Auto body repair & detailing: Paint touch up, ppg, one more thing

Question
My kid Painted his 64 mustang @ 2 years ago DBC BC/CC.
The car was broken into, they tagged the door fender and roof. We matched up the paint, fender and door color blended
great and cleared the entire fender and door. The roof however, color blended OK but the clear did not. We can see the edge of the new clear. I tried to thin it at the blend area (no luck) Its DBU2011 clear.
 Is there a trick to blended clear and can I still fix it some how.  Oh yes one more thing. After a few days there seems to look like white powder in the roof patch

Answer
Hi Larry,

PPG makes a fantastic product for blending called DX840 Blendease. It can be used to aid in blending color or clear-coat. The white powder you're most likely seeing is the oversprayed edge. If you use DX840 Blendease on that edge immediately after clear-coating it will melt the clear edge in and blend into the surrounding area. It is designed to work on all PPG clears. I hope this helps out.