iron tacks in air dried oak frame???

[thersites]

I'm planning a project to make two chairs in air dried - or even green unseasoned - oak. I'm experienced with woodwork, but not with upholstery. In general, its a no-no to put iron together with oak, especially if the oak is moist, because the iron reacts with the tanine in the oak, which corrodes the iron and makes a black stain in the wood too.
I had a look for non-iron tacks for the upholstery on-line but didn't find any. Is there a usual solution to this problem? Any thoughts appreciated.

[fingers]

 I've seen plenty of old oak frames with tacks. And yes there is a small, localized stain. Right off hand the only solution that comes to mind would be to use stainless staples.
There's a vague memory in my brain of a box of Cross tacks I once had......maybe aluminum.... or zinc coated......what I remember most about them is when I put em in my mouth the little buggers didn't jive very well with my fillings.
Can we see a picture or illustration of your chair? The forum members like to help and a pic will help the thread keep going.

[kodydog]

Hi Thersites and welcome to the forum. Maybe I'm not reading this right but if the tacks are used to hold the fabric in place then any stains they create will be under the fabric, out of sight. If the concern is the tacks will corrode to the point that they will eventually fall out, I've never seen that happen. A lot of woodworkers will use a different type of wood on the frame parts that get covered. And use the oak on the exposed parts.

I'm no expert in woodworking but generally for chair frames, woodworkers use air dried or kiln dried wood. I think you'll have problems using green wood. Hopefully Mike can jump in here and clarify this for me.

[thersites]

thanks for both these replies. Fingers - I can't show a picture as the chairs don't exist yet. I'm just trying to plan them at the moment. Really they're meant to be test peices to see if the technology works - that is, using wetter wood than is usual these days. So what I could do is use iron tacks and just see if it works out in the long run. It's meant to be a test anyway so that works.

I'll try to scan a sketch of what i'm doing if I can get to a scanner. But it will be similar to a Jacobean chair - not a fancy one though.

Hello Kodydog, thanks. yes the stains don't matter, i needn't have mentioned them. It's true that people don't use green wood really for chairs. But they did do this in the past I think. I found two craftspeople in North America who have been experimenting with these old methods (this isn't "bodging", its green wood joinery). One is called Jenny Alexander, the other Peter Follinsbee. They have websites if the fancy takes you to have a look. I'd like to try the sort of thing they are doing. But they don't use upholstery so far as I can see.

If I can get these things made I'll certainly come back and post some pictures, even if they are justof piles of wood and cloth and tacks on the floor (idon't think this will happen though).   

[kodydog]

Only got a chance to read Jennys home page and look forward to reading the rest.
http://www.greenwoodworking.com/

I'm an amiture when it comes to fine woodworking and if you ever saw my feeble attempts you would agree. But I find the whole process fascinating. Please keep us updated with your progress.

[byhammerandhand]

Wow.  I made that chair in a class in NC, based on John Alexander's book.   At first I thought it was a typo, then I thought maybe his daughter took over the business.   Then I discovered Jenny used to be John.

I learned a lot from Jenny/John's book.  Every piece in that chair is oriented a certain way and dried to a certain level to give optimum strength.   It was a fun class.   Monday morning we started with a log.  Using wedge, sledge, froe, drawknife, spokeshave, brace and bit, and a bit of chisel work, we had chairs to take home at noon on Friday.

[mike802]

I have not gotten a chance to look at the site, but Keith is correct, the process that I am familiar with does not use green wood for every part of the frame, but rather uses wood that is less dry for the legs than the wood for the stretchers.  The gran is arranged when cutting out the legs so as the wood air dries it will shrink onto the tenon from the stretcher, thus grabbing it real good.  This used to be a normal way to build chairs before the industrial revolution, to do it today requires that the craftsman become more involved with obtaining lumber because everything at the mill is kiln dried down to about 7%, you cant pick and choose your moisture content, so having lumber for the stretchers bought from the mill, and having some air dried lumber of your own that is wetter become necessary, but I an not familiar with what the % of moisture content should be between two pieces being joined, or how they would have been able to tell that 100 years ago!

[kodydog]

Wow.  I made that chair in a class in NC, based on John Alexander's book.   At first I thought it was a typo, then I thought maybe his daughter took over the business.   Then I discovered Jenny used to be John.

Whew! For a minute there I thought someone was pulling my leg big time.

The only problem I can see with using green wood on upholstered chairs is when you cover all that wood with padding and fabric where does all that moisture go? Seems it would take forever to dry and I'm thinking mold problems. But if you built the frame using this method and set it aside for 6 months, maybe then it would be dry enough to upholster. Just a thought.


Sure would be great to get her/him on the forum to give her views.

[byhammerandhand]

When (in class) we made the posts and stretchers, we split and shaped them to dimension.  Then we steam bent the back posts.    These were set aside to dry for six months, and we "swapped out" them for the prior class' posts and stretchers that had been in the barn for six months.  WE put the stretchers in a makeshift kiln (aka "hot box") for about 36 hours and we weighed them every so often to watch the moisture content drop.

At that point, we took the posts that were slightly over wet with the stretchers that were over dry.    As both reached indoor EMC, the joint locked down.  This was called the "wet-dry" joinery.

We split out the back slats, shaped them, then poured boiling water over them and hand bent then into the post mortises.

So, other than the back splats, they were not sopping wet green, just air dried.

What impressed me about John/Jenny was that he/she is a lawyer and did a rigorous analysis of these chairs and determine why they worked the way they did and how they had been put together.