Grain vs Wood filler

Discussion in 'Finely Finished' started by oregomike, Sep 21, 2021.

  1. oregomike

    oregomike Tele-Holic

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    I might have already answered my own question, but going to shoot this out anyway.

    I'm about to paint a nice ash JM body, but need to use some filler before anything goes on it, and I've pretty much settled on getting some Tomahawk "Grain Filler."($24 for qt/946ml) A couple questions actually.

    1. Tomahawk also sells a grain filler thinner. (also $24) Should I assume it's best practice to use their thinner?

    2. Can you use a wood filler instead? I'm thinking that it might not be viscous enough to get into the small areas since it's meant more for larger voids.

    It'd be nice to just go to Home Depot and get it. For some reason the guy there was like "no idea what grain filler is. You mean wood filler?" Nope.

    Anyway, thoughts?
     
  2. Timbresmith1

    Timbresmith1 Tele-Afflicted

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    Wood filler wood be a poor substitute.
    Sherwin Williams might have a grain filler in stock if you have one of their stores nearby.
    I kind of doubt you need the thinner. If you were doing large tabletops or something, you might.
     
  3. dsutton24

    dsutton24 Doctor of Teleocity Ad Free Member

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    As you suspect wood filler is for holes and wouldn't work as a grain filler. It might be that you could thin wood filler enough to grain fill with it, but that'd undoubtedly be a messy proposition.

    If you're painting, plain old drywall compound works fine. It's cheap as heck and compatible with every finish that I can think of.
     
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  4. oregomike

    oregomike Tele-Holic

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    Ah, okay. Thanks. That was sort of my thought too. As far as the grain filler, my understanding was that it's a paste (?) and some use the thinner to help it flow into the cracks easier. I'll try it first w/o the thinner.
     
  5. Timbresmith1

    Timbresmith1 Tele-Afflicted

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    See if anyone else chimes in.

    I found it a tedious process evin in the best circumstances. Surely someone else here does it better.
     
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  6. oregomike

    oregomike Tele-Holic

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    Yeah, I didn't need to with my alder body, but ash is a definite must. At least this body is. Not looking forward to it.
     
  7. wadeeinkauf

    wadeeinkauf Tele-Afflicted

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    I have used bondo in my guitar building. One member uses it as a grain filler before painting. Here is a Youtube video talking about using automotive bondo. They also make a bondo grain filler product...
     
    Last edited: Sep 22, 2021
  8. Freeman Keller

    Freeman Keller Poster Extraordinaire

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    Ash is an open pore wood like some of the tropical hardwoods. The pores need to be filled or finish will shrink back and not be smooth and shiny. There are lots of good products for filling pores, pastes are fairly common. I happen to like a finishing resin which also does an incredible job of enhancing grain and figure in the wood. Its also a good base for the lacquer that I apply.

    Most of the time paste pore fillers are applied with something like a squeezie or a plastic card and is forced into the pores, any excess is sanded back level with the surface. Basically you don't want any on the surface. Some are water based, some are solvent based, if you want to thin them look at the instructions on the container.

    If you are going to apply an opaque finish almost anything will work, if you want to enhance the grain and show it off thru a clear or transparent finish then the choice of pore fillers is important. As with everything else in finishing, experiment on scraps of the same wood.
     
  9. old wrench

    old wrench Friend of Leo's

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    Not familiar with Tomahawk - if you are talking about Mohawk grain filler, which is the same as the old Behlens product - it's good stuff, but you do need to thin it out for grain-filling Ash since it's pretty thick just as it comes in the can.

    I haven't bought or tried the suggested Mohawk thinner, instead I thin the Mohawk grain filler with regular old mineral spirits.


    .
     
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  10. Midgetje94

    Midgetje94 Tele-Afflicted

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    I had to order grain filler online. Kind of a snot like material you slather on the wood. Squeegee it in. Let it dry, sand, and repeat if needed. It seeps into the grain itself. While wood filler is more putty like to mold or fill dings and plug holes.
     
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  11. eallen

    eallen Friend of Leo's

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    +1 on Freeman & Old Wrench.
     
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  12. oregomike

    oregomike Tele-Holic

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    Thanks. Yeah, this will have an opaque finish. Mohawk seems to be a good product, so probably going that route unless I hear of a better brand.
     
  13. oregomike

    oregomike Tele-Holic

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    I don’t know why I keep referring to it as Tomahawk. Ha. Anyway, yeah, Mohawk is where I was going. Good to know about the mineral spirits. I already have some of that.
     
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  14. wadeeinkauf

    wadeeinkauf Tele-Afflicted

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    When I first started building guitars, I tried just about everything for grain filling. Below are just what was left in my bottom shelf. As Freeman said, for you since you are painting almost anything will work. Most of the oil based fillers have to dry overnight, sanded reapplied and dry overnight again….In my experience. The water based products I tried were not very effective…took several applications with long drying times between. The only finishing resin I used other than the one I use is Z-Poxy. I think this is a great product but takes 3 hours to cure which is great by the standards of most other products. The only product I use now for a sealer/filler is Solarez UV-Cure Grain Sealer… Crystal clear “cures" in under 10 minutes in sunlight. I use a lot of reclaimed lumber, open grained like American Chestnut. I can put on 3 applications including sanding between coats in under an hour and be ready to spray my top coats. Grain filled/sealed and ready to spray in one hour. One container can do at least 15 guitars.


    20210921_174928.jpg 20210921_174949.jpg
     
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  15. oregomike

    oregomike Tele-Holic

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    Thanks for the great info. I'll look into this!
     
  16. Freeman Keller

    Freeman Keller Poster Extraordinaire

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  17. Sax-son

    Sax-son Tele-Afflicted

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    If you are going to paint a solid color, drywall compound works well. If you are going for a transparent, you may want to stick with the oil based fillers. I recently used Timbermate on a clear alder strat body and it came out well. Some folks don't like waterbased materials of any kind, but I have never had problems with it. Timbermate is forgiving and all you have to do is add more water if it starts to dry. You just make a water paste and apply it with a brush. You have to be careful when sanding because it sands easy. Once you get the results you want, I just lock it in with nitro sanding sealer.
     
  18. oregomike

    oregomike Tele-Holic

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    Welp. Placed an order for Solarez. Sold me on the curing time and no shrinkage.
     
  19. wadeeinkauf

    wadeeinkauf Tele-Afflicted

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    The way I use this is to put a 1/2 teaspoon of the filler on the body. Wear rubber/latex gloves. Then take a credit card, or I use two business cards stuck together in place of the credit card (they are more flexible) , and spread over the body. Put more filler on the wood as needed. Put as thin a coat as possible. Turn the body over and place on two narrow ½ wide or so pieces of wood to keep off the surface and do the same to this side. For the edge and rounded parts of the body I dip my finger into the filler and using my finger I rub the filler on. It will not take more than about a tablespoon full of filler for the body. Do not overwork spreading. Just pour in on the wood and spread it out. When it stops spreading put another ½ teaspoon full and so on. The material will thicken quite a bit if you over work it. Take it in the sun for a few minutes. It will dry/cure in 3 or 4 minutes on each side in bright sunlight. In an overcast it may take 10 minutes for each side. When it is cured it will not be sticky. If sticky leave out in the sun longer. I sand/level with 220 grit paper. I use a 2 inch pink eraser like a child has in school and wrap my sandpaper around it. Works great for leveling. Very gently by hand around the edges with just the sandpaper. After 3 or less applications it should be level. If you have one or two spots that is not filled you can put the filler on just these spots and cure and sand. It will blend (to the eye) with the previous layer. If you sand back to wood on your last coat and all is well except for this area, you can dip your finger again and just rub the filler on this area, cure and sand.

    The reason I have gone into such detail is because I put way too much on the first few times I used it. It takes a lot of sanding to get it level and makes a mess…..One other thing. This cannot be thinned. Something to do with the chemical makeup. I talked directly with the founder and “inventor” of this product a few years ago when I started using it. There is a topcoat product as well. I do not recommend it. I have tried it. It “cures” with just a bit of haze. You get a better finish with lacquer or a 2K product as a topcoat. Please follow up here after you use it.


    Here is a good video from Highline Guitars. I sand and level between coats. Again I do not recommend using the Gloss top coat product. It is very hard to prevent pinholes/bubble holes from forming. I have never had a problem with the grain filler/sealer. Other members that have tried the top coat also had problems with it.




    Wade
     
    Last edited: Sep 22, 2021
  20. Vizcaster

    Vizcaster Poster Extraordinaire

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    Behlen's is the DIY brand label they sell in woodworking supply catalogs (and at my favorite hardwood supply lumberyard which is now long gone), from the same company as the Mohawk professional brand.

    Timbermate is a "wood filler" that you can thin with water to get the "thick cream" (never understood that analogy, I prefer to call it "yogurt") consistency for grain filling.

    Lately I've been using Aquacoat as a grain filler for mahogany but Keller turned me on to Z-Poxy (harder to sand back but fantastic results).
     
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