I was watching a good video on YouTube on woodworking, and the guy just glued one piece of a board before clamping. I use Titebond III and try to avoid end grain joints with tenons, rabits, or what ever. But I generally apply glue to BOTH pieces before clamping. For example, gluing up 3 six inch boards to make an 18 inch panel, 3/4 inch final thickness: Glue to all edges, then clamp.
So, What is the concensus for putting glue on one piece, or both? Is there a risk of glue starvation on an otherwise snug joint?
I put glue on both mating surfaces, as recommended by the manufacturer. But there are some glues that should only be applied to one surface. Based on experience, I can get very close to limit the amount of squeeze-out. In my earlier days glue dripped all over the place. Like global warming, I don't believe "glue starvation" is an issue and never heard glue manufacturers address it.
Both surfaces. Always. Ever brush glue onto a surface over a large area then come back to where you started and see all the places you missed or where it didn't get into the pores? I'd imagine the same thing would be true of the unglued piece inside the joint that you can't see once you've put them together.
In 30 years I cannot remember a time when I applied regular wood working glue to both sides unless end grain in involved. You really don't want to glue both pieces if one is a veneer. I have never had a joint fail because I did not put glue on both sides. Really, the glue gets on both sides when you put them together. If you have a good tight joint to start with there will be no starvation.
That said, if you glue both sides you do have more open time on a complicated glue up.
The conventional wisdom is to wet both sides with glue. I think the reasoning is partial skinning, with yellow PVA especially, prevents full wetting of the mating face. It's easy enough to check. Stick two faces together and then pull them apart and see if both faces are fully wetted. There were distinct dry patches when I did this even, with an excess of glue. What does it mean? I guess most joints are over-designed in regards glue surface to begin with.
Which is made up for by requiring more time to spread glue on the other side. I do wish it were so, though. I'm tired of rushing the glue up to get them into clamps soon enough.
It depend on the type of glue being used. Directions for polyurethane adhesives, for example, suggest dampening one edge and applying the glue to the second edge.
Hmmmmmm... My take so far is to glue both sides, as there seems to be no downside, and possible gain if both pieces are not wetted. Veneer or similar exceptions noted. I wonder if there have been any tests as to bond strength with only one side wetted? And I question the mfg saying do two sides, since there may be bias from their legal dept, or sales dept. Hmmm, this will take some more thought. Maybe glue some scrap, and see how it breaks apart.
In a panel glue up that thick, the joint is so strong what difference is a theoretical couple of spots that didn't adhere going to make? Nil. But having more glue than you need contributes to the boards sliding around out of alignment, wastes glue, more cleanup. You could do it on both sides at just the ends if you really thought it would make a difference.
In a contest between glue spread out evenly on one side, and glue on both sides but just a bead run down without spreading, my money would be on the spread on one side being stronger.
Yeah but if the glue skims over, it does so on both pieces does skimmed over glue stick well to skimmed over glue? ;!)
With lots of practice you eventually learn to get the glue out spread quickly qirh out muxh fuss. I remember a time when glue up required lots of set up time. Not so much any more. I probably should have qualified my statement more. If glueing end grain I tyically apply glue to the end gran and let the soaking in start up, glue the mating surface and then rewet the end grain side and then clamp.
With polyurethane the "wet" water is the catalyst, it really does not do much other than activating the glue. If you applied glue to the wet side you start to get foaming and curing sooner than you might want.
I wrote unclearly. By the time you're done painting up the one side, part of it will have already skinned over. If you glue only one face, leaving the other face dry, that joint will be skinned glue on bare wood, and probably compromised. Skinned glue on skinned glue is the normal case, I think, and perfectly OK.
Might be that my view is skewed from using glue that seems half dried from the start. The low humidity isn't helping, either.
A coupla weeks ago, I did a simple box shape, 4 sides and a ply sheet, 16 biscuits in all, that had to come together as one glue up. The glue was some old yellow Elmers I had left over from last century, and skins over almost as it's leaving the bottle. I'm thinking of chucking the remaining half gallon and just get simple white glue. Fuhget about Titebond dis or dat, and watertight nuthin. I just want the glue to still be glue when I stick the pieces together. It was a hectic footrace, and I had 12 of them to do. The last few weren't any more fun than the first few.
As the old saying goes, glue is cheap compared to your time an other materials. Get rid of your old glue. I keep several glues on hand and mostly for color. TB II IMHO has a pretty long open time for a regular wood glue but tends to be runny and a bit messy and you need very good fitting joints to hide the yellow. The old Elmer's Tite Bond had a fast tack but fried closer to white. TB III seems a bit thicker and dries to an actual medium brown wood color. Recently I have used Gorilla WHITE PVA Woodworkers glue because it is white and does not dry with a distracting color, this was for a maple project. Also TB Trim Adhesive is white and dries to a non yellow color however it dries a bit more quickly and is very thick, IIRC it will not pour out of the bottle, you have to squeeze the bottle to dispense. Then there is the slow set TB glue for longer open times. I buy poly urethane as needed, it's expensive, has a short shelf life, and is really messy if you are not careful.
Personally, if Leon says he hasn't glued both sides and never had a failure, thats good enough for me. I've always glued both sides, or one side and rubbed the two together to get even distribution. Now I think the glue companies say glue both sides to sell more glue... 30 years experience trumps just about anything...
I'm sure that's true. Personally, I glue as needed, and it depends on which glue I am using.
Glue has become such an integral part of my repair/remodel business, I think the only things we use more is screws.
If I am doing a utility glue, I only glue one side, unless the material is rough and porous like OSB or CDX. Most repairs, the same way. When I put a small broken piece of material back or attach a piece of trim, I just glue one side.
I still glue both edges when I do a layup, though. I don't worry about a "glue starved joint" or any business like that. No matter the amount of prep, the edges may not mate up to standards of invisibility when attached. I want glue in the hairline joint, no a void I have to fill later after sanding or planing. I think my odds of filling that tiny void are much better with both sides glued. Maybe not... but I know I am not alone; that's why we have colored glue, right?
Think about it. How many non-trades people use so much glue that they constantly replace their supply? How fresh is the glue that many DIYs are using? Think how many posts have been here about guys that are trying to make the remaining skinned over gel in their bottles work by heating, adding water, etc., instead of buying a new $4 bottle of glue.
I think the "glue both sides" part of the equation is to make up for poor technique and joining failure as much as possible. That way not enough clamp pressure, improper surface preparation, improper application, and maybe even stinginess with the glue can be at least partially overcome with glue on both mating surfaces.
I think the "glue both sides" part of the equation is to make up for poor technique and joining failure as much as possible. That way not enough clamp pressure, improper surface preparation, improper application, and maybe even stinginess with the glue can be at least partially overcome with glue on both mating surfaces.
Just a thought...
Robert
Actually my comments are strictly concerning furniture and cabinet grade building when referencing a single side glue application. If gluing construction grade I am not too sure that too much is "too much".
Also simple surface tension; even if you are fast enough to avoid skinning, you still have to physically break through the "skin" that any liquid will have on the surface.
I knew what you were saying, I just took the liberty to expand on it a bit.
Heh heh... no kiddin'.
When building a site built sandwich beam or a large header, I rely on TB II 100%. Plywood and wood become as one. Never seen one of those break or even deflect past the camber. Most of the time, not even that much.
On another track, I am a big fan of the old school liquid nails, but about 3 years ago tried the polyurethane tube glues. They seem to hold like hell, fill in gaps well, and dry hard and completely water resistant. The only downside is the tendency to creep and for the glue to seep out of the joints. So for structure work, or for something you will mechanically secure it's great. Works well on the back of hardened masonite panels if you run into that kind of paneling.
I thought about that. Use more glue, sell more glue. Experienced woodworkers know how much glue to apply. Glue dripping all over is both a waste and a mess. If I were applying to one side only, this would be the time to change and apply to both surfaces. A rubbed joint is almost as good as applying to both surfaces.
I've never had a "skim over," but I plan a glue up carefully to get the piece assembled quickly. Glue brushes, glue roller, unused credit card, and finger is what I use to spread glue quickly. Clamps, jigs, damp rag are nearby. Dryfitting everything speeds everything up and if the item is complex, I'll glue up part of it.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.