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chuckt
05-06-2015, 08:59 PM
I take it some people prime before caulking and some don't bother? Everyone primes after caulking it seams. I saw a thread where Peerie and Jay agreed it was good to prime before caulking. Some videos on youtube don't mention it and neither does Larry Pardey in his book.

My seams are, even now, pretty narrow. I am actually using a thin artist's brush to paint the seams. But it doesn't work all that well.

Ian McColgin
05-07-2015, 09:00 AM
Prime for sure. Unprimed wood in contact with caulking just does not seal up as well. Unprimed wood in contact with seam compound leaches the oils out of the compound leaving it brittle. Best practice on larger wooden boats is prime with red lead because it remains a bit soft but there are modern alternatives.

sheerline
05-07-2015, 11:12 AM
Well I go the other route and caulk unprimed but prime after caulking is in prior to paying up.

Trev

gilberj
05-07-2015, 11:13 AM
Prime if possible......I would agree...The grain of the wood should be sealed as much as reasonably possible

Jay Greer
05-07-2015, 11:22 AM
If you are using oil based seam compound over the cotton or oakum then priming prior to driving the fiber is what I was trained to do and always do. If I am caulking a deck and plan to use marine glue then I prime with bee's wax and turpentine which is rather thin. This is repeated after driving the cotton prior, to paying the seams with marine glue. For topsides and bottom seams I use red lead that is well thinned with turpentine as well prior, to and after the cotton is driven.
Jay

chuckt
05-07-2015, 12:21 PM
Thanks gents. The caulker just requested a few moments ago that I prime the seams so that is what I will do. It is kind of a pain because the seams are narrow but I can get in there with an artists brush.

J.Madison
05-07-2015, 12:58 PM
Can you get in there with a home-made squeeze bottle? I mean the kind where a rubber cork is pushed into an old soap bottle and a small copper tube is put down through the cork and flattened on one end. You could file it down pretty thin and shoot two coats of thinned paint into the seams.

I'll try to find a picture of the one I made.

Here it is:
http://i1123.photobucket.com/albums/l545/JMadison1/Crabbing%20Skiff/DSCN9945_zpsf5b7d4b4.jpg

chuckt
05-07-2015, 02:23 PM
Ah! Yes--I may try that. Thanks.

Paul G.
05-07-2015, 03:15 PM
Chuck just get a cheap 1" brush and paint sideways! Don't over complicate it, you have to sand the hull anyway so a bit of extra paint is no problem.

chuckt
05-07-2015, 08:56 PM
Yeah--tried that. Doesn't work as well as you might think with seam 1/8" wide.

Mikey Floyd
05-07-2015, 09:02 PM
Give your brush a Mohawk haircut and usually shorten it somewhat from the supplied length. It will get in there.

J.Madison
05-08-2015, 02:50 PM
A little tip if you make the squirt bottle:

Put a very thin shim in the end of the tube before hammering it flat. Keep it there while filing it down if you need to do that. Otherwise you will peen it shut instantly and it will be surprisingly watertight!

boattruck
05-08-2015, 07:50 PM
Chuck, thin your desired priming product a bit and force it in there with a cheap throw away brush, in moist boat yards you'd get beat up for bringing an artist brush to this chore...once we have the seam primed we neaten up the plank surface with the same dry-ish brush or a rag to even out any awful looking drips etc , Cheers, Steve

PS, yes, if you are not careful, this thin stuff will try and drip down to your elbow ,or further, use precautions...red lead in the armpit is considered sub-optimal...

wizbang 13
05-10-2015, 11:59 AM
The top shipwright from Carriacou now pays his cotton with.... Wait for it.... Epoxy.

sheerline
05-11-2015, 04:11 PM
Oh dear!

Trev

Aquinian
05-11-2015, 05:34 PM
The top shipwright from Carriacou now pays his cotton with.... Wait for it.... Epoxy.

I've heard of this twice now recently here in Perth. One is a Herreshoff and the other is a 56' jarrah-planked cruiser. Both were done at least a year ago and both are performing well so far (the 56' cruiser's on my jetty and the owner told me it's the driest timber boat on the river - he manually starts his bilge pumps every now and again to make sure they're working). This seems completely wrong by everything I have read here and elsewhere. Would the timer taking up not create terrible stresses since it is held apart by an incompressible medium?

Regards,
John.

gilberj
05-11-2015, 06:55 PM
I suppose this is something like splining the seams....
Most of the old woody fishing boats have used cement for underwater seam filler for generation's around here.

chuckt
05-11-2015, 08:32 PM
Epoxy in the seams? What happens when you need to repair? or recaulk? Or address a leak? I don't see that working long-term.

Peter Malcolm Jardine
05-11-2015, 09:54 PM
The traditional primer was, of course, red lead. Red lead has no biocidal properties, but the lead is an excellent primer which just about anything will stick to.

Chippie
05-12-2015, 10:19 AM
Air spray primer the whole outside hull that will take care of the problem you are creating then caulk/pay/ prep/second coat primer.

wizbang 13
05-13-2015, 06:56 AM
Epoxy in the seams? What happens when you need to repair? or recaulk? Or address a leak? I don't see that working long-term.
I see the opposite Chuck. Traditional caulking is a self fulfilling prophesy of leaking, repairing and re caulking.

Concordia 33
05-13-2015, 09:51 AM
I see the opposite Chuck. Traditional caulking is a self fulfilling prophesy of leaking, repairing and re caulking.


I've seen problems with epoxy when the boat has been on the hard a little too long. The wood shrinks so much that the epoxy seal get's broken at which point it leaks pretty reliably.

chuckt
05-13-2015, 11:14 AM
Yes-The plank is going to expand and, if we locked everything up tight with epoxy, I would worry frames would break or fasteners get pulled out or loosened. In a way, that happened to the Concordias. They were built tight-seamed and pretty soon they broke their frames at the tightest point of the curve because the frames couldn't handle the expansion of the planks.

wizbang 13
05-13-2015, 12:26 PM
Chuck, the frames already broke. Because of bad caulking? No, undersized steamed frames. You are worried about repairing an epoxied boat in the future? I am more worried about cu$t seams blowing out in the future, I were you.

willin woodworks
05-13-2015, 12:27 PM
Maybe I'm missing something....if the planks are dry enough to get a decent bond with epoxy caulking they are going to take up when the boat goes back in the drink. Now they expand against a hard seam filler. What happens next? They pull fastenings or they split frames as ChuckT describes. Is there cotton in the seam as well and does that now become some epoxy saturated rock solid string to crush plank edges or act as a fulcrum at the hard turn of the bilge to help spring fasteners and crack frames?

I'm confused

wizbang 13
05-13-2015, 12:30 PM
I've seen problems with epoxy when the boat has been on the hard a little too long. The wood shrinks so much that the epoxy seal get's broken at which point it leaks pretty reliably.
All carvel boats leak reliably until they swell. I do not understand why folks are so afraid of a superior seam. An epoxied seam will leak if the boat shrinks, sure. Then it will swell back up and put the planks will push on the seams and the hull will have compression and it will stop leaking again. Meanwhile, one will not be wasting time with making believe a caulking iron and cotton is a black magic art

willin woodworks
05-13-2015, 01:28 PM
An epoxied seam is great if that was the way it was designed and built from the get-go. I don't see how a typical carvel planked boat can be caulked with a seam filler that is not compressible without sustaining damage to either the planks or the frames.
I don't think for one second that cotton and seam compound is a black art but I know that it takes advantage of the natural wood movement to work properly. Is it the best method? Probably not but it's worked for a few hundred years...
There are any number of edge glued and strip built boats out there doing fine but that's because they were built that way.

sheerline
05-13-2015, 02:01 PM
All carvel boats leak reliably until they swell. I do not understand why folks are so afraid of a superior seam. An epoxied seam will leak if the boat shrinks, sure. Then it will swell back up and put the planks will push on the seams and the hull will have compression and it will stop leaking again. Meanwhile, one will not be wasting time with making believe a caulking iron and cotton is a black magic art
So going by that statement, both methods will leak if the boat dries out and both will take up when back in the water. So why does this make epoxy seams better with that logic?
Epoxy has earned it's place in modern boat building but hasn't dispelled traditional techniques as a viable method. A properly caulked hull doesn't leak and those that claim otherwise can't caulk or have bad caulking.

Trev

Lew Barrett
05-13-2015, 02:21 PM
My experience demands I agree with Trev (and many of the other notables on this thread).

Chuck, it sounds like all you need to do is listen to your caulker. It seems (seams?) he knows what's up. While caulking isn't black magic, it takes a deft hand, more so on a lightly built boat. Applauding your decision to have a pro handle the chore. A full on job is hard work that the pros can handle with alacrity, while pikers like us will take forever and more likely than not cock up.

wizbang 13
05-13-2015, 05:22 PM
Oh well,lost that one.

Lew Barrett
05-13-2015, 09:01 PM
Oh well,lost that one.

You win your share, plus some. Nobody with experience ever reckoned you for a fool. And I for one would never bet against you in a soft pad sander race or a hard blow. And maybe you're on to something here. I don't think so, but there's always that chance.......:D

Aquinian
05-13-2015, 11:48 PM
I don't see how a typical carvel planked boat can be caulked with a seam filler that is not compressible without sustaining damage to either the planks or the frames.

I tried to get to the bottom of this a month or two back on here and it's an emotional issue (well, for the traditionalists, anyway). I'm a traditionalist by instinct anyway, so that's fine. The data seems to be that loads of old boats have been glued up and survived, and others have not, so the question remains, what factors are to be taken into account when deciding whether or not to depart from tradition in this matter? And the answers do not seem to be known, at least not with any consensus. It's ALL a bit of a dark art, I think. But that's just my impression.

Regards,
John.

sheerline
05-14-2015, 03:58 AM
Large scantlin grown framing will take the pressure of hard caulking and cement paying but light steamed timbers will crack under the pressure of the same treatment.
Deciding where in the scale your frame work falls dictates the type of caulking and paying suitable for the job.

Trev

chuckt
05-14-2015, 05:57 AM
Well, I honestly would be interested in learning if it would work and under what circumstances. But I'm not doing that experiment on this boat. If for no other reason that, if I ever did decide to sell her, such treatment might likely scare off a buyer.