Well, strictly speaking it means it's more heat resistant.  But it's
probably also more waterproof and very likely stronger as well.

My own experience of using epoxies in contact with gasoline or gasoline
vapors is that after a few months they get rubbery (this was Marine-Tex, a
similar filled epoxy).  Same experience using it to fix a turn-signal
switch from a Toyota Tercel* -- it was made of some engineering plastic
that nothing sticks to; I built up and surrounded with epoxy and it was
great for about six months, then became rubbery from the plasticizers in
the plastic (I finally fixed it with serrated strips cut from tin cans,
embedded in "Liquid Steel" which is acetone-based.

*I visited my brother wearing a trench coat -- he sez "watch out you don't
catch the bottom hem of the coat on your turn signal and tear the coat,"
and I sez "Right.  Who is this really," and went away laughing.  Three
weeks later I caught the bottom hem of the coat on the turn signal and
ripped it right out of the column!!  I then spent about sixteen hours of
repair time fixing it twice because I refused to pay Toyota $72 for the
complete assembly when it was a $1 piece of plastic that broke.  Guess I
showed them, yes sir.

david

At 12:10 AM 1/25/2001, Paul Gilland wrote:
>I've always been curious if JB Kwik Weld (cures in 4 hours) was as
>strong as regular JB Weld (cures overnight).  This is because I once
>spent an night out in the woods waiting for regular JB Weld to fix a
>puncture in my gas tank.
>
>I just checked the JB Weld web site and Kwik Weld is rated at 300
>degrees F, and regular is rated at 500 F.  I guess this means that
>regular JB Weld is stronger.

David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"