At this time I am in the finish stage of the build. I have completed the pre-finish assembly as I posted last time and I now am ready to fill the pores of the Walnut. This will save me a ton of time and finish.
The customer has selected a Tru-oil finish for this bass. As most people know Tru-oil is a gun stock finish made with linseed oil and plastic resins that cure into a very durable finish. Tru-oil is actually a polymerized oil that is more like a varnish than oil. It cures rather quickly and can have a beautiful look to it if some care is taken during application. There is tons of articles and "how-to's" on the web so I will not bore you with it all, but for those who do not have a spray booth and want a nice looking durable finish...you may wish to give it a try.
I once used just plain wiping varnish but I noticed many of my instruments, after a couple of years of playing, showed a lot of patina. Some players love that broke in used look and some do not. I have since changed to where I use either Tru-oil (for a glossy sheen finish) or a catalyzed waterbased urethane for my endurance finishes. I promise I will cover the WB urethane in detail next time I post a build. (I have found a way to get that nice deep rich color with the speed and ease of waterbased products that can be applied in doors without spray equipment.) But for this bass we are going with the polymerized oil.
Here we are with the disassembled bass bracketed and mounted in my Stew Mac finishing stand. I have sanded the finger oils and any marks out of the wood from the pre-finish assembly. I have also wiped the wood down with naphtha and let it dry. I prepared the neck and electronics cavity cover the same way.
Next I use this Timber Mate brand waterbased pore filler. It is rated for any type of finsh so I have no worry of oil over waterbased issues. I like this filler as if it ever dries out all you have to do is add some water and it is as good as the day it was first opened. You can get it at Stew Mac.
I mix up some of the filler with some water to make it flow a little easier. I just mix it in a cup and until it is like pudding. I use a small artist brush to dab it onto the headstock. I then brush across the grain until the whole surface is covered. I avoid the Maple sections as they are tight grained and do not need filled pores. I also want to avoid having the pigment in the filler from staining the Maple. I did get some on the Maple and I am pleased to report that it had no effect on the Maple as far as staining. But why do it if I can avoid it.
After the area is coated....
......I wrap an old washcloth around a rubber block and use it to rub off any excess filler. I don't even allow the filler to fully set up. The filler dries completely in like 30 minutes so you do have to keep moving.
I finish it off with a shop towel. If the filler has dried too fast I may dampen the towel. The water does raise some grain but I will have to sand away any filler left on the surface so I can knock off the rasied grain as well.
For the bigger areas I used a larger brush. I avoid getting too much into the ferrule holes and neck mounting holes as you do have to scrape it out later. If I didn't then finish will make the filler as hard as a rock creating more work.
And the same block and towel to wipe the extra filler off.
Now I said that I tried to avoid getting filler into the holes but I always do anyway, so here is the time to scrape it out.
After the filler has cured I sanded with 320 grit paper and then with 600 grit to make the surface as flat and scratch free as I could. I did the whole process of blowing off the dust and then wiping once again with naphtha. The look of the wood was so that I could not even see that any filler had ever been on the instrument. That is the goal. If there ever is any open pores left, I apply a little more filler and then sand and remove dust as before.
The first coats of tru-oil. I followed the same basic techniques that I use for all of my finishes. I ball up a paper shop towel and then wrap it in another shop towel to use as an applicator. I pour some finish into a dish and dip and blot the finish onto the wood. The effect is like sponge painting and you will be surprised how much it looks like a sprayed finish when you are done. This works well with the tru-oil as the oil seems to level itself out very nicely with no wipe marks. This first two coats are to build up the finish. I do one coat and wait one day. Then I buff with fine grit plastic steel wool pads made by 3M. After the second coat I wait 3 days so that the finish has plenty of time to cure.
Then all other coats to be applied will be applied like you would normally apply tru-oil. Very thin coats. Probably 12 or so with some light sanding with micro mesh in between.
Next time I will have some more photos after a few coats. She will be looking pretty sweet by then.
Thanks for checking out my build.