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another french polish question...

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Rockley

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I bought some colron french polish to finish a chessboard I've been working on (my first project) and am having lots of trouble with getting the high gloss finish I want! Ive probably sanded it back significantly about 3 or 4 times but I guess my persistence will eventually pay off.

My question is what lb cut is colron french polish (from B&Q, I cant post links sorry :roll: )? There is no info about the ratio online and it feels too thick (>2lb cut) to be putting on straight from the bottle so I've been diluting with isoprop alcohol but I want to know roughly if I'm in the right ball-park...or should I just bite the bullet and make my own?
 

ED65

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You can work with shellac at <1 lb cut ('spit coat' consistency) all the way to 4 lb cut and above if you had to, you just need to use the right technique to apply it. For me that means using as much oil as I need to to prevent the pad from sticking or dragging. Lots of guides suggest that beginners should use oil as little as possible (or not at all) but IMO you should do the reverse, use as much as you need to to prevent problems. It's easy as pie to remove excess oil, not so easy to fix the surface defects you get from a pad that sticks during a stroke!

Edit: this is assuming padding it on, if you're brushing it on you shouldn't be expecting to get a superb finish from the brush (in fact it can look pants without affecting the final outcome). You should build up the shellac until it's thick enough, then basically you sand it smooth and polish it.

This is heresy to any fan of shellac but if you want an easier time of it getting a nice gloss finish consider wiping on varnish instead! Although there is a lot more waiting about for drying this method of varnishing is basically beginner-proof :)
 

custard

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Rockley":aa0m8pk8 said:
am having lots of trouble with getting the high gloss finish I want! Ive probably sanded it back significantly about 3 or 4 times....should I just bite the bullet and make my own?
Yes, you should make up your own, personally I aim for about a 2 1/2 lb cut for the initial work and about a 1 1/2lb cut for the final spiriting out stage, don't sweat this too much, every polisher I know has different mixes but all seem to do pretty decent work. There are lots of alternative explanations for the problems you're experiencing, an obvious one is rubbish ready mixed polish, so get rid of that possibility. Next do some research into grain filling during the french polishing process, it's not unusual for the polish to sink into open grain overnight leaving a patchy surface which needs at least three or four rounds of bodying-up over consecutive days. That's not a fault, it's just the way it is, a lot will depend on the timbers you've used and how you prepared them.

Incidentally, a chessboard isn't the easiest finishing project. As I said, a lot depends on the actual timbers you've used, but the killer problem is dark sanding dust getting into the grain of the pale squares. On most woodworking projects there are those potential cock-ups that you can dig yourself out of, and those that you can't. Sanding dust contamination falls into the latter category, so every time you pick up a sheet of sandpaper a red warning light should start flashing, if you're french polishing correctly all you'll need is a tiny bit of de-nibbing.
 

SteveF

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watching with interest :)
what do you use? meths or special stuff?
what oil do you use?

Steve
 

Rockley

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thanks for all the info. From what I read its best to put it on in very small diluted layers especially if your technique is off, so I diluted (with denatured alcohol) the shellac down to an unknown mix but one which I felt comfortable putting on and gave me the results I was looking for. It's by no means perfect but I can live with it now.

For info the board is out of black walnut and maple and I was using olive oil. I read somewhere that it was quicker to fill the grain with danish oil and sanding so i tried this before even staring the french polishing, and then used fine pummice powder with the french polishing to fill in anything left over.

Overall I think the polish made the maple yellower than I wanted but I can live with it. Pieces next then a river table...

Now can I post a picture :?
 

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Rockley

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ED65":1j5tfryk said:
You can work with shellac at <1 lb cut ('spit coat' consistency) all the way to 4 lb cut and above if you had to, you just need to use the right technique to apply it. For me that means using as much oil as I need to to prevent the pad from sticking or dragging. Lots of guides suggest that beginners should use oil as little as possible (or not at all) but IMO you should do the reverse, use as much as you need to to prevent problems. It's easy as pie to remove excess oil, not so easy to fix the surface defects you get from a pad that sticks during a stroke!

Edit: this is assuming padding it on, if you're brushing it on you shouldn't be expecting to get a superb finish from the brush (in fact it can look pants without affecting the final outcome). You should build up the shellac until it's thick enough, then basically you sand it smooth and polish it.

This is heresy to any fan of shellac but if you want an easier time of it getting a nice gloss finish consider wiping on varnish instead! Although there is a lot more waiting about for drying this method of varnishing is basically beginner-proof :)

FYI I was padding it on, I tired with cotton wool in the core but I didn't like that so ended up using scrunched up linen as the core, surrounded by more linen if that makes sense.
 

ED65

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Well that looks super! Nicely done Rockley.

Rockley":1bkry9qg said:
I was using olive oil.
That does help reinforce the idea, one I personally subscribe to, that the type of oil doesn't matter much.

Rockley":1bkry9qg said:
I read somewhere that it was quicker to fill the grain with danish oil and sanding...
Given the much faster drying time of shellac I'm not sure why that would be!
 

custard

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I'll use oil when french polishing, but I don't like to and so keep it to the smallest amount possible. The first problem with oil is that it makes it difficult to accurately read the polished surface, generally it makes things appear much better than they really are, personally I'd rather just know the reality of the job. The next issue is removing the oil, I prefer naphtha, but naphtha comes with a hazard sheet as long as your arm so I wouldn't feel right recommending it. I know a lot of old time polishers say it's just lighter fuel but I'm not convinced, and not being a chemist I'm never going to get a full understanding. When I first feel the rubber dragging I find that by working more slowly I can postpone having to use oil for quite a while.

Regarding grain filling, the simple answer is that Danish Oil or a light cut of shellac are both pretty rubbish solutions. Walnut will always need grain filling if you're aiming for a full gloss finish, or indeed if you want a uniform finish across both the Walnut and the Maple. However, I'm not sure maximum gloss is best for board games, the reflections might become a tiresome distraction.

One piece of advice, Black Walnut fades badly in direct sun. I've posted previously showing fade test results on ABW. I'd suggest storing your board away from direct sun in order to maintain the contrast.

Nice job by the way, I hope carving the pieces goes equally well!
 
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