I'm not familiar with the Valspar, in fact the whole refinishing trade has changed dramatically since the limitations on voc emissions.
However, a broad generalisation or two.
do not mix different manufacturer's products and systems.
just because a 2-pack product will air-dry, doesn't mean it will have the same characteristics as the proper, catalysed chemically-cured mix.
A "dry" coat willtend to show more orange-peel also the film density and strength are questionable.
30% is a LOT of thinner! note the "speed" of a thinner has a huge effect on the finish...you really need to understand the science behind spraying ...there are many textbooks and some manufacturers used to do excellent tech. sheets. / maybe still do.
Viscocity of the medium is affected by temp and solvent-content....you then need a correct air-pressure and volume to atomise to right droplet-size (uniform,with minimal fog or heavy particles) then the thinner-formulation.....once the fluid is atomised, the "fast"portion evaporates between nozzle and work...thus the droplet consolidates...it should contain enough solvent, that it flattens and dissolves into it's neighbouring droplets without splashing a fog everywhere (dulls the finish and alters metallic colours)...too little that flashes -off too quickly, means the droplet won't fully flatten and merge = "orange-peel! "
So, no matter how warm the paint and the work, if the ambient is yoo cold, your finish will be affected.
Another little-understood facet ,=the air-supply!
a compressor and airline act like a primitive fridge!!!!
air is compressed and so is the heat it contains so your compressor gets hot and the moisture condenses out (important to drain the tank regularly and use an oil/water separator on the output)
the tank full of compressed-air will stabilise at ambient but, of course, contain less heat ( think kettle of boiling water V egg cup full....both contain boiling water, the kettle holds a lot more heat )
When you pass it through the spray-gun, it expands...suddenly , the heat in 1 cubic of compressed air,is now dispersed into , say 5 cubc feet of free-air...so the temperature drops your paint-droplets congeal, but don't flash-off the solvents the same as when they're warm,,,also the temp-drop can condense ambient moisture into the paint and onto the painted surface......
I'm only scratching the surface of the subject, but observe the basics...clean, dry and warm, thin, properly "wet" coats (although there are exceptions - some etch-primers are specifically dusted in a dryish translucent film) correct viscocity and correct volume and pressure at the gun.....airline has a known pressure-drop depending on diameter and length, so 60 psi at the regulator ,could well be only 35 at the gun!
Many old-school painters knew nothing about the forgoing, it was all empirical knowledge, passed-down through apprenticeship and experience,-what worked, what didn't and the little dodges....paint too thick? reduce flow-rate /move gun closer to the work, and so-on.
hth. steve
good results can be obtained with very modest gear....many young mechanics are conned into a chestful of snap-on spanners at £20 a go and many painters are convinced that ONLY a£200 De Vilbiss gun will paint properly......in both cases, it's a mix of brain and brawn....think objectively and apply to your hands...you can't buy skill but you can readily learn it!
Last edited by cockney steve; 21st Nov 2013 at 12:05.
Reason: added info