How to finish coarse grained timber?

[Dengue]

I have been given a few boards of oak, not sure which, but it is fairly coarse open grained timber.

Normally I finish a box or a box lid with Kunos Oil #244, or Wattyl Scandaniavian Teak Oil, but not sure if they would be really good with open grained timbers.

Can anyone please advise a good way of finishing open grained timber?

[Arron]

I generally keep away from open grained timber as I don't see the point in making extra work for yourself.
However I do use oak, silky oak and NG Rosewood when it comes my way and what I do is:

Sand to 240 grit
Spray 2 coats of nitrocellulose sealer. No sanding between coats.
Put some Timbermate in the microwave till its syrupy. Apply this, grinding it in a bit. Wipe off the excess but don't undercut.
Allow to dry.
Sand with 320 grit on a ROS. You must use a variable speed machine and minimize vibration.
Spray 2 coats of precat lacquer. No sanding between coats or after.
Buff quickly with Meguiars Fine Polish.

Quickest way from rough to smooth.

cheers
Arron

[Dengue]

Many thanks for this information, Arron, I really appreciate it. You have raised a point that I have often wondered about grain fillers.

Put some Timbermate in the microwave till its syrupy. Apply this, grinding it in a bit. Wipe off the excess but don't undercut.
Allow to dry.
Sand with 320 grit on a ROS. You must use a variable speed machine and minimize vibration.

What colour do you select for silky oak, and after it is dry do you sand back with the ROS to bare timber?

[LGS]

Hi Dengue,

This was finished with hard burnished Scandinavian Oil.

Regards,

Rob

[Arron]

For colour on silky oak, I generally go one shade darker then the timber. I have lots of the little pots in different colours and mix it up as I need it.

When sanding, I sand back to the surface level of the sealer. No more. With the boxes you are making, it should be only a few seconds of sanding per face - any more then that and you are doing something wrong. If your process involves too much sanding then you start getting that overwrought look - rounded corners and not-crisp edges.

If you think about where I am positioning the final (320 - 400 grit) sand in the above process then its economical because I'm only doing it once - capturing the final sanding of timber, sealer, grain filler and gap filler all in one process.

I should also point out that I sand with an ROS and very rarely by hand (due to hand injuries). I use an ROS with variable speed so I can slow it right down and have learnt to be very gentle and accurate with it.


Generally, though, I always have reservations when I recommend Timbermate. Its not a magic bullet, or even very good, its just better then the other products around.

I'm always searching for a better product but so far no success. There is a clear filler in the US called Crystalac which sounds too good to be true but I cant get it here.

You'd think some chemist genius would have invented the perfect filler by now, but not so. I guess if they have it would be targetted at the professional market, come in 200 litre drums and be sprayed on. Normal DIY channels dont need the product because the customers dont understand filling.

Its not made any better by the fact that most amateur woodworkers resolutely refuse to understand the difference between:
gap filling
grain filling
sealers
sanding sealers

So, with open grained timber you need to decide first what you are after. Are you wanting to:
1. Fill the grain completely, giving a piano finish.
2. Fill the grain nearly completely, so a bit of the grain still telegraphs through the final finish.
3. Leave it open, and just apply a surface finish.

I'm assuming you dont want 3, otherwise you wouldnt be asking. However, this is what satisfies most DIY types and grain fillers and sanding sealers are getting scarcer every day at the big box shops.

Simply recommending a product like oil, poly, lacquer or Scandanavian oil is not solving the problem because all it can deliver you is number 3. These are finish coats with no filling properties. The pores on oak run very deep and will soak up gallons of these products before they are filled to the surface. You have to fill these first, and be confident they are filled before progressing to the finish coats.

I have a strong perference for something that is both a gap filler and a grain filler because I like to do both at once and have both look the same.

Therefore, I dont use these other old standbys:

Shellac - a good sealer but not a filler - too many coats required - doesnt fit in with my do it once and once only ethos.

Shellac with filler (eg talc) - probably my second choice and good for grain filling on finer grain, but not for gap filling and not for coarser grain.

Sanding sealers - these generally dont have any real grain filling properties, though people still seem to confuse them.

Fibreglass resin - this stuff sets hard. Its not self levelling so you end up having to do robust machine sanding, which is not good for a finely crafted surface like your boxes. Same applies to epoxy.

Grain fillers from the brand manufacturers (like Feast and Watson). Last time I used one of these it had some putty-like filler settled out in the bottom. Putty in appearance and putty in colour. The final product looked awful. I dont think tinting would help - the liquid would change colour and this would tint the timber, but I think the filler would still be putty coloured.

Sealers, like Wattyl Readiseal. These have a small amount of filler in them - I think its silica ? They have limited build however and will only fill fine grained timbers like walnut or blackwood.

So that leaves me using Timbermate.

I hope this clarifies something - not sure what.
cheers
Arron

[Dengue]

Thanks for sharing your valuable experience with grain filling and finishing, Arron, there is real food for thought in your post. i appreciate the time you took to do this.

Q1. Which surface finish are you aiming for with the Timbermate, 1 or 2 ?
Q2. Does your process change the look and colour of the natural timber finish you get by just wetting the timber with water or turps?

I was going to try the FW grain filler, but think I will save my money after your experience with this product.

[ian]

Hi Dengue

this Tassie Oak table top was filled using Wattyl's grain filler -- which as Aaron described was putty like.
(The dark stripe is a gum vein where the lose material was replaced with a solvent based timber filler stained stained black-purple with spirit based stains. I mixed the colour I wanted on a bright white bathroom tile.) I did this before applying the filler.

It took a bit of effort to completely mix the filler into the solvent carrier as it settled out in the can.
Grain filler starts dull yellow but can be stained with spirit stains.

Using the grain filler is a fair amount of work as it has to be pushed well into the grain and the excess then scrapped off.

However, in the end I was happy with the result

[Arron]

Thanks for sharing your valuable experience with grain filling and finishing, Arron, there is real food for thought in your post. i appreciate the time you took to do this.

Q1. Which surface finish are you aiming for with the Timbermate, 1 or 2 ?
Q2. Does your process change the look and colour of the natural timber finish you get by just wetting the timber with water or turps?

I was going to try the FW grain filler, but think I will save my money after your experience with this product.

Q1

I think my approach would support both 1 and 2.

If I wanted No 1 then I would have to put a little more work in. Most likely it would be a couple more finish coats with some pullover between. Maybe some sanding between finish coats too. Possibly repeating the filler stage too - to deal with any misses or undercutting. It would depend on the timber.

Personally, I dont mind the old piano finish look but I have noticed that most people now dislike it. Especially young people. Tastes have changed. I think its the Made in China effect.

I guess people want to see a glimpse of the natural raw material and the hand of the craftsman. Its a bit of a cliché but I've found it to be true.

I therefore aim for No 2.

Q2. No, I expect it would be pretty close. Remember that when grain filling the filler will only remain in the grain (pores) - which are unlikely to ever make up more then 10% of the surface area.

The good thing about a canned product like Timbermate is that it doesn't stain the surrounding material - once its sanded away the timber between the pores is the same colour as before. My concern with tinting a product like F&W grainfiller is that the dye would leach out and stain the timber - perhaps Ian can clarify whether this is a real issue or not.

cheers
Arron

[A Duke]

Hi,
Quote "Its not made any better by the fact that most amateur woodworkers resolutely refuse to understand the difference between:
gap filling
grain filling
sealers
sanding sealers"
Its not just the users, the Dick Heads who name the products on the tins seem to be just as confused.
My tuppence worth
Regards

[ian]

The good thing about a canned product like Timbermate is that it doesn't stain the surrounding material - once its sanded away the timber between the pores is the same colour as before. My concern with tinting a product like F&W grainfiller is that the dye would leach out and stain the timber - perhaps Ian can clarify whether this is a real issue or not.

a sealer coat will protect the base timber from staining.

In my case I was using the grain filler to learn how to do it, to try and make the grain stand out, to try and achieve a glass smooth surface and my client (read SWMBO) wanted something not quite so yellow as the base timber -- we settled on a pale pink. I added one or two drops of colour to the filler till it was around the colour I wanted -- I recall making 3 or 4 trial mixes before SWMBO was happy with the colour. Before I started I lashed out and bought a full pallet of colour stains.

Using the grain filler was a lot of work -- but I am very happy with the result. I now know how to use it and what can be achieved.

[Hermit]

.....Its not just the users, the Dick Heads who name the products on the tins seem to be just as confused.

Yep. I bought a can of Wattyl 'Sanding Sealer' a while back, and it was full of talc or similar, really a grain filler.

I swapped to dilute shellac for sanding sealer and shellac/talc for light-weight grain filling. Much better, and the shellac/talc is much easier sanding than the Wattyl stuff. (The Wattyl clogs sandpaper in seconds.)
I use Timbermate for heavier grain filling too, but didn't know about the microwave method. I thin it slightly with water, to a slightly thicker consistency than toothpaste. Have to try the microwave.

[AngelaPetruzzi]

Hello Dengue
If you wanted to use the Kunos natural oil sealer, I think you have two choices and both will depend on the amount of work or look you want.

1. If you really wanted to fill the grain completely, sand to....maybe at the most 240#, then fill with timber mate putty to suit. Timbermate comes in all kinds of colour and if too dark, mix some of the natural to lighten. Remember when oiled, it will deepen in colour. You can either microwave it quickly or add some water and fill. When dry, sand back till you are happy with the surface. By not sanding too too finely, it will allow the oil to penetrate. You can always work up to a “smoother” finish. Apply the oil and carry on as normal.

2. Alternatively, and again, it depends on who you are making the box for, many want to see and feel the timber and accept natural imperfections too. Sand and don’t fill. Oil, wipe off excess, then next day, cut back with e.g. 0000steel wool or scotch brite of some sort. This flattens the wax crystals in the oil, giving the surface more seen (and you work up to the “fine” finish). The wax fills the pores and keeps this part of the timber lighter in colour (than if you puttied it). The second coat will “top up” the pores and again, by cutting back on the third day prior to oil application, give a smoother feel and more sheen. In this method, the wax actually fills in the more porous part of the timber.

Hope this helps. Not sure what happened to the font but I can't correct it.

[Arron]

What we have mostly been talking about so far is filling the grain before applying the finish coat. This seems logical, but its not the only method.

You can also use 'pullover'.

When using pullover you apply a coat or two of finish and then wait for the finish to partially dry, or when newly dry, and then use a cloth pad loaded with a mix of the solvent, the product and denatured alcohol. You simply drag the wet pad over the surface. The newly applied coat of finish is re-dissolved by the pullover mixture and the resultant slurry can be dragged across the surface in such a way that the pores are filled. You can repeat the process as many times as you want till you get the desired effect.

Then sand it smooth and then apply another coat of finish.

Thus you are using the finish coats to do the filling.

Pullover can be used on any finish that relies largely on solvent evaporation for drying and doesnt go through a catalytic reaction - examples are Nitro lacquer and shellac.

I dont think it works on products like poly or Danish oil as there is a catalytic reaction, so they cant be redisolved in their own thinner.

I think that with pre-cat lacquer its quite doable as well, though you probably need to do it before the finish dries - about 3 minutes in this weather. Thats because pre-cats have a small partial calalytic reaction and thus dont redisolve in their own thinner as easily as NC lacquer.

I havent used this for a whole object but I am reliably told that this is the method piano finishers (literally) used to get their piano finishes, back when they were done by hand.

I have used this method a lot for repairs and it works amazingly well - saved my bacon many times.

My spray area is very confined and I often knock and bump objects when I shift them immediately after spraying. This is how I do a small repair without having to respray the whole item.


Angela's method No 2 above is an interesting variant on this because it relies on mechanically shifting included waxes into the pores.

cheers
Arron

[ian]

Yep. I bought a can of Wattyl 'Sanding Sealer' a while back, and it was full of talc or similar, really a grain filler.

I swapped to dilute shellac for sanding sealer and shellac/talc for light-weight grain filling. Much better, and the shellac/talc is much easier sanding than the Wattyl stuff. (The Wattyl clogs sandpaper in seconds.)

I doubt the filler was talc, more likely a resin or sterate of some sort.

I think the problem people have with the Wattyl stuff is they don't let it cure long enough -- Wattyl says it takes 7 days to fully cure.
The times I've used a sanding sealer I've due to circumstances have been able to let it cure for about a week, so haven't had a problem with sanding

[Hermit]

I doubt the filler was talc, more likely a resin or sterate of some sort.

I think the problem people have with the Wattyl stuff is they don't let it cure long enough -- Wattyl says it takes 7 days to fully cure.
The times I've used a sanding sealer I've due to circumstances have been able to let it cure for about a week, so haven't had a problem with sanding

Where do they say 7 days? It didn't say 7 days on the label. (Thrown out now). From memory, it said something like 3 hours. Even so, I was leaving it a minimum 24 hours. And I've left it a couple of days with no improvement in sandability. (Is that a word? Should be.)

The main point, though, was that it had a filler in it, making it a grain filler and not a 'sanding sealer'.

Shellac, whether used as a sanding sealer or with talc as a grain filler, dries in an hour or less.

Edit: I just checked the Wattyl datasheet, for accuracy. It's true that it says fully cured in 7 days, but the instructions say sand and recoat after 3 hours:

Instructions For Use
- Stir contents thoroughly with a flat stirrer before and during use.
- Apply one (1) coat to a correctly prepared surface directly from the can by brush, roller or spray. Allow 3 hours to dry, sand lightly with fine sand paper in the direction of the grain before applying the required finishing coats.
- An additional coat on open-grained timber will provide a smoother finish.

I was leaving it a minimum 24 hours to dry before sanding/recoating. Well over their claimed '3 hours'.