Replies

1. 
   CAGIV | Jun 02, 2006 07:08pm | #1

   Will the painting be completed after or before installation?

   If after I'd use Bondo or the miniwax version of bondo.

   

1. 
   PaulBinCT | Jun 02, 2006 07:12pm | #2

   Before CAG...I was thinking Bondo myself.  Great minds and all that ;)

    

2. 
   RustyNail | Jun 02, 2006 11:03pm | #5

   I've had good luck by priming the MDF (I choose oil-based primer), apply (I believe it's Elmer's) interior/exterior wood filler (it's a yellowish colored putty), let dry, sand lightly, hit with spray bomb S-W Prep-Rite primer.  Take a look, if you still see any evidence of the nail hole, reputty, respray.  If you're in a hurry, Prep-Rite SF-1 dries faster than the normal Prep-Rite.  (Both are available in spray bomb).

   Also, if you lay a heavy coat of Prep-Rite on, you can block it out with 220.  I have plenty of MDF work that no one would ever be able to find the nail holes.

   FWIW, I like the Elmer's over bondo in that it sands easier...

1. 
   jimblodgett | Jun 02, 2006 11:24pm | #6

   I'm no painter, Paul, but I work with MDF quite a bit.

   To me the issue is how porous the putty (or filler) dries.  That's the main characteristic of MDF surface, right?  How dense it is?  How light slides across it uninterupted? 

   I think I'd try bondo, or a similar filler, then go over that with an auto body primer, which has great pore filling capabilities.  I'm pretty sure that's the difference between really good looking paint jobs on autos, the lack of pores.

    

    Tipi, Tipi, Tipi!

   http://www.asmallwoodworkingcompany.com

1. 
   PaulBinCT | Jun 02, 2006 11:30pm | #7

   Thanks guys. I think I'm gonna go with my original plan which was Bondo... appreciate all the feedback!  (If I discover any amazing new process, I'll let ya know!)

   PaulB

1. 
   Snort | Jun 03, 2006 12:36am | #8

   Maybe it's because I get Bondo at Wall Mart, but I've never had a telegraph problem on the few miles of MDF I've had to mess with. Use light coats that don't need much sanding...and, don't use water-based primer. It messes with any fuzz you get from excessive sanding. I need a dump truck, baby, to unload my head

2. 
   Sphere | Jun 02, 2006 07:39pm | #3

   Boo news. ANYTHING will telegraph, without a lot more prep or top caots than the savings of using MDF will trade off.

   Durhams Rock hard Putty will raise the surrounding area and then finish off, bondo will show forever.

   Drywall mud is the next step after the Durhams is sanded..think pore filler or nitro for a clean sheen.

   Spheramid Enterprises Architectural Woodworks

   There is no cure for stupid. R. White.

1. 
   CAGIV | Jun 02, 2006 10:55pm | #4

   why do you say the bondo will show forever?

   I made a simple little bookcase for my bathroom out of some scrap MDF, filled all the nail holes with bondo, sanded smooth, and you can't see where I puttied.

   Nothing as large as a screw head, but I'm not sure how that would make a difference. 

1. 
   Sphere | Jun 03, 2006 02:12am | #9

   Why/? cuz it is me, I musta fu'ed last time I played w/ it.

   Spheramid Enterprises Architectural Woodworks

   There is no cure for stupid. R. White.

2. 
   DougU | Jun 05, 2006 05:10am | #11

    bondo will show forever.

   Sorry but your doing something wrong, I've used bondo on MDF and I'll put a  lot of money on the fact you cant find it!

   Go with bondo

   Doug

1. 
   Sphere | Jun 07, 2006 12:40am | #18

   Ya know what? I DID screw up, I used a W/B poly-crylic type sealer...or latex primer. I have not had the pleasure of MDF in my shop for quite some time..that I had to fill at least.

   I hate the stuff 80% of the time, but man that 20% of when ya gotta use it, it is the deal.

   Actually, I have been roofing so much, little woodworking has been going on at all...too tuckered out in the eve's and too much else to do on weekends...( oughtta be the 'weak-ends' for me).

   Spheramid Enterprises Architectural Woodworks

   There is no cure for stupid. R. White.

1. 
   DougU | Jun 07, 2006 12:51am | #19

   I hate the stuff 80% of the time, but man that 20% of when ya gotta use it, it is the deal.

   I dont like it that much! But your right, when ya need it it cant be beat.

   I've done the latex primer myself, thats why I can talk like such an expert now! :)

   Doug

    

1. 
   Snort | Jun 07, 2006 02:28am | #20

   Doode, if you don't fock up, you don't learn<g>sanding a little wet sanding sealer on mdf cuts and abrasions helps beat them fuzzies, too...and yeah I hate it, but yeah I use it<G> I need a dump truck, baby, to unload my head

2. 
   zachariah | Jun 12, 2006 04:34am | #24

   I do a lot of repair/renovation bondo is the only filler to use in paint situation.I have used it in numerous applications and all types of paint with complete success, I LOVE it!!

3. 
   maverick | Jun 03, 2006 04:02am | #10

   Like someone else suggested, go with the elmers latex putty. it works fine for MDF and dries to near same consistency as MDF so it sands easily, and dries fast

   then use Gliddens Gripper latex primer, dries fast also. sand after the first coat of primer and apply a second, then paint.

   You can thin gripper with a little water if you want to spray it, of course they wont tell you that

4. 
   RRooster | Jun 06, 2006 04:02am | #12

   Here's what a former painter/friend did:

   1. Sand all fastener holes in an elongated "gouge",
   2. Fill in with bondo with a putty knife,
   3. When bondo dries, sand smooth and skim coat with bondo,
   4. Final sanding.
   5. Paint to smooth as a baby's ####.

    

   http://grungefm.com

    

5. 
   jwinko | Jun 06, 2006 06:51am | #13

   I have made many cabinets with MDF and finished them with a high gloss lacquer. BONDO is the solution, DO NOT use a latex primer. Use an oil base primer and thin it with lacquer thinner. The water based primers all raise the grain? (surface) of the MDF. The oil base primer will need to be sanded with a 220-400 grit paper. But it will look good.

   good luck

   john

6. 
   nordindevelopment | Jun 06, 2006 07:35am | #14

   I've had good luck with MH ready patch, or similar painter's filler.

7. 
   tek | Jun 06, 2006 04:17pm | #15

   Follow the advise of using an oil based primer.  We've seen very smooth fill jobs go bad with a latex primer.  The MDF will raise slightly with the latex, the filler won't and what was once nice and smooth is now a crater.

1. 
   PaulBinCT | Jun 06, 2006 05:44pm | #16

   Many thanks guys... I knew I'd find the answer(s) here.

   PaulB

8. 
   JJV | Jun 06, 2006 05:49pm | #17

   Sounds like everyone else has the same idea but we always used Bondo at the cab shop I worked in.  We used a lot of MDF so we used a lot of Bondo.  No telegraph problems because everything was sprayed with a lacquer-based topcoat.  Never had any problems that I recall. 

   Maybe someday I'll know a little something.
9. 
   RichMast | Jun 07, 2006 04:03am | #21

   For little holes like from am 18 g nailer, I use spotting putty.  It's what auto body shops use to take care of little scratches before painting.  It is like bondo, but only one part so no mixing. It comes in a tube, dries fast and sands smooth.  I guess you could also fill with it.  You can pick it up in any store with a auto department, like sears or walmart.

   Hope this helps.  Rich.

1. 
   Sphere | Jun 07, 2006 06:29am | #22

   AKA, Nitro-stan or Green dragon..BTW, it shrinks like all get out in larger apps.

   Spheramid Enterprises Architectural Woodworks

   There is no cure for stupid. R. White.

1. 
   RichMast | Jun 09, 2006 04:00am | #23

   You bet.  Even 18 ga holes often need a second hit.  Dries fast, tho, so not too bad.

   Rich.