Replies

1. 
   mudman | Dec 08, 2005 11:00pm | #1

   I find that I have to use a good quantity of retarder. The Thinner flashes off too fast to prevent the dry spray that is likely causing your problem. A retarder slows the cureing of the laquer, this is different from adding thinner. I have been using Sherman Williams lacquer and usually add 20% retarder and around the same or less of thinner. This seems excessive to me but it gives the best results.

   Mike

1. 
   caplacq | Dec 09, 2005 06:57pm | #2

   Thanks for the info. I never used a retarder in my lacguer. I'll go to Sherman Williams and pick some up.  I have used an additive to prevent fish eye which has helped me in the past. 

   Paul

1. 
   mudman | Dec 09, 2005 08:22pm | #3

   Be sure to test it on something safe first. Suposedly you are suposed to use compatible products. However as I understand it Retarder is a pretty generic thing, like thinner. I've been mucking my way through all this as well so please post your results.

   Mike

2. 
   DougF | Dec 10, 2005 06:06pm | #4

   The problem could be the material feed/air ratio, spray pattern setting and/or the wrong cap/tip.  I think that model is a 3-stage HVLP and you should not have to thin Deft to achieve good results.  Since Deft is formulated as a brushing lacquer, it is already loaded with retarders so the flash-off rate should not be your problem.  It sounds like you are not laying down sufficient amount of lacquer.  If you are not experiencing any problems spraying gloss, the same setting should be close to right for semi-gloss. 

1. 
   caplacq | Dec 11, 2005 01:34am | #5

   I didn't relized deft had reaters in it. I used to spray sanding sealer and lacquer, which i would thin down. But i was having trouble getting it al the time, so I switched to deft. I will try cutting back on the thinner and spray  a heavier coat, and see how that works.

   Paul

1. 
   2x4 | Dec 11, 2005 04:36pm | #6

   I am not a finishing expect in any way and have been getting buy for the past 20 years. Took 12 hrs of training over the past 2 weeks and one of the things I learned was in spraying lacquer it is a good idea for the first coat to be a thin coat. This coat will flash off quickly and you will not have any runs. Any subsequent coats can be heavier and will be held in place by the first coat and will not run. I use ML Campbell finishes. Good Luck

   Brian

2. 
   mudman | Dec 12, 2005 07:42pm | #7

   Good Point, I didn't know that Deft was a brushing lacquer. I would think that it should have a ton of retarders in it. I am still trying to figure out haw to spray lacquer and I probably gone through 5 gallons of it! Thick coats do seem to level out better, but it gets difficult to prevent build up in the coeners and rounding off the mouldings.

   You mantioned changing caps. I have a Fuji 4 stage with a #5 cap on the gun. I've wondered what using a smaller cap would do. It seems that it would cause it to srray even drier, but increase atomization. Can you help me?

   Thanks,

   Mike

1. 
   DougF | Dec 13, 2005 05:35pm | #8

   A #5 aircap is too large for lacquer.  Fuji has 6 aircap sizes and  #'s 5 & 6 are for heavy material.  I would recommend you have on hand a #3 for water=based and shellac and a #4 for lacquers and slightly thinned enamels.  I think you will find that you will get better feed and fan control with the right aircap.

1. 
   mudman | Dec 16, 2005 07:43pm | #9

   "Fan controll" has seemed to suck on my gun. I guess it is from the cap size. Thanks a lot.

   As I understand it using a smaller cap increases atomization (a good thing), but dosent that also cause the material to dry more in transit? AKA dry spray? I have always atributed my problems to dry spray and thought the solution was in the mixing. What are your thoughts?

   Mike

1. 
   DougF | Dec 16, 2005 09:07pm | #10

   Atomization is affected a combination of tip/air cap, pressure, material flow, material viscosity, flash-off rate (how much thinners/retarders), fan (spray) pattern, ambient temperature, turbine air temperature and distance to the surface.  The tip/air cap is a critical component to give you control over many of the factors affecting the material that ultimately hits the surface of the piece being sprayed.  It is not unusual to change your settings from morning to afternoon or evening, as the turbine air heats up if you are dong a lot of pieces or large surfaces or the humidity changes.  

   I can't speak for others but my procedure is to start with a fairly large test piece, ususally a large piece of cardboard or plywood and keep adjusting until I can get a full pass laying down the amount of material I want.  I repeat this step every time I start a new coat or add more material to the cup/pot in case something has changed.  If the material is really running hot I check the air cap frequently to make sure that solevents are not building up and blocking air flow or disrupting the fan pattern.  This is also a clue that you may need to adjust you mixture and/or settings.

   Hope this helps. 

2. 
   mudman | Dec 16, 2005 11:24pm | #11

   You have been helpfull. I follow the same procedure as you. And it is true that there are many variables, and probably no "right" combination. Ill order the #4 cap for my next job.

   Mike