Finishing oak so pores are filled in

[John Hammes]

Hi all:

I'm finishing a piece of oak veneered plywood to use for a new desk top. I'd like to get as much advice as I can find about what to use to fill the pores in the wood so after I've finished the grain can only be seen and not felt. Thanks in advance!!

John Hammes Sr
Mattoon, Illinois, USA

 

[woodbloke]

Hi John and welcome from this side of the water.....I'm not an expert on polishing techniques but I seem to remember that Plaster of Paris is used to fill the grain in open pored timbers before staining and polishing. I'm sure that others more knowledgable on this topic than myself will be along shortly to give a more informed opinion - Rob

 

[Scrit]

Hi John and welcome!

As woodbloke says Plaster of Paris or possibly pumice. If it needs to be coloured I'd use an analine dye to get the required colour. What end colour are you after and do you intend staining the timber before polishing?

Scrit

 

[Sgian Dubh]

Where John is Scrit, in Illinois, he can buy Behlen and Por-O-Pac brands of grain filler off the shelf at places like Woodcraft, A US franchise, and halfway decent paint stores: Sherwin-Williams seem to have a store on every corner and many of those sell polish supplies too.

Plaster-of Paris is indeed a way to fill grain. I use it when the mood takes me. I colour it with water based powder paint and apply it over a surface that's been sealed with a film forming polish of some sort, e.g., shellac, varnish lacquer, etc.. It's hard work and the canned stuff is a lot easier.

As John is US based he might consider visiting Jeff Jewitt's website, http://www.homesteadfinishing.com/ Jeff has a load of articles on finishing there, offers technical help and sells all the products needed to do a decent job-- although, of course, knowledge and skill to polish properly can't be got without some learning curve pains, ha, ha. Slainte.

 

[Scrit]

Have you ever seen the canned stuff here? Most of the time I spray and leave the grain visible, so just curious.

And yes I know that Plaster of Paris is hard work.....

Scrit

 

[Chris Knight]

John,
The best way to fill is with pumice. Pumice is a volcanic glass and when used as I describe will be fairly transparent, giving a good depth to the finish. Jef Jewitt describes a shortcut method with pumice that sounds like it should work but I have never had success with it. I use the following method - which I learnt from Bruce Luckhurst, for all my finishing where I need a really high quality filled finish.

1. Make a pounce bag with a square piece of cotton sheeting or similar - about four inches to the side. Place a small quantity of fine pumice powder on the square and fold it up and secure the ends with a bit of masking tape.

2. Make up a very, very dilute shellac mixture (about a half pound cut)

3. After preparing the wood with planing, sand to 320 grit. Blow clean with an air line if available, otherwise vacuum off the dust.

4. Use the pounce bag to sprinkle a small, repeat small, amount of pumice on the wood.

5. Make up a rubber for applying the shellac - make it good and hard. It doesn't need to be a special shape since you are doing a flat surface.

6. Wet your rubber with the shellac mixture - whack it against your bench leg to distribute the shellac in the rubber. Should feel damp - not dripping.

7. Apply the rubber to the work - make small circles around the circumference, working into the middle in ever decreasing spirals. Finish off each go over the top with longitudinal strokes to eliminate circular marks. Apply these like a plane landing and taking off.

8. Keep repeating the use of the rubber till the pumice can't be felt on the surface. Then repeat with fresh pumice. You can rest at any stage - I usually do about twenty minutes at a time on something the size of a desktop, leaving the shellac to harden for half an hour between goes. If doing a small surface, take more frequent rests otherwise the shellac gets too soft as you go over it again with the damp rubber and you lift the pumice out of the pores.

9. You will know when you are getting there as the wood gets glass smooth. At this stage leave it overnight and have another go the next day. It will probably accept another couple of applications before the pores are completely filled.

Check the rubber frequently as the pumice is very abrasive and wears through your outer cover quickly - replace as needed.


FWIW this is the "correct" way to prepare an open pored wood for French Polishing

 

[Sgian Dubh]

Have you ever seen the canned stuff here? Most of the time I spray and leave the grain visible, so just curious.Scrit

Morrells are one company I use. They sell a range of canned thixotropic grain fillers.

This link might work to a PDF of their products. http://www.morrells-woodfinishes.com/productguide.pdf If it works, look on page 17, or thereabouts. Otherwise you can find them easily enough using an internet search. Slainte.

 

[Scrit]

You know Sgain, I've been buying lacquers off them for years, but I've never had French polishing stuff from there......

Scrit

 

[Sgian Dubh]

You know Sgain, I've been buying lacquers off them for years, but I've never had French polishing stuff from there......Scrit

To be honest Scrit, I've always considered grain filler and grain filling to be a separate technique. I don't link it specifically to shellac and french polishing techniques, although some people incorporate pumice into french polishing to fill the grain.

I've never been fond of that techniques as it was described earlier in this thread by, er, I forget who now: it usually ends up showing white under the polish after a number of years.

I'll fill the grain under (or between coats) of any film forming finish where the job requires it, e.g., pre-cat, post-cat, varnish, shellac, etc.. Of course, I'm fond of getting polish on with a spray-gun, and that includes shellac. Two or three coats of sprayed shellac, and I'm done and off to the pub, ha, ha. Slainte.

 

[Scrit]

I'll fill the grain under (or between coats) of any film forming finish where the job requires it, e.g., pre-cat, post-cat, varnish, shellac, etc.. Of course, I'm fond of getting polish on with a spray-gun, and that includes shellac. Two or three coats of sprayed shellac, and I'm done and off to the pub, ha, ha. Slainte.

Ah! A man after my own heart! Prut!

Scrit

 

[houtslager]

SD wrote

To be honest Scrit, I've always considered grain filler and grain filling to be a separate technique. I don't link it specifically to shellac and french polishing techniques, although some people incorporate pumice into french polishing to fill the grain.

Well I have been a French polisher first then a restorer now a Maker, and I use the technique as described by Waterhead, but then when the time/job required it I have altered the technique in ways simerler to SD.

It all depends on who's paying and what time constraints are put on me :?

A good book to read and digest is the one by Charles B Hayward on FP and Wood Finishing, as rare as hens teeth but still to be had :wink:

 

[Anonymous]

John

i have had really good results with Rustin's grain filler from Axminster - and it is cheap

http://www.axminster.co.uk/product.asp?pf_id=22802&name=grain+filler&user_search=1&sfile=1&jump=0

 

[John Hammes]

Thanks. You guys have been a great help on this. I'm going to look at doing the french polishing technique, but it looks like I have quite a bit more reading to do before I proceed!

Lots of advice here, much appreciated!

 

[Sgian Dubh]

A good book to read and digest is the one by Charles B Hayward on FP and Wood Finishing, as rare as hens teeth but still to be had :wink:

And I have two copies of that book believe it or not houtslager! One hardback and one paperback. Good information on french polishing, but some dodgy polish reviver tricks incorporating linseed oil. Slainte.

 

[gidon]

Chris - out of interest - why is using pumice better than using a ready made, easy to use grain filler like the one Tony linked too?
John - here's two good links if you have FWW subscription (if not PM me and I can send you the PDF's).
http://www.taunton.com/finewoodworking/ ... px?id=2664
http://www.taunton.com/finewoodworking/ ... x?id=24148
Cheers
Gidon

 

[Chris Knight]

Gidon,

I do use commercial grain fillers but on the whole I find they have a tendency to "muddy" the final finish and where very open pores as in oak are concerned, this tendency is increased. If one is doing a lot as in a commercial job, I wouldn't hesitate to use a ready made grain filler. In say an oak library, chances are no one would notice and indeed, perhaps appreciate the uniformity that results.

Since John wanted the pores filled (personally, I wouldn't do this to oak in a piece for myself, as I like the open pored result in say, a simple oil finishing job) and the job is a desktop, I suggested the longer-winded approach. As he is dealing with an oak veneer, it is possible that the pores are largely filled with glue already, so he may not have to spend too long on the job as I have described it.

The method also lends itself to colouring with earth pigments like the ochres and umbers that have permanent colour fastness and can be mixed in as a powder with the pumice.

Finally, one has absolute control over this method whereas with a commercial product you have less control - especially regarding what actually goes into the filler recipe. Application is also a bit all or nothing compared with the pumice method.

 

[gidon]

Thank you Chris. I've never tried even the bought stuff also preferring an open pore finish, but this thread has got me interested!
Thanks again,
Gidon

 

[dennyk]

axminster sell grain filler , I have used it on AWA with success