Black Max 380 for Thread Locking

This is continuation of past discussion. I had been asking for the best way to really lock down the brass jet or seat in an old castiron carb/mixer. I broke off 1/2 or 2/3 of the threads and dont want this thing to get sucked into the engine. Future removal is not a concern.

Some good ideas were suggested including general epoxy products like JB Weld. I am reluctant to use JB Weld type solution if applied to threads and shoulder only. it seems to thick. I am not going to bead blast of drill anchor holes either and I dont want any loose epoxy into the engine. Although, I do belive it would work based on advise presented.

My friend plays with firearms suggested I try Loctite Black Max 380. This is so strong it supposed to hold sights on a gun bbl. And unlike std loctite is suggested stored in refigerator. Resists solvents. I got some and think i will give it a try, while i was there I also got a cheeper bottle of Loctite 262. The 262 sounds like the recommended product for hi-temp and gasoline exposure. In my case hi-temp is not very high practically speaking 200deg F, higher if things go seriously wrong.

Any comments on Black Max 380 vs 262 ?

IIRC, Black Max is CA with a Neoprene filler in it to give it toughness. I think that may be a very fine powdered neoprene. I used it to bond neoprene to powder coated steel, not an easy application, and it worked well, and this was for a BMW accessory item we made for them, so it had to be good. I would consider the loctites intended for thread locking and retaining. If you have excessive thread clearance regular loctite will not work well but there are grades for larger gaps.

John,

Sorry I dont understand "CA" ? Are you thinking neoprene will not standup in this application?

As I write this, i am starting to wonder if hi temp is even a concern with a carb. its filled with liquid gas. How hot could that get. the gas is sprayed threw this piece and evaporated on the other side. that should have a cooling effect.

cyanoacrylate , ie superglue. I would check Loctites website, they have materials specific to gas exposure and thread locking.

Use it. I use cyanoacrylate for thread locking all the time. Especially if the gaps are larger than recomended for by loctite anerobic. Heat with a propane torch and it will release no problem. Also acetone for 20 minutes will release it. Clear is not as thick as black, but it will not leave your hands black. Use clear.
--Doozer

Anything that is room temperature cure is only going to be good to about 275°F If you need strength at elevated temperatures you are going to have to cure at elevated temperatures. I don't think that temperature is going to be a problem in your case.

Loctite cures in the abscense of air and is catilized by the Iron. In cases of Brass or Aluminum there is a primer recomended. Talk to Loctite they make a vast number of compounds.

I've used quite a bit of Black Max 380 and it is not very strong, due directly to the rubber filler it contains. It's been handy for mounting small optics such as precision mirrors, where a rigid bond was not desirable. Den

boucher,

thanks. I did not know about the what loctite calls passive metals. I will stop back at the supply house and get loctite activator 7649. I decided to use basic loctite 262, which is 100% gasoline resistant. I just read the fine print on black max and not gasoline resistant.

This is getting more and more complicated. After boucher threw a wrench in the works. I went back to the loctite web site. SOB! They spec holding power for brass on steel. And my 262 is crap. Next re-read every single thread locker specifcation. After narrow down the search I printed out several technical spec sheets. Those were read line by line, every detail.

I found 262 which I plan to use and seemed most popular choice in stock only had 25% strenght with brass on steel. But I do discover 277 is 100% for brass on steel. Also rated 100% strenght with gasoline exposure. temperature rating adequate, but far from the highest. It was not specified how 262 would perform if used an activator was used on the brass. Loctite recommends always using an activator (at 18 bucks per can, sure why not?). So after a long night reading, I was back to industry supply bright and early. I traded in the 262 for 277 and got a can of 7649 activator(surface prep cancer in a can).

I was bit worried, I might hear some negative comments about dealing with off-the-street customers. But, the clerk seemed impressed with all my full color tech specs in hand with graphs of strength vs temp, matterial and activator used and curing times. At least until another clerk walks by and says it all the same stuff in the bottle! I dont think so?

Thats it- I am done fussing over this.

Thanks all,

I have used loctite black max for a lot of things, it sure is not weak, it will hold a #11 percussion cap on the nose of a 22lr projectile...the projectile revolves at 48,000 rpm and travels at 1000 fps, and I'm sure the #11 cap is not exactly centered.

I have glued sleeves onto rifle bolts with it too, and some other things here and there....it is pretty amazing stuff IMHO, my typical uses for it are similar to what you would silver solder, but don't want to heat the part, or nit it right now.

Bill

"At least until another clerk walks by and says it all the same stuff in the bottle! I dont think so?"
Loctite has first class products and there are real difference between them, most counter guys seem to be some sort of frustrated arm chair enginneers that are really idiots. [present company not included if there are any here]