Sanding sealer last sand

Discussion in 'Finely Finished' started by MojoTrwall, Mar 17, 2019.

  1. MojoTrwall

    MojoTrwall Tele-Meister

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    Hello Everyone,

    I'm coming toward you for my first DIY guitar project.

    I'm currently doing a 2 tone sunburst with some Nitrocellulose paint, on a one piece roasted swamp ash body.

    I filled the body with Water based Pore filler.

    Yesterday, I shot three coat of sanding sealer which I just wet sand today.

    I had low spot and I went through the nitro so I did an heavy coat today which.

    After the coat sanding I had these holes which I don't how to handle.

    Can someone help me with what went wrong in my step ?

    Were these parts unfilled so the wood just soaked up the lacquer ?

    Do I have to sand everything and shoot lighter coat of sealer ?

    Or I just have to put more thinner in the lacquer and do a light shoot of coat ?

    Sorry for any grammar mistakes English is not my first language.

    Best regards,

    Sofiane

    Stratocaster bas.png Stratocaster face.jpg
     
  2. eallen

    eallen Tele-Afflicted

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    Don't worry on the english. Yours is as good as mine and it is my ONLY language.

    It is hard to tell from the first pick but it looks like an end grain of the wood maybe? If so, end grain often soaks up sealer and coating more. Depending on the wood I sometimes sand the end grain with a finer grit. Since ash has very deep grain the end grain may not have been filled enough. If so, even if you get a flst sanded finish the lacquer will sink into the recesses later. On the other hand, if it is just absorbing the finish, it should disappear as coats are built up.

    On the spot in the second pic. Is that after shooting more lacquer or before? If after, my guess is you went thru the sealer as well and maybe some pore filler. If so, you can try spot applying some sealer and seeing if the color begins to match up again.

    Keep trying!

    Eric
     
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  3. MojoTrwall

    MojoTrwall Tele-Meister

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    Thank you for your answer !

    I don't really understand what End Grain is ? (Technical language is the hardest to get).

    But I do think that with the low edge, I did not put enough pore filler in it and the wood keep soaking the lacquer, and I'm afraid it wont build a proper coat when I'll go to the color coat.

    Concerning the spot on the face :

    I did sand after my first three coat which were too wet (Hard to control with an HVLP), and I had this spot.

    When I did my second shoot the coat did not covered the spot, I felt like the wood was soaking up the lacquer again.

    I'm in holidays at the moment, so I'm planning to shoot another coat tomorrow.

    But I'm really unsure of what do for both of spot :

    I was planning to grain fill the lower edge of the body which really soaked a lot of the coat on my first three coat, and on the fourth (post-sanding coat)

    And to see if the spot just soak up the wood because I sand through or if it's the grain again messing with the lacquer.
     
  4. tubedood

    tubedood Tele-Meister

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    End grain is the edge that's left after a piece of wood has been cut... It tends to be very thirsty and soaks up the fillers or coatings that are applied onto it more than the other parts of the board.
     
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  5. MojoTrwall

    MojoTrwall Tele-Meister

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    Ok so I'm pretty sure that for the first picture it's not enough filled with the pore filler.

    I'll sand it and fill again so it won't soak each coat.

    I'll see tomorrow for the sand through spot with light coat if I manage to match the color of the body.
     
  6. eallen

    eallen Tele-Afflicted

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    What is your goal for your final color? A full body pic would help as well.

    Eric
     
  7. bullfrogblues

    bullfrogblues Friend of Leo's

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    One tip, don't wet sand sanding sealer.
     
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  8. MojoTrwall

    MojoTrwall Tele-Meister

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    Understood for the dry Sand.

    I'm planning to do a 1954 Sunburst, pretty Dark Ash due to the roast.

    I put on the end grain more Pore filler, weather was set today I can't shoot untril wednesday.
     

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  9. eallen

    eallen Tele-Afflicted

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    ^^^ Yes, don't wet sand sealer. Dry sand only. To add to that, I never use water to wet sand at any time! If water gets into holes it can expand the wood and crack the finish or get under it. Myself and others use naptha or mineral spirits to wet sand in for that reason.

    Actually, the odd color change in the finish on the edge, unless it is grain or figure color change, reminds me of some sort of contamination that makes me wonder if moisture has gotten entrapped in the finish some how.

    Eric
     
    Last edited: Mar 18, 2019
  10. MojoTrwall

    MojoTrwall Tele-Meister

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    Thanks for your answer !

    I think I'm gonna sand and recoat the whole body with finer coat.

    I'll give you a feedback of the résult !
     
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  11. Silverface

    Silverface Poster Extraordinaire Ad Free Member

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    Also that's an unusually high number of coats of sanding sealer. And there should be no film left when you dry sand it - it's a sealer, not a coating.

    Normally I apply sanding sealer and dry sand first; then grain filler, one to three applications to fill the low spots and create a smooth surface (with grain filler usually tinted to a color to "pop" the grain - make it stand out visually) ; then one more coat of sanding sealer, dry sanded.

    At that point it should look like smooth wood. NOT wood with a coating on it. The color, or toner, or clear coats (or combination of the three) are what build the actual protective and glossy film. They are applied very lightly - 3 light passes per coat, with a coat of even opaque lacquer being very transparent.

    There is NO sanding between coats except to fix small runs. Lacquer melts into itself and the system creates on single coat. If a coat is too rough it was applied too heavily, or at an angle, or too closely - and all these details of technique should be worked out by practicing on scrap before working on the actual guitar.

    I suggest sanding the sealer down to where t looks like wood - because that's how it *should* look.

    Then STOP. Apply the ENTIRE system, including all preparation and final buffing, on scrap wood. Get it *right*, work out problems and refine your spray technique - and understand what each part of the system is supposed to look like - BEFORE going back to the actual guitar.

    From your question and the pictures it seemed to me that you started applying materials without really knowing what you were doing. Have you read all the materials on the ReRanch site? That's a great starting point. And there are hundreds of threads here that explain what to do...and expect...coat by coat.

    But it really does take practice FIRST. some people get lucky and just start spraying away, but that's VERY unusual. Reading, understanding, and LOTS of practice - that saves a lot of time, problems, headaches - and money in wasted coating.

    Good luck!
     
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  12. MojoTrwall

    MojoTrwall Tele-Meister

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    The three coats was coming from Stewmac and Manchesteguitartech which both recommands three coat.

    Sanding was because I had runs on the sanding sealer, which I read must be recoated explaining the fourth coat.

    Going from theorical point of view, to the application is a little bit different, and that's because I'm unsure I'm asking from what I read on various sources (Here, Stewmac, Manchesteguitartech etc), even though I read a lot, there's a gap between watching and practicing.

    I had hard time with these two spot, as I'm unsure for the face if it's a sand through or not which I'm trying to avoid, because left horn is not shiny but matt and do not have a coat look.

    Just a color shift which I'm wondering if it's a sand through.

    They both look like wood, and there's no rough part and that's my difficulty here.
     
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  13. Silverface

    Silverface Poster Extraordinaire Ad Free Member

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    I meant natural wood - consistent grain, but with a little bit of a graying look from some sanding sealers.

    I'm not familiar with Manchester, but in the US Stewmac provides very unusual finishing recommendations - multiple sealer coats and long dry times between coats and before buffing, among others - that are very unusual except when using deft products. It may be that the Colortone products they sell specifically require those coats/times, but virtually every other commonly available product does not.

    And if using grain filler there's NO reason for 3 sealer coats beforehand. It's a complete waste of time, material and money. The filler and post-filler sealer coat will take care of it.

    The only "3 coat" sealer thought that makes sense is if they meant 3 light "passes" - which is how ONE coat is normally applied. But3 full coverage coats of ANY sanding sealer is a waste.
     
  14. MojoTrwall

    MojoTrwall Tele-Meister

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    Ok I definitely see what you mean now.

    I put way to heavy coat for my first nitro spray and the natural Wood looking is the spot on the face

    I must Sand more of it because of the heavy coat.

    I have a scrap piece of pine which I'm gonna practice over.
     
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  15. DrASATele

    DrASATele Poster Extraordinaire

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    If that stain is possibly oil based you can try using an hot Iron and a piece of paper or cloth. It's a trick used by dry cleaners. It can work really well on some woods
     
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