Cypress is very porous. Almost anything you put on it will soak in,
at least, 1/8" in some spots. The more viscous a coat is, the less it
will soak deep into cypress. BLO or tung oil don't dry fast, anyway.
When either has soaked into the wood, it will take even longer to
dry. Your chairs may take 2 or 3 weeks to dry sufficiently for
sitting on them.
If you coat cypress with anything, try to get your coating into every
little nick and cranny. It may have been best to apply the (any)
coating before assembly, then soak nail holes (spots), screw spots or
other attaching apparatus. If there is one little spot where rain can
penetrate, it will often wick into other areas of the cypress from
that entry point, even though cypress has its own natural oils.
Finishing cypress for outdoor (exposed to the elements) use is a hit-
or-miss proposition, often missing over the long haul. When exposed
to the elements, the wood will expand and contract, eventually making
an opening, somewhere, and rain will penetrate and get under your
Penofin is not available locally, but I suppose can be ordered. I've
read the specs on Penofin, and I'm not convinced of its reliability,
since it seems to have the basic ingredients of other similar
finishes, so I've been hesitant to order some. I've never used
Penofin, so I really can't say anything negative about it.
I've worked with cypress, old and new, for 35 years and I still don't
always get it right all the time. I do like BLO only or tung oil
only, but you just have to let them dry fully, about 2 to 3 weeks, at
least, in my opinion.
For fine furniture pieces, I rub it in (the BLO or tung oil), in small
spots at a time, until heat is produced, kind of like cooking it into
the woodwork. That's lots of work and I wouldn't do that for outdoor
I hope this helps...
And also this: http://www.craftsman-style.info/finishing/069-cypress.htm