Mastering post cat conversion varnish

[alexh]

Hi, sorry for the long post but I wanted to show my failures...

I have been using the Campbell products for a while. Started out with pre cat tinted (at that time was 275 VOC) and after struggling a while I discovered that the only way to make it work was to slow it down with Butyl Cellosolve. Otherwise it came out of my HVLP gun like sand! For a later project I decided to switch to a post cat product because of the pre cat limited shelf life and my pre cat projects cracked something awful - probably because too much film thickness. Very discouraging as stripping those units the first time was not easy.

So I purchased Campbell Resistant tinted and they seemed to have relaxed VOC requirements on this because it's 550 VOC and I can now get Flow Enhancer 2 and Care Retarder. Using a gravity turbine HVLP gun, 1.8mm tip, 100% Flow Enhancer 2 and 30 secs Ford I was able to spray the cabinet drawer fronts horizontally and they came out perfect even though atomization was poor as it seemed to self level. However when I moved on to the cabinet carcass sides I was stopped in my tracks. They are about 18" x 40" and I found it impossible to maintain a wet edge. even with 100% Flow 2 the product dries so fast! I even tried using Butyl Cellosolve but I don't think that works too well on conv varnish, it seemed that it did not mix well and not really sure it slowed it down any more than Flow 2.

Upon searching the web I found that even the pros using Kremlins or pressure pots seem to have this issue on large surfaces but are able to overcome it by increasing flow and moving fast. I needed a new gun anyhow so I purchased a 3M Accuspray gun with pressurized cup. I have been practicing on a 2'x3' piece of MDF using 1.8mm tip, 50% Care Retarder, 50% Flow 2, 30 secs on a Ford cup and it's still not easy to maintain a wet edge and avoid runs but with practice I can probably make it. The pressurized cup definitely helps but I have to open the needle more on the sides and then close back down a bit for the narrow parts and do it quickly.

So I was wondering if this level of difficulty is expected. I also have a stain grade project with 4 interior sides of 15"x 40" and I'm hoping the post cat clear is a little more forgiving. It seems to be as I have seen amateurs reporting good results with it.

Thanks