Finishing advice sought for an elm desktop

[Benpointer]

Hi,

Novice alert! - Apols for the long post...

I would appreciate some advice on finishing a 2' x 8' sawn elm board I have acquired to make a desk top to go into an alcove in my study. The board is through-cut, 2" thick with some lovely grain and a couple of knots with minor splits. It has been air-dried in a barn for a few years down to 11% according to my mini moisture metre. It's moved a little in drying with a slight bow (about 1/2") along it's length, which I can live with but it shows no sign of having cupped at all across its width - it's nice and flat across-ways.

I used a power planer to remove sawmill blade marks but that has left me with a few areas of tear out where the grain is quite interlocked. I have now moved on to using abranet on a makita ROS and I expect to be able to remove any edge lines left by the planer and most (but maybe not all) of the tear out.

I plan to finish in Osma Polyx. Any suggestions about what use to fill the few small areas of deepest tear-out I may not be able to sand out, bearing in mind I will then be finishing with Osma? same filling the knot splits (though I could leave these unfilled as they are just part of the wood's character)

Also, the grain is quite open - would you recommend grain filling before finishing? If so any recommendations?

Finally, do I need to acclimatise it in the room it will be going into before trimming to final size and fixing in place? It's going in an alcove so I imaged fixing to a batten along the back wall and then slot screw fixings to wall battens at each end. I plan to leave the front waney edged so I am not worried if it shrinks a bit across the board width.

Thanks in anticipation for any advice!

Steve

 

[ED65]

Re. tearout in general for the future I'd highly recommend getting on friendly terms with a suitable hand plane and/or a card scraper. With a little practice planing can leave no tearout worth noting the majority of the time, and when there is a bit because the wood is particularly tricky a scraper will take care of it with ease.

They both have the advantage of making no noise and producing no dust, always a plus in my book.

I plan to finish in Osma Polyx. Any suggestions about what use to fill the few small areas of deepest tear-out I may not be able to sand out, bearing in mind I will then be finishing with Osma?

I think straight epoxy is a good option here. Are the areas quite localised or a bit more diffuse than that? If localised tape off around the perimeter of each area to reduce cleanup afterwards, spread epoxy inside each 'cell' and sand back once the epoxy is good and hard. Don't be tempted to sand too early or you could make a mess. Epoxy sands best when it is fully cured.

Splits in knots I'm a fan of filling with epoxy tinted black, or with a black filler like charcoal dust. If you'd prefer not to highlight them then you can mix sanding dusts to approximately match the knot colour. If the colour ends up close or just a bit darker the splits can become nearly invisible.

As for the grain filling that's really up to you, there's no right or wrong just personal taste. Some people love a full grain-filled job, others much prefer an open-grained look.

It's going in an alcove so I imaged fixing to a batten along the back wall and then slot screw fixings to wall battens at each end. I plan to leave the front waney edged so I am not worried if it shrinks a bit across the board width.

Sounds like a plan Stan! Er, Steve

 

[Benpointer]

Thanks ED65, I'll have a try with epoxy on an offcut. The tear-out is very localised, just around one of the knots.

Re a hand plane, I couldn't face hand-planing 2 sides of 16 square feet and I have no confidence in getting good results... but I take your point - I should spend some time learining how to use one better.

Thanks for the advice!

 

[Bm101]

I can't give advice (! idiot alert !) but I'd be looking at a scraper for the tearout. You can buy a set and a burnisher to turn the edge or you can make one if that's your fancy. The cheapest but more temporary option that I know is get some old (ideally plate) unwanted glass. Wrap it in newspaper and give it a good hoof with some decent boots on or maybe even a hammer if you have more common than me. You'll get a a lot of waste but you'll also get a load of free but temporary scrapers. They will wear blunt fairly quickly but, ya know. Is what it is. I used to know a chairmaker in Wales who swore by throwing pebbles at it because he reckoned you got more useful curved shards that way. True? No idea. He was a good chairmaker though so maybe.

 

[thetyreman]

try a cabinet scraper, stanley no80, amazing for this problem you have, I like it a lot for difficult grain.

 

[Benpointer]

Thanks all I have bought a set of veritas scrapers from axeminster. Seems to work like a dream!

Did anyone have any thoughts about whether I need to acclimatise the wood to the room, now I have rechecked the moisture content it seems to be around 15%, not 11% ...

"... do I need to acclimatise it in the room it will be going into before trimming to final size and fixing in place? It's going in an alcove so I imaged fixing to a batten along the back wall and then slot screw fixings to wall battens at each end. I plan to leave the front waney edged so I am not worried if it shrinks a bit across the board width."

Thanks

 

[MusicMan]

+1 for the stanley no 80. Easier on my elderly fingers and thumbs than card scraper, though of course I have these and they are great.

See more info here:

http://www.popularwoodworking.com/woodw ... et-scraper

Maybe you already bought the veritas equivalent, which is also very nice. But Stanley no 80 often comes up cheaply on eBay.

If you use slots for the screws at the sides you will not need any more acclimatisation as they will accommodate movement. No need to slot the ones at the back (parallel to the end grain which virtually does not move).

Card or scraper plane is better than sanding for removing planer lines. It is worth scraping the whole surface, not just patches, as scraping leaves a better ("sharper") surface than sanding, and absorbs the finish a little differently hence a partially scraped, partially sanded surface can look blotchy. It won't take long.

Fiddes Hardwax Oil is my finish of choice, but a lot of people like Osmo.

In a wany-edge yew desk I made, I left the knots as holes, to preserve the rustic appearance. Pure matter of choice though.

This should look lovely. We demand photos when finished, in return for all the advice!

Keith

 

[ED65]

...scraping leaves a better ("sharper") surface than sanding, and absorbs the finish a little differently hence a partially scraped, partially sanded surface can look blotchy.

+1

One workaround for this where there are only localised areas of tearout and you don't want to scrape the whole surface is scrape the problem areas then sand the surface to bring it back into line with the parts that were sanded only. Obviously you can't scrape too much in any one spot though or you'll end up with an undulating surface, but sometimes this is acceptable.