I finally got the finish work on the Bloodwood + Red Oak comb done. I chose 100% Pure Tung oil for the finish so I had to wait at least a day or two between coats. The oil smells a bit like peanuts, but it undergoes an oxidative chemical reaction as it dries and the smell goes away. I went with tung oil because of its water resistance, non-toxicity, ability to be reapplied, and oxidative drying. Tung oil does come from a nut, so if you're building for someone with nut allergies maybe consider linseed oil. I was hesitant to use a nondrying oil because it just seems like it would be a little gross to be oiling your hair as you combed it (smelly too). It is possible that you could just let the comb oil itself with human oil (shudder) as it was handled, but you'd have to take great care not to expose it to moisture. I decided against doing any sort of enamel or spray finish because I didn't think it would hold up to repeated handling.
Here it is right after applying the 4th and final (so far) coat, direct light really brings out the red, in the dark it looks purplish:
I was applying successive coats with 600 grit wet-use sandpaper. The oil mixes with tiny bits of the bloodwood to create a red slurry that looks really cool once it gets into the pores and holes. I let it dry a week and a half and then buffed it out with a cloth. I'm pretty happy with the results, though I do wish it was more red.
I'm considering selling these, custom made. I don't really want to build the same thing over and over (easy and cheap, but not very fun). I have some cool ideas for potential variations and wood combinations. Luckily the cost of the materials is fairly low, but they'd still be pretty pricey, a lot of time goes into them. I've been wanting to build a CNC machine, I'd probably do that if I had to make a lot of these. If you're interested drop me an email at firstname.lastname@example.org and we can discuss woods, finishes, ect. Would be pretty easy to incorporate wood/designs from an old family property or decaying heirloom too, might as well make things extra personalized.
More pictures below. Since taking these pictures I've gone back with a needle and some glue and carefully filled some of the holes that developed around the inserts during the sanding and finish work. Direct sunlight really brings out the red, sadly the pics below were taken under overcast conditions.