I’ve been putting glue on both surfaces of parts to be joined since I was knee high to a grasshopper (and that been a while). I’ve recently seen several documentaries and a guitar factory tour in which glue was only applied to only one of the surfaces to be joined; presumbly with good results. What do others do?
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Replies
The only time I apply glue to both surfaces is for mortice and tenons, but I apply the glue more thinly, so the amount of glue is more or less the same.
Rob Millard
http://www.americanfederalperiod.com
According to the techinal service people at the Franklin Co. (Titebond) they say "best results" are obtained by applying glue to both surfaces. I usually follow this rule but the few times I didn't I have had good results. Don't know if this is true for all glues. I basically only use Franklin products
I apply to both sides. Of course there are going to be others who claim to only do one side with no problems. Yet, how each of us perform the task is probably quite variable.
Back many years ago, I did some test to see if I could get satisfactory results, by only applying to one surface by different amounts and wiggling in, / working faster or slower, then breaking the glue-up after 10~ 15 minutes. While there may have been enough to hold the joint together, I could never get a 100% coverage.
I would recommend anyone who cares about their work to do their own test to see what they are actually getting, rather than what they think they are getting.
It is called Quality Control. If 75% or whatever your results yield seems about right for you, well,,,,,,,,,,,,,, all rightie then.
Some woods absorb differently - depending on the surface - sometimes one side is enough - other times I at least wet the other surface with a thin layer of glue -
Quickstep,
Really it depends on what you are gluing and how much glue you apply .There is no one correct answer to this question .
For example , when I make face frames with pocket screws I only apply glue one piece .when I glue a face frame to a cabinet box I also only apply to the face edge of the box .
There are many different beliefs and practices and as long as you get adequate coverage and dry time it is all good .
Personally I apply glue to both sides of my stile and rail frames for doors and such but very carefully so as not to get squeeze out in the wrong place .
regards , dusty
Like you I was taught to do both sides. I adhere to this most of the time but there are times when I only apply to one side. I factor in how much, what type of glue, what type of surface and required open time. I've had ocasions where I did not have time to get (easily) a total two surface coverage and get the joint together. In those cases I did one side and have not had a failure of glue joints ever. Maybe I've been lucky and I have had issues for other reasons, but not glue.
When a teacher in Norway looked at glue squirting out all sides of a clamped joint he asked causticly, how much space do you think is between those boards? I was chastened. Glue cost money and at the time Norway was a poor country.
You hear many things. Should it surprise us that a glue company would tell us to use more?
Peter.
I do both sides because I have always done it that way!
Until a week ago I only did one side applied rather liberally but not to much to avoid heavy squeeze out. A slight rub of dry surface to wet surface before point zero where it would set. You get the feel after many years.
But.. I decided to do two sides (no real reason other than curious) just last week in a glue-up of a top and two shelves. Applied one side moderately thick (wet with back-brush to take any chance of run out of equation).. the other very light as in almost dragging my chip brush to simply wet it.
The results of both methods proved satisfactory as there was a bit more run-out with two sides used. But.. I plan so I am always there between a 2-3 hour period to take it out of clamps and any squeeze-out on either side of the work gets scraped immediately with a flat side of an old hand plane iron. Glue comes off easily at that point where it has hardened but not quite yet set. I put it back in the clamps for another hour generally.
Took several paragraphs to explain how I do something that I don't give the slightest thought too.. I just do it! You get the feel after many years of doing it. ha.. ha...
Not!
That is not a good reason to continue doing so.
As in most woodworking, preparation is 90% of the secret to success with the final product.
For edge gluing you must to have a very good fit between the two boards before the glue is applied, once you have a good fit then very little glue is needed to make the joint and you will only need to apply the glue to one surface.
I test and adjust the fit of my joints by clamping one of the two pieces I am jointing to the apron of my bench, and place the mating board on top of it with a good light behind the joint. When I get at eye level with the seam even a slight mismatch between the edges will show up as light coming through between the boards. I use a plane set to take a very fine cut to adjust the fit until I get to the point where there is no light coming through anywhere along the joint, which means the boards are ready to glue up.
When working with ordinary yellow glue, I dampen the edge of one board with a damp cloth and apply a line of glue along the centerline of the edge. Moistening the edge first keeps the glue from thickening up too quickly allowing me extra time to work.
I use a finger to spread the glue across the width of the edge, I have never found a tool that works half as well as a finger for this purpose. I keep a wet paper towel ready for clean up with once I have finished spreading the glue.
The final step is to moisten the edge of the second board just before closing the joint and placing the assembly in previously set up clamps.
When the wood is properly prepared, it will only take moderate clamp pressure to get a very tight seam with just a tiny bit of glue squeezed out from the joint, a line of tiny pearls should appear along the seam. If any more glue than this squeezes out you have applied too much.
FWIIW I brush a thin layer to both surfaces when I can. My excuse is that the brushing works the glue into the grain and therefore promotes better bonding.
I apply glue both surfaces for edges, and most other joints.
That's what I was taught, and the glue companies(who want me to use more glue) suggest it as well.
Some of this depends on what glue you are using. Over the years I have watched others glue up edge joined boards with what I would say is -- too much glue for my comfort zone. On the other hand, a glue starved seam is a headache.
A couple simple tests I have tried when I am using one of the yellow glues is a simple rub joint with one edge glued. If I don't use much glue and spread it evenly I have found dry spots on one edge when I pull them apart?? Unfortunately, I have not taken the time to put glue on one edge sparingly and clamp them to normal pressure and then pull them apart to check for even spread of the glue on both surfaces. I don't have that much time or curiosity I guess.
I have to watch my yellow glue supply and check the date/age of the stuff. I don't use it very much so it sits around for weeks at a time. I use hot hide for just about all of the work that I do. When its not convenient to heat up the pot, I use Olde Brown Glue from Pat Edwards. Warm it up a little to get the glue nice and thin and you have a glue with lots of time before it sets up.
I am not inviting a debate or putting down yellow glue. It good stuff for the right application and its convenient. It has serious drawbacks for some furniture joinery and its a pain in the a$$ to clean up at times.
Like John White stated: a good clean edge with a nice tight seam is the foundation for a lasting joint.
dan
Dusty
Whats wrong with the backside of your trousers or handherchief? Not scared of SWMBO are we?
wot
Yes, I put glue on both surfaces before gluing up a joint. I remember the old phrase, "now put a little glue" from the New Yankee Workshop. Norm always applied glue to both surfaces, and Norm always had some type of instruction on how to remove squeeze out or how to remove dried glue with a chisel before putting a finish on the project.
Seriously, though, adding glue to both surfaces is maybe not the best or most proper way of gluing up a joint, but in my limited experience as a woodworker, I have never had a joint fail because it was glue starved. (Ha, Ha!) I have had joints fail because of assembly techniques, but not because of the amount of glue used. If I do have a little glue squeeze out, I just wipe it off before it dries with a moist shop towel or rag. I have never had a problem applying a finish and having the glue preventing the finish from penetrating the wood where the glue squeezed out. Maybe I'm just lucky, but like the old saying goes, I'd rather be lucky than good". (Ha)
"The Ladywyfe puts up with
"The Ladywyfe puts up with much , she would like it if we had a sort of a vacuum tunnel I could walk through before entering the house ."
A colleague says that he realised how bad the dust problem was when his wife began following him with a broom, sweeping after him as he walked through the house.
I always apply glue to both surfaces, especially if using hide glue.
I put glue on both sides, then using a notched plastic scraper I spread and wipe off the excess leaving neat rows. The spacing between the notches is important. (Notching the scraper too close leaves too much glue and makes a mess.) After clamping a wet towel to wipe up if needed.
Using my finger is convenient but for me it takes more time and makes more of a mess especially if I'm in production mode... and the glue dries out my skin in this dry season.
Fingers & glue
I've read somewhere that using your finger to spread glue may cause the joint to fail due to the oils in skin. Since reading that, I generally do not spread glue with my finger, prefering instead a spatula.
Popsicle sticks work well as glue spatulas, as do tongue depressors. I square the working ends, however, and wrap the other end with narrow cane, so they take on a Japanese appearance - gluezukis. ;-)
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