question on fabric finish

Discussion in 'Finely Finished' started by Steve 78, Oct 24, 2019.

Tags:
  1. Steve 78

    Steve 78 Friend of Leo's

    Age:
    41
    Posts:
    2,137
    Joined:
    Oct 27, 2015
    Location:
    Melbourne, Austraila
    I am attempting my second finish and first fabric finish. If I understand correctly, the general process is -

    glue on fabric -> bury fabric -> clear coat (-> burst -> clear coat)

    I have done about 6-7 applications of trying to bury the finish but it is still not even / completely buried.

    tartan2.jpg

    It's a bit hard to photograph, but if in the foreground for example, the foggy lighter parts are the varnish that has been sanded and the dark spots are the lower points. My process is to brush on the varnish then lightly hand sand with 800 between coats.

    On my test patch I tried clear coat over the top and it looks pretty good. Not professional, but not a finish I would be unhappy with.

    So what should I do from here? Do I keep applying coats and sanding until the finish is entirely even? I am wary of the varnish being too thick as well. Should I be more aggressive with the sanding or changing grits? Or can I apply clear from here and use that to fill out any inconsistencies? (I am using automotive acrylic lacquer for the clear).

    This is the varnish I am using. I tried testing with sanding sealer as well but it darkened the fabric too much.

    varnish.jpg

    (Also note, the pattern is actually warped a little, i.e. not completely straight lines so the finish won't be perfect no matter what I do. I would like to try to get it as good as I can though).
     
  2. Crafty Fox

    Crafty Fox Tele-Afflicted

    Posts:
    1,278
    Joined:
    Nov 25, 2011
    Location:
    Perth Australia
    So it was you who nicked my kilt!

    I wonder if you could 'grain fill' with epoxy? I use West Systems to grain fill wood. I've also heard good things about Bote Cote.
    I seal first with U-Beaut Hard Shellac, then grain fill, then colour, then clear coats; using nitro lacquer.
    But I haven't tried working on fabric.........yet.
     
    Steve 78 likes this.
  3. Crafty Fox

    Crafty Fox Tele-Afflicted

    Posts:
    1,278
    Joined:
    Nov 25, 2011
    Location:
    Perth Australia
    Anderson tartan?
     
  4. Peegoo

    Peegoo Tele-Meister

    Age:
    59
    Posts:
    110
    Joined:
    Oct 11, 2019
    Location:
    USA
    When finishing over a fabric, the thinnest you can go with finish is the thickness of the fabric. The best results I’ve gotten is to apply it just like gel coat and Fiberglas cloth, using epoxy resin and a rubber roller.
     
    Steve 78 likes this.
  5. Steve 78

    Steve 78 Friend of Leo's

    Age:
    41
    Posts:
    2,137
    Joined:
    Oct 27, 2015
    Location:
    Melbourne, Austraila
    Haha, according to ebay it's tartan from the infamous Japanese schoolgirl cosplay clan :lol:
     
  6. Steve 78

    Steve 78 Friend of Leo's

    Age:
    41
    Posts:
    2,137
    Joined:
    Oct 27, 2015
    Location:
    Melbourne, Austraila
    Thanks, so I should keep applying until it is even? Unfortunately it's too late to try another product now as it's already on the guitar, but as I said, my test patches look pretty good so even if it isn't perfect (and it won't be!) I'll still be happy.
     
  7. netgear69

    netgear69 Tele-Afflicted

    Posts:
    1,467
    Joined:
    Dec 21, 2012
    Location:
    england
    This applied with a sponge brush... if the sun is out there down under it will cure solid in a couple of minutes couple of coats will bury that fabric
    solarez.jpg
     
  8. Crafty Fox

    Crafty Fox Tele-Afflicted

    Posts:
    1,278
    Joined:
    Nov 25, 2011
    Location:
    Perth Australia
    [QUOTE="netgear69, if the sun is out there down under

    The sun is always out here.......no, wait, he's in Melbourne, so its not out...yes it is....oh, its gone again....:cool:
     
    Steve 78 likes this.
  9. jvin248

    jvin248 Poster Extraordinaire

    Posts:
    7,871
    Joined:
    Apr 18, 2014
    Location:
    Lions & Tigers oh Mi !
    .

    It will take more time and coats than you think and want. Especially deeply ridged fabric. I only attempt printed cotton that is like bed sheet or button-down shirt fabric.

    Last one I got impatient with the poly and went with shellac since those coats cure in fifteen to twenty minutes you can build up pretty fast. However, it will likely relic fast if you spill beer on it at a gig, at least I know furniture with it gets rings if people are not careful about putting down coasters under their wet glasses ...but it got the guitar done so I could work on the other important steps of assembly and playing (prototype to see how I wanted to change the next one).

    Look up the Texas Toast youtube channel, they have a few videos on how they are doing fabric tops and it seems to work pretty well.

    .
     
    Steve 78 likes this.
  10. Luthi3rz

    Luthi3rz Tele-Meister

    Age:
    49
    Posts:
    241
    Joined:
    Jul 22, 2018
    Location:
    AZ
    Sorry but that's not how you do a Cloth Top finish on a guitar.

    You glue the Fabric to a body blank , make a wood frame around it that act as dams
    and pore Epoxy on it to seal the fabric in. Then you rout the body out of that.


    This is covered pretty well on this guys You Tube Channel.
    https://www.youtube.com/user/thebigdguitars/videos
    FABULOUS! Fabric Topped Custom Guitar - Green & Gold Tele
     
  11. Silverface

    Silverface Poster Extraordinaire Ad Free Member

    Age:
    67
    Posts:
    9,404
    Joined:
    Mar 2, 2003
    Location:
    Lawndale CA
    ALWAYS avoid applying any lacquer, oil-based or water-based or any other containing a solvent of any kind (water is a solvent) coating too thickly. It results in solvent entrapment, where the top dries/skins over, preventing or slowing the solvent below from evaporating. The coating will remain soft, bubbles and blisters can form, and the coating can delaminate - sometimes months later. Lacquers should generally be applied in coats consisting of 3 very thin passes, with a single coat NOT covering or flowing completely like paint does - it's NOT paint!

    Varnish can be applied more thickly, but you still want to build up thin coats - especially when you are saturating something on the surface. During yor practice runs use a micrometer to measure the thickness of the cloth, and figure your total varnishDRY film thickness (if applied on a smooth surface) should be about 50-75% of the thickness of the cloth.. You really should have a wet film thickness gage so you can understand how much material you actually apply with each coat; then multiply that by the solids by volume of the varnish(found on the product data or MSDS sheet - or you might have to call the company) to determine the DRY film thickness.

    It's pressed into the wet fim and the serrations checked for coating contact - that will tell you how thick your wet film is. If it's 3 mils and the solids by volume are 37%, the DRY film thickness per coat will be just over 1 mil. This is a good example of how thin lacquer coats are - generally you can only apply 2.5 mils without runs, and the solids by volume are only about 7% - so a coat of lacquer has a dry film thickness of 0.175 mils!

    This is a wet film gage - most contractor oriented paint stores have them, or you can get them on Amazon (I'm NOT advertising PPG - I just bagged this picture from the internet):

    wet film thickness gage.jpg

    Honestly, I've never heard of using a varnish for cloth saturation as it will probably take a huge number of thin costs, and there's too much of a chance of solvent entrapment (and air bubbles) regardless of thickness. I've always done it and seen it done with 100% solids, 2-component polyester resin - either chemical curing or UV-cure. i.e. surfboard or boat resin used with fiberglass, like the Solareze product posted by @netgear69 - which I have used for years for surfboard ding repair!

    I'm a bit surprised the lacquer's solvents didn't attack the water based varnish - and regardless, there is only mechanical adhesion between lacquer and a non-lacquer product. There is no chemical bond. So you need to scuff sand the varnish to provide some "tooth" for the lacquer to grab onto. Lacquer's mechanical adhesion, though, is very low compared to other products and generally it can be easily scratched/damaged. Urethanes and polyesters have far greater mechanical adhesion (normally by a factor of 5-10x!).

    I would test the finish coat adhesion on a practice piece by letting the lacquer dry overnight (that's all it needs - lacquers do not "cure", they dry only by evaporation of solvents); then take a new single-edge razor blade and cut a 3mm crosshatch of 10x10 squares.

    place a strip of regular clear adhsive tape stright across and rub it in lightly with the back of a fingernail - then pull it off across itself no higher than 3 mm. If you get just a bit of removal at the corners that' fine, but if anything more thn 1/4 squares or so come of anywhere you will likely have adhesion issues, and should switch to a polyester or polyurethane finish.

    Hope that helps
     
    failsafe306 and Steve 78 like this.
  12. RodeoTex

    RodeoTex Poster Extraordinaire

    Posts:
    8,802
    Joined:
    Sep 14, 2005
    Location:
    Nueces Strip
    I just put a few coats of sanding sealer on the one I did. Worked out ok, but mine was just a bandana.
     
    Steve 78 likes this.
  13. Steve 78

    Steve 78 Friend of Leo's

    Age:
    41
    Posts:
    2,137
    Joined:
    Oct 27, 2015
    Location:
    Melbourne, Austraila
    Thanks, I appreciate you pointing this out. To be honest I was only going with the acrylic lacquer finish as it had worked quite well on my first re-finish, and I had some left over. I'll see what urethanes and polyesters I can find locally and do some test patches to compare.
     
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.


  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.