Newbie: Between coats treatment -- purpose?

[rbrandywine]

I'm currently testing 3 finishes on a piece of scrap:

Behlen's 100% Tung Oil

Formby's Tung Oil Finish - Lo gloss

Minwax Tung Oil Finish

The directions of each for between coat treatment is different:

Behlen's -- scuff sand with 400 grit sandpaper

Formby's -- rub lightly with 0000 steel wool

Minwax -- nothing

What is Behlen trying to accomplish? I thought scuff sanding was to get a new coat to stick to previous coats -- which doesn't apply to non-building finishes like 100% Tung Oil.

What is Formby trying to accomplish with the steel wool? I thought that was to adjust gloss after the final coat.

I'm tempted to follow Minwax's advice and do nothing between coats (besides wipe with a lint free rag to remove dust).

Thanks for your thoughts

[Jim]

No, you are fundamentally burnishing the surface to make it smoother. The purpose is to make the finished surface as smooth as possible.

Same thing.

Maybe their finish does not require the burnishing, or maybe they just don't care how the surface looks.

While have used Formby's for some time, I am ready for alternative products. I would, regardless of what they say, go over the finish lightly with 0000 steel wool. Jim

[rbrandywine]

Thanks, but are you talking about doing this *between* coats or just after the final coat?

[Leon]

To smooth out the surface. There is always going to be a slightly uneven surface when applying anything. It may not feel uneven or rough but it is. Plus the sanding will help the surface absorbe more oil on subsequint coats.

Basically the same thing.

Well, I am not suprised with the Miniwax dirrections. I think they assume you are not going to care one or the other. I personally do not care for their products.

[Stephen M]

IME the first pass of finishing will raise the grain ay least a little bit. This needs to be leveled. A card scraper and/or sambpaper with a block works well.

I do finishing on my shop. It is damn near impossible to get the dust down to where *NONE* ends in the finish. I will generally take a very light wipe with 220 along the grain.

If you want a top notch finish, you need to ensure that every layer of finish is flat and smooth.

-Steve

[rbrandywine]

Okay. Now I have 320 grit, 400 grit, and 0000 steel wool. How about I finish to 320. Sand lightly with 400 between coats, and use the 0000 after the final coat? Does that sound like a plan?

[Stephen M]

Yes, that would work. I think 400 is is overkill however (unless you are going for the crystal clear 8 ft deep pool of distilled water look). IME the next coat will pretty much fill the scratches. But I always sand with the grain to that even if a scratch were left unfilled or partially filled, it would be camouflaged by the grain of the wood.

BTW, Denibbing (smoothing between coats of finish) does not create much of a visible difference. Use you fingers to feel the surface before and after.

I am a fan of 0000 aplied with wax as a lubricant for the final deglossing. But final sheen is a personal choice (chocolate and vanilla).

Cheers,

Steve

[Jim]

Both Jim

[gadgetman]

that's pretty much what I do and I get a very nice kind of satin finish. I don't go for the high gloss much, more th natural. I agree with the need to smooth the surface between coats. I also apply rather thin coats of tung oil (or it's various derivatives) and have learned to thin it to get the "right " consistency which kind of an individual thing. I end up with 400 to 600 grit and use synthetic steel wool or real steel wool at times. I reacently did an electric bass guitar for my son with fornby's tung oil varnish (6 coats and it looked right) which probably has little tung oil in it (becuase of internet luthier recommendations) and it turned out wonderful - what a suprise. Everybody kept grabbing it at guitar center when we went to get a case. The thin coats seems to be very important for me.

MBR

MBR

[Stephen M]

Snippage

So true.

Let me second that. I case it's not obvious, let's say it out loud that thining the finish results in a thinner coat (same word, different meanings). An imperfection in a thin coat is much easier to correct than an imperfection in a thick one.

-Steve