How to avoid getting pinholes in paint after its dry

[The Dec]

Hi guys

I painted my MDF warddrobes and was seeking some advice.

The doors themselves are recessed and have MDF mouldings inside of them. The design of the doors are similiar to those you would find in old Edwardian and Victorian homes.

I painted the gaps between the moulding's and have noticed that some of the paint has dryed but with little pinholes. Does anyone have any tips as to how I can repaint them so that they dont have these pinholes appearing within the paint.

Thanks

The Dec

[Master Splinter]

There's cissing (http://i711.photobucket.com/albums/ww119/papangcun/Prep%20Tutorial/CISSING.jpg), which is what happens when the paint hits something hard to wet out, typically silicone products (furniture polish is always a candidate), or pinholing (http://pc.dupont.com/dpc/en/US/html/visitor/s/trouble/PDSG_Pinholing.html) which is where something (evaporating solvent, water, paint roller) forms a bubble in the paint, and the bubble pops later, leaving a hole.

If you have been using a roller, use the roller to put on paint quickly, then lay it off with a brush to force out any air trapped under the paint.

If your painting technique is good, then the door needs a good clean with a pre-paint cleaner like Prepsol (http://www.oilchem.com.au/products/solvents/prepsolprepwash) to get rid of silicone. The correct way to use it is to pour some on a rag, wipe a section, discard the rag, get new rag, pour prepsol on the rag, wipe new section, discard and so on, otherwise you are just spreading the contamination around.

[The Dec]

Thanks for your advice most appreciated.

However I am not using a roller to apply the paint just a brush in these area's given that it is the gap between the moulding and the door I am painting

Thanks

[Master Splinter]

A photo perhaps?

[The Dec]

Yeah I shall get a photo

Thanks

[rantenNraven]

waiting for the photo, but like master splinter said the most probable cause is foreign deposit. it could be anything from cleaning products, grease, grime..... the list would be endless. are you painting it with matching paint (enamel on enamel) (water based on water based). did you clean the surface before painting, then sand with very light sand paper (600), then clean again, then undercoat (not a sealer but an actual oil based or water based primer undercoat) then follow recommended drying times, then paint with your top coats.... it sounds like a lot but in the time people get it wrong then try and work out how to fix it they have to do all i mentioned anyway.

[Cecile]

We had this issue with a high-quality semi-gloss kitchen and bathroom acrylic paint, tiny bubbles appeared all over it. It was a new plasterboard wall, and had been sealed and undercoated with high-quality three-step primer/sealer/undercoat. We finally figured out that the roller probably wasn't completely dry.

We've had it suggested to us that we should buy cheap brushes/rollers, and throw them out after every painting job. Sanding yours down will be a pain, but might be necessary.

[rantenNraven]

it wouldn't matter if the roller was wet......the paint was acrylic (which is water based). it has more to do with the roller you used, the nap of the roller, how you applied it, the coverage rate and finally how much you worked the paint. (when i say worked i mean how many times you went over one spot and at what rate).

being a professional painter for years ,one thing i can absolutely guarantee- use cheap products and tools expect cheap results.