needle sizes when spraying

[tsb]

Can anyone explain how you know if you have the right needle size for your finish, when you're spraying. What would be the problems you would have if the needle was too big or too small for the finish you are trying to spray. I'm going to try a earlex 5000 hvlp system, which comes with a 2mm needle size and have a go at spraying some lacquer. Have watched the woodwhisperer video on the earlex and he changed the needle to a 1.5mm. Can .5mm make a difference?

 

[wizer]

Funnily enough I re-watched that episode recently. From what I gather, the more viscous the finish, the finer needle you can use. However, from what Marc was saying, it seems that you get good results with a range of needles. I think it is a case of testing it out and seeing what suits you.

 

[johnnyb]

if the needle is to small you will struggle to put a decent wet coat on fast enough. this will be obvious on large items like doors. and vice versa but this can be compensated for a bit. there is also considerable overlap on needle sizes BUT the ideal needle is probably the bigger one.

 

[JonnyD]

On my fuji HVLP system the 1.4mm nozzle is more than adequate for spraying lacquer. The bigger you go with the nozzle the thicker the liquid you can spray but you often get a rougher finish which is a bit like fine orange peel. My advice would be to use the smallest nozzle that allows you to spray the lacquer without thinning it down which on the earlex will probably be 2mm.

jon

 

[wizer]

spooky