Oil finishes -confused

looking nice what oil is it you useing.your much better off putting thin layers on that way you can decide when the finish is right . put it on thick and you will end up with a big sticky mess

 

I have never sanded an oil finish, only buffed

 

With Tru-Oil I will use many very light coats basically just rubbing it on, never thick. Depending on the quality and sanding level of the raw body, may need a light sanding of the first coat if the grain lifts. Some woods will have more grain lift and some have more open pores that may want a pore filler applied first then a sanding.

 

An oil finish isn't meant to "build" like other finishes. It is meant to preserve the wood without adding much thickness. It soaks into the wood and hardens and will fill some grain if you sand between coats. Some people actually apply it with 600 wet sandpaper. After several coats, you are mostly wasting oil as no more can soak into the wood. Anything extra will likely stay tacky or wear off.

Oil finishes look and feel great, but they don't form a hard shell like poly and other finishes.

 

I guess it's debatable if tru-oil is really an oil product, but in my experience it can be built to a (visually) lacquer like mirror finish, does not stay tacky or wear off at least with four years of daily use. So it's not just something that soaks in the wood. I don't have experience with other oil based products though. I do agree Tru-oil is not as hard and definitely not as thick as other finishes, especially compared to typical "cast in plastic" poly shell found in factory guitars.

 

Apparently Tru-Oil is a wiping varnish. There are (at least? ) three types of products people call "oil," so it's confusing. Really good article on the topic, explaining the differences:
https://www.popularwoodworking.com/article/the_basics_of_wiping_varnish2/

 

Great article! I knew some of those "oil" finishes actually had a hardener (varnish) but didn't know what it was. I used to use a Formsby-like product (I believe it was Minwax Antique Finish or something like that) on antique furniture decades ago and it worked very well. It didn't resist cat claws and water very well, but otherwise has held up well. Recently my work with oil finishes have been with boiled linseed oil, but I have not used it on guitars.

 

Just finished the 3rd coat of Tru Oil.

 

Some oil finishes will build a film. As stated above TruOil is actually a varnish. Polymerized Tung Oil will build. Waterlox is a polymerized tung oil and is used for hardwood floor finish and makes a great guitar finish. There are other oils that have a combination of linseed oil, tung oil, and poly i.e. the Sam Maloof wiping oil that Rockler carries or carried (don't know if they still do) that will build. Even Linseed Oil will build if you apply enough coats.

With wipe on oil, the general rule is to apply thin. If you apply thick, your coats will not fully cure or dry and your finish will stay sticky pretty much forever.

Apply the oil with a rag "rubber" and rub in thoroughly ideally until the rag gets warm from friction. After you've applied, take a rag that is not soaked in finish and wipe off excess, don't wait until the finish is tacky. Lay your oil soaked rags outside flat and not in a wad or bundle, and let them dry before you dispose of them. They will spontaneously combust if you just throw them in the garbage can in a wad. Let your project dry for amount of time recommended by the product container, and then rinse and repeat. Usually somewhere between 4 and 8 coats will start to build, but you'll never get to a point where it looks like thick coated lacquer or poly.

 

most oil products are really finishes, like Formby's Tung Oil (finish) or Minwax Tung Oil (Finish), same manufacturer and really the same product. I used to use McCloskey's Tung Oil and use almost a french polish technique. You can achieve a very nice gloss in that matter and you do get some build. No different than most spray finishes, light coats are better. It will not dry well if you put on thick. While boiled oil will work and harden the other products represent "improvements".

 

This is a good word of caution with soaked rags I forgot to mention. I have a background with education in traditional art and this is something that was repeated to remember when working with something based on linseed oil. I was told many artist ateliers have burned down because of this in the history of oil painting. In my experience with tru oil 50-100 thin coats rubbed in will get you to a nice mirror finish resembling sprayed lacquer, but yes, still paper thin.

 

I have a good friend who lives about 1/2 a mile down the road from me. He put a new cedar deck on his house a couple years ago, and used a linseed oil based finish to finish it. He applied the oil heavy with a brush and the finish container recommended that the excess be wiped off with a rag, which he did. He then put the rags in his garbage can which sat right next to his garage which is attached to the house. He awoke at 1:00 AM to a strange noise, got up and opened the door into the garage which was completely on fire. The fire spread to his attic and by the time the fire was put out his house was completely ruined. He spent the next year rebuilding it.

I couldn't believe that he did not know that oil soaked rags are combustible, but he didn't. So, I tell everyone now just to make sure they know. I believe that TruOil is a linseed oil based varnish. I treat rags soaked in any oil like they could spontaneously combust at any time. Better safe than sorry.

 

Check out the various TruOil Gunstock finish videos on YouTube and you'll get the drift. Typically applied cut 1:1 with Mineral Spirits for the initial coats including sanding wet to grain fill. Successive coats at full strength sanded with successively finer grits down to 0000 steel wool between coats, compound buff to high gloss or leave as applied for satin finish. Most finishers recommend TruOil Aerosol for evenness of application for final coats if high gloss is desired.