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Lacquer health concerns vs water borne desert concerns

Discussion in 'Finely Finished' started by thorbjorn88, Apr 22, 2021.

  1. thorbjorn88

    thorbjorn88 TDPRI Member

    Aug 12, 2020
    Tucson, Az
    I'm working on finishing my 5th and 6th from scratch guitars. I decided to stop messing around with hand applied finishes and got some spraying equipment. I decided to use waterborne finish specifically target coatings em6000 instead of lacquer for the health reasons.

    I live in Tucson Az and am having some trouble using the waterborne finish. It's been about 70-80 degrees and 10% humidity in the space I've been spraying. I think it's not flowing out because it's drying too quickly. I'm experimenting with target coatings retarder and it is working better but it still isn't flowing enough, I added 5% last night and I'll try 10% tonight.

    I finish about one guitar and one furniture project a year. If I use lacquer and a respirator that's probably not enough exposure to worry about right?

    Is lacquer significantly easier to spray in hot/dry conditions? If so am I worrying too much about exposure if I only finish a couple projects a year with it?

    If you successfully spray waterborne in hot dry conditions do you have any tips?
  2. 10orgtr

    10orgtr Tele-Meister

    May 3, 2011
    western PA
    Lacquer can present the same problems. However, if you use automotive acrylic lacquer you will find that the manufacturers have a variety of thinners and retarders to make it work under varying temps and humidities. Your local body shop supply should be able to recommend the proper combination for your conditions. The woodworkers lacquers I have dealt with generally don't have this available. Don't sweat it not being nitro. The difference is the binder in nitro is organic, whereas the binder in acrylic is man made.
    VonBonfire likes this.
  3. eallen

    eallen Friend of Leo's

    Jul 30, 2013
    Bargersville/Indianapolis, Indiana
    A couple projects a year, or for that matter alot, of nitro is not going to be a health concern if proper respirator and ventilation is followed. Wear your respirator until the air is cleared by your ventilation system. If you take your mask off and the odor is still strong across the room it isn't clear.

    With nitro you use a slower rate thinner or retarded if you need to slow it. I am doubtful you would need to.
    old wrench and dkmw like this.
  4. dkmw

    dkmw Poster Extraordinaire

    Mar 30, 2016
    Florida USA

    Given a good respirator (and good cartridges), don’t even worry about it if you’re only spraying a few days per year.
  5. Freeman Keller

    Freeman Keller Poster Extraordinaire

    Aug 22, 2018
    I have built 27 instruments to date and have finished most of them with nitrocellulose lacquer. One French polish, a few with early water born lacquers, specifically the first stuff that StewMac was selling about 15 years ago and KTM-9 which LMII (used to sell). I have not tried the Target stuff, it comes very highly recommended by a couple of luthiers I respect. (but then so did KTM-9).

    Think about "water born lacquer" - that is not water based or water soluble lacquer. The resins are dissolved in glycol ethers which are slow evaporating alcohols. There is an emulsion of this stuff in water which acts as the vehicle. The resins are not soluble in water at all - its the ethers and alcohols are dissolving them. They are also not purely evaporative finishes like solvent based lacquer - they go thru some sort of cross linking reaction as they cure. (I'm paraphrasing an article by Mike Doolin and John Grevin in an issue of American Lutherie).

    OK, short story, they don't act like nitro. Some of them have a bluish cast, they don't melt in to previous coats like nitro. There are some tricks which I learned the hard way ((after sanding between coats shoot a mist of DNA which will slightly tack the surface, the next coat will adhere better. It is very easy to get witness lines when you sand and they are about impossible to get out.

    Anyway, I wanted to like these things - I liked the lower (but not zero) toxicity, I liked being able to shoot in my shop with normal ventilation, I liked cleaning up with warm water (and DNA). But the simple fact is my finishes were better with nitro.

    I know I should try the target stuff but here is the simple fact - I know how to shoot nitro, I get very good results with it, I shoot outside with a respirator and feel that is safe. When put 5 or 7 hundred dollars into materials and a couple hundred hours in labor its pretty hard for me to try something new, particularly when I have not had good luck with similar products.

    ps as far as your questions about temperature and RH - as long as I shoot above 65 degrees and below 65 percent with nitro I have absolutely no issues. The one time I got blushing the RH was too high - and I knew it.
  6. jvin248

    jvin248 Doctor of Teleocity

    Apr 18, 2014
    Lions & Tigers oh Mi !

    Nitro can be flammable, like you need explosion proof exhaust fans.

  7. old wrench

    old wrench Friend of Leo's

    Feb 2, 2017
    corner of walk and don't walk
    There are pretty much the same type of retarder thinners and straight retarder available for "woodworking" lacquers as for "automotive" lacquers.

    I wouldn't want to assume what someone else's exposure level should be for anything toxic :).

    But, you can definitely protect yourself with the proper PPE and keep other people and critters out of the spraying area.

    Some of us N-C lacquer spraying folks that live in high humidity parts of the country sure would like to have some of that Tucson weather once in a while, though :).

    eallen likes this.
  8. fleezinator

    fleezinator Tele-Meister

    Apr 4, 2020
    I'm by no means an expert only having 3 Crystalac projects under my belt. I'm in Houston so while my temps might have been near or higher than yours, our humidity is definitely higher. Not sure what your space is like, but have you considered running a humidifier there prior to spraying?
  9. telemnemonics

    telemnemonics Telefied Ad Free Member

    Mar 2, 2010
    You don't mention any exhaust fan or ventilation?
    Depending on how much time you spend spraying multiple coats on a good size piece of furniture, without the overspray being pulled out by a spray booth or exhaust fan of some sort, it's possible that "exposure" is too much from a medical standpoint.

    A spray booth leaves almost no vapor in the room, yet we wear a respirator.
  10. GunsOfBrixton

    GunsOfBrixton Tele-Afflicted

    Dec 9, 2011
    Rochester, NY
    Shoot the owner of Target coatings an email. He is very helpful and may have some ideas on how you can get better results when spraying in the Tuscon heat.
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