polyurethane finish

[Green]

I've just discovered this site while searching for some help. It look very impressive.

Last year I took a couple of french polishing courses at evening college and I'm hooked. I can't keep away from second hand furniture auctions and I've restored a couple of pieces that came up a treat. Unfortunate the family don't share my obsessive behaviour and tend to put hot cups, etc, on the items with the resulting burn marks spoiling my once precious items.

I'm in the process of restoring a sideboard that has ceder veneer on the doors. I've used a polyurethane finish for the first time to stop any future heartbreak but cant get anything like a flat finish. Is it the veneer reacting? I've tried four coats, sanding back each time, but it always ends up with a series of waves.

So far I've only played with one door but I'm thinking of stripping it back, using shellac, and fitting a glass top. HELP.

[echnidna]

Poly tends to be like that even with a spraygun, which can be a pain.
The aerosol cans seem to go on ok though.
But you can pad poly on (similar to french polishing) and achieve an excellent finish.

[Taffy]

Removing the wet rings on your already restored pieces, try a warm to hot iron with a pad of cloth between the wood and the iron, this will tend to lift the damp ring out of the timber finish, also ther is a product called "Ring remover" that restoration shops sell.
As for the new job you could try finishing with a poly impregnated oil, if this is what you meant, surley not Estapol or the like.

Best of luck

Taffy

[Harry72]

How thick are you putting the poly on?

[Green]

thanks guys

I'm afraid it is Estapol - by the sounds of it I've done the wrong thing.

As for coat thichness, I've tried light and thick - same wavey result.

Green (or should that be 'Very Green'!)

[Harry72]

When you mean wavey, do you mean a dimpled finish(like 2pac car paint)or rippled. Is the whole panel the same or is it in patches?

Has the grain been filled?
Did you raise the grain before painting?
I assume you would have being a polisher.
Most poly's will self level if put on thick enough(like enamel paint) the longer it takes to flash off the better, not using any driers/thinners are you?

[Harry72]

Oh and how cold is it where you are, cold weather kills poly!

[Green]

I stripped the old layer off.

Gave it a 120 and then a 320 sanding - nothing else, no filler.

The wave crests run then length of the panel (45cm) same direction as the brush strokes. The crest are about 7-8mm apart. It look like a washboard.

[Harry72]

Ah, sounds like your working it too much with the brush. Once poly is layed dont go back over it, just like enamel paint.
If you flood it on(horizontal only!)it will self level to a mirror finish, just dont try and rework it.
Once layed you've got no more than 1-2min working time(in ideal conditions), which becomes a real problem if doing large areas.
The spray gun seems to be the best way of applying it IMHO see pics, the first was applyed with a brush with the poly liturely poured on and spead, second pic is sprayed.
The biggest drawback of poly is how long it takes to dry and keeping the dust off it...

http://img.photobucket.com/albums/v725/ST170ish/woodwork/3d0ec954.jpg
http://img.photobucket.com/albums/v725/ST170ish/woodwork/Laurenkateboxshiney.jpg

[Green]

I'll try one last thick coat tonight and see how it goes

thanks

[Richardwoodhead]

Hi Green, I was having many of the same problems. Then I watched someone apply finish with a spray gun. It was so amazingly smooth and even. Also, you might consider an oil / polyurethane mixture. They spread more easily and dry faster. Tung Oil urethane mixtures are available. They brush and spray on well. A light sand (320 or finer) and then second coat works well. It's a very durable finish. Although more satin, not high gloss. Good luck.

[Green]

Once again, thanks for the tips.

I tried a very thick coat - actually I just let the poly run off the brush and never actually stroked it. It appeared to give a smooth finish but I could still see the waves reflected. I gave up and stripped it all back. I figure that if I can only achieve a smooth finish on horizontal surfaces then I'll face future problems. At this stage I'll borrow a spray gun and give the poly one more shot. So much for my plans to do the whole thing over Easter!

Is the poly my only option for a stain-resistant surface?
Does the tung oil and urethane mix resist stains well?

[vsquizz]

Green, Thin your poly by at least 10%. I have thinned to 20% with better results but this is against the manufacturer's recommendations..:rolleyes: then again, what would they know;) . Seriously, it works.

Cheers

[Richardwoodhead]

Green, you're going to spray! Now you're talking. Get hold of Neil's book on finishing from Ubeaut. It's a good introduction to various finishing options and methods. In that he talks about spraying. Probably the most commonly sprayed finish is LACQUER (usually nitrocellulose lacquer). It's a very hard, waterproof, stain resistant and quick / easy to apply spray finish. And makes the wood look beautiful. But you can also spray Tung Oil / Urethane mixtures. Danish oil is OK, but I recommend (highly) Feast Watson's "FloorSeal". It's a pre-mixed Tung Oil / Urethane finish that sprays well, and results in a hard, waterproof, stain resistant satin finish. Needs 2 coats with a fine sand (320 orbital) after the first coat. Cheers.

[ubeaut]

http://www.ubeaut.com.au/hardshell.htm

[turbo]

quite often , pending the age of the unit your restoring , the solvents in whatever finish your applying can disturb the glue underneath the veneer.

your best bet is to strip it back raw , make sure you wash off the stripper well (neutralise it with water or thinners) , sand it with 180-220.

use a 2pack (poly) sealer , sand that with 400 , then apply your topcoat.

it is much better to spray the product rather than brushing , but if u do brush , use a very fine haired/bristled brush and make the first coat light.

i am a furniture polisher by trade , allthough i have only done a little of the older techniques of french polishing.