Red/blue Stripes On Pug Bolts

[dobboy 231 2 Cars]

Can anyone tell me what the stripes often found on the threads of pug bolts indicates?

[welshpug 1,657]

its threadlock.

[dobboy 231 2 Cars]

Thanks, i thought it might be, but wondered why even new bolts have it on them. Is it heat activated stuff? Or is it just permanently on them to tighten up a few threads?

[JeffR 51]

I think it is heat activated by the process of friction when tightened.

 

Many task specific bolts these days are pre-coated. Think of the time it must save in automotive manufacturing.

[petert 586]

It's anaerobic. ie it goes off when there is no oxygen present.

[dobboy 231 2 Cars]

Interesting, so i take it if a bolt has been removed that had it on then loctite should be used when replacing the bolt?

 

(Which i've been doing)

 

Do you normally cover where their strip was only, with Loctite?

[JeffR 51]

I usually wire brush (in a drill) the old stuff off and apply a couple of drops of new roughly in the same spot.

[dobboy 231 2 Cars]

That sounds a good idea, wish i had known 4hrs ago!