Found this info on Loctite for gun screws.

michael sr.

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Loctite® and Gun Screws.

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Hello. The purpose of this thread is to shead some light on the use of LOCTITE® and Gun Screws.

I believe we'll all agree that the common gun screw is well under 1/4" in Diameter. So let's take a look at what LOCTITE® has to offer for screws up to 1/4" in diameter.

First, theres Blue No. 220, but, it's a wicking grade thread locker for pre-assembled fasteners up to 1/4" Dia., so, it's pretty much out for gun use.

Second, theres Purple No. 222 for fasteners up to 1/4" Dia., but, it doesn't meet certain agency approvals such as MIL-S, ASTM D, Ect..

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Third & Thankfully, there's PURPLE*** No. 222MS, it's an easy removal thread locker designed for fasteners up to 1/4" Dia., and, 222MS meets the approvals of many different agencies including MIL-S.

So, going by the LOCTITE® Catalog, it sure looks like PURPLE*** No. 222MS was specifically designed for fasteners up to 1/4" Dia. and is the best suited thread locker that they offer for small gun screws.

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What makes the Purple No. 222MS so much better for small gun screws? Well, it's viscosity was designed for small screws & threads (it stays in the threads during assembly), it's easily removalable (so it's helps save your screw driver tips, screw heads & threads), not to mention it was specifically designed for small screws that's under 1/4" in Diameter.

Clean & Dry your parts well, and always Use a primer when "both" surfaces are considered inactive, ie. Plated Parts, Anodized Aluminum, Titanium, Stainless Steel, Galvanized Steel, Zinc, Pure Aluminum, Cadmium, Magnesium, Natural or Chemical Black Oxide, Magnetite Steel, Iconel, Silver, Gold & Plastics.

Active Metals are considered to be, Iron, Plain Steel, Copper, Brass, Commerical Aluminum, ie. T 6061, Bronze, Nickel, Maganese, Monel & Kovar.

LOCTITE® 7471 Primer T has a 7 day on-part-life, and LOCTITE® 7649 Primer N has a 30 day on-part-life and is Ideal for cure conditions below room temperature. So, if it's room temp or above and your gonna install your screws in 7 days or less, use 7471 Primer T, and if your in colder areas use 7649 Primer N.
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*** TRIED 3 X'S TO CHANGE FONT COLOR...NO LUCK! :O(
 
Re: Found this info on Loctite for gun screws.

Good info. Haven't heard of the <span style="color: #993399">Purple</span> stuff, and used to only work with <span style="color: #FF0000">Red</span> and <span style="color: #33CCFF">Blue</span> and <span style="color: #33CC00">Green</span>, for liquids. Various different numbers, but the categories are the same.
That was in/for Heavy Industry though. I've never used Loctite on any firearms, yet.

Be sure to have what you want tinted "Highlighted" for when you choose your color. Hope that helps.

 
Re: Found this info on Loctite for gun screws.

Interesting information.

I see screws in laptops working loose all the time.
They are typically 2mm-3mm diameter screws with blue threadlocker.

Sounds like the makers need to consider using purple instead of blue.
 
Re: Found this info on Loctite for gun screws.

From Loctite:

Industrial Threadlockers By The Colors:

Blue - Medium Strength, Removable
Green - Wicking Grade
Purple - Low Strength, Small Threads
Red - High Strength, Permanent

Then there's consumer grade Loctite, as found in big box stores:

Blue #242 - removeable with hand tools
Green #290 - Localized heating and hand tools are needed for disassembly.
Red #271 - can only be removed with explosives or by heating up parts to 500°F (260°C).
 
Re: Found this info on Loctite for gun screws.

Why is Blue locktite in a <span style="font-weight: bold">RED </span> tube ? And Red locktite in a <span style="font-weight: bold"> BLUE</span> tube ?
 
Re: Found this info on Loctite for gun screws.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sullybr549</div><div class="ubbcode-body">Why is Blue locktite in a <span style="font-weight: bold">RED </span> tube ? And Red locktite in a <span style="font-weight: bold"> BLUE</span> tube ? </div></div>

Always wondered that myself. If you make that mistake, it usually only happens once.