For Every Airbrush Artist!

Ready to get involved? Register for free and you won't see any google advertising!

Register

Guitar cracks??

Discussion in 'Troubleshooting!' started by Souldog Airbrush, Jan 24, 2018.


  1. Souldog Airbrush

    Souldog Airbrush Triple Actioner

    Joined:
    Dec 30, 2017
    Messages:
    61
    Likes Received:
    178
    Trophy Points:
    31
    Location:
    The Netherlands
    Hello Airbrush lovers,

    Iam working on a bass gitar , sanded it flat , threw primer on it but this happend:

    1.jpg 2.jpg 3.jpg
    What is going on here?

    I dont have this problem on the body itself.

    Thanks in advance

    greets Souldog Airbrush
  2. markjthomson

    markjthomson AKA QuickDraw and very happy #nobrushleftbehind Staff Member Mod

    Joined:
    Jul 16, 2014
    Messages:
    7,195
    Likes Received:
    6,694
    Trophy Points:
    126
    Location:
    Auckland New Zealand
    Did you sand it back to bare wood?
  3. Souldog Airbrush

    Souldog Airbrush Triple Actioner

    Joined:
    Dec 30, 2017
    Messages:
    61
    Likes Received:
    178
    Trophy Points:
    31
    Location:
    The Netherlands
    I see bare wood now yea , photo in a moment
  4. Souldog Airbrush

    Souldog Airbrush Triple Actioner

    Joined:
    Dec 30, 2017
    Messages:
    61
    Likes Received:
    178
    Trophy Points:
    31
    Location:
    The Netherlands
  5. markjthomson

    markjthomson AKA QuickDraw and very happy #nobrushleftbehind Staff Member Mod

    Joined:
    Jul 16, 2014
    Messages:
    7,195
    Likes Received:
    6,694
    Trophy Points:
    126
    Location:
    Auckland New Zealand
    Ok so the cracks were already there, you've painted over them and now you know why surface preparation is 8/10 of the job! You only sanded back to some wood. I can still see cracks in the area you didn't sand. You need to fill them in before you put paint over the wood. What you need to do is take all the paint off, back to clean wood (as the original paint will have cracks), feather the edges of the paint back, then fill the cracks with (I expect) a suitable wood putty. For me I would use an epoxy filler, sand that back then start the painting.
    ilzeairbrushing likes this.
  6. SiRoxx

    SiRoxx Party Boy UK Style Very Likeable!

    Joined:
    Aug 15, 2017
    Messages:
    2,962
    Likes Received:
    3,424
    Trophy Points:
    126
    It looks possibly like there’s some sort of contaminant under the paint. Were the cracks in the wood there before the paint went on?


    Sent from my iPhone using Tapatalk
  7. Souldog Airbrush

    Souldog Airbrush Triple Actioner

    Joined:
    Dec 30, 2017
    Messages:
    61
    Likes Received:
    178
    Trophy Points:
    31
    Location:
    The Netherlands
    @SiRoxx The neck(thats the name right?) was white at first , like u see on the last one , at that point there where no cracks yet,
    The last pic is the result of resanding the (dark prime) even further to check wassup , now it's showing the bare wood suddenly.

    @markjthomson , The first coat primer (dark grey) , i had just baby small cracks , i filled those in with epoxy filler.
    I hoped that worked but the cracks are worse then ever before now.
  8. markjthomson

    markjthomson AKA QuickDraw and very happy #nobrushleftbehind Staff Member Mod

    Joined:
    Jul 16, 2014
    Messages:
    7,195
    Likes Received:
    6,694
    Trophy Points:
    126
    Location:
    Auckland New Zealand
    OK, if you had cracks in the primer they will be worse in the top coat. If you have any cracks in the substrate they will transfer to the paint as most of them shrink. When you fill in cracks, you don't fill in the cracks in the primer, you have to fill in the substrate. You may also need to feather the cracks in the wood out a little to assist filling.

    Strip it back, fill in the cracks in the wood and start again.
  9. SiRoxx

    SiRoxx Party Boy UK Style Very Likeable!

    Joined:
    Aug 15, 2017
    Messages:
    2,962
    Likes Received:
    3,424
    Trophy Points:
    126
    I agree with what Mark has said. Also it could be that the filler wasn’t properly cured before paint went on and is causing the lifting. I don’t know that for sure, it’s just a guess
  10. Souldog Airbrush

    Souldog Airbrush Triple Actioner

    Joined:
    Dec 30, 2017
    Messages:
    61
    Likes Received:
    178
    Trophy Points:
    31
    Location:
    The Netherlands
    Thank u guys very much for helpin me out

    I can see that some cracks lead to the bare wood ( there seems to be a very thick transparant layer on top of the wood) Is that a clearcoat ?
    And can i safely fill those cracks too with a epoxy filler without crackin that transparant layer even more?

    @SiRoxx , i waited a hour, but i dont know for sure if its a epoxy tho , it says Uni Pol Polyester-Sprachtel by Airo Automotive.
  11. SiRoxx

    SiRoxx Party Boy UK Style Very Likeable!

    Joined:
    Aug 15, 2017
    Messages:
    2,962
    Likes Received:
    3,424
    Trophy Points:
    126
    It could be a sealer coat for the wood. I’m still not sure why it’s cracking though. The drying time for the epoxy varies from one brand to another. I would either check on the pack to see if it states a drying time or maybe try Google and the details on the manufacturers packaging. Sorry I can’t be more help.


    Sent from my iPhone using Tapatalk
    markjthomson and Robbyrockett2 like this.
  12. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot!

    Joined:
    Sep 29, 2017
    Messages:
    3,282
    Likes Received:
    3,118
    Trophy Points:
    126
    Location:
    Jacksonville, NC
    Any cracks in the wood were there before, under your original coating. What made them show is 1. Your primer was incompatible with the white that was on it. (likely a lacquer primer over an enamel white)
    2. You may have also simply had it too wet at some point.
    SiRoxx likes this.
  13. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot!

    Joined:
    Sep 29, 2017
    Messages:
    3,282
    Likes Received:
    3,118
    Trophy Points:
    126
    Location:
    Jacksonville, NC
    That clear is likely either sanding sealer or lacquer clear.
    Which was then painted over in white.
    Polyester primer.... there its, thats the cause
    SiRoxx likes this.
  14. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot!

    Joined:
    Sep 29, 2017
    Messages:
    3,282
    Likes Received:
    3,118
    Trophy Points:
    126
    Location:
    Jacksonville, NC
    The good news..... Sand it all down to that clear coating. Then put down a lacquer primer. Sand that between coats to fill and level the cracks, if the cracks are just in the clear coating lacquer primer can bond them together.
    What do you plan to paint with and what do you plan to clear with?
    That will determine your next steps after that.
    SiRoxx likes this.
  15. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot!

    Joined:
    Sep 29, 2017
    Messages:
    3,282
    Likes Received:
    3,118
    Trophy Points:
    126
    Location:
    Jacksonville, NC
    I'm having to guess because I dont know what primer you used.
    Before you actually follow what may have been bad advice because I kinda jumped the gun.
    What primer did you use?
    This definitely a compatibility issue
    Last edited: Jan 24, 2018
    SiRoxx likes this.
  16. Souldog Airbrush

    Souldog Airbrush Triple Actioner

    Joined:
    Dec 30, 2017
    Messages:
    61
    Likes Received:
    178
    Trophy Points:
    31
    Location:
    The Netherlands
    A that makes sense no more polyester filler then,
    @Robbyrockett2 I used the primer Finixa out of a spraycan
    I just got a 1.2 minigun too , the plan is to spray the autoborne sealer on top of the primer first ,
    Then go mad with the airbrush (etac , some createx intercoats , auto air pearls and spray the 2k with the same minigun (SSG Hamach).
    The clear will be the KRISTAL Universal TimeClear.

    But haha at this point iam looking at my new minigun and asking myself if i need to put that little filter (white one that goes into the hole at the cup) into the gun or not :p
    GeeDonV likes this.
  17. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot!

    Joined:
    Sep 29, 2017
    Messages:
    3,282
    Likes Received:
    3,118
    Trophy Points:
    126
    Location:
    Jacksonville, NC
    I dont' use the filters but i use filter cones when i pour in the paint. YOu only have to have the filter out for metallics , pearls, and high build primer.
  18. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot!

    Joined:
    Sep 29, 2017
    Messages:
    3,282
    Likes Received:
    3,118
    Trophy Points:
    126
    Location:
    Jacksonville, NC
    Hers the problem, We don't really know what that clear is. It could be acrylic lacquer, nitro lacquer, polyester, polyurethane we just have no way of telling.
    If you can give us the model of guitar we may be able to figure out what the original finish was.


    BTW polyester filler is not a problem, just polyester primer over well a lot of different finishes.
    Last edited: Jan 25, 2018
    SiRoxx likes this.
  19. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot!

    Joined:
    Sep 29, 2017
    Messages:
    3,282
    Likes Received:
    3,118
    Trophy Points:
    126
    Location:
    Jacksonville, NC
    What you sprayed over it and the reaction tells me its a good chance that it was either enamel or nitro originally. I'm really leaning towards nitro from the way it cracked and what kind of primer you used.

    If it is one of those two;
    1. Sand to bare wood and skip the primer, go straight to autoborne.
    You wont get rid of it all even sanding it to bare wood.

    2. I would say sand to the clear and then just go straight to autoborne but heres where my lack of experience is. I dont really know if autoborne is fully capable of keeping the solvents of the clear your going to use from reaching the substrate. It could be ok im just not sure. Im also not sure of autobornes abiility to stick to nitro.
    So you could do a test patch just sanding to the clear, goin right to autoborne ,sanding it smooth over a crack, putting wicked over that and then clearing.

    3.Your other option is to use shellac as a primer filler, basically shellac and sand then shellac and sand until the cracks are gone. Then you can shoot what you want over it.
    Last edited: Jan 25, 2018
    SiRoxx likes this.
  20. Robbyrockett2

    Robbyrockett2 Air-Valve Autobot!

    Joined:
    Sep 29, 2017
    Messages:
    3,282
    Likes Received:
    3,118
    Trophy Points:
    126
    Location:
    Jacksonville, NC
    Last thing, guitar guys can be picky about the feel of the finish on the neck. Looks like your planning to use a 2k auto clear.
    Probably going to need waxed somewhat frequently to not have the high friction plastic feel.
    Look into it some more. You might want to finish with shellac as a barrier and then a nitro or polyester clear.

Share This Page