paint nitro

[mastupeppe]

hi guys,here I am to you for a question.
a few day ago I have varnish three brackets.after to have give the nut dye and do it dry have smooth down,after have give three hands of nitro base smoothing any hand,when I gone at the finishing nitro too the superficial are become at orange peel.I have think about warm since in these day in Italy there are 36-37 degrees,but I varnish in morning.
I have try to change the hole of my paint air from 2,5mm to 1,8mm service pressure between 2 and 3 bar,but don't happen nothing.Icannot understand.

please what's happen?

thanks
cheers

Carmine

 

[Chris Knight]

Carmine
There are several possible causes for orange peel and hence there are several possible remedies - see here for example http://www.furniturefinishwizard.com/orangepeel.htm

I would guess that in your hot weather, the finish is drying too fast, also that your nozzle size is still too big (I use 1.3mm for nitro). Try holding the gun closer - say not more than 150mm from the work.
Good luck!

 

[mastupeppe]

thank you Chris,me too have think this,maybe like you say,since it's much warm,the solvent nitro do evaporation fast.I have try to diluite 50%,have try to use too solvent more slow but dont' have more aim because the nitro use for to dry fast.maybe own of to reduce hole of my gun.

thank you waterhead,you are very kind

cheers

Carmine

 

[Sgian Dubh]

Carmine, Try and get a 1.2 mm or 1.3 mm needle, nozzle and air cap for your spray gun. Also use only about 5% to 8% lacquer thinners. Add to the mix between 3% and 5% lacquer retarder (sometimes known as anti-bloom thinners.) This means you should have about 10% to 12% in total of different thinner types to 88%- 90% polish. Try to avoid thinning nitrocellulose lacquer type polishes any more than this.

If you go much thinner than this you can end up putting too few solids on per coat and don't get good flow-out. The solvent flashes off leaving too few solids behind and, can actually be the cause of sandy coats, orange peel and other faults.

Sometimes very thinned coats are applied for specific reasons, e.g., sealing open pored woods, creating a bonding coat on oily or other problem woods, or sealing between dying and staining, or sealing between staining, grain filling, and/or glazing coats, etc..

A word of caution. Be careful of using retarder. Yes, you can use large percentages of the stuff and get away with it. You could use 10% or 15% retarder, but this can cause the polish to remain at risk of imprint damage for days, even weeks, if used too generously, and this is definitely not good.

I'm sorry I can't write or speak Italian, which would help ease communications, but hope you can work out what I've written. Slainte.

 

[mastupeppe]

Carmine, Try and get a 1.2 mm or 1.3 mm needle, nozzle and air cap for your spray gun. Also use only about 5% to 8% lacquer thinners. Add to the mix between 3% and 5% lacquer retarder (sometimes known as anti-bloom thinners.) This means you should have about 10% to 12% in total of different thinner types to 88%- 90% polish. Try to avoid thinning nitrocellulose lacquer type polishes any more than this.

If you go much thinner than this you can end up putting too few solids on per coat and don't get good flow-out. The solvent flashes off leaving too few solids behind and, can actually be the cause of sandy coats, orange peel and other faults.

Sometimes very thinned coats are applied for specific reasons, e.g., sealing open pored woods, creating a bonding coat on oily or other problem woods, or sealing between dying and staining, or sealing between staining, grain filling, and/or glazing coats, etc..

A word of caution. Be careful of using retarder. Yes, you can use large percentages of the stuff and get away with it. You could use 10% or 15% retarder, but this can cause the polish to remain at risk of imprint damage for days, even weeks, if used too generously, and this is definitely not good.

I'm sorry I can't write or speak Italian, which would help ease communications, but hope you can work out what I've written. Slainte.

hi Sgian Dubh,
don't worry, I have understand that you have write,you are much clarify.
thank you Sgian ,I'm honoured to frequent this forum.

regard