Monday, October 27, 2014

Glue

There is one thing about glue.  Eventually it will fail.

Sure there are things hide-glue together STILL together found in Egyptian pyramids after 4000 years, but those items were also not touched.  I dare say a glue ejector left in a dry gunsafe with little temperature variations would also fare that well. 

Hide glue is made from animal skin and bone.  A protein based glue.  Apply a bit of steam and you dissassemble the joint

Modern wood glues?  Elmers.  Polyvinyl white glue.  "The glue joint is stronger than the wood"  as the old saying and commercial goes.  Of course it does still always fail next to the joint when they show that in action... 

So, a dresser drawer is glued at the joint.  But the glue will fail.  A cheap dresser drawer has simple 'mechanical' joints holding it together.  A butt joint is just glue holding it together.  A dado joint has a groove one board fits into on another and is slightly better.  Finger joints try to maximize surface area that the glue is in contact with and ensure there is less end-gran to the flat grain contact which is inherently weak.  But if you store something like shotputs in your dresser everytime you open the drawer they impact the back of the drawer and hammer it apart over time.   Same thing happens with lighter material than iron spheres, but it takes longer to hammer apart.

The best is a dovetail joint.   Those little wedged fingers mechanically hold the two boards together in one direction even without glue (so it will last longer with those shot puts, even without glue).  But a dovetail joint also has a lot of surface area contact for the glue to be attached too, just like the finger joint. 

Why not pin a wooden joint with a bit of metal?  A screw, an nail, a rod?  Dissimilar materials can give you problems later.  You've seen nails work their way loose over the years, right?

But we aren't concerned with wooden drawers.  We are concerned with things glued onto GUNS.  And I've been talking about the ejector on the 1911 lately.

Glue the ejector in place only is sorta like the dado joint.  The part does have those legs entering the frame, so some mechanical advantage is there.  They could have filed those off and just glued a flat ejector in place, and that would work for a few rounds...  But it's not as strong as glue-plus-stake.  That is more of a 'dovetail joint'.   Glue, plus 'legs', plus a pin holding the legs down.  Ideal.   This combination will see longest time to failure.  But is it just suspenders and a belt?  Why not just glue? 

Well, there is the heat from firing.  Really?  Is it that much heat?  Well, it'd be worse if it was glued to the barrel, certainly.  You've gotten fired brass down your collar, right?  At least the brass had three feet of air time to start to cool, the ejector is RIGHT THERE....  Yeah, but...  And steel doesn't conduct heat as much as other things.  Like brass or copper or aluminum.  Heat doesn't 'travel' down the metal as easy via conduction with iron based items.  But it still heats.  The case still impacts.  Impact/heat/begin-cooling every time you fire.  A little bit.  Vibration, impact and a bit of heat expansion.  Plus solvents when the pistol is cleaned...  Even glues that need to heat to break the joint are gonna fail.  Not like they would with a blowtorch and tools yanking on it, but fail, the glue will (/yoda).

But when?  If after 100 rounds that is unacceptible.  If after 10,000 rounds?  Well that's a lot less to worry about. 

So...  what glue was used to lock down the ejector?  The gunsmith thought it was 'Loctite Black' or equivalent.  What the hell is that?  Well it ain't Elmer's wood glue.  Loctite is a company brand name for a product that was originally designed to lock the threads of a machine bolt or screw so they wouldn't come loose.  They have more products now and a plethora of adhesives for all sorts of applications.  A basic gunsmith toolkit might include Loctite Red, Blue, and 'Black'. 

Loctite Red #271.  It's for the threads of something you screw on and never intend to unscrew.  To unscrew you will almost definitely need to heat the area to break the seal.  500 degrees farenheit.    It is... red in color.  Surprise.  The color makes it harder to screw up when you grab a bottle.  Good for the attaching the grip panel bushings to the frame. 

Loctite Blue #242.  Another thread locker but not as strong as Red.  You can still disassemble this with just tools after use, and not a touch of flame.  So you attach the bushings to the frame with Red, and the screws holding on the grip with Blue.  Not the other way around.  You do it the other way and then go to unscrew the grip screws and you just undo the bushings and it's a pain to get the bushings off the screwtips at that point. 

Another tip!  Don't fail to put Red on the bushings then Blue on the screws.  Same things happens at disassambly with a slightly easier problem to tackle gettin the bushings parted from the screw.  And a warning...  Springfield owners.  Springfield is known to pin the bushing to the frame mechanically.  So if you remove the bushing you might just mung up the frame.  As long as you don't mung up the frame this can be a good thing, havign them pinned, as they are in there pretty good.  If you do mung up the frame, adding metal to the hole and then retapping it for the screws is a PITA.  So removing the bushing to put Red on them is even more problematic.  What do you do if you don't know if they are pinned and don't want to risk removing your factory installed bushings?  Well, it's a pain to remove a normal bushing locked on a screw with Loctite Blue, but it's not that bad, all things considered.

Loctite 'Black' #480.  Used in parts assembly.  Requires less heat (100 degrees Celsius instead of 260 C, if I am reading the spec sheets right.) to break free than Red, but is for a part that you don't normally take apart.  Sort of a 'gentler' Red.  Other application for 1911s? Assembling the plunger tube to the frame before you stake THAT on there.  Note... not really a THREAD locker, per se.   Thread lockers are kinda thin, but they don't expect to have to hold across a big gap.  Male-female mate pretty closely with screw threads.  Loctite Black is more of a gelled superglue.  And is pretty cool!  I like super glue that stick like a gel to things.

To clairfy.  Loctite Black is just a nice rubberized super glue.  Cyanoacrylate family.

So, Springfield determined that this glue is good enough for a gun in one of their budget lines.  And I am sure it is for most users.  It'll be decades before it is a problem with most users, maybe.   I get that.  It the same impulse that puts $5 mags in with it instead of $20 magazines.  They can cut the price $30 that way.  I just want a Performance Center gun that I initially paid the GI Standard price for.  Everyone wants to maximize value while minimizing outlays.  And I took the chance of getting an improvement for free because the gunsmith I took a class from said Springfield has added the staking in the past for free.  Not so lucky, me.  Oh, they'll do it for me if I pay them.  It might even be a cheap procedure in itself (I didn't ask).  But the cost adds up when you consider shipping costs, so... That's why I am looking to perhaps doing this myself with proper adult supervision.  Also, to go over the types of adhesives, what they are good for, and share with you my blog readers.  Maybe do a service, thusly.

"If you want a Performance Center Gun (that always comes staked, btw) T-Bolt, just suck it up and pay for it!  You're gonna pay for it in the end anyway just nickel and diming yourself with parts and occasional professional gunsmith shop service"

Yeah, but then I wouldn't have all this fun with it, learning.  It's not like the gun isn't a gun now.   It functions just fine.   Plus I kid myself that I am saving money putting in my own sweat equity (I am paying a LOT of money learning how to put in my own sweat equity, you see...)

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One other thing.  Another nod to Springfield just gluing:  "John Moses Browning staked em, so that must be the way to go.  Who am I and who is Springfield to go against HIM?!"  Well, glues like this are MUCH better today than they were 100 years ago...  Ideally you pin and BRAZE the part on, but even JMB would blanch at that labor, and time, and skill-intensive industrial assembly option.

2 comments:

Tam said...

Well, hey, you've got it all figured out. :)

New Jovian Thunderbolt said...

Ugh. 'Orrid proofreading job. I really shouldn't be allowed to post anything without running it by an editor. You'd think I'd learn.

English? Do I speak it?