Benzine
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| posted on 6/6/09 at 07:38 AM |
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Sealing tongue & groove
I've got an old horsebox, the main box is made of thick mahogony tongue and groove. How do you go about sealing it/making it weatherproof? I
cleaned all the gaps nicely and put some clear silicon in which worked for about a week. Then the hot weather came and the tongue and groove
contracted and ripped all the silicon away, leaving gaps again  So silicon is out, i'd have to keep re-applying it year round. Is there any
kind of super-duper 2pack/resin wood paint that can move with it? or is there another way? Hemp/rope + pine tar? 
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mookaloid
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| posted on 6/6/09 at 07:47 AM |
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Wrap it in aluminium sheet?
"That thing you're thinking - it wont be that."
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Benzine
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| posted on 6/6/09 at 07:49 AM |
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quote:
Originally posted by mookaloid
Wrap it in aluminium sheet?
Too pretty to do that
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JoelP
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| posted on 6/6/09 at 08:37 AM |
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id say that nothing solid could resist the movement and not crack. Maybe oil it? Will protect the wood at least, if not the contents 
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trextr7monkey
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| posted on 6/6/09 at 09:05 AM |
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Strip it bare then 3 good coats of Sadolin- stuff in the yellow tin, it breathes and moves with wood and shoulld last for donkeys years, no pun
intended 
http://www.flickr.com/photos/14016102@N00/ (cut and paste this dodgey link)
Our most recent pics are here:
http://s129.photobucket.com/albums/p211/trextr7monkey/
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ReMan
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| posted on 6/6/09 at 09:08 AM |
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I would have thought oil too, varnish at a push
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trextr7monkey
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| posted on 6/6/09 at 11:02 AM |
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Teak oil etc Ok for iroko and teak where the natural oilyness of wood makes it difficult for other finishes to stick but if out side it needs applying
every year. Mahogany will take a stain and isn't so durable so I'd stick with sadolin- as used on high quality doors and window frames
etc which are subject to similar changes in weather as your hoss box.
Bit wet for those jobs today though
http://www.flickr.com/photos/14016102@N00/ (cut and paste this dodgey link)
Our most recent pics are here:
http://s129.photobucket.com/albums/p211/trextr7monkey/
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Chippy
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| posted on 6/6/09 at 11:15 PM |
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You could do what the boating boys do with the teak deck joints, but not at all cheap. You need to clean out the joints with some form of scraper,
back to fresh timber,there is some kind of primer that you should apply first, but cant remember what it's called, then gun in Sikaflex, (sp),
and once that is dry clean of the excess. Not a quick fix, but done properly should last the life of the H/Box. HTH Ray
To make a car go faster, just add lightness. Colin Chapman - OR - fit a bigger engine. Chippy
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Benzine
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| posted on 7/6/09 at 09:49 AM |
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quote:
Originally posted by Chippy
You could do what the boating boys do with the teak deck joints, but not at all cheap. You need to clean out the joints with some form of scraper,
back to fresh timber,there is some kind of primer that you should apply first, but cant remember what it's called, then gun in Sikaflex, (sp),
and once that is dry clean of the excess. Not a quick fix, but done properly should last the life of the H/Box. HTH Ray
That sounds pretty good, I think part of the problem with the silicon was that I wasn't cleaning the surfaces enough beforehand. What's
sikaflex? I hear of it all the time, just another sealant like silicon? Any idea where I can find out what that primer is you mentioned?
Many thanks
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mr henderson
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| posted on 7/6/09 at 11:16 AM |
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Are you trying to seal the wood, ie to stop it deteriorating in the weather, or ais the varying gaps int he t&g that are causing a problem?
If it's the former then I would go with the others who are suggesting oil or Sadolin, something that soaks into the surface rather than lies on
it, like varnish.
If it's the latter then I would want to know more about the problem before making suggestions
John
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Benzine
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| posted on 7/6/09 at 01:25 PM |
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quote:
Originally posted by mr henderson
If it's the latter then I would want to know more about the problem before making suggestions
John
It's the latter (the varying gaps) that's the problem. The wood itself, as old as it is, in in great condition (thanks to the rot
resistant properties of mahogany)
What furhter information can I give about the problem? I'll try and explain a bit more but let me know what else I can add... In the winter the
gaps are tiny (either no gap or roughly 1mm) With the recent hot weather the gaps have moved anything up to 4mm. In winter it leaked a little, now
when the rain comes it can be pretty bad. The roof is fibreglass and I recently re-sealed that, so that's fine. It's the capillary action
of water getting into the tongue and groove that's causing the problem. So I need a solution that takes the movement of wood into consideration
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mr henderson
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| posted on 7/6/09 at 02:16 PM |
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Tongue and groove, unless it has really deep grooves and matching tongues (which is unlikely due to the material that would be lost during
manufacture), isn't really suitable for creating a weatherproof structure as large as a horsebox. The expansion and contraction as the timber
tries to establish moisture content equilibrium with the relative huidity is too great. T&G is ok for a panel the size of a door, but I presume we
are talking about a much larger surface.
I studied this subject in depth many years ago when I was involved in guitar making, where it is vitally important to control moisture content.
I'll think about it some more, but at the moment I don't see an effectiveanswer to it.
John
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Benzine
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| posted on 7/6/09 at 02:39 PM |
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Thanks for the info, John. I'm wondering whether it'd work if I put strips of wood on the T&G that attached to the upper section of
wood, goes down over the T&G gap, but isn't attached to the lower tongue and groove, with a gap of a few mm so water can't go back up
with capillary action. It'd mean you couldn't see the tongue and groove, but I could stain them to match the rest of the wood, and it
would move with the wood when it expands/contracts...
That description may have made NO sense whatsoever ^
[Edited on 7/6/09 by Benzine]
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Chippy
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| posted on 7/6/09 at 10:07 PM |
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Hi, in answer to your question, Sykaflex is a available from most marine chandlers, as is the primer. as I said its not a cheap option, but the
flexability is quite huge, something like 100 percent flex, so 3mm gap sealed will remain watertight to 6mm, I have used it on boats, (very damp
environment), and never had any problems with it.
Note to Mr Henderson, never knew they made guitars out of T & G, Cheers Ray
To make a car go faster, just add lightness. Colin Chapman - OR - fit a bigger engine. Chippy
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trextr7monkey
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| posted on 7/6/09 at 10:35 PM |
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quote:
Originally posted by Benzine
if I put strips of wood on the T&G that attached to the upper section of wood, goes down over the T&G gap, but isn't attached to the
lower tongue and groove, with a gap of a few mm so water can't go back up with capillary action. It'd mean you couldn't see the
tongue and groove, but I could stain them to match the rest of the wood, and it would move with the wood when it expands/contracts...
Extending that line of thinking you could cover the whole mahogany set up with thin overlapping ship lap boards- cedar would be nice
You must be pretty attached to that horse taking all of this trouble......or is the horse some one elses toy which gets you garage time if it travels
along in a snug dry box?
atb
Mike
http://www.flickr.com/photos/14016102@N00/ (cut and paste this dodgey link)
Our most recent pics are here:
http://s129.photobucket.com/albums/p211/trextr7monkey/
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Benzine
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| posted on 8/6/09 at 07:49 AM |
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quote:
Originally posted by trextr7monkey
You must be pretty attached to that horse taking all of this trouble......or is the horse some one elses toy which gets you garage time if it travels
along in a snug dry box?
Yeah, very attached. I'm in it at the mo on mobile internet And the horses have gone along with their rubber matts and division walls etc to
be replaced by an equally hairy stallion :p
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