Kiln Drying Cypress Planks for Near-Term Use

[Nathan Jordan]

Nathan, the increase in drying time is actually between 2.5x to 3x when comparing 8/4 to 4/4 drying rates.

You are correct, I just threw that in my last comment as an after thought without doing any research to confirm first (I'm doing all this sitting in my office at work lol).
You can clearly see it in the data for air drying, but there seems to be a lack of data on drying lengths, especially for vac kilns - or at least I've found very little so far.

I agree that two weeks is probably not possible no matter what route is taken, I also agree the best bet is to find a kiln operator that regularly deals in cypress.

There is a kiln schedule out there that is recommended for 8/4 cypress, T11-D2, if anyone was so inclined to attempt it. (table 257 on pg 99 https://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr57.pdf - looks like if your target mc is only 15-16% you just hold 150 deg. until you hit it! Of course this table doesn't give any time frame. For me holding 150 for more than 24 hrs is too scary I would not attempt it without a few more years exp. The other woodweb one says hold 90 deg. that I could handle but it would take months for sure.)

[Scott T Smith]

There is a kiln schedule out there that is recommended for 8/4 cypress, T11-D2, if anyone was so inclined to attempt it. (table 257 on pg 99 https://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr57.pdf - looks like if your target mc is only 15-16% you just hold 150 deg. until you hit it!

I recall that the T11-D2 schedule is for a conventional (steam) kiln. I've not found many conventional kiln operators that accept small loads from individuals, so he is more likely going to find someone with a DH or vacuum kiln.

Vacuum kiln drying time varies depending upon the depth of vacuum. The iDry system is becoming very popular, but it is not a deep vacuum kiln. It actually depends upon keeping some atmosphere present in the kiln chamber in order to convey heat to the lumber.

Typically an iDry would take a couple of weeks, but Den Socling (noted vacuum kiln designer) has indicated that thick cypress can be problematic in a vacuum kiln, and tends to leave pockets of moisture behind.

The deep vacuum kilns will dry more quickly, but again there are not as many of them around that would agree to dry a partial load for others.

[Nick Baggs]

Hello Scott, Nathan and Jamie. You have sufficiently prepared me to seek out the "right" type of kiln and now I know what questions to ask--so thank you for all of your insights. I can probably take it from here and will report back once there's something interesting to report. After processing everything I'm at a bit of a fork in the road however. Wondering whether I should continue down the current path--to buy fresh green lumber and have it dried--or should I put my energy into resuming the search for a supply of 8/4 x 6" wide heartwood 16 footers that have already gone through this process? I can do a lot of searching for already milled/dried material in the 3-6 months I'll spend waiting for the boards to dry. You might say, yes, do that, but I spent the better part of a week looking for this stuff and couldn't find it. Is that par for the course for cypress or am I just looking in the wrong places. Thanks again.

[Nathan Jordan]

Sounds like par for the course, the big time guys probably aren't motivated to keep something like that in stock since its not exactly a high demand item (at least I don't think it is), and the small time guys make more money on slabs. Of course you could turn a slab into a 2x6 pretty easy but 16' slabs are pretty hard to handle, at least for a small timer like myself. I'll ask around here in TX, never hurts to keep hunting. I talked to a vac kiln guy this morning he said about a week and a half per inch so around 3 weeks for 8/4 cypress in his kiln (only 12'), he also said the bigger ones can dry it even faster. I would think any of the vac kiln issues associated with cypress, like leaving wet pockets, might not be a huge issue considering your intended final use is for a ships hull, seems like the critical part would be dimensional stability. Another problem you're gonna run into with any kiln guys is like what was said earlier, the small vac kiln guys that would do small loads can't handle 16 footers, so you'd have to find one of the fewer big kilns that either will do partial loads or has a partial load waiting. I almost feel like by the time you called every lumberyard and vac kiln operator in the country you could have your green lumber dried in a conventional kiln or dh kiln in the same amount of time. I reckon it all hinges on how hard of a deadline you're working under, and of course your budget. A small dh kiln isn't that hard to make if it came down to it, but you'd have to be careful, i.e. it would be a lot more work and time. (I feel like a lot of this has already been said so I apologize for repeating it lol). Good luck to you, post some pictures if you have any we all like to see fresh milled lumber.

[Kevin L. Waldron]

You might check with these folks to see who is close in your area.

https://idrywood.com/