Panther6834
Active Member
I know I'm a new member to this forum, but I was unable to find any "general" thread dedicated to this subject...so, I thought I'd add my 4-cents-worth, and create one. I have come across several threads that reference threadlock, asking about 'this' or 'that'...but no threads specific to the different types of threadlock, and what, exactly, their uses are. For the greatest part, most people seem to think there's only 'blue' & 'red', with some knowing about 'purple'...but, there ARE others. Additionally, I've seen some "confusion" (in this forum, as well as others) about 'green' threadlock vs retaining compound.
I'll start with 'green', as Loctite produces two completely different 'green' fluid, with two completely different uses. 'Green' threadlock, such as Loctite 290, is a wicking threadlocker. It is thinner than most of the other threadlockers, and can be used on already-assembled parts (as long as they are vertical, so that the threadlock can "seep" downward). In some sense, it's a low-strength threadlock, because it requires the lowest amount of torque to release it...yet, at the same time, it's also a high-strength threadlock, because it has a high "holding strength" (not as high as 'red', but higher than 'blue'). And, believe it, or not, 'green' DOES have usefulness in RC - specifically, seating bearings. Some parts where bearings are pressed into place hold those bearings very easily, while others have such a "loose" grip that the bearings can easily fall out. For parts falling into that second group, taking a Q-Tip, and running a light coat of 'green' threadlock around the outside edge is the solution. This will not only allow the parts "holding" the bearings to have a better hold, but will also make it easier to insert the bearings. Just be careful to not get ANY of the threadlock onto the bearing's seal/racer, as that could potentially lead to internal "resistance" (it won't "seize", but could cause problems).
At the other end of the spectrum is Loctite 638 & 680, both of which are 'green', but are NOT threadlock...they are retaining compounds, and will PERMANENTLY bond metal-to-metal. If you think 'red' threadlock is strong, you ain't seen nothing. Technically, 'red' is NOT permanent...with enough heat & torque, it can easily be removed. It's most common use is in automotive & motorcycle applications. Loctite 638 & 680 are something I use in RC boats, such as when bonding two different tubes together to create a non-Teflon-lined stuffing tube. In normal RC applications (such as cars & trucks), my suggestion/recommendation is to NEVER use retaining compound.
With 'green' taken care of, it's time to move onto the next three...namely 'blue', 'red', and 'purple'. I don't think much needs to be said about 'blue' & 'red', as almost all RCers are quite familiar with both - 'blue' is (obviously) the standard "go to" for metal-on-metal, while 'red' is for those times when you're 110% certain you won't have any need to disassemble the parts in question. Put another way, 'blue' is your "BFF", and 'red' is that "friend" you only call upon when absolutely necessary. Below 'blue' is 'purple', which has a holding strength about half that of 'blue'. Personally, I don't know any RCers who use 'people'...and, honestly, I'd never recommend using it. I got back into RC approx 10-12 years ago (after a 35-40yr absence), and in that time, I've never used 'purple', and I don't personally know anyone what who uses it.
Now, we get to the "good stuff"...and, the primary reason I'm posting this whole thing. There are times when 'blue' isn't strong enough, and 'red' is overkill (especially for speed run cars...which, I'll admit, I'm new too, having built only one (a 4Tec 3.0 Corvette-based car), and just about to start building my second (Lim V2)). So, what do you do? Do you use 'blue' (maybe even an excessive amount), and "hope for the best"? Do you use 'red', even though you know removing it will be somewhere between "a PitA" & "impossible"...or, even worse, destroying parts in attempting to disassemble? The answer is "NO"...as, there IS a better solution. While Loctite doesn't have anything between these 'blue' & 'red', Permatex DOES: 'orange'. The great thing about 'orange' is that it has the general "holding strength" of 'red', but does NOT require heat to release. Yes, it does require greater torque to release than 'blue', but nowhere near as high as 'red'...in other words, it can be released by hand tools. For anything that's needing the strength of 'red', but requiring occasional disassembly (grub screws for spur/pinion gears, outdrives, motor mounts onto the chassis, etc), maybe it's time to starting thinking of 'orange' as your "second best friend" - the strength of 'red', combined with the removability of 'blue'.
I'll start with 'green', as Loctite produces two completely different 'green' fluid, with two completely different uses. 'Green' threadlock, such as Loctite 290, is a wicking threadlocker. It is thinner than most of the other threadlockers, and can be used on already-assembled parts (as long as they are vertical, so that the threadlock can "seep" downward). In some sense, it's a low-strength threadlock, because it requires the lowest amount of torque to release it...yet, at the same time, it's also a high-strength threadlock, because it has a high "holding strength" (not as high as 'red', but higher than 'blue'). And, believe it, or not, 'green' DOES have usefulness in RC - specifically, seating bearings. Some parts where bearings are pressed into place hold those bearings very easily, while others have such a "loose" grip that the bearings can easily fall out. For parts falling into that second group, taking a Q-Tip, and running a light coat of 'green' threadlock around the outside edge is the solution. This will not only allow the parts "holding" the bearings to have a better hold, but will also make it easier to insert the bearings. Just be careful to not get ANY of the threadlock onto the bearing's seal/racer, as that could potentially lead to internal "resistance" (it won't "seize", but could cause problems).
At the other end of the spectrum is Loctite 638 & 680, both of which are 'green', but are NOT threadlock...they are retaining compounds, and will PERMANENTLY bond metal-to-metal. If you think 'red' threadlock is strong, you ain't seen nothing. Technically, 'red' is NOT permanent...with enough heat & torque, it can easily be removed. It's most common use is in automotive & motorcycle applications. Loctite 638 & 680 are something I use in RC boats, such as when bonding two different tubes together to create a non-Teflon-lined stuffing tube. In normal RC applications (such as cars & trucks), my suggestion/recommendation is to NEVER use retaining compound.
With 'green' taken care of, it's time to move onto the next three...namely 'blue', 'red', and 'purple'. I don't think much needs to be said about 'blue' & 'red', as almost all RCers are quite familiar with both - 'blue' is (obviously) the standard "go to" for metal-on-metal, while 'red' is for those times when you're 110% certain you won't have any need to disassemble the parts in question. Put another way, 'blue' is your "BFF", and 'red' is that "friend" you only call upon when absolutely necessary. Below 'blue' is 'purple', which has a holding strength about half that of 'blue'. Personally, I don't know any RCers who use 'people'...and, honestly, I'd never recommend using it. I got back into RC approx 10-12 years ago (after a 35-40yr absence), and in that time, I've never used 'purple', and I don't personally know anyone what who uses it.
Now, we get to the "good stuff"...and, the primary reason I'm posting this whole thing. There are times when 'blue' isn't strong enough, and 'red' is overkill (especially for speed run cars...which, I'll admit, I'm new too, having built only one (a 4Tec 3.0 Corvette-based car), and just about to start building my second (Lim V2)). So, what do you do? Do you use 'blue' (maybe even an excessive amount), and "hope for the best"? Do you use 'red', even though you know removing it will be somewhere between "a PitA" & "impossible"...or, even worse, destroying parts in attempting to disassemble? The answer is "NO"...as, there IS a better solution. While Loctite doesn't have anything between these 'blue' & 'red', Permatex DOES: 'orange'. The great thing about 'orange' is that it has the general "holding strength" of 'red', but does NOT require heat to release. Yes, it does require greater torque to release than 'blue', but nowhere near as high as 'red'...in other words, it can be released by hand tools. For anything that's needing the strength of 'red', but requiring occasional disassembly (grub screws for spur/pinion gears, outdrives, motor mounts onto the chassis, etc), maybe it's time to starting thinking of 'orange' as your "second best friend" - the strength of 'red', combined with the removability of 'blue'.
