Finishing a walnut slab table - can I use different finishes on top and bottom?

[Peter Franklin]

Hello,

I'm in the middle of finishing a large 2" thick slab table in walnut, but am not happy with the finish. Have been using a wiping varnish but find the look too polished on the surface. I don't want to rub it off -- don't have any experience doing that and I'm not sure it'll give it that in-the-grain, natural look I was looking for anyway.

So thinking of cutting my losses, stripping off the finish and making my own mix of oil/varnish mix for a more natural in-the-grain look. Pratt/Lambert 38 dull / Pure Tung Oil / Mineral Spirits in equal parts.

It would be less work if I could leave the finish that I already have on the bottom of the slab and just strip the top and sides to redo. But this means it would have two different finishes -- 3 wiped on coats (not brushed) of wiping varnish on the bottom, and then a bunch of wiped on oil/varnish coats on the top and sides.

Am I asking for trouble?

[Prashun Patel]

Post some pictures.

This has happened to me many a time.

I don't think you need to strip the finish yet.

Assuming you have not built a thick film (if yes, then this advice will change): I would just sand with 400 then 600. Then I would mix a little bit of boiled linseed oil right into your wiping varnish (I am assuming this is an oil based varnish). Little bit means between 10 and 20%. Apply the finish liberally with a brush or rag. Then buff it off. Don't SCRUB it off, you're wiping gently but completely. After a few coats, the sheen will remain satiny- and in the wood as I suspect you are after. If the finish is sticky and hard to buff off, you have waited a bit too long. The oil is there to just prevent the varnish from setting up too quickly.

Be patient with the application. Give it several coats, and time to dry in between. It's quite a straightforward and simple finish. Where people get into problems is quitting too soon, and (biggest) leaving too much finish on the surface. This can result in a tacky finish that never dries hard. Even this is not the end of the world; the cure is to dampen a cloth with mineral spirits - and then buff the surface. Let it dry, and continue.

[Peter Franklin]

Thanks for your advice Prashun. It can't hurt to give that a try. Photos aren't showing anything well, but I do have only a light coat on.

Additional background: I am using an oil based product -- Waterlox low VOC sealer finish and their low voc finish. Wiped on a coat of sealer/finish to start and then went to their low voc satin finish. I wiped on a couple coats over a couple days and found it looked streaky (not too built up, just streaky...) Researched and found out the WL low voc Finish is different from their sealer finish and meant to brushed on, not wiped on. But that would give it too thick a coat so I stopped using. I have a few off-cuts I was able to test and went back to wiping on a coat of the sealer finish, which did remove the streakiness and made it look much better, but per my original posting, it's too shiny and built up for my taste...

Couple questions re your suggestion:

1. Is there a reason I can't use Pure Tung Oil instead of BLO? I've got that and would prefer as I don't want to darken wood more than necessary. I also have Japan Drier if it's a drying issue...
2. By sanding with 400 to 600 I assume these are dry sandings? Or done wet with sealer/finish? Is this after each coat, or just the first one that's streaky?

Thanks again.

Post some pictures.

This has happened to me many a time.

I don't think you need to strip the finish yet.

Assuming you have not built a thick film (if yes, then this advice will change): I would just sand with 400 then 600. Then I would mix a little bit of boiled linseed oil right into your wiping varnish (I am assuming this is an oil based varnish). Little bit means between 10 and 20%. Apply the finish liberally with a brush or rag. Then buff it off. Don't SCRUB it off, you're wiping gently but completely. After a few coats, the sheen will remain satiny- and in the wood as I suspect you are after. If the finish is sticky and hard to buff off, you have waited a bit too long. The oil is there to just prevent the varnish from setting up too quickly.

Be patient with the application. Give it several coats, and time to dry in between. It's quite a straightforward and simple finish. Where people get into problems is quitting too soon, and (biggest) leaving too much finish on the surface. This can result in a tacky finish that never dries hard. Even this is not the end of the world; the cure is to dampen a cloth with mineral spirits - and then buff the surface. Let it dry, and continue.

[Jim Becker]

Peter, always try the finishing steps and products on spare/scrap material before you commit to your full project...so in answer to your question(s), yes, you could have a different finish on top and bottom and that's not unusual. You can also try your proposed mixture on scrap to see if you like the result better than what you have been using.

[Peter Franklin]

Thanks Jim -- I did that. About 6 different samples from an offcut of the same wood. I guess the samples were small enough that the streakiness wasn't apparent. Only in finishing the entire table did the problem become evident.

I mistakenly thought the waterlox low VOC finish (not sealer finish) was a premixed version of an oil / varnish finish I've made in the past using the waterlox sealer finish. It was wipe on and steakiness was never an issue. The only reason I was doing samples this time was to test using shellac as a pre-coat to prevent the color from darkening as much. So I was just using samples to look for color...

A lot to learn with finishing. I've always just used either shallac and wax when water isn't an issue or an oil/varnish mix using varnish, tung oil and MS in equal parts. Super easy to apply and great looking. Little to no technique needed to applying. My kind of finish.

Thanks again.

Peter, always try the finishing steps and products on spare/scrap material before you commit to your full project...so in answer to your question(s), yes, you could have a different finish on top and bottom and that's not unusual. You can also try your proposed mixture on scrap to see if you like the result better than what you have been using.

[Jim Becker]

Any chance the Waterlox product wasn't fully mixed up?

[John C Cox]

The old rule is fat over lean. Most likely, your richer mix could go over the old just fine. I would try sanding an area you have already coated and apply your mix over it. Most likely - a new waterlox product will go over an older one without too much trouble and vice versa (unless they say so) - as you know they have nominally tested their own products for compatibility. Walnut isnt cranky for finishing like rosewood - where you may have to sacrifice a goat to ensure your finish cures out fully.

I don't see any issues with leaving the bottom be or using that as your test area once you check on scrap. The bottom of a table only usually gets enough finish so chewing gum comes off in the future.

[Peter Franklin]

I was pretty careful about mixing it well. I think the problem was the low voc finish (not sealer finish) isn't supposed to be wiped on.