Hi,
What grade is recoomended for sanding down between coats of undercloat/primer ?
I rubbed down some door frames with 80 grit and have used some all in one primer/undercoat and was just wondering what grit would be suitable to give it a gentle down down before glossing ?
Or do I need wet and dry ?
All is revealed here
Don't use sandpaper: for the bottom of the budgie cage is about all it's good for.
Wet and dry is OK - it tends to be nice and sharp - but not actually wet if its on water based paint or there is any bare wood showing.
Abrasive grades are peculiar things and I have to admit I don't quite understand, how two makes with the same numbers on can be completely different - some will cut and stay clog free for ages, others block almost straight away.
Unless you went along the grain with your 80 grit it will have left grooves too deep for paint to fill that will look horrible - except horrible 'one coat' paints that just leave huge brush marks instead.
Now, if you have used water based primer, you will probably find that anything you try to rub down with simply cloggs up and rips the nasty stuff off again. The only way I could find round this was to scrape the rubbish off with a scarsden scraper, which if you are careful also gives a smooth finish. Then prime with some hard varnish that you can sand smooth with a fine-ish paper (cloth if poss).
Then, if you can find it, get a roll of 120 grade CLOTH BACKED alox abrasive. I kid you not. Last summer I was rubbing down windows with a roll of paper backed stuff, and spending all my time picking the lumps off it and changing torn pieces. Meanwhile, a carpenter, putting in a whole new window used just a couple of pieces of cloth backed stuff ( sadly the bits didn't have the writing on the back...). Once the carpenter had gone, I found the bits he had been using, still sharp, in the bin, retrieved them, and have been using them ever since!
So unless you are a perfectionist, that is what I would recommend. If you want to give a final key before a top coat, a say 400 or 600 grade of the white sheets is sufficient. (A sprinkling of talc helps keep them fairly unclogged,)
Another tip to save slipping around: get yourself a roll of double sided tape. Cut an oblong piece of your abrasive of a suitable size (4"x2" fits under the fingers nicely.), then fold it in half and stick the two halves together with a piece of the double sided tape. That really does put power under your finger tips. The other advantage is that as the edges get used up, you can trim down to a new bit with scissors.
Also, keep a wire brush in your back pocket, to unclog the abrasive regularly - often just thumping it with the wire will remove the lumps. And a decent sized bodkin or other spike is good for picking off any stubborn lumps of paint (if you leave them they scratch up your paint more than smoothing it.).
And vacuum down with a soft brush attachment before you paint - with your good (not yukky ptfe) paintbrushes. Try to paint with upward strokes and the brush pointing downwards, so the paint goes where you want it rather than clogging the brush and running up your arm. And keep extending the same edge of wet paint: don't be tempted to go back: you'll get the missed bits with the next coat.
Lots of thin coats (with thinned paint) gives a better finish than one thick one.
All rather depends on how good you want it to be and how much time you have. One last trick: now we have electric screwdrivers it can be easier to take the moveable windows out and paint them flat. Just don't drop them when you put them back! (And number them with a chinagraph to make sure they go back in the right openings.)
Hmm: this was just meant to be a quick one !
Cheers, S
80g was to course for the wood, you should have gone to 180-220, unless the primer is a sandable type you will have to wait a long time for it to cure hard enough and not clog paper and then it should be 220g if you are using oil as a finish, if its latex probably non is really necessary since latex dries to fast any way. You gove no mention of what products you are using, a real paint store would get you what you need
a 240 grit or finer... some 400 grit wet'n'dry usually works nicely for ne-nibbing.
You don't need it in the sense of needing the wet use ability, but sometimes its easier to find very fine papers in that form.
The decorators rolls from SF are good value for applications where the paper is going to clog before the abrasive wears out. IME this includes most surfaces, not just painted ones.
Shame Screwfix don't specify their rolls as paper or cloth, Rolled up they look v similar and even the staff at our local branch didn't know, till I got them to open one. and it was paper: and the one's I.'d already had from them had very little bite - more like sandpaper in fact, Shame cos I'd like a roll of the good cloth stuff (that I could afford...)
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