Its always something isn’t it?
We caulked all our seams with regular caulking cotton; done with it…except…there are two places along the rabbets that we were advised (by a more knowledgeable fellow than us regarding caulking) to place a strand of oakum over the cotton–or to use 3M 5200 (eek! no, no, no–so “non-traditional”).
Both of these spots (port side stem knee area and port side deadwood area) were of concern to our “adviser” friend because he though the swelling of the oak stem and deadwood rabbets would push out the cotton.
On the stem knee, there’s a 15″ length of seam where the fit of the plank was such that we had 1/4″ or so of the backing rabbet showing instead of the outgage tightening down in the back to nothing showing like everywhere else. So, little actually holding tha cotton in there with such a wide seam. I’m also a bit concerned about this area and considered epoxy-ing a spline along the plank to make a better outgage but was advised to simply use a strand of oakum to “catch” on the sides better than the cotton will. The plank is 1-3/8″thick so there’s plenty of depth, I suppose to do this.
Regarding the port side deadwood area that the adviser is concerned about, I’m not concerned nor understanding his concern–but trust that he knows what he’s talking about. It is a very, very deep rabbet, tight and good outgage, which should close up nicely locking in the cotton as the planking and the oak deadwood swell. He seemed more freaked out by the very deepness of the rabbet. Same 1-3/8″ depth, but just allowed a bare 00 caulking iron to go back in about 1-1/8″ wereas most of our seams were so tight that the 00 caulking iron could only go in between the planks anywhere from 1/4″ to 3/4″, most being about 1/2″
Well, anyway, the adviser friend said he didn’t have any Oakum but we should top the cotton with oakum and he’d know who to come to when he needed oakum since we’d have plenty extra! Well, I can’t find small quantities of the sort of oakum that is used for caulking wood boats. I can get the kind that you use in plumbing–but it has benonite (spelling?) added to make it swell (advertised 10x) and specifically doesn’t have “tar”…the bit of reading on oakum I’ve done indicates that one wishes to use tarred oakum when caulking or just “oakum” but not something made to swell like a balloon! Our local expert/adviser cannot help with this issue. He doesn’t know if there’s a difference or not between plumbing oakum with benonite and regular oakum for caulking.
I’d read somewhere a little story about a fellow who needed oakum in a pinch and unwound some marlin (tarred hemp) that he had (using a drill to unwind) and I thought…hey…that’s not too bad…So, I bought a little bit of tarred marlin from Jamestown Distributors. It showed up…its Polyester!!! not hemp. I called them and asked for a refund. They were gracious and gave it and said they’d update their website to stick the word polyester in the description. Everything is a “fake” something these days it seems.
Still looking for that plain old oakum in small quantity. I noted that the (large quantities) that Jamestown Distributors sells is the “expanding” type with Benenite (or however you spell it!).
I noted that American Rope and Tar does have REAL marlin, so I guess I can try that route again.
Before buying it, I made a post on the wooden boat forum–hopefully one of the helpful folks there can advise me where to find plain oakum or what the difference really is between plumbing oakum and caulking oakum.
