Hello all,
I want to use mdf for a built up head piece detail on my windows (inside) and doors. There will be a rough cut edge facing down and I know that the edge does not take paint well. Unless you are looking for the rough fuzzy look. I am in need of a easy and sure fire way of treating this so it does not happen. I have about 280 ln. ft. with the edge that needs to be smooth.
As always thank you in advance for any help you can give.
Oh yeah btw. The guy I fired from “how to fire a guy?” is back in county again. Seems he got drunk and took a swing at a cop that was trying to get him off the ground and in a cab. So all I can say is I tried to help that poor s o b out and it did no good.
thanx again
Replies
Kilz
Then sand
then Kilz
then sand
then primer
then sand
now paint
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We paint MDF edges all the time. We sand it smooth (be careful because it's difficult to see saw marks until after you've painted and installed it). The we paint with water based paint. First couple of layers we gently scrape until they feel smooth(stanley knife blade held vertically) then a couple more layers of paint and there should be little or no observable difference betweeer the edge and the face.
We've tried specialist MDF primers but seems no different to ordinary water based paint
If you are using oil based paint then as long as the edge is sanded you should have no problem either
Remember what I said about the saw marks though
John
Glue sizing works best in my experience. One coat, then sand, the finish coat.
Expert since 10 am.
Same here. I schmear it with glue and when dry scuff sand it w/180 grit.
Spheramid Enterprises Architectural Woodworks
The secret to a long life is knowing when its time to go. M. Shocked
We have had great luck with a quick coat of primer, sand (this includes easing the visible front edge) , fill with spackle, sand then prime once more.
Oops did you say Easy? No such thing.
Jon
Russian saying
The gl;ue sounds likea good one. It has some body to function as a filler, is sandable, and compatable with paint.
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
That is a tried and true method used in cabinet shops for years.
I've run hundreds of ripped MDF for trim. done nothing but sand with maybe 120 - 220 with random orbital sander. maybe the trick is to use a good saw blade when ripping. ( I used Freud glue line rip blade)
I honestly didn't know people were having a problem with the ripped edges until I'd seen the same question posted as what your post is.
one thing I did notice, the factory edges are different story, I could see filling them as others have described to be very useful.
just reread your post...
"There will be a rough cut edge facing down and I know that the edge does not take paint well."
there's your problem...put the "rough" cut edge facing up. :)
Simply use an oil or alcohol-based primer, sanding sealer or shelac. Kilz works if sprayed in a very thin coat and not sanded off.
Anything that's water-based will raise the grain so to speak.
Sanding sealer or shelac are the easiest to clean out of the spray guns and dries fast, so that's my normal route.
A normal 15 amp. construction compressor can drive a small spray gun well enough to make it worth while. On the cheap end a $30 CH or Husky brand detail sprayer from HD is very simple to use. Simply fill with unthined sanding sealer and spray away. Don't try an oil-based primer unless it's thinned down.
I have one of these and it sprays about 2x or 3x what a rattle can will produce. Not a big gun, but perfect for spraying edges or small projects on site. It's my go-to gun on site for sanding sealer or lacquer mainly because the air compressor won't keep up with anything bigger.
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If you don't want to try a spray gun simply pick up some spray cans of shelac, sanding sealer or Kilz. If you use the Kilz, don't flood the surface, but simply make a fairly dry (thin) coat and don't sand through it or it needs to be redusted.
Having said all that, not all MDF is the same and the better stuff reacts much differently than the softer flakier stuff. Maybe it has to do with the density or the type of binders used.
Good luck
Beer was created so carpenters wouldn't rule the world.