[tjk87]

Hi there,

I just started my first woodworking project - refinishing a redwood slab and making a coffee table out of it.

After thoroughly sanding it, I've been refinishing it with 100% pure tung oil, sanding it lightly with 0000 steel wool then wiping with tack cloth in between coats.

I've applied twelve coats so far, allotting a day or two in between coats (first coat took about a week to cure).

The issue is that there are still some dry spots, and the surface itself is slightly tacky. I made sure to wipe off any excess oil after each coat, so I don't think that's the problem. I'm also debating whether I should thin with mineral spirits, but I don't want to damage the wood.

Should I continue applying coats, or should I thin the oil? Any feedback would be appreciated. Happy to provide pics as well if that would make things easier.

Thanks for your help!

Trafton

 

[Steve Neul]

Hi there,

I just started my first woodworking project - refinishing a redwood slab and making a coffee table out of it.

After thoroughly sanding it, I've been refinishing it with 100% pure tung oil, sanding it lightly with 0000 steel wool then wiping with tack cloth in between coats.

I've applied twelve coats so far, allotting a day or two in between coats (first coat took about a week to cure).

The issue is that there are still some dry spots, and the surface itself is slightly tacky. I made sure to wipe off any excess oil after each coat, so I don't think that's the problem. I'm also debating whether I should thin with mineral spirits, but I don't want to damage the wood.

Should I continue applying coats, or should I thin the oil? Any feedback would be appreciated. Happy to provide pics as well if that would make things easier.

Thanks for your help!

Trafton

Tung oil is a good finish and was originally used on hulls of boats so it will build as a finish. You just have to be patient with it.

You have two basic problems. Redwood is very soft and will readily soak up the tung oil you apply. Then tung oil dries a lot slower than you think and if you put another coat on prematurely it's just going to soak it up. The previous coat needs to completely dry to build on. It may take a couple of weeks to a month for a coat of tung oil to completely dry. The best way to tell is take a clean dry cloth and briskly rub the surface and if it transfers the smell of tung oil to the rag the tung oil isn't dry enough for another coat. If you stay at it you can build the finish with tung oil that would look like varnish or polyurethane but it won't build unless the previous coats are dry. Thinning the tung oil is only going to make the problem worse trying to build a finish. It will just make it take twice as many coats to achieve the emulsion you want.

Perhaps others might argue with this but I don't like the idea of using steel wool between the coats with tung oil. The stuff breaks down in little flakes and could get into the finish. I would use sandpaper between coats.

 

[cabinetman]

On bare wood, I usually thin pure Tung Oil 50/50 with either mineral spirits or VM&P Naptha, for the first few applications. It penetrates better that way. Then I apply full strength 3-4 applications allowing sufficient dry time. A build will develop.

.

 

[tjk87]

Thanks for your replies! Very informative.

I just heard from another friend who has done some work with tung oil, and he also thinks that I applied the additional coats too soon and that the first hadn't cured properly.

I guess my questions moving forward are:

1) Do I apply paint thinner with steel wool to strip the tacky parts (what my friend recommended) or do I just wait until those areas have dried thoroughly?

2) How do I know when I have applied enough coats?

3) for a slab that's 5 feet by 1.5 feet, how much should I be applying with each coat?

Really appreciate everyone's input. Have a great memorial day weekend!

 

[Steve Neul]

Thanks for your replies! Very informative.

I just heard from another friend who has done some work with tung oil, and he also thinks that I applied the additional coats too soon and that the first hadn't cured properly.

I guess my questions moving forward are:

1) Do I apply paint thinner with steel wool to strip the tacky parts (what my friend recommended) or do I just wait until those areas have dried thoroughly?

2) How do I know when I have applied enough coats?

3) for a slab that's 5 feet by 1.5 feet, how much should I be applying with each coat?

Really appreciate everyone's input. Have a great memorial day weekend!

If you are trying to build a film finish with the tung oil then don't wash off the tacky spots. Let it dry and lightly sand it and apply another coat. Then when it starts looking like varnish you have enough. When I'm trying to make a film finish with tung oil, I apply it like it was varnish and let dry.

If you are wanting a more satin non-film appearance then wash off the tacky spots with mineral spirits or if it gums up use lacquer thinner. Then apply another coat of tung oil and wipe off the excess with a clean cloth and let dry. When you get it to a uniform sheen you will have enough coats. For that type finish I apply as little tung oil as I can at one time.

 

[tjk87]

Great, thanks Steve. I'm looking for more of a non-film finish, so I'll go ahead with your advice. I'll send over some pics once it's done.