Pockmarked gloss

Yorkie1

Thanks Keystone. Is wet and dry a type of sandpaper but not the 'standard' sandpaper; I've not come across it before? You mention water - is there a particular technique?

I'll leave my little mouse sander in the cupboard then.

keystone

Wet & Dry is very fine grit abrasive on a waterproof paper. Soak it in weater before use and keep it wet in use. You'll need to have a sponge or cloth available to keep wiping up your surface and you'll also need to occasionally clean the abrasive - I use an old washing-up brush. You can also get it as a sanding sponge.

Power sanders are only (IMHO) good for sanding work in carpentry.

Cheers

har0ld

Is it possible that you might be using a low odour water based gloss on an original oil based gloss paint?

(if you can clean your brushes in water then you are not using an oil based paint!)

Cure: Light sand and prime with oil based paint and top coat with oil based as well.

Yorkie1

Thanks all. Was definitely oil-based gloss as it had to be cleaned in white spirit.

grizzly1911

If I am painting prepainted gloss, I tend to rub down gently as others have said and then wipe over with a lint free cloth (bit of old poly/cotton pillow case or similar) with some white spirit on it.

Helps clear away the dust and clean away grease and such.

I also use the single coat stuff indoors.

I have had similar problems in the past, as you have experienced but the above prep has resolved.

Yorkie1

Now that's the sort of added bonus advice I like - eat the chocolate first! Excellent!!

Yorkie1

Resurrecting this thread as this issue has raised its head again - but on windowsills which appear to have been previously painted with something other than gloss; probably emulsion?

I've stopped work, re-cleaned to ensure no dust, but any sanding will just remove the existing thin paint layer.

Should I sand back nevertheless, then apply my combined primer / undercoat, then gloss?

Can't locate any wet / dry sandpaper; I thought I had some but it might be hidden in a cupboard currently behind the entire contents of my kitchen and dining room. Will regular sandpaper suffice?

Yorkie1

Shameless bump in case anyone knows the answer

HarriDec

This is called cissing in the trade, it's a common problem. Something on the surface is incompatible with the gloss and could be a number of things including silicone contamination or most likely; household polish. The reason it has happened on the cills is probably because people polish them and not so much on uprights/verticals.

Funnily enough, this reaction isn't usually visible with undercoat and normally just reacts with the gloss (through the undercoat) whether you are using oil OR an acrylic system.

You will need to sand it back to flat before you can apply any more paint because you will see these imperfections through any subsequent coats of paint.

My remedy would be:

1. Sand back flat using p120 sandpaper OR 180 wet n dry sandpaper with detergent and water.
2. Clean the cills with sugar soap/detergent/Krud Kutter.
3. Allow to dry.
4. Apply one coat Zinsser Cover Stain (just to be on the safe side).
5. Apply one oil based undercoat.
6. When dry, rub down with fine grade sandpaper and apply oil gloss coat.

All should be fine after this. If you want to use an acrylic gloss (which I must add is more difficult to achieve the desired finish) you may have to double gloss and would swap step 4. to using Zinsser Bullseye 123+.

Don't use products like Solo gloss or One Coat gloss, they are rubbish!

HarriDec

You can also buy anti-cissing additves that can be added to paint, they basically 'pre-contaminate' the paint so that it doesn't react on application. Although this is mainly for automotive painting and french polishing we have used it many times in gloss with good results. See here: http://www.amazon.com/U-Pol-Fish-eye-Eliminator-Anti-silicone-Additive/dp/B003TQGFZ6