I have heard that you need to let purple heart sit in the sun for a little bit before you finish it also rub it down with acetone. I cant remember exact. Any recomendations before a CA finish?
Sitting this timber in the sun enhances the colour. I don't know about rubbing with acetone. I never have and get a good finish with both CA and UBeaut ultrashine.
I've tried several different methods and haven't found anything better than just finishing purpleheart first, and setting it in the sun later. A day in a south-facing window and it will turn purple, finish or no.
Best think you can do for purpleheart is get some of that 'feed and wax' paste and use that in the end. instant superb rich color. so far no fading and holds quite well.