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Forum topic by TheGeekPub posted 02-15-2016 03:41 PM 957 views 0 times favorited 15 replies Add to Favorites Watch
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TheGeekPub

13 posts in 405 days


02-15-2016 03:41 PM

Topic tags/keywords: wood glue glue screws joint test

I made a little video over the weekend that created just a ton of controversy on YouTube and Reddit.

I get a lot of comments on my videos about why I chose to use glue instead of screws. My arcade cabinet project is littered with people suggesting I should have “also screwed the cabinet together because the glue alone is not strong enough.”

So I put a test together this weekend to rip some boards apart. Some glued, some screwed. I admit my methods need some refinement. So that is why I am here. If you’re so inclined, please watch this video and then tell me how I could better test this. I know one thing I need to do is come up with a way to shear them apart. What other methods would you recommend to really take this test to the next level?

https://www.youtube.com/watch?v=nW0AmZ9aF70

-- The Geek Pub, Mike Murray, http://www.thegeekpub.com/


15 replies so far

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MadMark

978 posts in 917 days


#1 posted 02-15-2016 04:10 PM

Glue properly set is stronger than the wood itself. People who demand screws are idiots, ignore them.

M

-- Madmark - Madmark2150@yahoo.com Wiretreefarm.com

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Holbs

1377 posts in 1494 days


#2 posted 02-15-2016 04:34 PM

One thing I have learned with the internet… the more “generalized” a site is, the more of the less informed human gene pool. Take a look at LJ’s or other specialized wood working websites with their sharing of knowledge of skills & projects, in regards to replies and comments. As compared to sharing skills via YouTube replies and comments. Enough said :)

Also, screws VS glue debate has been going on since pocket screws became a thing, or dowels, or biscuits. I think it’s more of a personal preference. If I had a heavy load, torque or shearing concern… I will do glue & something else (but also have to consider end product visualization and prettiness) while weighing in rabbets & tenons and other joinery methods.

One thing I’ve never heard about glue vs this or that… 100% of the joint is secured with glue, but the only place secured via screws is that 1 and only spot. Something to think about.

-- Yes, my profile picture is of a Carpenter Bee! The name is derived from the Ancient Greek "wood-cutter"

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Ocelot

1470 posts in 2103 days


#3 posted 02-15-2016 05:18 PM

Sam Maloof used screws in his chairs (with glue).

I don’t know why.

There are several reasons to use both. First, the screw serves as a clamp so in some cases, you don’ t need to clamp the thing, I suppose.

Another is that glues sometimes fail due to wood movement and in such a case, the screw might continue to hold.

Who knows, but I’m pretty sure we shouldn’t call Sam Maloof an idiot.

-Paul

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bondogaposis

4032 posts in 1816 days


#4 posted 02-15-2016 05:40 PM

One way to better test and without the need to measure the results is just to put together a board where one side is screwed and the other side is glued and just see which side fails first.

-- Bondo Gaposis

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TheFridge

5765 posts in 951 days


#5 posted 02-15-2016 06:02 PM

Matthias Wandel of woodgears.ca did a bunch of different strength tests with glues, screws, mortises and tenon, half lap, scarf, dowel, and some others. He is pretty thorough.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

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timbertailor

1592 posts in 889 days


#6 posted 02-15-2016 06:20 PM



Glue properly set is stronger than the wood itself. People who demand screws are idiots, ignore them.

M

- MadMark

Agreed. Today’s glues are stronger than the wood itself.

-- Brad, Texas, https://www.youtube.com/user/tonkatoytruck/feed

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hotbyte

842 posts in 2440 days


#7 posted 02-15-2016 07:10 PM

I say if you want to use glue and no screws, tell the complainers to glue themselves…or something like that :)

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SuperCubber

870 posts in 1749 days


#8 posted 02-15-2016 07:24 PM

Wood Magazine issue 173:

-- Joe | Spartanburg, SC | "To give anything less than your best is to sacrafice the gift." - Steve Prefontaine

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Rick M

7922 posts in 1845 days


#9 posted 02-15-2016 07:54 PM

First let me say, good job on your videos. But looking I didn’t see the controversy you claim to have started. And your arcade video jumps from cutting sheet goods to assembled cabinet so there wasn’t anything to prompt a controversy. I wouldn’t have known you didn’t use screws until now. And cntrl-f searching the page, the word screws doesn’t pop. I completely understand the desire to get more views/subs but since the glue vs screw thing has been done alot, is rarely relevant, and because you were dishonest about the controversy, I’m out. (Shark Tank humor) Putting that aside, I like the way you did the glue test, it was a little bit different.

-- http://thewoodknack.blogspot.com/

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jdh122

879 posts in 2282 days


#10 posted 02-15-2016 08:34 PM


Glue properly set is stronger than the wood itself. People who demand screws are idiots, ignore them.

M

- MadMark

Agreed. Today s glues are stronger than the wood itself.

- timbertailor

Yesterday’s glues (hide glue, at least) are also stronger than the wood itself: http://www.popularwoodworking.com/article/hide-glue-in-liquid-form

-- Jeremy, in the Acadian forests

View mummykicks's profile

mummykicks

85 posts in 1267 days


#11 posted 02-16-2016 01:56 AM

An ideal joint is where there are no differences in strength between the members being joined. If the glued areas are stronger than the wood, it will fail at the boundary between the glued wood and the parent material.
Having said that, I use pocket screws and glue for joints, the screws enable me to dry fit everything, pull the joint closed so I’m not scrambling for clamps before it sets, and gives some insurance for the unlikely glue failure event,

View chiseler's profile

chiseler

121 posts in 353 days


#12 posted 02-16-2016 02:09 AM



Sam Maloof used screws in his chairs (with glue).

I don t know why.

There are several reasons to use both. First, the screw serves as a clamp so in some cases, you don t need to clamp the thing, I suppose.

Another is that glues sometimes fail due to wood movement and in such a case, the screw might continue to hold.

Who knows, but I m pretty sure we shouldn t call Sam Maloof an idiot.

-Paul

- Ocelot


chairs have to deal with more abuse due to constant racking and I believe the screws are there in case the glue does fail.There is a time and place for them.I’m from the the school that if you have a good fitting joint all you need is glue and clamps (and maybe a strategically located peg :)

-- Scott.Triangle,NY Becareful and don't forget...They cut meat too!

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oldnovice

5730 posts in 2832 days


#13 posted 02-16-2016 06:51 AM

I have two problem with your test.

Your base sample was one piece of what looked to be 2×2 but your first “glue test” piece doubled the thickness in the glued area.

  1. In my opinion, a more valid test would have been two 1×2 glued fully length wise to be the same thickness as your base piece and the same holds true for testing screwed test piece.
  2. Secondly, glue doesn’t hold up well under shock not the kind of strees you applied!

Now, don’t get me wrong I agree with your basic assesment; after all, the call the glue lams not screw lams!

-- "I never met a board I didn't like!"

View Tennessee's profile

Tennessee

2410 posts in 1979 days


#14 posted 02-16-2016 12:45 PM

From my perspective, we already know that a glued joint will become stronger than the wood itself.
Your test proved that, since no board broke right at the glue line.

Screws, on the other hand, tend to fail where they make contact with the wood.

So which is stronger? Having worked in the furniture industry for a while, making upholstered furniture and chairs, almost all sofa frames are glued with some simple air staples to hold the joint while the glue dries. They KNOW that the glue is stronger than the wood.

Whenever I would get over to the return area, where they made repairs, almost universally the wood would be broken, not the glue joint, unless some idiot on the line put in too many staples in the glued joint, weakening it.

Chairs use glue wherever they can, and then screws are often used where the racking occurs like in corner braces, as Scott said. This is not true for some colonial and american style chairs with lots of spindles that are glued into the chair seat, etc., but that is from necessity of style.

I think to do a fair test, you have to design two tests, same wood species, same plank if possible, and do a shear test where you demonstrate shock perpendicular to the grain faces secured, (glued and then screwed), and a stress test, where you add ever increasing steady stress to the joint.

Your test was basically a test of how strong the boards themselves were since they were holding the pieces behind the trees.

-- Paul, Tennessee, http://www.tsunamiguitars.com

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8iowa

1546 posts in 3226 days


#15 posted 02-16-2016 01:03 PM

I use both screws and glue, and even occasionally biscuits. Wood has far greater movement across the grain than with.

If the joint has the grain running the same direction, thus expanding and contracting together, a glue joint will last forever. If it’s a high stress area, biscuits might give you a little more confidence in the integrity of the joint.

The problem arises whenever a joint has the grain in opposition. Over time, a glue joint might fail. Screws make a lot of sense in this instance.

-- "Heaven is North of the Bridge"

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