# Filling nail holes in mdf trim



## Leeboy20

What system are you guys filling mdf pin/brad nail holes in trims etc. Over the years, I used to use drywall mud and have zero selling or problems and you could never see the hole after I was done. Over the years I noticed mdf likes to swell once the filler hits it. I've tried dry dex, light weight non shrink, drywall mud, dried up drywall mud, all seems to want to swell a bit. I hate 2 coating them, so I over fill just a tad. What works best?


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## capn26

I use lightweight. Never had any issues with swelling. Mdf is a sponge though and I know anything moist will be a problem. Of course I do mix a tiny bit of dry Sheetrock mud in my lightweight before I start using it. Just a ball in my hand I dust and kneed together.


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## RH

Elmers wood putty.


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## capn26

Yeah good call RH. That works great but it you leave too much sanding can be a pita. The Mdf will sand before the filler sometimes. And while pretty expensive for what it is, famo-wood is water free.


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## journeymanPainter

We use dynamics dyna-patch. 2 really light fills and your good to go. Can be a real pain to sand sometimes


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## ridesarize

Leeboy20 said:


> What system are you guys filling mdf pin/brad nail holes in trims etc. over the years , I used to use drywall mud and have zero selling or problems and you could never see the hole after I was done. Over the years I noticed mdf likes to swell once the filler hits it . Iver tried dry dex, light weight non shrink, drywall mud, dried up drywall mud, all seems to want to swell a bit. I hate 2 coating them , so I over fill just a tad . What works best ?


You do know that nails beingshot in mdf make it swell up pretty good about the size of a nickel or a quarter for larger nails? I have never had a problem with filler making it swell. 

I mix 25% elmers and 75% spackle (Crawford's). Of course you have to over fill and leavesmooth edges though, or else you're defeating yourself.. Also I presand and vac out nailholes on mdf before I fill whenever I can. 

When I hand sand that filler I stop sanding when there is a light haze of spackle over the area still which completely blends the hole and keeps it from appearing. Usually if you sand all spackle from the surface there is a chance the hole dishes or shows up somehow.


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## stelzerpaintinginc.

1st: Run 5-in-1 across hole to remove protrusions, (on higher level work, we'll even sand areas around nail holes before filling them to remove the lump).

2nd: Vac holes, (since spackle/putty often creates poor bond otherwise and will fall back out during the sanding process.

3rd: Flush-fill holes twice, allowing dry-time between each, (applied via putty knives on flats, fingers on more intricate work). The problem with leaving a build is that the putty either gets sanded back out of the hole in the process of sanding or the wood around the putty has to be sanded too much while trying to sand the putty flush, or the build isn't thoroughly sanded, which shows through the primer & paint.

4th: Sand with sandpaper, not sponge. A sponge will contour to the hole and can leave a divot, creating a less-than-flush appearance.

The spackle I use for normal pin, brad, nail holes is 3m. It dries quickly, sands to powder, won't flash through top-coat in the event more is needed after primer, and it has plenty of grab.

The putty I use for larger holes is either Elmers or Minwax. I've had success with both.

These are MY systems. If you don't like them or don't agree with them, awesome. I don't care. I've put an ungodly amount of time into finding a system that works for me and I'm sure there are plenty of different systems that work besides mine.


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## Rcon

Leeboy20 said:


> What system are you guys filling mdf pin/brad nail holes in trims etc. over the years , I used to use drywall mud and have zero selling or problems and you could never see the hole after I was done. Over the years I noticed mdf likes to swell once the filler hits it . Iver tried dry dex, light weight non shrink, drywall mud, dried up drywall mud, all seems to want to swell a bit. I hate 2 coating them , so I over fill just a tad . What works best ?


wood filler.


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## PNW Painter

Does anybody else add a small amount of blue paint, or any color for that matter to the filler they're using? Otherwise I find that's it's easy to accidentally miss a spot on white preprimed mdf.


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## RH

PNW Painter said:


> Does anybody else add a small amount of blue paint, any color for that matter to the filler they're using? Otherwise it's way to easy to miss


Never had trouble spotting the Elmers. On white trim it usually stands out enough to be easily seen. Or, if I did miss one it wasn't that big a deal. 

I've also never had any problems with sanding it. In fact, that's one of the things I like about it.


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## capn26

Elmer's is very sand able. I've used blue and red chaulk before because someone convinced me it was a great idea but no mas.


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## MNpainter

Chainsaw or a torch. And a hammer upside the head for the gc that put that sh... in.
ymmv


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## jacob33

I never have been a big fan of mdf but I just spackle it with crawfords.


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## ridesarize

PNW Painter said:


> Does anybody else add a small amount of blue paint, or any color for that matter to the filler they're using? Otherwise I find that's it's easy to accidentally miss a spot on white preprimed mdf.


When I mix elmers in with spackle it colors it just enough to see all the spots easily, and the eyes can decipher if it's been sanded enough or missed just due to the color of the filler.

Also I have added just a dab of red paint to a quart of filler or a drop or two of red oxide colorant to the quart.


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## Damon T

Stelzer - which 3M spackle? 

My guys usually mix Elmer's wood filler 50/50 with lightweight. Gives you the sand ability of lightweight and the hold and body of wood filler. Also the color of wood filler helps as was mentioned above.


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## capepainter

The 3m patch and primer would work good on MDF also I did a large jib a few years back and we primed it first with some oil problock then filled holes don't know if it made a big difference.


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## ridesarize

I kind of dislike the 3m patch and primer. It dries like fix all or hotmud on your putty knife way too fast, it doesn't seem to harden on bigger voids. It does not sand down nice and flush very easily. 

I used it on a large portion of a remodel and mill pack. We went through and sanded the same holes 3 times just to get rid of lumps that weren't seen until side-lighted. So the pre-primer got sanded down way before the actual filler, that's okay since we primed again, but that defeats the patch/primer idea.

On top of that I tested the primer factor in it, and it flashed dull through the paint. It is a product failure in my opinion..

So I'm ticked my favorite local store carries this stuff and no Elmer's. Elmer's is hard to find now I think.


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## stelzerpaintinginc.

Damon T said:


> Stelzer - which 3M spackle?
> 
> My guys usually mix Elmer's wood filler 50/50 with lightweight. Gives you the sand ability of lightweight and the hold and body of wood filler. Also the color of wood filler helps as was mentioned above.




This for smaller holes, again, flush-filled only. I understand some don't care for the sandability of it when trying to leave a build, but we don't try to leave any build. I wonder how many folks who have problems with sanding this try to sand with sponge vs. paper? All too often, the sponge just bends right around it, rather than sanding it flush. 150-220 grit works great. I love the convenience and flexibility of a sponge, but we don't pull those out til we're sanding primer.


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## Repaintpro

Am I reading this wrong or do you guys not have linseed putty over there? The moisture out of fillers will make MDF swell, but the Linseed oil putty is not water based.


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## Repaintpro

PNW Painter said:


> Does anybody else add a small amount of blue paint, or any color for that matter to the filler they're using? Otherwise I find that's it's easy to accidentally miss a spot on white preprimed mdf.


If your doing this...........just us a little bit of tinters. Adding paint would affect the sandability, adding a bit of tint won't. We use to do this for some small wall patching is the wall colour looked too close to the patch/filler.


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## wje

PNW Painter said:


> Does anybody else add a small amount of blue paint, or any color for that matter to the filler they're using? Otherwise I find that's it's easy to accidentally miss a spot on white preprimed mdf.


A trick I learned was adding chalk from a chalk line... It was an awesome trick from a drywaller I learned. Just enough to slightly tint the mud to make it visible for sanding


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## Jmayspaint

Repaintpro said:


> Am I reading this wrong or do you guys not have linseed putty over there? The moisture out of fillers will make MDF swell, but the Linseed oil putty is not water based.



Yeah, we have it. It used to be my favorite hole filler. Cram a hole full, knock it down with a piece of sand paper and the hole can disappear totally if you do it right. Easy, no dry time. 

Myself and a lot of other guys I think are moving away from using it along with oil primers. Unless you prime the oil putty with oil primer there is a risk of bleed through. Doesn't always happen and it doesn't always happen right away. But months down the road the oil from the putty can start to bleed through acrylic primers and paints. Looks horrible when it does happen.


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## Damon T

That's why I don't use it anymore.

Thanks for the tip Stelzer on filling flush. I had trouble sanding that product. Sounds like less to sand the better.

I like the Crackshot and the Drydex sands nice too.


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## stelzerpaintinginc.

Damon T said:


> That's why I don't use it anymore.
> 
> Thanks for the tip Stelzer on filling flush. I had trouble sanding that product. Sounds like less to sand the better.
> I like the Crackshot and the Drydex sands nice too.


I'd agree that the Crackshot sands as good as any spackle I've used. I just think it lacks the grab, (especially when filling more shallow holes).


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## ridesarize

stelzerpaintinginc. said:


> I'd agree that the Crackshot sands as good as any spackle I've used. I just think it lacks the grab, (especially when filling more shallow holes).


That's weird I find the crackshot to not sand well, actually it seems to sand well but usually doesn't go down flush easy, it lumps. 

I do like drydex though, for walls or trim. I've also found that I like the two SW fillers that imitate crawfords and the elmer's.


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## ridesarize

Repaintpro said:


> If your doing this...........just us a little bit of tinters. Adding paint would affect the sandability, adding a bit of tint won't. We use to do this for some small wall patching is the wall colour looked too close to the patch/filler.


Adding paint (some) does not affect the sandability. I do it all the time with spackle. Now if I tinted my Elmer's I may be tricked to think the paint is making it harder to sand, but it doesn't.


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## ejs

I also use Crack shot with some paint. A 23 gauge pinner and a mix of paint and filler followed with a damp rag will work well. Not at eye level on a door casing of course; however this finish work with trim depending on the installers application will always be a pain. I bought a pinner this summer and gave it to the carpenter who installs the trim on our crew. *http://www.cadextools.com/en/* and we are making some progress. 18 gauge, MDF, young kids, bad news.


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## Repaintpro

Jmayspaint said:


> Yeah, we have it. It used to be my favorite hole filler. Cram a hole full, knock it down with a piece of sand paper and the hole can disappear totally if you do it right. Easy, no dry time.
> 
> Myself and a lot of other guys I think are moving away from using it along with oil primers. Unless you prime the oil putty with oil primer there is a risk of bleed through. Doesn't always happen and it doesn't always happen right away. But months down the road the oil from the putty can start to bleed through acrylic primers and paints. Looks horrible when it does happen.


I agree acrylics don't stop the bleeding like oil based undercoat does. 100's of ways around the bleeding but it's good to hear there are other solutions.


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## Painter-Aaron

Repaintpro said:


> Am I reading this wrong or do you guys not have linseed putty over there? The moisture out of fillers will make MDF swell, but the Linseed oil putty is not water based.


Are you talking about linseed putty thats also used for glazing windows? 

My old boss had me use that on nail holes, mainly in baseboards as we never did new construction. it always left a lump or an indent.


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## Repaintpro

Painter-Aaron said:


> Are you talking about linseed putty thats also used for glazing windows?
> 
> My old boss had me use that on nail holes, mainly in baseboards as we never did new construction. it always left a lump or an indent.


Yes linseed putty. There is an art to using it with a putty knife or you overfill and sand off with paper. Does not shrink or crack... imho the best nail hole filler around especially if you get the hang of it. No going back to sand filler.


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## Wildbill7145

Shurstik featherweight filler. Been using it ever since I started painting. Always loved it.

Only thing I hate about it is they've never figured out a decent plastic lid to put on the container so you get dry crunchies all over the top which is really annoying. Years ago I started putting it in peanut butter jars with a screw top as soon as I got a new container.


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## journeymanPainter

Wildbill7145 said:


> Shurstik featherweight filler. Been using it ever since I started painting. Always loved it.
> 
> Only thing I hate about it is they've never figured out a decent plastic lid to put on the container so you get dry crunchies all over the top which is really annoying. Years ago I started putting it in peanut butter jars with a screw top as soon as I got a new container.


I hate that stuff. .... at least on walls. It doesn't hide worth a damn when doing patches, abd sand like a$$ in my experience. I found it smelled like xylene as well


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## journeymanPainter

We've been trying something new on our latest job. Using half dried drydex. Most of the moisture is already out of the mud so there isn't any swelling. It's nice cause you can double prep in one day (double fill, and sand). It also sand a heck of a lot nicer than dynapatch as well


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## Jmayspaint

journeymanPainter said:


> We've been trying something new on our latest job. Using half dried drydex. Most of the moisture is already out of the mud so there isn't any swelling. It's nice cause you can double prep in one day (double fill, and sand). It also sand a heck of a lot nicer than dynapatch as well



That's how I like to do it with the Crackshot. When you work out of a spackle container for a while, say patching walls, the spackle that gets left on the sides of the can starts to dry a little. When it gets to that "sweet spot" of being half dry, you can actually make a ball out of it and use it like a putty ball. Being half dry already, it shrinks less.


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## Rbriggs82

Anyone ever try adding some flour to Elmers wood filler and use it like a putty ball?


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## TJ Paint

Rbriggs82 said:


> Anyone ever try adding some flour to Elmers wood filler and use it like a putty ball?


Why not just lightweight powder?


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## rwransom

Love me some MH Ready Patch...


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## Rbriggs82

TJ Paint said:


> Why not just lightweight powder?


Or that, I've always used flour for regular putty so that was my first thought. 

I've never tried it but if it didn't get too crumbly I'd imagine it would be easier to work with than all gooey like it normally is.


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## Wildbill7145

journeymanPainter said:


> I hate that stuff. .... at least on walls. It doesn't hide worth a damn when doing patches, abd sand like a$$ in my experience. I found it smelled like xylene as well


Huh, that's interesting. I've never had an issue with the hiding factor. It is a little tougher to sand than regular drywall mud though. Never noticed the smell, but my sense of smell has deteriorated over the years.


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## Workaholic

I am set in my ways and still use Crawfords.


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