For those that want to know things....
- Thread starter Dave38
- Start date
Back when I was a machinist and inspecting my materials there were various height tooled steel blocks. Taking 2, rubbing and pressing the air out of the contacted surface, nobody was able to pull those apart 90 degree from it's face. One had to twist (shear) it apart.
Now add a just little glue to those surfaces to keep air from infiltrating... not gonna pull it apart.
Adding tooth to surfaces allows trapped air and that's a weak point. IF you're lucky enough to fill all those scratches with glue, it's bonded.
Now add a just little glue to those surfaces to keep air from infiltrating... not gonna pull it apart.
Adding tooth to surfaces allows trapped air and that's a weak point. IF you're lucky enough to fill all those scratches with glue, it's bonded.
DeeDeeCues
Well-known member
That is called 'wringing' and it is based on the smoothness of the face and having a thin coating of oil. Definitely doesn't relate to gluing. Might seem like it should relate, but it doesn't.
The reason some surfaces must be slightly roughened for glue is based on the surface tension of the material.
My point was, less glue makes a better bond since glue keeps air from separating objects, as per your oil point.
There wasn't any oil, not even from our hands. They were well wiped with no lint rags. A spec of dust interferes with 0.0005 tolerances.
We'd take the same blocks and slide it on the granite inspection table. It did so on a very fine layer of air for several feet, again, no oil. When the air ran out, that block was seemingly bonded. We had to slide (sheer) that block to the tables edge to pick it up.
Roughening gives glue a 'tooth'.
Doesn't relate to gluing? In away it does, by creating and maintaining the absence of air.
Everyone has different explanations & opinions, I'm simply relating my various experiences to this billiards venue. MAYBE someone else would chime in and we would find a better solution to other 'X' issue(s).
There wasn't any oil, not even from our hands. They were well wiped with no lint rags. A spec of dust interferes with 0.0005 tolerances.
We'd take the same blocks and slide it on the granite inspection table. It did so on a very fine layer of air for several feet, again, no oil. When the air ran out, that block was seemingly bonded. We had to slide (sheer) that block to the tables edge to pick it up.
Roughening gives glue a 'tooth'.
Doesn't relate to gluing? In away it does, by creating and maintaining the absence of air.
Everyone has different explanations & opinions, I'm simply relating my various experiences to this billiards venue. MAYBE someone else would chime in and we would find a better solution to other 'X' issue(s).
Last edited:
Jo blocks ... named after Carl Edvard Johansson who first developed the blocks.
And they also stick together due to surface tension of the oil in the wring film.
An interesting video that shows wringing with/without oil and/or air.
Now back to glue ...
Dave
YES that's what they are. Over the decades I forgot the TECH terms.
OK...
Another one from Jr. High School... tho in Chicago's Museum of Science & Industry there were 2 HUGE stainless steel balls hung that showed the below gravitational effect of non-magnetic MASS.