Grain filling

[cjbfisher]

I have finished a few benchtops at work lately, and I haven't been happy with the results that I have achieved. First was some laminated Melunak tops, and today it was laminated New Guinea Rosewood. Both times, the process has been 2 coats of Feast Watson sanding sealer, sanded back with 240 grit, followed by two/three coats of poly rubbed back with 0000 steel wool between coats. Oil based for the Melunak, and water based for the Rosewood.
I don't have a lot of experience with finishing, and I've done things this way because that's what I've been told to do. I have done this before on Blackbutt, and was quite happy with the result, but the more open grain of the latest two timbers is causing me grief. How do I go about filling the grain so that the poly doesn't suck down into the surface? The sanding sealer is supposed to have some grain filling properties, but obviously not good enough.

[FenceFurniture]

I have been doing some extensive experimenting with this just recently. One or two others have followed a similar procedure and have been as happy as I am with the results. One or two others may disagree violently with my methods, but may also have never tried them (that's just a bit of a caveat). Also, bear in mind that it depends upon the particular timber, it's colour and how it responds.

Furthermore, I am hopeless at following instructions that say "stop sanding at 240 grit". For me that it utter bollocks, and anyone who subscribes to it has never seen what happens to the grain of great (Australian hardwood) timber from grits 500 through to 4000. This is not about smoothness (although that is quite literally SENSATIONAL!) but rathermore what happens to the grain visually as each finer grit is stepped up. It's a bit like trying to convince a virgin how good *certain activities* can be....

So, before I get to the technique, this is what you can achieve with sanding to (in this case "only" 3000) with no finish applied - bare wood.

http://www.woodworkforums.com/attachment.php?attachmentid=324203&d=1409738461

Note that I have focussed the camera on the reflections rather than the timber grain. You can very clearly see the reflection of the alum extension table of my thicknesser on the left side, and the green locking handle (et al) of my Kapex mitre saw on the right. In the middle is the reflection of the light source itself. Remember - no finish applied yet - just sanding.

So that was an experiment to show what can be achieved with just sanding. What I actually do these days is sand to (probably) 500, and then do two coats of sanding sealer (ensuring that I sand each one back to bare timber). This naps up the grain which can then be sanded off. At $40 per litre for Feast Watson SS - yer boss is wasting his dough badly. I get some expired liquid shellac ( in this case Forum Owner Dewaxed White Shellac) and dilute it to about 8:1 with ordinary meths (i.e. not hell expensive and difficult to source Industrial Meths). It actually recommends this on the Shellac bottle when it is out of date.

I have compared this to the hell expensive FW "specific" SS and it is just as good....if not better because it dries in either seconds or minutes as opposed to 45(?) minutes for FW SS. Oh yeah, and it's kinda free because the shellac was "useless" and meths cost bugger all.

So 2 coats of that, sanded back to bare timber - 10 minutes depending on job size of course - and now you are ready to apply the next step, which is grain filler.

You can use some pigmented things like Timbermate (not for me....) or Intergrain filler, but the smoothest one I have used is AquaCoat (NOT AquaCote or BoatCote). The first time I used AquaCoat is well documented in this thread:
http://www.woodworkforums.com/f187/blackwood-table-son-219847/2#post2071342

A pic from that thread:
http://www.woodworkforums.com/attachment.php?attachmentid=430341&d=1519347853

I cannot take credit for the beautiful timber, but I will take credit for making the most of it....... but with good products.

It is crazy easy to use. Rub it in like paste wax, sand it off - repeat only if necessary, dependent upon timber and how open the grain is. In my opinion it does not work well on blonde timbers, as it showed up dark in the tests that I did on some very very curly Blackbutt (but I may have overworked it rubbing it in).

The smoothness is FANTASTIC!

After that, apply whatever finish the job requires.

AquaCoat is available from Australia's only supplier, and you'll be chuffed to learn he is in Brisbane.
https://armstronglutherie.com.au/products/

I used a tiny amount for that 1500x900 table (it is documented in the thread, but from memory I think <100ml?)


You may also get some benefit from these threads:
http://www.woodworkforums.com/f9/osmo-polyx-raw-oil-playing-221673
and particularly this one by qwertyu
http://www.woodworkforums.com/f9/grain-fillers-221802

[yvan]

So, grain filler is not the same as sanding filler?

[woodPixel]

FenceFurnitures summation is spot on.

If you don't have AquaCoat, use two or three light costs of shellac, then spray down 6 wet coats of polyurethane, then wet sand it perfectly flat, then polish (Google "rubbing out")

If time isn't on your side and you can't wait for the poly to harden, use nitrocellulose or Mirotone Mirolac 3220. Epoxy also works brilliantly.

Shiney!

[FenceFurniture]

So, grain filler is not the same as sanding filler?To be honest I'm not knowledgeable enough to say categorically. I can only say what I have found gives an excellent result. As far as I'm concerned, and I'll stand corrected, sanding sealer is to raise up the remaining fibres so they can be knocked off when sanded back again. You can certainly feel the surface has become rough after the SS is applied. If this isn't done then the next wet thing that goes onto the timber will raise up the grain - if that is the finish itself which is not going to be sanded back at all then you will have a permanently rough surface.

Grain filler is to fill the pores in the timber, and so different timbers will have different requirements, depending on how open the grain is of that species. Australian Red Cedar is very open grained and will probably need two applications of AquaCoat, maybe even three in parts. OTOH, Gidgee would only need one. Certainly grain fillers like TimberMate :puke: and Intergrain won;t raise up the grain because they are super viscous with almost nil moisture content.

I suppose that the SS step could possibly be deleted when using AquaCoat, given that the AC is wet and would raise up the grain. I am just loath to change a process that is giving me the results I want - and I enjoy finishing, unlike some who find it a chore. Watching the grain pop out when using each grit past 500 is really rewarding.

Another point - I do not subscribe to the view that sanding up to very fine grits just burnishes the timber so that the finish cannot penetrate the timber. Timber is porous and will still absorb oils. Other finishes like Shellac, varnishes et al tend to sit on top of the timber anyway, so what's the difference?

[Cliff Rogers]

Also worth a look for clear grain filling is Pacer Z-POXY EPOXY Finishing Resin PT40 ZAP.
You'll find it on eBay.
https://www.ebay.com.au/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=Pacer+Z-POXY+EPOXY+Finishing+Resin+PT40+ZAP&_sacat=0

You'll find demos on youtube.
https://www.youtube.com/results?search_query=Pacer+Z-POXY+EPOXY+Finishing+Resin+grain+fill

[woodPixel]

If you are super skint, you can use egg white.

It acts as both. Luthiers have been using... Forever

[cjbfisher]

Thanks for the replies. Looks like I have a lot of learning to do. Are there any good books out there that you would recommend for learning about the different types of finishes and where/how to use them.

[woodPixel]

You know, there are many very talented woodworkers here and a lot of good threads on finishing.

I honestly think the VERY best finishes and detail work are completed by Luthiers, especially acoustic guitars. Their finishing, attention to extreme detail and inlays are astonishing.

[ian]

I have finished a few benchtops at work lately, and I haven't been happy with the results that I have achieved. First was some laminated Melunak tops, and today it was laminated New Guinea Rosewood. Both times, the process has been 2 coats of Feast Watson sanding sealer, sanded back with 240 grit, followed by two/three coats of poly rubbed back with 0000 steel wool between coats. Oil based for the Melunak, and water based for the Rosewood.
I don't have a lot of experience with finishing, and I've done things this way because that's what I've been told to do. I have done this before on Blackbutt, and was quite happy with the result, but the more open grain of the latest two timbers is causing me grief. How do I go about filling the grain so that the poly doesn't suck down into the surface? The sanding sealer is supposed to have some grain filling properties, but obviously not good enough.
Hi cjb
first you need to recognise that the three timbers you mention -- Melunak, NG Rosewood, Blackbutt -- are very different in terms of how open their grain is.

A sanding sealer will do some limited grain filling on close pored timber like Blackbutt, but on open grain woods like NG Rosewood there is just not enough "filler" in the mix to fill the grain.
Your options are to use multiple coats of finish -- you keep applying until the pores are full -- with a traditional shellac finish you added talc to the mix to achieve -- after several days -- a piano finish.

The other alternative is to use a grain filler like that made by Wattyl. Wattyl Craftsman Grain Filler (http://www.wattyl.com.au/en/find-the-right-product/wood-care/Interior/FurnitureBuiltinFurniture/Stains/WattylCraftsmanGrainFiller.html)


As to books, etc.
Almost anything by Bob Flexner https://www.amazon.com/Bob-Flexner/e/B000APORGS
https://www.popularwoodworking.com/woodworking-blogs/flexner-on-finishing-blog/

[rustynail]

To be honest I'm not knowledgeable enough to say categorically. I can only say what I have found gives an excellent result. As far as I'm concerned, and I'll stand corrected, sanding sealer is to raise up the remaining fibres so they can be knocked off when sanded back again. You can certainly feel the surface has become rough after the SS is applied. If this isn't done then the next wet thing that goes onto the timber will raise up the grain - if that is the finish itself which is not going to be sanded back at all then you will have a permanently rough surface.

Grain filler is to fill the pores in the timber, and so different timbers will have different requirements, depending on how open the grain is of that species. Australian Red Cedar is very open grained and will probably need two applications of AquaCoat, maybe even three in parts. OTOH, Gidgee would only need one. Certainly grain fillers like TimberMate :puke: and Intergrain won;t raise up the grain because they are super viscous with almost nil moisture content.

I suppose that the SS step could possibly be deleted when using AquaCoat, given that the AC is wet and would raise up the grain. I am just loath to change a process that is giving me the results I want - and I enjoy finishing, unlike some who find it a chore. Watching the grain pop out when using each grit past 500 is really rewarding.

Another point - I do not subscribe to the view that sanding up to very fine grits just burnishes the timber so that the finish cannot penetrate the timber. Timber is porous and will still absorb oils. Other finishes like Shellac, varnishes et al tend to sit on top of the timber anyway, so what's the difference?
Oil requires a much finer sanding than either poly or lacquer. Both the later are surface finishes and require a key to keep them in contact with the timber. Time is the teacher here. After a while, the poly is inclined to lift from over-smooth surfaces, particularly if the surface is concave, as in a moulded table edge. Without a key, this degradation manifests much earlier. And with poly, it now has to be stripped right back before recoat.
An oil finish can be slurry sanded on the first coats to give an effective grain fill. This method can be repeated until the surface has reached a suitable level of fill which will vary specie to specie. With lacquer, the surface can be "pulled" to minimise grain indentation. This method is used to avoid the overmasking of the grain feature when fillers are used. A beautiful piece of flame or fiddleback timber needs to have s*#t rubbed into it like a hole in the head. Poly is a great name for a cocky but not nice to wood.

[woodPixel]

I'm not so sure that all poly is crap. Some of the vendors I've been speaking with recently have some seriously amazing formulations. I'm obviously not talking about Bunnings discount stuff, but Behlans, Intergrain, Norglass and Bondall....plus my personal favourite Mirotone.

Luthiers that I talk with, who sell $5-$8000 acoustic guitars use Mirotone and Behlans. They swear by it.

Given these blokes are the absolute undisputed rockstars of finishing, they are worth looking in to.

I'll dig up some links and pictures

[rustynail]

I agree, they do come up a treat. Refinishing is where things start to come unstuck (literally).

[Robson Valley]

What's the value in constantly shredding the wood surface with sandpapers?

Try cutting the wood for a genuine smooth surface with cabinet scrapers.
You can make your own out of scrap steel with a chalked up file.
I've got dozens, they are so cheap and simple to make.
Sandpapers are for sharpening.

[auscab]

A good way of going in the right direction with grain fill that I like is .
Make a pva / water soloution . About 15% pva. Sand the surface with something like a 320 grit paper around in circles across the grain in a slurry. Its got to be watched closely that its not to wet . That just washes the slurry out of the grain if it is . To dry and you start skidding over slurry dry build up . Just right and you see a full grain fill happen in front of your eyes . let it dry and the glue sets it off. When you touch it next your not wiping dust out of the grain. If it sets with dry circular slurry over the top then that can be fine sanded back straight later. Sometimes I do the second sand back with oil and turps . The dry circular slurry over the top acts like sight lines , the moment they disappear I know when to stop sanding. Cutting back and grain filling can be done like this between coats as well . Its great on timbers that are not stained . It gets a little more tricky if it is stained and you go through in spots . You just have to touch up . If its being done in between coats then the water / glue mix should have a darker pigment added. Anything filling the grain either has to be the same colour as the wood or darker . Never lighter. it looks wrong if it is . Just a touch of Brown Umber with some Black oxide is one way . I use Vandyke with some Black .

Rob

[cjbfisher]

Thanks again for the replies from everyone.
My understanding is that the sealer is used to raise the grain of the timber, and to then sand those fibres down to a flat surface, but unless it is a very tight grained timber the sealer will do very little filling. Correct?
When sanding the sealer, should you really go back to bare timber? Wouldn't this be exposing more loose fibres that will lift with the next coat?
I have borrowed a French Polishing book from the local library, and am waiting for another by Bob Flexner to arrive. I'm sure the questions will continue.

[ian]

A bit more on grain filling ...

The following image is from https://www.popularwoodworking.com/articleindex/30921/

https://www.popularwoodworking.com/wp-content/uploads/2011/01/Aug_Page_56_Image_0001-300x170.jpg

I'm guessing that the left half is what you are getting on the open grained New Guinea Rosewood, while the right side is what you would like?

[auscab]

Sealer is not for raising the grain . Water or water based products raise grain . If water based products are to be used on raw wood then raising and cutting back the raised grain should be done first .

[cjbfisher]

I'm guessing that the left half is what you are getting on the open grained New Guinea Rosewood, while the right side is what you would like?
Correct.

[ubeaut]

Sanding sealer was originally developed to fill the grain before spraying it with lacquer. The sealer was cheaper than the lacquer and formulated to help fill the grain whilst being easier to sand back without clogging the abrasive the way lacquer would. Thus saving time and money rather than filling up with grain filler or lacquer.

My U-Beaut Sanding Sealer (http://www.ubeaut.com.au/sandseal.htm) is based on our White Shellac (Dewaxed) (http://www.ubeaut.com.au/dewaxed.html) and rather than filling the grain it is designed to raise the grain that has been torn during the sanding process. This raised grain will stand up and go very brittle and will be easily removed not by sanding but with a wipe over the surface with your finest grit abrasive. Sanding will take you back beyond the wipe to raw timber and once again leave you with torn grain.

You can make a grain filler using U-Beauts White Shellac (http://www.ubeaut.com.au/dewaxed.html) and adding a small amount of our pure Talcum Powder (http://www.ubeaut.com.au/talc.html) this will fill the pores of the timber in a couple of coats (may need more depending on the timber) and will not come out white in the pores. The talc helps to fill the grain and makes it easy to sand the shellac back without clogging the abrasive.

You can also make a brilliant grain filler that can be colour matched to the timber by making a thin gesso using our Hide Glue (http://www.ubeaut.com.au/hide.htm), water , Talc (http://www.ubeaut.com.au/talc.html)and either Water Dyes (http://www.ubeaut.com.au/dye.html) or universal tint.

Proprietary grain fillers can be good also. Wattyl Wood grain filler used to be my favourite that worked well every time. Haven't tried the Craftsman Grain Filler which as replaced it but if it's as good as their original wood grain filler it should be a goer.

Have a look at "A Polishers Handbook (http://www.ubeaut.com.au/book.html)" for more info on grain filling and lots more.

Hope this is of some interest and help.

Cheers - Neil :U

[cjbfisher]

Thanks Neil.
I'm currently doing a bit of reading through several books that I have borrowed from our local library. There's a lot of information to digest, and I'll probably have forgotten a fair whack of it by the time I'm finished reading. I'm also struggling to comprehend some of it, as I'm more of a hands on type learner. I can read about it, but once I actually do it the understanding seems to develop.
One thing I haven't come across in my reading thus far is which type of finish is best used in which application. I'm sure I'll come across it at some stage.

[ubeaut]

My apologies for the blatant advertising above, but couldn't help myself. :B

A bit more on sanding sealer (at least the U-Beaut one) below:

Ever applied a surface coating like polyurethane, lacquer or shellac to a work piece sanded to around 240 grit (often sold as fine). If so, when it dried and you ran your hand over the finished surface, I'll bet it felt like someone had thrown a hand full of sand into the finish.

This gritty feeling is the torn grain from sanding being raised by the finish. It is even worse if the piece you coated was plywood, as so much of todays cheaper unfinished furniture is.

U-Beaut's Sanding Sealer was designed to raise that grain, make it brittle and then be sanded/wiped off with fine abrasive. by doing this you eliminate all those little nibs and get a smooth surface when you apply your finish.

My preferred way to use Sanding Sealer:


Ideally use a Random Orbital Sander I have a Festool, but even the cheaper ones will do the job well.
Sand through the grits 120, 180, 240, 340, 400, 600 and 800 then stop. With a good ROS it shouldn't take long.
Moisten a clean soft lint free rag/cloth with Sanding Sealer. Not wringing wet.
Wipe the SS over the entire surface of the work once, if needed add a little more to the rag to to cover larger area.
Allow SS to dry at least an hour, more if needed. Timber should look and feel dry. If you have the time leave over night.
Put a piece of 1200 grit onto ROS turn sander on to low speed (if variable speed) and basically wipe the grit over the surface. Don't scrub at it or work like you are sanding, it is basically one wipe over the surface and nothing more.
When done get a clean lint free cloth and wipe the surface clean of any dust that may remain.
Surface should feel silky smooth and will be ready for finishing.
At this point you can add a water dye to the work if you wish to colour it. The dye will soak into the timber without raising the grain
You can use a turpentine based stain over the SS but not alcohol based stain or dye as this could well make a mess of the surface especially if you intend to use shellac or any other alcohol based finish.
Your surface is now ready to receive your preferred finish.


Personally I would finish with White Shellac or Hard Shellac for a horizontal surface that needs to be tough. Shellac will key into the pores of the timber where polyurethane needs a rough surface from sanding to key itself to.

WARNING:
Putting Poly over a very finely sanded surface could be a recipe for disaster down the track. I have seen a table top finished where the poly had completely delaminated into one massive bubble because it was applied to a very finely sanded surface and subjected to extreme heat. Hilariously horrific, terrible to repair and really costly.

Sorry for the ramble but hopefully it will be of help to some.

Cheers - Neil :U

[cjbfisher]

No need for apologies, Neil. After all, who would be more qualified than you to comment on your own products?
With regard to the shellac going out of date, what is the shelf life once mixed, and what happens once past the "use by" date?
If I was an irregular user, would I be better off buying flakes and mixing it as required?

[Cliff Rogers]

There should be a 'Best By' date on the label somewhere.

[cjbfisher]

Yes, there is a best by date on the bottle. Just wondering what the shelf life is leading up to that date, and what happens to the product once past that date.

[Cliff Rogers]

This is off the internet from 2 different places, it doesn't say what happens to it.
I had an old bottle of mixed shellac that I tried to turn into sanding sealer by diluting it with metho but it wouldn't set hard enough to sand without clogging the paper, I chucked it out.


The Hard Shellac is premixed & has an 18 month shelf life.

Once shellac flakes are mixed with alcohol, the mixture has a shelf life of no more than a year and a half.

[ubeaut]

Yes, there is a best by date on the bottle. Just wondering what the shelf life is leading up to that date, and what happens to the product once past that date.

Shelf life is until the best by date on the bottle.

White Shellac (dewaxed):
Best by date on the bottle means shelf life for polishing is 18 mths from the time it's put into the bottle until that date. Caution. Be aware that some sellers may not sell much of it so it could already be a year old or more when you buy it. Always check the best before date before handing over your hard earned.

After that date it will not fully harden on the surface. It will dry and feel hard but if you were to leave something heavy sitting on the surface for a few days, when you remove it there could well be an imprint from the base of that something, left in the surface of the finish.

If it is White Shellac you can mix it down 10 parts Industrial Methylated Spirits (either 95% or 100%. If it's off the shelf at the supermarket then it's all but useless) to 1 part white shellac and you should have sanding sealer that will work for years.

If it's been out of date for a few years toss it out.

If the White or Hard Shellac is a dark brown in the bottle and not a honey colour, it will be because it has been exposed to bright light. Ideally keep it and most of our polishes in an esky or somewhere else that is dark and has a bit of temperature control. We keep all our products in a refrigerated container that's pitch black inside and is kept at a constant temperature of around 12-13oC.

Hard Shellac:
Hard shellac also has n 18 month shelf life. However because it is hardened with a melamine solution it appears to work well beyond it's shelf life. I have had reports of people using it 5 years after expiry date and still not having a problem with it.

My short answer for Hard Shellac is once it uses it's best by date..... Throw it out, get rid of it, dispose of it (thoughtfully) ditch it, chuck it.... :D and buy a new bottle. :2tsup:

Hope this is of some help.

Cheers - Neil :U

PS
For Cliff and others:
Only use the White Shellac (dewaxed) for sanding sealer if you use ordinary shells there is a wax component in the shellac that makes it not work well as a sealer and will clog your abrasive. The dewaxed White should work well and not clog abrasive. Hard Shellac won't work and will more than likely clog adrasives. Most other shellacs will be pretty much useless, unless the wax component has been removed.

However... For what it's worth, common old everyday waxy gold/brown shellac is really good at sealing pitch into pine and stopping it from leaching out.

[Cliff Rogers]

Beauty, thanks. I can't remember what is was.... just when out to the shed & looked, I have White & Hard on the shelf & the hard is at the front so I most likely used it. :-