Grain fill under tru-oil finish

Parto

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I am just ready to start the finishing process on my second build and, having read various threads on the subject and watched Beau's demonstration video, am thinking of using CA for the grain fill.

I have bought some Starbond 150 (which Chuck has recommended in previous posts) but before I start just wanted to sure there will be no issues under a Tru-oil finish. I want to use Tru-oil again as I have no spray equipment and like the fact it has low VOC.

Mike's thread on issues with CA and nitro have started to make me panic a little.

Thanks in advance for your advice.
 
The nitro problem happens to be my first effort using Nitro. All my previous builds have been Tru-oiled. I can't say i've used ca to porefill but I've used it to glue rosettes etc, with no issues under tru-oil. I think you'll be ok, but if you want to be doubly sure, then wipe over the porefilled sanded body with a couple of coats of shellac, before the tru-oil. Shellac is magic in that way, it's worth your while having some in your cupboard but make sure it's de-waxed blonde flakes and mix it with meths.
 
Not an expert at this, but I have used CA for various filling applications. It'll work. It'll stick to (dry) oil surface, but...it's really hard compared to the surrounding wood, so sand with blocks or backing, and finally, I think you are going to wind up with shiney dots where the CA is left. Clear coating with Nitro or Shellac will cover those shiney spots and they will disappear, but with oil, not so much. Probably depends on which wood too, big pores or little pores?

I'll add that on most woods, for me, wet sanding with the oil finish fills the pores just fine and it's much easier to sand.
 
Nitro over cured starbond is fine.

It is wet/fresh ca glue that eats nitro.

I have no idea about tru oil- i'd ask Aaron Keim as he has done 10001 tru oil jobs.

On thinking about it- the ca would seal the wood and the tu oil wouldn't penetrate the wood which might be a factor in how it hardens???- (unless you sand the ca back to wood just leaving the pores filled with ca-= but thats a pain)
 
Tru-Oil is fine over CA provided you do the shellac wash coat in between. I've done that many times.

There are certain woods that may inhibit TO from hardening, such as Macassar ebony and Bolivian RW (aka Morado and a few other names). So, even if your goal is not a pore fill, it's necessary to create a barrier between the wood and the TO. Sometimes, shellac does the job and sometimesnot. It seems that whatever oil or other chemical in the wood prevents hardening of the TO can migrate through the shellac and infect the TO. So always test your finish regime on scrap wood before forging ahead. Undoing a screwup is way too much work. This is one of those "please don't ask me how I know" things. :( My point is that the preliminary CA step is useful not only as pore fill but also as a barrier coat that can keep that screwup from happening. Even if your goal isn't a smooth and fully pore filled finish, CA can still be used as an initial barrier coat on troublesome, oily woods when followed by shellac and then TO as the topcoat.

I use CA to fill all the time and like it. Do have a fan available to blow the fumes away. I have a window over the part of the work bench where I do the stinky stuff and keep a box fan on the window sill to suck the bad stuff out. Like anything else, it takes a while to get good at it. Until you get the knack, you can make a mess by over applying the CA and/or applying it unevenly, both of which can add some serious sanding effort. So best to apply too little and more coats than too much.

I know you already have the CA but for many projects it may not be necessary at all. If you are finishing a wood that has pores so big that you could lose your Exacto knife in one and your goal is a perfectly smooth finish, you need to use CA or some other form of heavy pore filling artillery like epoxy. For smaller pores (and only with the woods that don't inhibit drying of the TO) TO alone can get you there with a lot less fuss and work. As was mentioned in another post, wet sand with TO to fill the pores with a slurry. You might start with 220 for a couple of coats, then move to 320 and then 400, allowing time to dry in between. The grit schedule depends on the wood. It helps to thin the TO with mineral spirits. Even 1:1 doesn't have any adverse effect and it makes the sanding much easier. This can be a fun process. It doesn't stink and each pass takes only a few minutes per day for the few days that it all takes. If you have something like a light wood with ebony bindings, you don't want a dark slurry messing things up so first do two or three wipe coats of TO and then start the sanding.

One advantage of CA pore filling is that you'll never get any shrink-back over time. A TO pore fill will shrink back but no more so than many other finishes and this makes for a look that is well accepted and even valued in the instrument world. If that weren't the case, all of those valuable pre-war Martin guitars wouldn't be worth nearly as much.

Finally, if you want to get to a perfectly pore filled and glossy TO job, the work you have to do is nothing like a MyaMoe style finish. I like that style a lot and do use it. It's easy, quick and very appropriate in some situations. What you have to remember is that for a beautiful three or four coat wipe-on-wipe-off finish you don't have to give any thought to getting the surface of the dried TO to be smooth. It just doesn't matter. But once you have laboriously created a smooth substrate for your final finish, the surface of the dried TO topcoats can be very important. To get an attractively smooth final finish takes some care. This video shows a good technique to use and I'm sure there are others:

https://www.youtube.com/watch?v=A6zmitxywKU

The video doesn't mention that adding some mineral spirits to the TO can be helpful in getting it to lay down smoothly.

Good luck and check back in if you have any questions!
 
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I use CA as a pore fill under Tru-Oil and it works just fine. I do not use a shellac coat between the CA and the Tru-Oil (the CA sands so much better) and I have never had any adhesion problems.
 
Thanks all for the advise. I'll definitely try a couple of samples, one with a washcoat of shellac and one without, to make sure there are no adhesion issues. I have seen the MyaMoe videos on TruOil application but will check that one out as well.
 
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