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Stripes in Finish5/24
Just finished spraying ML Campbell Stealth with a Kremlin MVX Gun, MX 14 cap and 09-094 tip. fluid pressure 30lb. air pressure 10 lb. CV 275 voc with 5% catalized, 3% retarder, 10% reducer sprayed 8" from surface with a 50% overlap. Panel is coated wet but when dries appears to have stripes. I have upped both fluid and air pressures and eliminated reducer with same effects. Any ideas or solutions as to what I'm doing wrong, had this happen with clear CV awhile back but can't remember how i fixed it. Have sprayed for the last 2 years this way with no problems. Thanks for input.
Stealth has a 10% catalyst ratio..
8" is pretty close, move the gun back.
Have you shot some burst patterns to see if it's uniform.
Spraying in Southern Cal. so Stealth is 275 VOC. and uses new 5% catalyst mix. has been like this for several years. Getting new tip for gun today and will try some tests with gun farther from surface. thanks for input.
Not sure about Stealth 275 but we spray regular Stealth and reduce it with their Flow Enhancer instead of lacquer thinner. Seems to flow out nicely. Also, we spray it pretty heavy.
Ignoring any tip issues here (which i bet is the likely cause):
Stealth is regularly very high viscosity (70 seconds ford #4) and has to be thinned. It's about 250 CPS.
Stealth 275/Sl is currently very low viscosity (10-15 seconds ford #4). It's about 20-40 CPS (so 5-10x less viscous).
I thought Stealth 275 was reformulated a bit into Stealth SL (stealth 275 used to be thicker) , and this was done before changing the label to say "Stealth SL".
I mention all this because as you can imagine, Stealth definitely requires thinning. Stealth SL (these days) shouldn't require thinning at all, and is very thin already. It's thinner than a lot of spray stains. For reference, the viscosity of the microton spray dyes is 8-9 seconds.
You also definitely can't easily apply things that work for Stealth to Stealth 275/SL.
Here, i definitely would actually stop thinning it, unless you are doing it to have it flow better on hot days or whatever.
(I only know all the above the hard way -
OK so got a new 09-094 tip from kremlin as per their suggestion which is what we have used for over 10 years. using the Stealth 275 voc for california, i catalyzed 5% with appropiate catalyst, reduced 20% with care extender and 5% retarder with 35lbs. of fluid and had to go 20lbs. of air to remove tails and sprayed wet coat. Same problem. Makes me want to go back to pre cat Magna max where the only problem was drying time. Still up for suggestions.
Did you do a series of fan pattern tests by just pulling the trigger into a piece of brown paper or scrap dark hardboard? See if the fan pattern is even at the distance away from the stock. Pull the gun back further, closer, more air, etc. Then you know more knowledge about the pattern. Don't spray a big panel expecting to analyze the fan pattern.
Have you talked about this with ML Campbell?
If the spray pattern is indeed OK then it seems like the finish is setting up too quickly, so the next pass doesn't flow into the one before it completely. If so, adding more retarder would be the right move.
tip is too small for that C.V.
OK I'm back with results, after trying different mixes and fluid and air settings we were unable to get satisfactory results and my rep was to contact ML Campbell. We decided to switch to Magna max to expedite and try and get this job finished while waiting for answer from ML Campbell. So after spraying i now have encountered a million micro dots that feel smooth but are visible.
Back again after another day of trials and info from ML Campbell. Not enough retarder, not wet enough on coverage!!
So we put 5% and gave it a good wet coat-WRONG.
I'm back at 4;30 in am its 60', the magna max with 15% retarder, feels perfect and sprayed a nice wet coat with a 50% overlap. Nope still getting micro dots.
I've never used 15% retarder , maybe 5% max. I'm still looking for answers.
I had a lot of little bubbles with Target Coatings EM9300. Target said I was using too small a N/N on my HVLP gun, even though the viscosity said otherwise. I upsized the N/N to what they recommended. Actually, it was the minimum the recommended, I could have gone even larger. There were fewer bubbles, but not perfect. I moved on to a different product rather than try an even larger N/N, but the point is, this might be the right direction to resolve your problems. Worth a try if you have a larger tip to try.
Have you tried spraying either of these products with a different gun type?