@Port Boy...........PB, on your next one like this, you could have the best of both worlds, some of it blackened with the Iron Acetate
solution, and some of it remaining the natural Oak.
To do this, draw a very straight outline of the forks shape, about a 1/4" to 3/8" in from the actual outside edge of the frame.....basically, it would
look like the same shape fork, only one smaller on the inside fork shape. ( not sure if I"m being clear on that or not ? )
Then, you can take a wood burner and burn in a fairly deep groove, following that inside line you made, in the shape of the fork. That would act as a
kind of stop cut, as wood carvers use, so none of the solution goes inside that burned in perimeter.
Once you have that burned in, apply some blue painters tape over the center shape that will remain natural Oak color, overlapping your burned in lines,
and using a VERY sharp Exacto blade, follow the burned in groove and cut through the tape all the way around, leaving the internal shape of the sling
covered with tape so you don't get any of the solution on it.
Then, being very careful, and not applying to heavily / wet, take a small model painting paint brush, wet the bristles, but shake off the excess, and cover the
outside edge of the sling with the solution, applying it to the darkness you want.
If you are careful, and don't have the brush too wet, none of the solution should go under the taped off area, and you when you pull the tape off, you should have
a two-tone sling...........dark border, and natural, Oak wood inside that border...........sand lightly and use finish of choice, once the darker wood area is totally dry
of course.
** If that's not clear or makes sense, I'll post a pic of a Native Flute I did this to, which was Walnut, and I wanted darker spikes around the foot of it, and used the Iron Acetate for this **