Finish questions: Teak Oil over Sanding Sealer?

[dadagoboi]

Polyurethane should work after 72 hrs.  Scuff sand w/400 and shoot it!  Sand lightly after 24 hrs if necessary and spray second poly coat.

I really believe you can skip the teak oil and second sealer coat (most sealers advise to use only one coat) and go directly to spray poly next time.  Try it on some scrap.  Alder is a close pored wood and shouldn't require a lot of sealing.  I suspect the darkness you saw was normal for end grain, it is the most porous part of the wood and really needs to be sanded back after sealing to lighten up.  I would use 320 before going to 400 from 220.  180 grits is a big jump when you are below 400.  Looking good so far.  A good rule of thumb is don't go down in grit number after a coat unless something is seriously wrong.

This is pine progressively sanded up to 240 with 1 coat of sealer sanded back w/320 and then 400 waiting for a transparent black nitro toner and clear topcoat if it ever stops raining!  Pine is much more porous than alder and nitro much thinner than poly.

[sniper]

looks like that is coming along nicely DDGB, with your history of furniture making, what is your opinion about a Tung oil (the real stuff) and a bees wax finish? i don't want to steal Ack's thread so you could open another here in projects if you wish.

[dadagoboi]

looks like that is coming along nicely DDGB, with your history of furniture making, what is your opinion about a Tung oil (the real stuff) and a bees wax finish? i don't want to steal Ack's thread so you could open another here in projects if you wish.

Every finish method has it's plus and minuses.  It's all about technique.   Tung oil and beeswax are very easy to apply and maintain, the more you work it the better it looks.  Lacquer and other spray finishes are less forgiving, your first steps determine the outcome and repairs are much more difficult to make.

[Lightyear]

Pure tung oil has to have driers added at the least if not thinners.  One the finishes that I've read most about is a mix of varnish, tung oil ( or linseed oil ) and turpentine - this recipe probably predated mineral spirits being commonly available.

I can't remember what Maloof's finish is but it's a witches brew as well and is it's very forgiving.

[Dave W]

Dave's knowledge trumps my basic understanding of things.  The compatibility between "varnish" (A non-oil based product) and poly is new to me.  I'm looking forward to learning more about this phenomenon............  

Poly is a varnish. A urethane resin varnish. The most common other resins used are phenolic and alkyd. Waterlox is an example of a phenolic resin varnish.

Just to be clear, when I mention an varnish-oil blend, I mean that the product consists of a varnish (a chemical combining of resin and oil) mixed with oil. More often than not, this is done for appearance reasons. These dry softer than a varnish alone. Of course how hard a varnish dries varies from one product to another.

If you haven't read it, check your library for Bob Flexner's "Understanding Wood Finishes." Or buy from Amazon. It's worth it.

Here's an informative article by Flexner about so-called oil finishes.

[Dave W]

and just to fully clarify, here's the process/layers (top-to-bottom)

Watco Teak Oil
Sanding: 220/400 (Sanded sides 120/150/220/400)
MinWax Sanding Sealer
Sanding: 220
MinWax Sanding Sealer
Sanding: 80/120/150/220
Bare/new Alder (1.75 inches thick)

Watco Teak Oil is a varnish-oil blend. Shouldn't be a problem topcoating with a spray-on poly so long as you let it thoroughly cure first. However long the manufacturer says.

[dadagoboi]

Pure tung oil has to have driers added at the least if not thinners.  One the finishes that I've read most about is a mix of varnish, tung oil ( or linseed oil ) and turpentine - this recipe probably predated mineral spirits being commonly available.

I can't remember what Maloof's finish is but it's a witches brew as well and is it's very forgiving.

Turpentine is distilled from pine resin and does predate mineral spirits which is a petroleum distillate.  There used to be a big tung tree plantation around here, the oil comes from the seed of the nuts and it is similar to linseed oil but has a golden color.  Technically tung and linseed oil ARE driers.  Linseed oil used to be the drying component of traditional enamels, replaced by alkyds in modern paint.

[sniper]

the one time i went AWOL (which i don't talk about much) the Marine company pusher that was helping me pass as a jarhead had me service the wood on my 14 (proves i am old as the 16 was not common issue yet) with a third part Tung oil, a third bees wax and a third turpentine. it waterproofed the wood. of course we had to do this inside and out on the stock but the results were great. the shine wasn't the best but more of a satin finish and it was easy to repair if one got a scratch in the wood. if we wanted it darker for camo reasons then a little boot polish helped that mixture.

the point being a walnut stocked piece in the swamps of Lejeune held up well in and out of the brackish water and was restored quite easily to inspection ready with little maintenance to the wood after training. the drying time was decreased with the increase of the amount of turpentine.

sorry i left out the point of this earlier. i'm getting more absent minded.

[ack1961]

Watco Teak Oil is a varnish-oil blend. Shouldn't be a problem topcoating with a spray-on poly so long as you let it thoroughly cure first. However long the manufacturer says.

Appreciate the info.
I'm waiting at least 72 hours - maybe more because of the sealer - before I spray on the first coat of Poly.
Should be interesting.
I'm going to practice on something, because I'm brutal with spray cans.

[Lightyear]

Turpentine is distilled from pine resin and does predate mineral spirits which is a petroleum distillate.  There used to be a big tung tree plantation around here, the oil comes from the seed of the nuts and it is similar to linseed oil but has a golden color.  Technically tung and linseed oil ARE driers.  Linseed oil used to be the drying component of traditional enamels, replaced by alkyds in modern paint.

Pure tung oil takes forever to cure - i tried it once in shop class - that paddle I made for one of the coaches is still probably too sticky to use .  The stuff I've read said to use japan drier and to thin it a bit so that it would penetrate the wood. 

Dave's right - most everything you buy that says tung oil is just a thinned varnish or poly with a small portion of tung oil added.  I been buying oil based poly for years and cutting it about a third with mineral spirits and making my own wiping varnish - works great and the price is right.

[drbassman]

Pure tung oil takes forever to cure - i tried it once in shop class - that paddle I made for one of the coaches is still probably too sticky to use .  The stuff I've read said to use japan drier and to thin it a bit so that it would penetrate the wood. 

Dave's right - most everything you buy that says tung oil is just a thinned varnish or poly with a small portion of tung oil added.  I been buying oil based poly for years and cutting it about a third with mineral spirits and making my own wiping varnish - works great and the price is right.

So, if you put one of the bastardized oils/varnish over poly, it will actually stick?  I'm surprised and learned something new!

[Lightyear]

I would be comfortable betting that something like Formby's would stick just fine as it seems to be more of a coating than a penetrating oil.  I would think that a homebrew mixture would not.

Don't get me wrong I like the off the shelf stuff - it's just not really tung oil.

[Dave W]

I would be comfortable betting that something like Formby's would stick just fine as it seems to be more of a coating than a penetrating oil.  I would think that a homebrew mixture would not.

Don't get me wrong I like the off the shelf stuff - it's just not really tung oil.

Formby's Tung Oil Finish is a wiping varnish, despite the name. See the Bob Flexner article I linked to above.

I agree that it's a good finish. If it's the look you're going for, no reason not to use it.

[dadagoboi]

Don't get me wrong I like the off the shelf stuff - it's just not really tung oil.

+1...I think they sprinkle a few drops of tung oil over the batch and  voila! 'Tung Oil'.  Or maybe they wave the magic tung nuts at it. 

[drbassman]

Well, I've used Formby's and it did a nice job as the only finish applied to an old project.  I also like Danish Oil a lot as a single finishing "oil."