Mahogany Stair Treads (Exterior)

[Drakmon]

I have four Mahogany stair treads I'm going to install to replace the sad old painted PT treads on the front of my house, leading up to the porch (which are falling apart). Aside from a nice sanding with 120, what would you all treat this beautiful hardwood with in order to ensure I won't have to re-treat it every month forever? ;)

The stairs are eastward-facing and get direct sun until about 3 - 4 pm.

FYI, I'm planning on attaching them to the stringers on the underside of the treads, using metal brackets and stainless steel exterior screws, with a bed of loctite for good measure. No squeaky stairs here!

[lthenderson]

For Mahogany, I would use Tung Oil with a thinning agent for the first coat. 100% tung oil doesn't penetrate tight grained woods like Mahogany very easily and thus why you thin it out. On the subsequent coats, I would use un-thinned 100% Tung Oil.

[paddedhat]

You might be well aware of this, but it's always good to cover for anybody reading. A lot of the typical woods used for marine and outdoor use, Teak, Mahogany, and especially Cedar, can cause a nasty allergic reaction, when  sanding. Oddly, I get it after a day of cutting fir lumber while framing. Masks and cheap respirators are helpful, since you don't need to discover that this is a previously unknown personal health issue, about the same time you think, "damn, it's really getting hard to breath"
The treads should be beautiful. I redecked my parents front porch with clear Mahogany T&G almost 20 years ago. It's somewhat under cover, and faces north. It's coated with spar varnish, and it still looks great.

[Fishindude]

I'd use Linseed oil.

[Miss Tash]

I put mahogany siding in small areas on my house and built a matching planter.  I treated it with Penofin Oil, specifically made for exotic hardwoods.  It looks awesome and after a year I reapplied a light coat to the planter.  The siding hasn't needed it yet.  Working with mahogany was interesting.  It's kind of stinky and it irritated my lungs so I wore a mask.  Super fun wood to work with though.

http://www.diyhomecenter.com/penofin-exotic-hardwood-formula-exterior-penetrating-oil-finish-1-gallon?gclid=Cj0KCQjw7pHLBRDqARIsAFyKPa7qoA72KeGCVpnYu9mst4D-zT8_jMC0p_3zI4NSiPHTCQLpB1NMl_gaAoMxEALw_wcB

Good luck.