Will Green Loctite Damage Cree XP-G?

[ti-force]

Datasheet shows that vapors from blue Loctite could be harmful to the emitter, but what about green loctite? I need it to seal two head halves together. Anyone had good results with something else that's widely available?

Thanks!

 

[CKOD]

What sort of joint do you have? is it threaded? or just a slip-joint you want to secure? Either way I'd be leery of green also, this just being a SWAG, the green is thinner, so could have more solvent in it which could be what's damaging the LED. If you want to be able to get the joint apart (since you're not mentioning red loctite...) I'd go with a dab of JB weld or other 2 part epoxy thats low solvent. Not a ton, just enough that you should be able to sheer it apart later if you want to.

 

[ti-force]

What sort of joint do you have? is it threaded? or just a slip-joint you want to secure? Either way I'd be leery of green also, this just being a SWAG, the green is thinner, so could have more solvent in it which could be what's damaging the LED. If you want to be able to get the joint apart (since you're not mentioning red loctite...) I'd go with a dab of JB weld or other 2 part epoxy thats low solvent. Not a ton, just enough that you should be able to sheer it apart later if you want to.

The joint is threaded, and you're right, I don't want to lock it down for good ; you never know. My main concern is keeping the head from separating under normal use, and sealing the joint so it's waterproof. Have you had good results with a particular brand of epoxy? Thanks!

 

[CKOD]

Nosying though the datasheets, they all seem to have Polyglycol dimethacrylate, but the blue loctite has Propylene glycol listed in the MSDS, and red and green dont. The cree pdf listing all the bad stuff for the LED's lists Glycol ethers, but plain propylene glycol isnt an ether. The loctite 384 adheisve listed as a nono also, has propylene glycol in it too, but also other methacrylates also. I suspect if the methacrylates were the issue they would have just said no to loctite, period, so the green may be viable. But I'd be nice to hear what people have had luck with in real life. I mean propylene glycol doesnt seem too likely to turn to vapor and craze an LED (if that is indeed what it's sensitive too), its vapor pressure is pretty low at room temp.

Dow Corning 1-2577 in their recommended conformal coatings list is 15-35% toluene, which is listed as a bad thing in the same section. And quite a few of the other recommended coatings have strong solvents in them, so I'm now at more of a loss then when I started.

Any chemists in the house?

 

[ti-force]

Hahaha...... Indeed it does get crazy sometimes in this hobby . Thanks for taking the time to help :thumbsup:.

 

[qwertyydude]

I red loc-tited all the led flashlights I gifted to friends and family no crazing or led failures or even hazy deposits to date. I can't even say that about most heatsink compounds. The cheaper one's develop a fogging in the lenses of lights. It's why I use arctic silver 5 it has the most solids with the least oils to evaporate.

 

[nailbender]

Hi

Permatex makes a medium strength thread locker that is a gel, I use it on modules and the gel stays where you put it. You twist the dispenser sort of like chap stick or something.

I have never had any trouble with it and it doesn't have the caustic fumes of some of the red permanent thread lockers.

You can get it at McMaster-Carr

 

[ti-force]

Thanks for the info everyone. Nailbender, is the stuff in the following link what you're talking about? Thanks!

http://www.autozone.com/autozone/ac...er/_/N-25obZ1z141rv?itemIdentifier=34493_0_0_

 

[nailbender]

Thanks for the info everyone. Nailbender, is the stuff in the following link what you're talking about? Thanks!

http://www.autozone.com/autozone/ac...er/_/N-25obZ1z141rv?itemIdentifier=34493_0_0_

Hi

That is it.
If you get it on something you don't want it on it wipes off pretty easy and alcohol cuts it well also. It works well because it doesn't drip.

Dave

 

[ti-force]

Hi

That is it.
If you get it on something you don't want it on it wipes off pretty easy and alcohol cuts it well also. It works well because it doesn't drip.

Dave

SWEET!! Thanks for the info Dave! I never imagined I could drive 10 minutes to my local Autozone and pick up something that would work for my needs. I bought some earlier today . Thanks for sharing :thumbsup:

Casey

 

[VegasF6]

I love that blue permatex lipstick, awesome stuff. But, for my builds I usually use MXLOC 22 purple. I get it for 3$ at harbor freight. (I don't know why it is red in that picture) If there is any VOCs that could be harmful to led, I wasn't aware of it, oops but, I have used it quite a bit and no noticable harmful effects. I am sure the blue will be great too, just remember a little bit goes a long way.

There is actually a thread locking tape out now too, but I haven't tried it yet.