As I mentioned in earlier post about moistening wood before gluing. All of you were correct in replies. I took the items to a friend to thickness sand. He dropped one and it fell apart at the glue joints. So much for my bright idea. I learn a lot from this group, thanks. Warren
I'm the same way, Warren. I've learned more little snippets from reading this group than I care to count. I suck up to the gods of the wreck from time to time, and this seems as good a time as any to thank everyone here for steering me, either consciously or buried in a post about something else, in a better direction than I might have gone on my own.
I'm not going to get into names, but there are a few here who consistently and patiently explain things on a text-only medium that has made my forays into the shop either more efficient, more fun or more safe.
For the most part, it's the pros or semi-pros who have the wealth of experience to put things in a more realistic perspective. But there are times when there's someone with as little experience as me who just seems to have the right answer.
And for all of that, I'm grateful that I found this group.
And BTW Warren. It's sure nice to see someone say that they made a mistake and own up to it.
Tanus
I'm not sure where you came up with the idea in the first place. Maybe it was planted in your head by hearing a correct idea and it got garbled up in the memory banks, as often happens to me.
In any case, I could see someone offering the advise to wet the gluing surfaces of the wood, then "let dry" before applying glue. This would act to open up the pores a bit and possibly help the wood soak up the glue.
I'm not saying it's a correct theory or practice... just saying I could believe someone might offer that advice.
Joint and surface prep are much more important to strength than the minimal diluting that surface moisture might have. Proper clamping and sufficient cure time also makes a difference. (But, to forestall further angst and squawking, it's certainly possible that the surface moisture interfered with the glue where it counts most, at the wood surface and just slightly below. I would still suspect inadequate surface prep and clamping first before buying in so easily on not tampering with the magic voodoo that comes in the glue bottle.)
Yeah the opening the pores up thing IMHO does not hold water either. You get a better bond on wood that is shiney smooth and no open grain. Take maple for example. I don't believe that the typical wood glue needs a "tooth" to bond well. Typically the more glue there is in a joint, in excess, the more likely it is to fail. There is really no such thing as glue starvation in a joint unless there is not enough glue to cover the surfaves in the first place. Squeezing the heck out of a joint with clamps is not a problem providing there is glue on all surfaces of the joint, and those surfaces touch each outher, regardless of how thin the lglue line is.
Would that include case-hardened maple direct from a jointer? Because at a door manufacturing company that I frequent, they scuff and moisten the edges before making the panels for the raised panels. They do let them dry throughly before gluing. They want tooth.
But do they use PVA or some other kind of glue that benefits from tooth?
Luigi
Would that include case-hardened maple direct from a jointer? Because at a door manufacturing company that I frequent, they scuff and moisten the edges before making the panels for the raised panels. They do let them dry throughly before gluing. They want tooth.
Lets just say that I have never had a failure and my maple surfaces are often burnished.
Resorcinol of course. *S*
And don't forget epoxy.
Lew
You won't LET me forget epoxy.
Lew won't let ANYONE forget epoxy, ever! :-)
Luigi
According to Franklin, clamping pressure should be 175-250 psi for hardwoods. No worry of over clamping.
Or let anyone else, for that matter. And that's a good thing.
Tanus
Fine Woodworking did a glue comparison test a little while back, and found that for most glues the tighter the better. They also found that for most glues, especially the most commonly-used PVA's, that there was also no glue starvation problem, as noted above.
After reading the article, I changed my clamping technique to clamping very, very tight on most joints, and have achieved greater success as a result. The only glue that I use that I don't worry about clamping too tight is epoxy, because epoxy has superior gap-filling properties.
When I first started WWing, I clamped things as tight as I could. No failures. Later, I read that was wrong, and you shouldn't over clamp. I tried less clamping pressure and you guessed it, no failures. Now, they seem to want more pressure... Personally, I quit worrying about it (never really worried much anyway) and clamp until no gaps, and maybe a tad more... somewhere between 10 psi and 1,0000 psi. Not sure, I don't measure it:-)
For me, the most important issue for ME to worry about is squeeze out. I don't want much (any), and I don't want a dry joint. If you know what you are doing, you get little squeeze out (unlike Norm and Scott) and no dry joints. It just ain't that hard. Well, it might be hard if you are on TV, not sure about that...
Clamping tighter helps on marginally prepaired joints, those that may not close when simply slid up next to each other and helps to prevent the joint from slipping if you move the assembly around shortly after clamping. Masking makes a great clamp if the surfaces are properly prepaired. Ths only problem I have witnessed from clamping too tightly is indentations where the clamping surfaces come in contact with the wood.
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