Llilith Posted June 2, 2015 Share Posted June 2, 2015 Hi - I'm painting the backs of the floor pieces that I've finished - white, since they will be the ceilings. However, even after three coats and sanding between, I am still seeing cruddy coverage and brush strokes. I'm using a sponge brush. It seems like a regular brush would leave even more lines. I didn't have any trouble with the outside of the house - but that had siding which I think was wood, not just mdf. Does anyone have any tips on painting the MDF material for a smooth, even finish? Thanks in advance! Quote Link to comment Share on other sites More sharing options...
Llilith Posted June 2, 2015 Author Share Posted June 2, 2015 (edited) Here's what I have after 3 coats Edited June 2, 2015 by Llilith Quote Link to comment Share on other sites More sharing options...
otterine Posted June 2, 2015 Share Posted June 2, 2015 I usually put on a first coat of paint and let dry completely. I then sand it heavily to get a super smooth finish. When you sand paint, it leaves a powder. I usually wipe this away with a damp paper towel to help remove most of it. For the second coat, I water down the paint slightly and use long brush strokes. You can put on several thin coats this way, sanding in between until you get the finish you want. If you use the paint in its original thickness for the second and third (etc) coats, it binds with the powder left from sanding and dries too fast to make a smooth surface. 1 Quote Link to comment Share on other sites More sharing options...
Dalesq Posted June 2, 2015 Share Posted June 2, 2015 You said it's MDF? Did you seal it before painting? It might have helped, although at this point the paint should be acting like a seal coat. I don't know what is causing the discoloration (maybe someone knowledgeable about working with MDF will chime in) but I'd make sure you are giving it adequate time to dry completely, then I'd sand it to get a smooth surface before repainting. You might consider giving it a coat of a gray primer to even the color, then painting over that with white. Just a suggestion. I'd also consider using a spray paint for this. You can get a smooth coverage that won't have any stroke lines. 1 Quote Link to comment Share on other sites More sharing options...
havanaholly Posted June 2, 2015 Share Posted June 2, 2015 I don't like to work with MDF. That said, for a really smooth finish I'd give the surface a light coat of spackle and let it dry really, really well and then sand it just as flat and smooth as I can before painting it white. Quote Link to comment Share on other sites More sharing options...
denkyem Posted June 2, 2015 Share Posted June 2, 2015 I've been sanding at least my first coat of paint on everything i've painted, from walls to trim, and it has helped a lot in improving the finish. What about using a small paint roller? That's what I used to do my floors, ceiling and walls, and i was really happy with the results (but I don't have MDF). 1 Quote Link to comment Share on other sites More sharing options...
Llilith Posted June 2, 2015 Author Share Posted June 2, 2015 Thanks for the suggestions. I didn't seal before painting - I (maybe wrongly) assumed the first coat of paint would seal it. I'm going to try sanding them really well, wiping it off and watering down the paint for now. I never thought about watering down the paint. I think that's going to work. Can't wait to try it after I'm done with work for the day! I don't have a roller or spackle - but I may have to get them. After seeing how this mdf takes paint, I am more inclined to wallpaper the entire interior now though. I had planned to paint some rooms and wallpaper some - but I don't want to have to deal with four coats of paint inside too. Quote Link to comment Share on other sites More sharing options...
Sable Posted June 2, 2015 Share Posted June 2, 2015 What does RGT say about painting the MDF? Quote Link to comment Share on other sites More sharing options...
Selkie Posted June 2, 2015 Share Posted June 2, 2015 Is it really humid where you are? That affects how paint dries and cures tremendously. I'm one that tends to rush paint and glue drying and most always regret it for reasons as you are experiencing. Paint that is dry to the touch may not be ready to sand yet. If is has any sort of cool or warm sensation to your hand, it's not ready. True curing can take a couple weeks or more but you don't have to wait that long. It tends to be humid where I am so it can take a good couple days to be ready for sanding without raising up more than I had for an uneven surface to begin with. 1 Quote Link to comment Share on other sites More sharing options...
havanaholly Posted June 2, 2015 Share Posted June 2, 2015 Kim, the one time I tried a foam brush for painting I had all sorts of stroke marks. I usually use a regular 1" - 1 1'2" paintbrush and paint the way I was taught, spreading the paint out in thin even coats, letting each coat dry thoroughly and outing the next cot on at right angles to the preceding coat. I don't get visible brush strokes and I rarely have to sand. 1 Quote Link to comment Share on other sites More sharing options...
Llilith Posted June 2, 2015 Author Share Posted June 2, 2015 (edited) Is it really humid where you are? That affects how paint dries and cures tremendously. I'm one that tends to rush paint and glue drying and most always regret it for reasons as you are experiencing. Paint that is dry to the touch may not be ready to sand yet. If is has any sort of cool or warm sensation to your hand, it's not ready. True curing can take a couple weeks or more but you don't have to wait that long. It tends to be humid where I am so it can take a good couple days to be ready for sanding without raising up more than I had for an uneven surface to begin with. I'm in the pacific northwest, and yes it's been quite humid the past couple of days. The humidity helps then? Kim, the one time I tried a foam brush for painting I had all sorts of stroke marks. I usually use a regular 1" - 1 1'2" paintbrush and paint the way I was taught, spreading the paint out in thin even coats, letting each coat dry thoroughly and outing the next cot on at right angles to the preceding coat. I don't get visible brush strokes and I rarely have to sand. Ah - good to know. I'll use a paint brush tonight! Right angles - So, you put the next coat on the opposite direction? Like if I went horizontally once, the next coat would be vertical? Edited June 2, 2015 by Llilith Quote Link to comment Share on other sites More sharing options...
Selkie Posted June 2, 2015 Share Posted June 2, 2015 No, the humidity makes it worse. It delays drying and curing times. Even though it's dry to the fingertips, it probably isn't dry enough to sand for a while after that. Sanding too soon pulls up too much at a time. Sorry I was not clear. I'm wordy but not clear most often according to my family. 1 Quote Link to comment Share on other sites More sharing options...
Llilith Posted June 2, 2015 Author Share Posted June 2, 2015 Selkie, no worries - it was probably me. I'm a little dense today. Sable - All I was able to find on that was "MDF is easy to paint" LOL, yeah right! I'm still looking though. They do say the MDF board are ready to paint, but I probable would have benefited from a primer on these. Quote Link to comment Share on other sites More sharing options...
jrchob Posted June 2, 2015 Share Posted June 2, 2015 For my MDF ceilings I used a small paint roller, think it was 4 inch. I could even get a texturized ceiling depending on the roller. Usually did 2-3 coats. (Also used for walls where painted) 1 Quote Link to comment Share on other sites More sharing options...
chapchap73 Posted June 2, 2015 Share Posted June 2, 2015 For my MDF surfaces, I just used a regular paint with primer added. I get the samples from Home Depot. 2 coats and no sanding needed. I think Selkie is on to something with the humidity. 1 Quote Link to comment Share on other sites More sharing options...
Llilith Posted June 2, 2015 Author Share Posted June 2, 2015 I'm going to sand it a bit more tonight and wait a couple of days I think. Just ordered a small roller from Amazon - and it will be here in two days. The weather says our rain is ending about then too - so maybe that will do the trick. You guys rock, you know it? It's so nice to have help while I'm figuring this out. Thanks! Quote Link to comment Share on other sites More sharing options...
havanaholly Posted June 3, 2015 Share Posted June 3, 2015 I have always thought the purpose for the forum was to ask and answer questions and help new builders along. 3 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.