Need some advice please... MDF painting

[oobaa]

Followed the advice on here and YouTube but struggling to get a decent rollered finish on mdf
Bizarrely maybe - no problem with edges

I’m using Leyland Trade Acrylic Primer Undercoat and Leyland Trade Fast Drying Paint Brilliant White satin, hd foam rollers

One primer coat and 2-3 top coat, 400 grit denib between coats when fully dry

Issue is I cant get a smooth finish - it’s showing roller foam marks - see pic
Tried on 3 separate projects and same result

Can’t afford the space for a spray booth so need to solve my incompetence
TIA

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[RobinBHM]

One of the Leyland range which is waterbased contains a bit of oil, it slows the drying time and helps the paint flow.

The problem is that waterbased paints dont flow out well, so rollered finishes end up with a textured orange peel finish and or bubbles, which leave a rough surface when dry.

The pros that hand paint kitchens seem to use solvent based paints. I was working where a Mark Wilkjnson kitchen was being site painted -it smelt really strong, I think they were using a 2 pack solvent based like an AC or similar.

 

[Marineboy]

Have you tried laying off the paint with a decent synthetic filament brush while still wet?

 

[oobaa]

Thanks - I did wonder if the "fast drying" was part of the problem - you can see the lack of flow as you apply the paint

the primer and topcoat choices were recommended to me and seeing pics of a pro applying them it looks like it is possible to get a good finish - just not by me

Maybe time for a change of top coat

 

[oobaa]

Have you tried laying off the paint with a decent synthetic filament brush while still wet?

I did try that but it left quite obvious brush marks even with a really fine synth bristle brush

As per one of the other suggestions - maybe its too fast drying and doesn't flow sufficiently

Thanks

 

[HOJ]

I have used the Leyland paint, and suffered the same results, now working on a unit using oil based paint from the Little Green Paint Co, gives a better finish, but not perfect, frustratingly takes +16 hours at least to dry, even then its not fully hardened off, so no good if your in a hurry.

 

[will1983]

Two pronged solution to this Oobaa.

First you need to add a bit of Floetrol to the paint, give it a good mix up and you will see the paint start to thin out a bit.

Secondly you need to warm your paint up. You can do this simply by placing the tin in a big pan of hot water or you can invest in a rice cooker.
Warming the paint has the same effect as thinning but without reducing the concentration of solid particles in the mix. It should be noted though that warming the paint wont make any difference if the substrate is cold, it needs to maintain its warmth long enough for it to flow out.

As a side note how much paint are you applying in a single coat, the photo looks like you've got too thick a layer on.

I use the leyland trade undercoat all the time, brushed, rollered and sprayed but have never have any issues with roller marks or orange peel. Because it is a waterbased product that is designed to dry fast you need to work quickly with the roller to get it on and spread out so work methodically in a small area at a time. Once I have the paint spread out I give it the lightest of back rolls to help it level out and then leave it alone, further rolling will upset the drying process and make a mess.

I usually do 2 primer coats, then 2 top coats, flatting with 240 on the RO between all coats.

 

[oobaa]

Thanks
I’ll give that a try - getting the paint to flow more and perhaps dry a bit more slowly makes sense

The photo was after 1 primer and two top coats btw


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[will1983]

I find that only one coat of primer isn't enough with MDF, as I give it a fairly heavy going over with 240 between coats I often go through the primer in places so need to give it a second coat.

Also I don't know if you already do this but I usually do all the cut edges and exposed core material first then do the faces before coming back to the edges and giving them a second going over as the first application just disappears into the material. This also ensures there is plenty of primer soaked into the MDF binding all the fibres together and giving you something solid to sand back smooth.

 

[oobaa]

Great advice thanks - will give it another crack and report back!

 

[Eric The Viking]

Peter Millard (of this parish) has some good MDF painting tips on YouTube, as does The Gosforth Handyman.

Peter recently tried some 4" rollers with a concave cone at each end (so the "corners" were really thin), which are supposed to minimise roller marks. He liked them, and I got some myself. I'm impressed so far - not cheap, but IMHO worth the money.

But as discussed above, it all depends on the paint you are using, etc. I've been using Zinsser 1-2-3 and several coats, too, with de-nibbing and cutting back between.

 

[Fidget]

Gosforth Handyman has this video on painting MDF which might be helpful

Crossed with ETV's post, sorry

 

[oobaa]

I've watched Peter and Gosforth's videos and based my approach around them - including the concave end rollers - that def helped

I think my problem is a combination of a lack of technique and fast drying paint

I'm going to try a slower drying / better flowing paint

Thanks for all the good advice

Peter Millard (of this parish) has some good MDF painting tips on YouTube, as does The Gosforth Handyman.

Peter recently tried some 4" rollers with a concave cone at each end (so the "corners" were really thin), which are supposed to minimise roller marks. He liked them, and I got some myself. I'm impressed so far - not cheap, but IMHO worth the money.

But as discussed above, it all depends on the paint you are using, etc. I've been using Zinsser 1-2-3 and several coats, too, with de-nibbing and cutting back between.