Thread: Grain filling

I don't know if any of the below will be of use to you - but it is offered in case it is.

I don't use grain fillers at all since I found (with my use) they took away from the natural beauty of the finish and/or provided a colouration I did not like. I keep polishing with shellac until I reach the desired gloss level. It can take a long time but gives the results that I want.

An old Austrian cabinet maker told me that, traditionally, before French Polishing, they had to polish the timber with metho in a rubber and very fine pumice powder mixed with a dry natural earth pigment until the wood gain was filled and the surface absolutely smooth. They also had to polish it for a day or so with a rubber and only metho. However, all the grain filling was done after the wood was reasonably smooth but before it reached its final 1000+ grit smoothness.

Early Australian furniture was not grain filled as far as I can see, but in the late 1800's a lot of Australian cedar furniture was grain filled with Plaster of Paris and a dye of some sort. Many of the dyes were fugitive (faded with time) leaving the timber speckled with light spots.

I finish most things with pre-cat lacquer these days so For grain filling it's either:

For very fine grained timber I just rely on the companion sealer (Readiseal). Two coats. It has minimal filling properties but enough for jarrah or black walnut.

For coarse grained timbers I use Timbermate. Soften it into a slurry by microwaving it. I apply it after sanding and AFTER applying two coats Readiseal. I have a wide range of colours so mix them till I come up with something a little darker then the FINISHED colour of the base timber. I have a wide range of sample boards with mixing ratios recorded to rely on.

If I want to provide a warmer hue I use shellac as a sealer. I like the colour but in every other way Readiseal is a better product. It doesn't really change anything anyway. Still 2 coats then fill.

The issue about Timbermate sanding out is a difficult one. I've always assumed that as a plastic product Timbermate has the same 2 stage drying/curing process as other plastic products. The first stage is just solvent evaporation, which is fairly quick, then there is a much longer catalytic curing process. Same as acrylic paint. The problem is that at the end of the solvent evaporation stage people think it's ready to go (well it feels hard) so they sand it, with disappointing results. If they had waited for the catalytic stage it wouldn't have sanded out. Are there any chemists on board to confirm this?

If you are using a high-build finish then sanding past 240 is a waste of time - in fact will more likely degrade your final product. 180 grit is the commercial standard finish. Obviously I'm talking high build here, not oil finishes etc.

Arron

Originally Posted by Arron

The issue about Timbermate sanding out is a difficult one. I've always assumed that as a plastic product Timbermate has the same 2 stage drying/curing process as other plastic products. The first stage is just solvent evaporation, which is fairly quick, then there is a much longer catalytic curing process. Same as acrylic paint. The problem is that at the end of the solvent evaporation stage people think it's ready to go (well it feels hard) so they sand it, with disappointing results. If they had waited for the catalytic stage it wouldn't have sanded out. Are there any chemists on board to confirm this?Arron

Isn't Timbermate water based?

Spokeshave .. it most definitely is ..

Aaron .. interesting points. So how long would leave a creamy mix of timbermate to cure ?

Originally Posted by spokeshave

Isn't Timbermate water based?

Yep, the solvent is water. Just like acrylic paint, which goes through the same processes. That's why acrylic paint is touch dry after a few hours but takes a couple of weeks to fully harden - after the full catalytic reaction.

Contrast this with NC lacquer which has a solvent evaporation stage but almost no catalytic stage. That's why nc can be dissolved in its own thinner but paint cannot. Shellac likewise.

Btw, I'm putting this out there for confirmation, not stating fact. I wish I knew more about it. In my own work I try to leave it for 3 days before sanding and the results seem to be good - though experience is limited.

I should volunteer to do some experiments and report back here when done. Guess I will.

Thanks arron. When you microwave it, does it turn to the consistency of milk ? Watching the timbermate video, the add water to reach quite a runny liquid.

I was probably a little thicker than the, but not by much.

I have also had problems with timbermate as a grain filler ...... it is trememdously wastefull and if you sand with dust extraction it pulls most of the timber mate out of the grain.

Timber mate is also opaque ..... if ya looking for depth of lustre, timber mate will not give it to ya.

these days , I tend to use sanding sealer compatable with the top coat....... that will fill the grain with a more translucent product.

cheers

Sorry Glenn. I may not have given you an answer. I have had good results after 3 days drying time. I just sanded up a bunch a few minutes ago and was pretty happy with it - zero undercutting. Less then 3 days and I get problems. This is anecdotal though - I know I said I'd do a proper experiment but that will have to wait till after my holidays.

Soundman, I like to use sanding sealer as the grain filler too - but only for fine grained timbers. But what sanding sealer do you recommend for coarse grained timbers (let's say English oak, so we know we are on the same page)? I find the only ones that work are equally opaque as Timbermate because they need to be filled with multifarious silicates and putty-like products to give them the bulk to fill coarse grain.

I'm aware that Luthiers use fibreglass resin for grain filling - and they get very good results - but then they are dealing with products that are worth hundreds or even thousands of dollars per sq ft of surface area so they can afford to lavish a lot of time on them. For the rest of us, I fear a transparent grain/gap filler that doesn't require endless coats remains a holy grail. I've kind of given up searching for it.

Agree that the lack of transparency is a shortcoming with Timbermate though.

Cheers
Arron

Thanks arron, its no problem ... You gave me something to go on.

Upon reflection, I wonder if I am introducing a couple of issues. First, not giving enough drying time. Second, I have often given the job a shot of compressed air to blow away residual dust. I wonder if I am blowing out the grain filling.

I just did some pieces (Sydney Blue Gum) with timbermate again, allowed around 36 hours to dry and did NOT shoot with air.

That said, I am awaiting some butenol to retard my shellac for spraying, with the hope it will flow a little easier into grain lines, so I can't say I am performing an apples to apple's test.

If your filler is so pathetic that it can be removed with compressed air then it's not doing its job so you should be rid of it. It should be rock hard and not bothered by anything much.

Filling with shellac alone is a process for those of extraordinary patience.

Also, I'm a little puzzled. Sydney blue gum has very fine grain (from memory, I could be wrong). I'm surprised you need a separate grain filling step at all. Are you talking grain filling or gap filling?

I read from this that you are after a perfect piano finish.

Cheers
Arron

I prefer to use sanding sealer mainly because it tends to be neutral in color.

I have tried FeastWatson and Cabot's (I think..it was a while ago) and in both instances it was a nightmare to sand away clogging the paper in double quick time.

The last time i tried it, I used a paint scraper to spread a thin coat around but it was a bit messy and required a couple of coats.

Aaron and Soundman...what is your prefered method to apply sanding sealer when you use it and do you have problems with clogged sandpaper when sanding it away?

Thanks for any advice.

Steven.

p.s Sorry to hijack your thread Glenn.

I use FeastWatson Proofseal and it works quite well for sealing the timber for varnish and lacquer. Cheers WC

Originally Posted by spokeshave

I prefer to use sanding sealer mainly because it tends to be neutral in color.

I have tried FeastWatson and Cabot's (I think..it was a while ago) and in both instances it was a nightmare to sand away clogging the paper in double quick time.

The last time i tried it, I used a paint scraper to spread a thin coat around but it was a bit messy and required a couple of coats.

Aaron and Soundman...what is your prefered method to apply sanding sealer when you use it and do you have problems with clogged sandpaper when sanding it away?

Thanks for any advice.

Steven.

p.s Sorry to hijack your thread Glenn.

I tried the Wattyl Sanding Sealer (red can) and it also was hard to sand. I couldn't figure that out - a sanding sealer that is hard to sand ?????????

Anyway, mostly I use Wattyl Rediseal. http://www.wattyl.net.au/industrial/...iseal%20v2.pdf I love it. Its a dream to sand. Zero clogging and just the lightest touch needed. Sands to a chalky dust which just falls away. Takes only about 5 mins to dry and be ready to sand. Note that its spray application only. It also has some kind of silica-looking solids floating around inside which I guess is intended to give it grain filling properties as well - though I can only imagine it working with tight grained timber.

cheers
Arron

Originally Posted by Arron

I tried the Wattyl Sanding Sealer (red can) and it also was hard to sand. I couldn't figure that out - a sanding sealer that is hard to sand ?????????

Anyway, mostly I use Wattyl Rediseal. http://www.wattyl.net.au/industrial/...iseal%20v2.pdf I love it. Its a dream to sand. Zero clogging and just the lightest touch needed. Sands to a chalky dust which just falls away. Takes only about 5 mins to dry and be ready to sand. Note that its spray application only. It also has some kind of silica-looking solids floating around inside which I guess is intended to give it grain filling properties as well - though I can only imagine it working with tight grained timber.

cheers
Arron

Thanks Aaron.

The Wattyl stuff sounds like the go, it's a shame though because I don"t have spray equipment and 20 litres for the smallest package is a bit too much to buy in one go.

Never tried Proofseal though, wonder how that would go.

Steven.