Would this work?

[Shiromisa]

I've seen threads in the past about having difficulties getting pony heads back on once they're painted without chipping the paint, but they have to be rehaired before you put the head on, right? Well...what if I put a strip of air-drying clay/model magic on the inside of the head along the hairline, painted it, and then rehaired? Think the hair would stick to the clay?

[Lady Anya]

Hmmm.. perhaps something like double-sided tape would work too?
Why would you like to do something like that? 

[Colorscapesart]

Some hair might stick, but most of it would probably not, sadly.  When brushed, any hair that isn't securely attached will come out.  Tape can only lightly hold a few strands of hair befire the sticky part of the tape is "full".  Air dry clay isn't particularly tacky?  So I dunno what would "grab" the hair.

[Shiromisa]

Oooh, I see. Thank you! Hmm...I'm trying to think of something with a hot-glue-like texture/stickiness that wouldn't dry for a long time.