RobertMP
Established Member
29.11 Changed the thread title as there is some general info on MDF painting on page 2 now.
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Bit of an essay... sorry.
I'm trying to spray a lot of MDF that I've turned into parts for refreshing our kitchen with new doors and trims as you may have seen
here in my WIP thread.
I thought I'd identified the problem I have been having with bits appearing in the finish coat of Dulux Trade Eggshell..... but now I'm not so sure.
There are some pictures in the other thread.
What happens is that the eggshell coat spontaneously develops 'dust' within a minute of being applied to the door panel - and a few 'fish eye' spots.
I spray the coat on and it is wet and even with no inclusions and as i stand there looking for problems they appear across the panel at random positions.
I've been doing some tests to try and work out what is happening and I'm getting more confused!
so far..
1, I stretched a plastic bag over a piece of chipboard so I had a guaranteed clean virgin surface and spray painted the bag with the eggshell. Perfect - no dust. no fish eyes. left it to dry - still perfect.
2, All doors etc are painted and rubbed down with a water based MDF primer made by Leyland paints. This was what I thought was the problem and reacting with the topcoat. Bought some oil based undercoat. undercoat shows only slight reaction. today I sprayed eggshell over the oil based undercoat... and got the same reaction
3, Tried spraying the paint neat but the gun won't have it. Bought some expensive high purity white spirit 'for thinning paint' (been using wickes stuff) and thinned by the minimum to get it to spray - same problem.
4, Tried wiping down with white spirit, meths, and even cellulose thinners in an effort to stop fish eyes. cellulose seems to reduce it a bit but is too aggressive on the primer.
5, tried not rubbing down an undercoated panel at all - same reaction. tried not wiping with anything on a sanded primed panel - same reaction.
6, I had a small amount of Leyland paints Eggshell so I tried that instead of the Dulux - it reacted slightly less but still reacted in the same way.
So I'm a bit lost as to what to try next. painting plastic proves the paint is clean and can stay clean. painting anything with a previous coat on it (even recoating sanded eggshell) just looks dirty.
Any suggestions gratefully recieved!
-
Bit of an essay... sorry.
I'm trying to spray a lot of MDF that I've turned into parts for refreshing our kitchen with new doors and trims as you may have seen
here in my WIP thread.
I thought I'd identified the problem I have been having with bits appearing in the finish coat of Dulux Trade Eggshell..... but now I'm not so sure.
There are some pictures in the other thread.
What happens is that the eggshell coat spontaneously develops 'dust' within a minute of being applied to the door panel - and a few 'fish eye' spots.
I spray the coat on and it is wet and even with no inclusions and as i stand there looking for problems they appear across the panel at random positions.
I've been doing some tests to try and work out what is happening and I'm getting more confused!
so far..
1, I stretched a plastic bag over a piece of chipboard so I had a guaranteed clean virgin surface and spray painted the bag with the eggshell. Perfect - no dust. no fish eyes. left it to dry - still perfect.
2, All doors etc are painted and rubbed down with a water based MDF primer made by Leyland paints. This was what I thought was the problem and reacting with the topcoat. Bought some oil based undercoat. undercoat shows only slight reaction. today I sprayed eggshell over the oil based undercoat... and got the same reaction
3, Tried spraying the paint neat but the gun won't have it. Bought some expensive high purity white spirit 'for thinning paint' (been using wickes stuff) and thinned by the minimum to get it to spray - same problem.
4, Tried wiping down with white spirit, meths, and even cellulose thinners in an effort to stop fish eyes. cellulose seems to reduce it a bit but is too aggressive on the primer.
5, tried not rubbing down an undercoated panel at all - same reaction. tried not wiping with anything on a sanded primed panel - same reaction.
6, I had a small amount of Leyland paints Eggshell so I tried that instead of the Dulux - it reacted slightly less but still reacted in the same way.
So I'm a bit lost as to what to try next. painting plastic proves the paint is clean and can stay clean. painting anything with a previous coat on it (even recoating sanded eggshell) just looks dirty.
Any suggestions gratefully recieved!