My experience with purpleheart is basically as an accent wood, so I have only used shellac, lacquer, varnish, and polyurethane as finishes.

We also get two types, one turns brown and the other turns more purple in sunlight. Do not know the way to differentiate.

PH is very dense, negating oil finishes as you found. It is also an oily wood, needing treated with thinner or alcohol before finishing in some cases.

It is naturally tough, have seen shipping pallets made from PH, so maybe no finish is necessary in your case. Just cleaning.

Thank you, Handy Mac- I'm going to try Penofin Marine Oil- in the end, I started calling boat people. It's pretty highly recommended for very hard woods.

We'll see.

That sounds like a well thought out plan.

Just in case someone wanders to this thread looking for a good penetrating exterior hardwood finish, The Penofin is remarkable! It's a penetrating oil finish with a little brown tint. We also used it on some greenheart joists and it penetrated a full quarter inch......my carpenter is astounded and thrilled since nothing penetrates greenheart. Wipe on, wipe excess off. Since it penetrates and does not sit on top at all, I'll need to wipe more on annually- no sanding- ever. I'll post pics if I remember.....

(we have to use these woods- we have the cartoon kind of termites that will eat a house to the ground)

i WOULD SUGGEST THE PENOFIN OIL STAIN