Putty for Nail Holes in Windows and Trim

Struggling to find a nail-hole filler that's compatible with waterborne clear finish. December 6, 2011

I am spraying about 25 detailed fir windows and trim with clear waterborne. I am first spraying a wash coat of shellac/methyl hydrate followed by spraying oil wiping stain/lacquer thinner and not wiping. At some point I need to fill nail holes. The finishing carpenter/project supervisor wants me to use an oil-based glazing compound coloured with universal tints. I am leery of this product under a waterborne. This product takes weeks to dry, I have been told.

Any suggestions for another product, or if I let it dry over the weekend on the oil stain, can I just spray another wash coat of shellac to act as a barrier and then spray my waterborne topcoats?

Forum Responses
(Finishing Forum)
From contributor D:
I would consider using a solvent based filler or putty before staining. Choose the lightest color to match the raw wood and sand before final prep for staining.

From the original questioner:
I am assuming you mean use the solvent based glazing putty coloured the same as the raw wood over my washcoat and then stain. How long do you think I should wait for drying? I am spraying my wiping stain 1 part to 3 parts lacquer thinner, so the stain flashes off pretty quick. If the putty is not totally dry, will it affect the quick drying solvent stain?

From contributor T:
Mohawk is one of several sources for the kinds of wax fillers made for your needs. Some are rub in, others are melt in. They come in assorted colors and are all ready to topcoat immediately with your choice of topcoat.

From contributor R:
If they insist on that type of hole filler, I suggest putting that on after all the finishing is complete. I wouldn't want to spray on top of a wax stick either. Shellac stick is something different, but I've never tried to do that on a vertical surface. Seems impossible, or messy at the least.

From the original questioner:
Would not want to use an oil based glazing putty over my finished waterborne topcoats. It would destroy my finish, not to mention create a different sheen.

From contributor R:
I was thinking of a product called Color Putty. I can't imagine it has enough solvent to cut into the waterbased after it was cured, but I haven't tried it. It wouldn't sit on the water based long, just enough to fill the hole and then buff off the excess.

From contributor C:
If I'm faced with a contractor or designer or site manager who asks me to use a particular product, I draft up a release form that covers my butt. Put in writing that you won't be responsible for the outcome should something go wrong or cause a delay in your schedule.

Make up samples of various fillings. Make up a sample showing the way you, the professional finisher who was hired to complete these fir trim/windows, would proceed. Get signatures on everything.

If you can get a hold of some Durhams Rock Hard Putty, you can mix in some dry powders or artists colors to get a close to the wood match. The Durhams Putty comes in a dry powder form. You mix in some water to achieve the consistency you want. Try it out on a few scrap samples until you're happy with the color.

Keep in mind that once you add water to the Durham's, you will have some decent working time, but when it starts to dry, it's gonna dry hard as a rock. This stuff sands up real good and I've yet to encounter a coating that won't adhere to it.

From contributor L:
Can I ask why you are using methyl hydrate with the shellac? Methyl hydrate is methanol and is far more toxic than the standard solvent ethanol. Shellac also dissolves faster in ethanol or larger alcohols (which is why the proprietary solvent Bekol contains isopropyl alcohol as well). While the methyl hydrate/methanol would flash quicker, it would seem to me this is likely to cause more problems with blushing, etc.

From the original questioner:
Basically I was in a quandary to find a sanding sealer to deal with the edge grain fir I was finishing. I read that #2 white shellac mixed 1:1 with denatured alcohol was the ticket. Methyl hydrate was pushed in the paint store as the available mix for shellac. I later read on the container for alcohol stove use. I used it, it worked, and that's my story. You would recommend I mix with which type of alcohol? And would I continue to mix 1:1 to use as a wash coat to prevent blotching of the fir? Thanks.

Also I tried a number of stainable fillers like waterbased Famowood and Timbermate. Big fail! I don't understand why these products are listed as stainable fillers. Good lesson though.

From contributor L:
I'm not sure why they pushed the methanol for the shellac but chemistry is very similar so it does work. Denatured alcohol is almost 100% ethanol (ethyl alcohol or ethyl hydrate). The same stuff that is in liquor, so that would be like 200 proof vodka. However to avoid the liquor tax, they add a small amount of chemicals that will make you sick if you try to drink it.

As we all know, ethanol (or alcohol) is toxic if someone drinks enough. However, methanol and all the other alcohols are far more toxic. Unfortunately that doesn't always stop people from trying them. So, the point is breathing a very small amount of ethanol (even with the additives) is far safer than breathing methanol.

Shellac is an excellent sealer. That's why it's in Bullseye and other sealers for pine knots. So to answer your question, diluting the 2# shellac with denatured alcohol (ethanol) would give you a 1# solution that is good for sealing.

As far as stainable fillers, I agree that they don't really work. The best I've found is hide glue mixed with sawdust, but even that's iffy. I end up matching after the finishing.

From the original questioner:
Thanks for the info. Do you use solvent or waterborne products? So if you finish at the end and you use waterborne, do you use wax fillers without a topcoat and not worry about a sheen difference?

From contributor L:
As far as nail holes go, I hate them! I've not found a great solution. The most invisible is to lift a wood chip, nail and put the wood chip back down with hide glue (Lee Valley sells a tool for this). Works great but only practical on furniture.

Contributor R's recommendation sounds interesting but I've not tried it. Sometimes sawdust and glue works well. I usually use a wax kit from Fastcap, sometimes mixing the colors. As far as sheen, I try to keep the fill to the absolute minimum with a plastic or wood scraper and then rub with white steel wool. If the wax gets smeared into pores it will show more.

One solution for that is to drive the nail through blue tape, then fill, remove the tape and smooth.

From contributor C:
I really like that idea about the tape. Gonna remember that one.

From contributor B:
I've used GF's WB coatings for years and I've put solvent based fillers like Color Putty and Mohawk Patchal on before the final coat (to match the color better) with no problems. I also use Crawfords painter's putty. (I use Color Putty/Crawfords the most.) I've also used Mohawks wax fillers lots of times. It's harder to put on so I warm it up to make application easier.

Put it on with a sanded down popsicle stick. Again put it on before your final coat to match the color and not change the sheen. On all of these I put them on before I sand the final coat (wipe them with a clean rag then use Scotch-Brite synthetic steel wool). If by chance you try and fill the holes before staining, try to get your putty as close to the final color as you can, not the wood's color. I've learned the hard way stains don't like to soak in to every putty I've tried, including hard putties like Famowood. Also you can blend the Color Putties or use Blendal powders on the Crawfords to get the right color. And the waxes can be melted together to the right color.

From the original questioner:
Thanks for the valuable advice. I mixed/kneaded oil 333 glazing putty with universal colourants, same colour as my stained/topcoated sample, and will use it between topcoats of waterborne.

From contributor C:
Glad you worked it out. If you find the painter's putty you mix up is just a bit too thin once you've added your universal colorants, you can mix in some cornstarch to give it more body.