Do you scrape lacquer?

[jmk89]

I have just been reading Tage Frid's 3 volume collection on woodworking. At the end of volume 2 he talks about finishing using NC lacquer. He suggests, rather than using sandpaper (or rather wet and dry used wet), between coats the surface should be scraped with a cabinet scraper (you know, a piece of thin steel with a hooked burr pulled across the work).

It seems to make sense and accord with my experience with using scrapers rather than sandpaper on the raw timber - it certainly gives a much better surface in that application. But before I give this a go, I just wondered if anyone else had tried this and if so, what the results were like and whether there are any wothwhile tips.

[old_picker]

i am no expert but no way would tackle a lacquered surface with a scraper unless i wanted to rip it all off and start again - i will however stand corrected

also i never got the beatifull sheen i get with fine abrasives with a scraper - at best its a tool to prep before initial sealing - if you know how to use it and its set up right

[blackhole]

I use the green kitchen scouring pads between coats, just lightly.

[jmk89]

I know it seems counterintuitive (love that word ), but Tage Frid was "da Man" in USA and if he says it can be done and works better, then there may well be something in it.

I will give it a go and report back.

[durwood]

If you were going to use a scraper on NC lacquer you would need to make sure you had a great many coats on the surface. The only time I've seen or used a scraper type tool is on cured 2 pack paints. A tunstan blade is used to chop off nibs in high gloss finishes as they are so hard they require lots of sanding whereas the tunstan blade can be used to just chop off the mark. without making the area around it affected by the exercise. Its then easy to polish the tiny mark away without it being noticable.

One coat of an enamel finish is equal to about 3 coats of lacquer. Lacquer is thinned with more thinner than the lacquer content therefore the amount that ends up on the surface is hardly anything. The solvent is the major part of the mix and needs heaps to allow the fast drying lacquer to get to the surface still wet. On enamels/polys (which are slow drying) the major component is the material and only a very small percentage of thinner is added therefore when it hits the surface the coat of material is 80-90% product. 2 coats of these paints equal 5-7 coats of lacquer depending how wet you apply the lacquer.

Sanding is done for a reason and that is to level the finish, just giving it a rub is a waste of time, you should be sanding it to remove any faults, such as dirt/ lumps orange peel scratches and if the surface is flat you need to use a block to make sure the high spots are taken off and it stays flat (just like planing or filing).

If you have no faults then there is no point in rubbing at all you are doing is removing material you already have applied and will have to apply again therefore using more material. You don't need to rub to gain adhesion to the lacquer the solvent remelts the previous coats and they weld together.

I would think a scraper would make the surface worse than before and its never been considered on finishes where a mirror finish is required. Marks it would leave would be way worse than your lacquer surface if you were doing the job properly. It would only be able to be used on flat areas.

Still lets see what jmk89 finds out.

[mic-d]

Sorry for reviving this thread but I did not see it earlier and I have something to add. Recently I was finishing a large mdf sheet for a worktop and looked into ways of preparing the surface for each successive coat. I came across this site:
http://www.highlandwoodworking.com/i...=Custom&ID=105
which suggested that a cabinet scraper could be used between coats.

Here's what I learnt:
I was scraping the spotted gum edging on the top and noticed that where the scraper contacted the mdf it took a layer and left no fuzz. I scraped the mdf a bit more aggressively as a test and although I took off quite a bit of dust, there was no perceivable difference in the scraped surface relative to the untouched surface. It looks like mdf responds extremely well to scraping and it might be the weapon of choice if you need to work the surface of mdf.

Secondly, between coats of tung oil/ poly blend, the scraper held lightly in the hand at a high angle and run lightly over the surface was able to take of the fine dust particles that had settled to leave a beautifully smooth surface ready for the next coat.
I will be experimenting with a scraper for this task a bit more, hopefully reduce the need for paper.

Cheers
Michael