- 19 March 2020 at 4:02 pm #653718
I built a Trestle table like Pauls, came out very nice, one of my best projects ever. Here’s what has happened. Table is about 1+ years old. Finished with Varnish.
The table sits outside under our Gazebo year round. 99.9% of the time shielded from the sun and weather. The sun may catch one corner or another for an hour or less as the sun crosses the Gazebo. For 10+ months absolutely no problem. The top is made of boards about 6 feet long, 8 inches wide and 1 1/8 thick. Cedar that I have had for a year sitting in my shop. Weather is pretty constant, about 80 degrees, humidity the same year round.
One outside board suddenly curled upward from the edge to 5 inches in. About 1mm or slightly more. I watched it for 3 y months now to see if it would get any worse or return to original position. It has stayed the same. It is being held very tight to the next board from the length of joined wood, so I can’t figure a way to get glue down inside. It’s absolutely tight. I am guessing the wood either had a memory and when wood wants to bow, it has a strength beyond glue. Maybe I clamped that end too hard and squeezed too much glue out.
So how to fix? I can plane that area flat again, but that does nothing to stop the wood from moving again. Second thought is to puddle glue against the raised edge and clamp it flat, release it and keep clamping and releasing to try to get the board to track the glue into the middle again. But the board is so tight I don’t know if that is possible. After that, I am totally out of ideas.
Index card show area affected in photos. About 5″ long.
Any possible thoughts would be welcomed. And thanks in advance.
PS.. I have smaller tables that sit out side in the same area, but get lots more sun and even rain. No problems with them.
- This topic was modified 2 weeks, 4 days ago by 5ivestring.
You must be logged in to access attached files.19 March 2020 at 9:33 pm #653759Larry GeibParticipant
What species?19 March 2020 at 10:36 pm #653766
Cedar.19 March 2020 at 10:44 pm #653767
While having a cup of coffee and staring at this joint problem I came across and idea. Take my smallest drill bit and drill 3 maybe 4 holes along the split at a 45 degree angle running with the split. Then using a syringe shoot some glue in the holes, move the board down to position and let it up and do that a few times to spread the glue. Then fill the holes with glue and dust and clamp it level again. Let sit for 2 days.
Or should I do as above with the drill and glue and then after moving the board the 1mm a few times with a clamp to try to spread the glue inside, then just clamp it in the natural position (raised) and let it set for a couple days, then plane smooth?
Good idea or bad?19 March 2020 at 11:34 pm #653772
Last idea I have. I just don’t know if any of my ideas are good or if there is a “professional” way of mending this.
Last idea. Drill a hole slightly smaller than the thickness of a finish nail starting on the low board side and 45 degree into the raised board while it is clamped into place.. Cut the nail so it won’t go all the way through the wood and counter sink the head of the nail. Then use glue and dust to fill the hole opening. I thought about using a wood dowel, but then thought if this wood has that much strength to bend, it might just split the dowel in two, but the nail, maybe 8p, would have a lot of strength.
Advise? I really don’t want to screw this table up, it turned out so nice.20 March 2020 at 2:10 pm #653818deanbeckerParticipant
Nails might not be your best bet they will come out eventually , especially out side.
The picture is hard to see but I think what you are saying is the joint moved.
You could epoxy it and clamp it flat , 1 mm isn’t a lot to flex. And epoxy might hold. Especially in cedar. It’s kinda oily and the joint is contaminated from old glue20 March 2020 at 10:34 pm #653874Larry GeibParticipant
I’m assuming you used PVA glue and the crack is the glue joint.
Unfortunately, PVA doesn’t re-glue well. Once tthe glue fully cures fresh glue doesn’t stick to it. Even epoxies don’t stick well to it.
I’d do what might seem like a drastic measure but in practice isn’t too bad. I’d saw down the length of the table, rejoin the edges, and re-glue the joint.
You will only loose the width of the saw kerf and some shavings. At that point, you will probably have to re-plane the top and refinish it. Chances are most of the wonky movement has worked itself out, and as long as the environment the table is in doesn’t change much from its current state, it will probably be fine.
You can’t clamp wood too hard using PVA glue. The tighter the joint, the better. it’s not gap filling and depends on a close chemical bond with wood. Chances are your shop doesn’t have enough clamps to worry about too much clamping pressure.
I would worry about the environment you do the glue up in. Do it in a place where you would feel comfortable reading a book or having tea. Too hot or cold prevents proper glue up. Get a fresh bottle of glue and Mind the expiration date.
. If, on the other hand, you use an epoxy resin, you actually can clamp too hard. Just bring the wood together and stop, when using epoxy.
One thing I’d check is that whatever method you used doesn’t restrict the movement of the top across the grain. If it is screwed to the undercarriage, the holes should be oval to allow movement
And if you used hide glue, you might be in luck. In that case you could probably fill the joint with a filler made of like glue and clamp it and call it good. You may still have to replace the top if you can’t clamp it where it should be.20 March 2020 at 10:57 pm #653875Sven-Olof JanssonParticipant
In lieu of supporting evidence, this probably isn’t worth a farthing; but, anyway, here are a few thoughts.
A temperature constant around 25 – 30 °C (80:s °F) and non-varying humidity would suggest US Southern East Coast, and thus Eastern Red Cedar, which must be a species found in a lot of traditional furniture dating to when hide glue (with or without drawboring) was the only adhesive available. Hence, I think that any water based glue should work (the wood database internet site also states that Eastern Red Cedar glues well).
The photos seem to show a slight elevation on the upper face and none on the lower. If so, would that be compatible with a twist in the board, or perhaps more indicating a very regional discrepancy in humidity? Reappearing warp does – in my depressingly rich experience – go all through the thickness, while the effects of changes in humidity don’t always do.
It is of course most likely that the somewhat more prominent glue line of the deviating 5″ is a shadow effect, but if not then perhaps an increase in humidity could have occurred.
All in all: would there be great risks in planing those obstreperous five inches flat, and then observe what happens, Alternatively, I imagine that opening up the joint line with a fret saw, or some other saw leaving a very narrow kerf, would allow for re-application of glue, and then clamping the edges very tight, while at same time pressing the faces flush.
Finally, if turn buttons are holding the top to the frame, would it be at all feasible to take the top off, find a bandsaw with a very narrow blade, a user of great skills, and saw along the glue line; allowing for a complete rework of the faulty board?
Royal Enfield: magnificent!
London, UK; Boston, MA21 March 2020 at 1:03 am #653895
@Sven-Olof Jansson, You are very observant. Yes, south east use would be close. I’m in Turbaco Colombia, near Cartagena. As for the Royal Enfield, love that bike!
I have a Japanese dovetail saw, 24 teeth, very narrow kerf. I failed to mention the curve is full thickness of the board. The Botton has the same raised gap as the top.
I think what I’m going to do is like you suggested and others did to, is cut the glue line. It’s only 5 inches or less. Glue and clamp.
Thanks to you and everyone else for the replies.
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