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Old 5th August 2011, 12:18 AM   #31
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I have laminated really thin ply on the outside of a box as a veneer. I cut it rough and trimmed it with a router, should work for heavier lamiates...

In Australia (at least) there is 'exterior' PVA glue. Not tried it but I assume it would keep Cal afloat longer than the regular stuff... I suppose a bit of damp resistance could matter for PA gear.

Is PVA glue ruined if it freezes in the bottle or just when it is supposed to be curing?
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Old 5th August 2011, 11:33 AM   #32
marce is offline marce  United Kingdom
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Thanks for the glue test info Carl. Got a shock as I have used gorilla glue a lot in the past, and didn't expect it to be the worse of the bunch!
Though nothing yet I have built with it has fallen apart yet.
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Old 5th August 2011, 02:36 PM   #33
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Quote:
Originally Posted by simon7000 View Post
Cal,

Attached is what I mean by "Figured" wood.
Thanks for the pic. Figured wood looks a little like burl. What are you showing us?

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And if you raise your own pine it would probably be better behaved.
Nothing I raise seems particularly well behaved.

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The family Pinaceae covers both commercial spruce and pine forgive me for being so imprecise.
Ya, smarten up would ya?

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Originally Posted by Mickatroids View Post

In Australia (at least) there is 'exterior' PVA glue.
Yes Titebond III calls itself water resistant also. I think that sort of means exterior grade, no?

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Is PVA glue ruined if it freezes in the bottle or just when it is supposed to be curing?
There's something long and complicated sounding that happens but what it boils down to is it will work but not near as well so you run the risk of ruing your project.
Throw it away.
Throw it far far away.

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Originally Posted by marce View Post
Thanks for the glue test info Carl.
Who's Carl?

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Got a shock as I have used gorilla glue a lot in the past, and didn't expect it to be the worse of the bunch!
Though nothing yet I have built with it has fallen apart yet.
Ya, I was surprised to read the results but like you, nothing I have built has ever suffered. Not like pre-frozen PVA has.
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Old 5th August 2011, 02:48 PM   #34
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You got me curious so I Googled and look what I found in Wiki.

Subfamily Pinoideae
Pinus - pines (about 115 species)
Subfamily Piceoideae
Picea - spruces (about 35 species)

I had no idea there is about 35 species of Spruce. I only know it from the lumber yard or as the trees in behind the wood shed.
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Old 5th August 2011, 07:09 PM   #35
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Cal,

Figured wood is what you call any wood with an interesting grain pattern. Nice for the visible wood on furniture, not so nice to keep trued up.

You raise knotty kids?

There are water resistant PVA glues, but if you build a boat with them, better know how to swim.

The folks who classify trees and other things go way overboard.

But West Virginia grown Spruce is different than what you have.

If I travel too far (200 miles or so) I begin to have trouble identifying trees. Of course the local Sycamores are more likely London Plaintrees and telling the difference ain't easy.

I was at the name brand retail store of a mail order chain where a fellow was buying small way overpriced pieces of wood to build a musical instrument. He was tapping the pieces and trying to find the musical ones. I have no idea where he got his ideas of what sound he was listening for, but all the pieces he liked were ones I would have used for secondary uses.

He didn't like dead sounds, but went for wood that had splits in it and gave him many higher frequencies for the same tap.
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Old 6th August 2011, 01:17 AM   #36
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Are there any telltale signs of PVA that has frozen and thawed? My shed is metal and (6x4m or 20x13') with an insulated roof. We have had -8C here in Canberra recently (15.5F), the water froze inside the chook house!

Might just have to chuck it in case it fails, will check where in the shed I stored it later. Cal, I assume you meant 'ruining' my project but perhaps not, I would certainly be ruing it too I would rue the day!

Edit: Have been googling.

"Do no let PVA glue freeze. It will not be good afterwards. With white glue, if the glue has frozen and then thawed, it will dry a white cloudy color instead of clear. If you are not sure if your glue has been previously frozen, test it first. If it dries white instead of clear, then discard the glue as the bond it creates will not be strong."

Last edited by Mickatroids; 6th August 2011 at 01:24 AM.
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Old 6th August 2011, 01:39 AM   #37
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I wish I had known that trick. I wonder if it's the same with yellow glue which happens to be what I use mostly now.
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Old 6th August 2011, 02:45 AM   #38
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Originally Posted by bunkie View Post
Much of the strength in butt joints in speaker cabinets comes from the fact that the joint is supported on more than one side. I have never seen a well-constructed speaker box made with butt joints fail. A closed box that basically just sits there its entire life doesn't need the sort of strength that a drawer does which is subjected to tensile and compressive forces on a regular basis. Save the dovetails for the drawers unless you are doing it for aesthetic reasons.

To answer the question about clamp pressure, a few years back one of the woodworking magazines did some testing to see if a joint could be starved of glue from too much clamping pressure. They found the exact opposite to be true which makes sense because glues joints are strongest when the film area is largest. Extreme clamping pressure pushes parts more closely together resulting in a larger contact surface area and more glue film.
Thanks, that is what I wanted to hear. I always seem to over tighten, or go to the excess when building something. At least I know I can safely tighten up the clamps without having to worry about things coming apart in the future.


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Originally Posted by Cal Weldon View Post
I have posted some testing done on wood glues.

The lowdown on wood glues
Thanks Carl, that was very helpful.
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Old 10th August 2011, 09:20 AM   #39
marce is offline marce  United Kingdom
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Sorry Cal, brain not working.
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Old 10th August 2011, 11:55 AM   #40
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A few points...

I gave up on polyurethane glue (Gorilla Glue and its ilk) for general woodworking. It's just too messy. I reserve it for gluing dissimilar things together (metals and plastics, for example). I use either Type I, II or III PVA (yellow) glue for all my woodworking. There is one exception which is when dealing with oily exotic hardwoods. Polyurethane glue seems to do a better job in those circumstance.

I love my brad nailer. While it doesn't add much in the way of clamping strength to joints, it's awesome for locking the position of two pieces together before clamping. With joints tending to slip as one applies the clamps, this is cheap insurance.

Type II and III PVA glues are water-resistant. But I would never use them on any exterior project. Mechanical fasteners or epoxy are the ways to go for these applications.

With respect to clamping, with PVA glues, you can usually remove the clamps after about 90 minutes. It takes about 12-24 hours for the glue to fully cure, but most of the film strength is there pretty quickly. This is important if you are doing a lot of assembly and suffer that universal malady known as clampus insufficientus.

Plywood warps. Sometimes it warps a whole lot, especially the awful "cabinet-grade" stuff from China that infests the lumberyards of America. It looks great when you buy it, but it has veneer that is, seemingly, a few microns thick, nasty voids and poor dimensional stability.
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