Wicking grade Loctite

[4th_point]

Yes, I can, and will, but I don’t think that’s as accurate of a measurement as initial torque setting. Anyway, I just assembled a set a few minutes ago. Will report back after 24hrs cure time.

It's a valid measurement. Your gauge might not be accurate though.

 

[SDHNTR]

It's a valid measurement. Your gauge might not be accurate though.

I have a Proto inch pound driver. It’s a good one and recently certified.

 

[SDHNTR]

As I suspected, this concept of “breakaway torque” escapes me and I was not able to measure it. At least not in the same way or to the same degree of accuracy as setting initial torque, and/or not with my particular torque driver. I did try though.

To test unscrewing resistance I set the driver to #20 expecting it to slip, since I set initial torque at 25. The screws came right out at 20 with no slipping. And it’s obvious the Loctite wicked about 1/8” up into the threads. I still deem this method successful as it’s obvious the Loctite is sealing the threads, the jury is just still out on “break away” torque and I will readily admit I’m no engineer and don’t claim to have any understanding of the actual physics involved with unscrewing things.

 

[4th_point]

I have worked in research and product development as an engineer, and assure you that breakaway torque is real and used.

A beam-type gauge is very intuitive, and allows you to "see" the torque applied. Some clickers are not repeatable. Some of the worst that I have used are very expensive and made by well known, reputable brands.

 

[4th_point]

I would just slather the fastener threads with the glue of your choice and torque. For base screws primarily, as they are difficult/inconvenient to inspect. I wouldn't bother with the ring caps as they are easy to inspect. If they are loosening, then there might some other issue.

My only issue is when seemingly helpful people regurgitate false information as the gospel... like "Loctite doesn't affect torque". Well, yeah. Torque is torque. The clamp load can change though. Whether it matters depends on the application.

 

[RockAndSage]

As I suspected, this concept of “breakaway torque” escapes me and I was not able to measure it. At least not in the same way or to the same degree of accuracy as setting initial torque, and/or not with my particular torque driver. I did try though.

To test unscrewing resistance I set the driver to #20 expecting it to slip, since I set initial torque at 25. The screws came right out at 20 with no slipping. And it’s obvious the Loctite wicked about 1/8” up into the threads. I still deem this method successful as it’s obvious the Loctite is sealing the threads, the jury is just still out on “break away” torque and I will readily admit I’m no engineer and don’t claim to have any understanding of the actual physics involved with unscrewing things.

Good information to see, thanks for sharing. They do list the 290 as being a variant you can disassemble with hand-tools, but also list it as "may need heat" in some circumstances. But based on what you've shared it looks good to go. The heat situations are probably for larger fasteners, maybe sitting for much longer periods of time.

 

[RockAndSage]

I have worked in research and product development as an engineer, and assure you that breakaway torque is real and used.

A beam-type gauge is very intuitive, and allows you to "see" the torque applied. Some clickers are not repeatable. Some of the worst that I have used are very expensive and made by well known, reputable brands.

This convo caused me to dig into some technical data sheets at Henkel, the company that puts out Loctite. It was extremely interesting. They use M10 bolts as a standardized platform for gauging breakaway torque.

The TDS for the Loctite 290 lists breakaway torque at 90 inch-pounds, after curing for 24hrs at temps of 22C/72F.

The TDS for the other common green threadlocker, Loctite 294, shows it being a lot more substantial, listing breakaway torque at 290 inch-pounds.

M10 bolts are quite a bit bigger than scope ring fasteners, and based on the OP's experiments it indicates the much smaller surface area means less breakaway torque, but the difference between the two variants of Loctite was very interesting.

OP, they list 290 and 294 as being ideal for application to already-assembled fasteners. The whole issue of wet-torque vs dry torque goes away with your idea of using the 290. They also mention that the 294 will still work even in the presence of some degree of oils, and that both work in sealing up porosities in metal.

Here's the overview of 290

Here's the overview of 294

 

[SDHNTR]

This convo caused me to dig into some technical data sheets at Henkel, the company that puts out Loctite. It was extremely interesting. They use M10 bolts as a standardized platform for gauging breakaway torque.

The TDS for the Loctite 290 lists breakaway torque at 90 inch-pounds, after curing for 24hrs at temps of 22C/72F.

The TDS for the other common green threadlocker, Loctite 294, shows it being a lot more substantial, listing breakaway torque at 290 inch-pounds.

M10 bolts are quite a bit bigger than scope ring fasteners, and based on the OP's experiments it indicates the much smaller surface area means less breakaway torque, but the difference between the two variants of Loctite was very interesting.

OP, they list 290 and 294 as being ideal for application to already-assembled fasteners. The whole issue of wet-torque vs dry torque goes away with your idea of using the 290. They also mention that the 294 will still work even in the presence of some degree of oils, and that both work in sealing up porosities in metal.

Here's the overview of 290

Here's the overview of 294

What do they list as breakaway torque for standard blue 243? That’s what I have used for many years. Subjectively, 290 wicked in and cured for 24 + hours, felt maybe slightly more difficult to unscrew than blue 243 applied in the traditional manner. But not by much. Curious to see if the published numbers substantiate that notion.

 

[RockAndSage]

What do they list as breakaway torque for standard blue 243? That’s what I have used for many years. Subjectively, 290 wicked in and cured for 24 + hours, felt maybe slightly more difficult to unscrew than blue 243 applied in the traditional manner. But not by much. Curious to see if the published numbers substantiate that notion.

Interesting...the closest apples-to-apples comparison for the Loctite 243 is a 72hr cure on slightly different M10 steel bolts, but it's showing 230 inch-pounds. However, it also shows specs for M6 bolts, which are much smaller than M10s and closer to what you might find on a gun. Breakaway torque is listed as 26 inch-pounds.

 

[Macintosh]

Everyone always worries about the additional
clamping force from using loctite compared to dry…but the screws come slathered in oil that Im quite certain 99% of people dont remove. It seems intuitive to me that the clamping force between same torque value applied to a loctited screw, versus a oil-covered screw right out of the packaging, might not be that different since they are both lubricated. Is “dry torque” assuming a degreased screw, or do the screws out if the packaging with visible oil on them actually count as “dry”?

 

[Choupique]

Is “dry torque” assuming a degreased screw

Yes. Totally dry.

 

[Macintosh]

Ok, so then if the screws out of the box are also in effect lubricated, shouldnt we be worried about comparing to the increase in clamping force from loctited screws compared to themj? No one seems to worry about scope damage resulting from torquing the screws right out of the box? I understand its probably hard to quantify because theres probably considerable variation, but that only reinforces the direction Im going…is this all (all=worrying about wet vs dry torque from using loctite) much ado about not much?

 

[mt terry d]

I just tack weld them.

 

[Choupique]

is this all (all=worrying about wet vs dry torque from using loctite) much ado about not much?

Yes. Just torque them to whatever.

If you REALLY want to do this right, you have to degrease the hole, degrease the screw, have a wrench that is actually calibrated and repeatable. Few people do all that. Just torque them to what the manufacturer says and worry about something else.

 

[SDHNTR]

Ok, so then if the screws out of the box are also in effect lubricated, shouldnt we be worried about comparing to the increase in clamping force from loctited screws compared to themj? No one seems to worry about scope damage resulting from torquing the screws right out of the box? I understand its probably hard to quantify because theres probably considerable variation, but that only reinforces the direction Im going…is this all (all=worrying about wet vs dry torque from using loctite) much ado about not much?

Valid point. Which is probably why after dozens and dozens of times, I’ve never damaged a scope after putting Loctite on ring screws

 

[4th_point]

I believe that Burris actually recommends light oil be applied to the threads.

 

[4th_point]

Also, 242 adheres really well to screw threads, even with light oil used for storage. I think that was mentioned earlier in the thread. I don't care about the oil. I take a few moments to clean off the corrosion but even when I haven't there has always been hardened residue in the threads. Can sometimes be a pain in the neck to remove!

 

[SDHNTR]

Also, 242 adheres really well to screw threads, even with light oil used for storage. I think that was mentioned earlier in the thread. I don't care about the oil. I take a few moments to clean off the corrosion but even when I haven't there has always been hardened residue in the threads. Can sometimes be a pain in the neck to remove!

FYI, 243 is the oil resistant version. 242 can get compromised by oil. I’ve seen it fail to cure due to oil, and I’ve seen cured turned gummy by oil.

 

[4th_point]

FYI, 243 is the oil resistant version. 242 can get compromised by oil. I’ve seen it fail to cure due to oil, and I’ve seen cured turned gummy by oil.

I worked for a company that designs and manufacturers industrial machinery. We never had an issue with 242 and used a ton of it. 243 might be better, but we thoroughly tested 242, and every other chemical, before approving it for use on machinery.

 

[SDHNTR]

I worked for a company that designs and manufacturers industrial machinery. We never had an issue with 242 and used a ton of it. 243 might be better, but we thoroughly tested 242, and every other chemical, before approving it for use on machinery.

To be fair, oil may not have been the exact culprit and it could have been some typical gun cleaning solvent. Or even a bad batch of loctite. But twice I’ve seen 242 get weird on me, assumed it was oil. Never an issue with 243.