Sellers wood finish and just have shellac flakes and denatured alcohol as the listed ingredients. It means that any manufacturer can develop a mix and name it Danish oil. Ronseal’s Outdoor Furniture Oil is a water-based product that has no oil in it. Is that not disingenuous or what? I have found no difference between the Danish oils here in the UK. deft stopped producing their Danish which is a shame because it had one of the most pleasing results in a rag-applied wood finish.