Struggling to paint a long MDF threshold

[stuartb3502]

I know there are a lot of previous questions about prepping and painting MDF. I believe what I'm asking about is slightly different, however (having read previous threads).

The short version is that I'm after a white paint which I a) reasonably easy to get a decent finish with and b) tough enough for an area which will be prone to knocks and scuffs.

We have had 2.4m MDF threshold installed as part of getting some bifolds. I'm struggling to get the thing painted and was hoping the gurus might have some tips and recommendations. Here's what I've done so far...

[FWIW - the French doors just replaced had a gloss painted threshold which was still perfect after 20 years - i.e. I'm not looking for something which will stand up to abuse.]

The new threshold came primed. I have primed again with Leyland MDF primer (it had a few sanded patches, filled screwholes etc). Sanded smooth.

A decorator's centre suggested Bedec Multisurface Paint (soft gloss). I've not gotten on with this. It's apparently got a quick drying time and is difficult to get on smooth at the best of times. In the hotter weather, I struggled even more brushing it.

I sanded back and got up early when it was cooler to try a foam roller. Disastrous. A dreadful heavily dimpled orange peel. I did consider trying to pass this off as an "anti-slip finish" for a second . I think this could have worked, but my inability to lay off and get an even coating very, very quickly is the issue.

I have sanded back flat again now with 120. Strangely, a handful of small chips appeared during sanding going back to nearly bare MDF. I have primed those and plan to level up with Toupret and prime, sand again.

I'm hoping for some recommendations on an alternative paint. I have been trying the multisurface paint on another test piece of MDF and although I can get a slightly better finish by improving my brush technique and dampening the surface before starting, it's still not great and very difficult to lay off neatly given the long length - at least for me.

I also understand now that this paint is a) not needed here since I'm priming and undercoating and b) has a very long (one month) cure time to be fully hard.

I am not too fussy whether we go gloss, satin or eggshell (it's white) on this. Getting a good finish which is tough is much more important. I read that Scuff-X is possibly an option here.

Any other suggestions?

 

[Wayners]

Use Uni-Pro High Tech Micro-Fibre 6.5" 4mm Nap
Stick to waterbased paint.
320 grade de nib.
Damp microfibre cloth
Use a primer like you have and roll plenty on. Many get problems and they are applying less than half the thickness required.
320 grade de nib.
Damp microfibre cloth
Apply top coat. Again get plenty on.

You can buy a comb and read paint data sheet to find the correct thickness.

 

[freddiemercurystwin]

I hate any quick drying paints, let alone in this heat.

 

[blup]

How is mdf ever a suitable material for a door threshold?

 

[Wayners]

Can't

I hate any quick drying paints, let alone in this heat.

Yeah. Only really spray when temperature is 25c or more. 27c is cut-off for waterbased paints. Real problem when you are trying to make a living.
I used to get to Jobs early but by 10pm paint dries really quickly making it difficult to impossible to paint

 

[freddiemercurystwin]

How is mdf ever a suitable material for a door threshold?

Or indeed painted in a gloss.

 

[DiyNutJob]

10 year oil paints have excellent self leveling ability that give a smooth finish. But the cure time could be a year before you can sand out any imperfections and paint again. Oil paints will yellow if not exterior. For door steps, there are special tough door step paints.

 

[Deluks]

Dulux Diamond Satinwood.

 

[opps]

10 year oil paints have excellent self leveling ability that give a smooth finish. But the cure time could be a year before you can sand out any imperfections and paint again. Oil paints will yellow if not exterior. For door steps, there are special tough door step paints.

I prefer oil based paints but with the right abrasives you can even sand gloss after about a week. Curing time is typically about 6 weeks (assuming that the paint is applied properly- i.e. not too thick).

 

[stuartb3502]

Thanks for the tips. Some feedback in case it's of help to anyone reading this later.

I couldn't get the Uni Pro 6.5 sleeves in time, but got some short-pile Two Fussy Blokes ones.

Got up early for lower temps (the Scuff-X has a working temp range of 10-32.2 deg C). Worked at 21 deg C or less.

Brushed a test piece of MDF (already primed) first to get a feel for the paint. Later wiped the threshold board with a damp microfibre. Cut in edges and then rolled the Scuff-X on and laid off once. I found this much easier to blend to the brushed edges and the wet edge from the previous section compared to the previous paint which was thickening before I could do anything.

It had a dimpled appearance initially, but because I'd done a test piece and knew what to expect, I was happy to leave well alone.

Flows out beautifully and was smooth after an hour.

Denibbed and second coat this morning.

I think a lot of the problems I had the first time (apart from my inexperience and use of the wrong roller type) were caused by the multi-surface paint, which was unnecessary and unsuitable.

As others have said, the Scuff-X is expensive. I probably would look at other decent quality paints if painting a bigger area. Because I had had issues with this piece already, had spent a lot of time sanding back and wanted something a bit more robust because of where this is, I plumped for the Scuff-X.

From my limited experience, the positive reviews elsewhere about using it are justified. That's not to say there aren't other good paints, of course.

Fwiw, the original gloss threshold was there when the house was built. We had it painted 20 years ago and it held up fine as shown here. There's one mark on the bullnose here, but that's only because I'd just jemmied the board out so we could check what's underneath with the bifolds surveyor.

I appreciate it might not be the optimum solution, but we decided against hardwood this time as we were decorating to lighten up the lounge and had chosen white bi-folds for this reason and to match the rest of the windows.