injector bosses

[Tom Cloud]

>Seth wrote:
>> 
>> On Thu, 28 Aug 1997, James Weiler wrote:
>[snip]
>> > Welding (I've been told) will distort the manifold too much.  What
>> > about bolting it to a pair of heads prior to welding?  Ideas anybody?
>> > I've heard alot of people have epoxied them in place but I worry about
>> > the durability of the epoxy.  How long will it take for gas to break it
>> > down is one of my concerns.  I don't know but epoxy just sounds Mickey
>> > Mouse.  Am I way out of line here?
>[more snip] 
>> I welded mine.  Lots of heat.  About 250 amperes worth for about 24
>> linear inches of weld.  I drilled all the bosses is a chunk of 0.75 by
>> 1.00 inch aluminum.  That keeps the centers consistent. Welding shouldn't
>> be a big deal, if you warp the mounting surface, it should be minimal
>> ,and a dust off on a belt sander should fix that, of if you want to get
>> trick, a flycut on a mill.  The intake gets hot for the use of DGEBA
>> (room temp) epoxies with the usual amine curing agent.  A pre-preg epoxy
>> for use and cure at elevated temp should be fine.  One I use cures for 1
>> hr at 325 F.  We use the stuff on several different intake parts.
>> 
>I haven't heard anyone mention the use of silver solder yet.  IIRC, it's
>pretty strong, very little heat xfered into the work, and pretty common.
>I can't say that I've used it for this, but it seems to me that this is yet
>another way to skin this cat.

this is not my area of interest -- at least not today (i.e. installing
injectors) -- but how do you silver solder aluminuminuminum  ???
Plus, how do you figure "little heat" -- you have to be danged near a
bright red heat (depends on the alloy) and aluminuminuminum melts
before that.  Other than that (Al, that is) I love silver solder --
I assume you're talking *real* silver solder -- not that "silver-
bearing" tin-lead solder that's sold as silver solder ??

I think that's what they were talking about .... as far as epoxy,
some of the filled epoxies (e.g. JB Weld, etc *might* work okay.
I've used epoxies in various applications with good success.

 - used to make jewelry -- had to find an epoxy that wouldn't
   turn yellow, that was hard and not soft, and that would take
   polishing without streaking (i.e. hard) ... after extensive
   testing, determined that Devcon II was the best -- but that
   was 10 or 15 years ago  (BTW, recently came across the teflon
   sheet I used to put the dabs of different brands of epoxies on
   and the DEVCON was still reasonably clear -- not yellowed after
   all this time -- I'm impressed.)

 - I have JB Welded warped heads and scratches in heads and
   never had a failure (but, not talking anything other than
   stock either).

 - I epoxied (Devcon II) a hole in a dishwasher once (in the
   bottom, near the heater).  It lasted for over five years --
   until I threw the dishwasher away for other reasons.

 - I epoxied a hole in a coffee pot (percolator) I had at work
   once -- it was in my office -- at that time, I was drinking
   two to three POTS of java a day -- und idt dinnent dew innithing
   tew mee  ;-)    .... the pot lasted for years -- until
   I changed offices and didn't need it and pitched it

 - I epoxied a leak in the gas tank on my 650 Triumph Bonneville
   and went lots of places with it  --  never a problem

A *true* epoxy will cure faster and harder when heat is applied
(remember, it's a plastic, so it has an upper limit where it's
damaged or destroyed .... I forget, but I think it's near 300 F).
Also, it will *resist* solvents and hot water (see below about fast-
curing epoxies).


 ** be aware that five-minute -- quick curing -- epoxies are
   not *true* epoxies (don't really know the chemical difference)
   and won't get as hard, are damaged by heat, are softened by
   hot water and by gasoline -- i.e. don't use them !

Tom Cloud

They say the mind is the first thing to go ... and I can't remember the second