[Klawman]

I am having trouble painting pre primered mdf crown moulding (actually ultra light mdf) with BEHR semi gloss (white; swiss coffee).

I was very careful applying it with a wet brush, but ended up with what I would describe as tiger stripes being visible in several places. (marks running across the long axis of the boards as thought they are left by macinery pulling them along).

Perhaps I shouldn't have sanded them. I used 180 and tried not to take much primer off. The paint is over a year old, but seems fine. Is this just the result of a less than premium paint. As is, I am going to try a second coat on these 4 boards, and that should fix them, but I have a lot more to do in my house and would like to avoid problems if possible.

I tried to take pictures, but can't get them to show. Running my finger across them it feels as if their are little ridges running across what would be the grain if mdf had a grain. I wonder if the ridges are not the problem, per se, but they caused the tips of the brush to not quite skip, but to lift away and not uniformly apply the paint. I wish I could explain the problem better. Any suggestions.

[After entering the above, I took a piece outside in preparation for giving it a second coat. a lot was missed, though I was careful to get all with a few wet strokes. I think it is crappy paint, and not just because it is old.]
Thanks.

 

[NAV]

yes, behr is crap paint

 

[Klawman]

yes, behr is crap paint

Just finished sanding the first coat with 180, vacuuming the dust off, and applying a second coat.

This time it wasn't as hot; pretty good painting weather. I kept the brush wet and worked extra fast. I was watching very carefully for tiger stripes and spotted some where I was at, as well as a few more were spotted as I checked each board as I finished (11' & 13"). Sure enough, some spots were caught and I got them as I went, with extra paint, as well as hitting a few places spotted as I inspected the finished boards.

I also added about a half a teaspoon of water each time I finished a board. (dribbled it over the brush and into the bucket so as to also keep the paint on the brush from getting thick)

I think it will look pretty nice (before the problems were apparent within 15 minutes of finishing a board), but could look better with less work if I paid the extra $30 a gallon for quality paint.

I instructed my daughter, a painter of the fine arts variety, to kick me hard if I even think about buying more BEHR. As it is, I may just donate the ten unopened gallons of what I have to a local school.

 

[user1007]

I think it will look pretty nice (before the problems were apparent within 15 minutes of finishing a board), but could look better with less work if I paid the extra $30 a gallon for quality paint.

I instructed my daughter, a painter of the fine arts variety, to kick me hard if I even think about buying more BEHR. As it is, I may just donate the ten unopened gallons of what I have to a local school.

Sounds like you learned your lesson without all of us jumping on you for using something like Behr! Ship the 10 gallons to HGTV. They love showing people using the crap. Makes me cringe, except for Tanye what's her name who paints with it in heels, designer fashions and jewelry!

Two tips for the future.

Use Floetrol when painting trim. It will really help take out brush strokes. It is inexpensive. Just mix it into the latex paint per instructions.

I never trust the factory applied primers. The stuff is just sprayed on too thin. Put a nice, new primer coat on next time, especially if you have to sand the stuff at all.

 

[chrisn]

Sounds like you learned your lesson without all of us jumping on you for using something like Behr! Ship the 10 gallons to HGTV. They love showing people using the crap. Makes me cringe, except for Tanye what's her name who paints with it in heels, designer fashions and jewelry!

Two tips for the future.

Use Floetrol when painting trim. It will really help take out brush strokes. It is inexpensive. Just mix it into the latex paint per instructions.

I never trust the factory applied primers. The stuff is just sprayed on too thin. Put a nice, new primer coat on next time, especially if you have to sand the stuff at all.

That and there should be no need to sand in the first place.I am not even going to comment on the paint:jester:

 

[tpolk]

I have'nt used enough fake wood stuff to notice but I do know with wood primed or not you need to presand before paint or install to remove the marks left by the shaper knives. It will telegraph thru. You can also tell how fast they were feeding the material by the spacing of the marks. close together =slow=good , further apart faster= not so good= more chance of blowouts

 

[Klawman]

Use Floetrol when painting trim. It will really help take out brush strokes. It is inexpensive. Just mix it into the latex paint per instructions.

Floetrol. That's the stuff I used a couple of times in the past to make the paint level more. Thanks.

 

[Klawman]

That and there should be no need to sand in the first place.I am not even going to comment on the paint:jester:

Good point, chrisn, that there should be no need to sand. It would be nice to take it from the yard, hit it with a single coat of decent paint, cut, cope and nail.

I was wondering what would have happened if I didn't sand the primer. It would have been thicker and possinle hid the tiger stripes; that is if they are machine marks and not the product of dry brush tips skipping. I will test it on some scrap from the mill that is still as it was when picked up. I may be making a lot of unnecessary work for myself.

 

[tpolk]

if you have roller feed marks on the material you might want to check into it I dont think they should be there

 

[Klawman]

I have'nt used enough fake wood stuff to notice but I do know with wood primed or not you need to presand before paint or install to remove the marks left by the shaper knives. It will telegraph thru.

You are almost certainly right, as I cannot imagine applying paint without some light sanding, but it will be interesting to see what happens. I have the end piecies of the 16's and will paint two at the same time within minures of the other. One's primer I will sand and the other left "virgin". I will be extra careful to apply the finish the same to each.

I may decide to try another vendor. What I have been using is from the El&El Mill in Corona, So Cal, but actually comes from Arauco (sp?) in South America. Cost to me is about 86 cents a foot They also sell plywood through Lowes and HD. I was going to try finger joint pine, but this stuff is supposed to be so stable I went with it.

 

[chrisn]

As already posted, the "pre" primed stuff is no good, it needs to be primed again.If the material needs to be sanded ,do it before priming and LIGHTLY sand your primer.

 

[user1007]

As already posted, the "pre" primed stuff is no good, it needs to be primed again.If the material needs to be sanded ,do it before priming and LIGHTLY sand your primer.

:thumbup:

 

[Klawman]

if you have roller feed marks on the material you might want to check into it I dont think they should be there

My guess is they aren't any kind of roller or other machine mark, but something caused by my poor painting technique (which may be the result of crappy paint causing the tip of the 2" brush to skip if it was too dry, but I really tried to keep it wet. I will know better when I run a painting test. As for roller feed marks, they seem to broad to be rollers. For that matter, and I just thought of this, I want to match them up with the width of my brush. This will be hard to do on the stuff I have been working on, as the second coat coverd all pretty well (and I sanded between coats. There are only a few small spots where the same problem is visible. I planned to get them when I do the final touch up after all is hung.