How to Eliminate Hard Paint Lines 

For sure extending the paint job to a body line or edge will make it easier to get a smooth paint job. But sometimes that's not practical, because someone may not want to spray an entire door for example. And in those cases the tape roll technique that feathers the paint does work very well. The paint lines you saw are from your primer not being sanded smoothly, as you noted. Even though it may have looked smooth, clearly it was not if you are seeing the line through the paint job. A general rule of thumb is that if you already have a tape line, the area needs to be completely sanded down to the original substrate or those lines will show through. Tape lines can be a real pain to deal with, no doubt. Another rule of thumb is that a smooth paint job is 100% all in the prep work. If the prep is done smoothly, putty/filler/primer, the final results will be much better. When primer is applied and sanded properly, along with using the tape roll method, a very smooth, shiny paint job can be achieved.

Pretty much the only way to 100% eliminate them is to sand them down and repaint.

You can try sanding and polishing. But most likely you'll need to sand them all the way off and repair, following the advice in the video.

To fix it after it's already been done, you need to sand down and begin anew. It's nearly impossible to remove hard paint lines after the fact.

Pretty much the only way to 100% eliminate them is to sand them down and repaint.

@@TouchUpDirect ok thanks I also got some basecoat blender . paint sheet says to mix with basecoat and step out into blended area . could you explain this ??

@@direct998 Hmmm...I can't really explain it exactly, I don't know about the particle product you mention. But you really should not need any type of blender and we definitely cannot guarantee that the product will work with our paint.

Flat out with 1200, then 2000 grit, wet and dry, or dry sand, if your rich enough to afford that luxury. Then machine polish.

It can be polished and improved using something similar to our Polishing Kit. touchupdirect.com/shop/accessories/auto-motorcycle-paint-preparation/polishing-kit/

Well, because most people do not know what that is or have it handy. In fact, I've never heard of it and could not easily find it online. But painter's tape is easy to find and works very well to not leave residue or mar the Colorcoat. Tapes designed for other purposes likely will not perform as well.

Door shuts are better left untapped, as long as it's scotched, the paint flows into the panel, ands disappears. I've tried different ways, they all left line's.

Not sure if that's a question, but rubbing compound will not remove hard tape lines.