From: Lehanover@aol.com
Message-ID: <1e.1f86232b.2d21aa3b@aol.com>
Date: Mon, 29 Dec 2003 11:03:07 EST
Subject: Re: [FlyRotary] aluminum hose bungs/fittings
To: flyrotary@lancaironline.net
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In a message dated 12/29/2003 8:52:56 AM Central Standard Time, 
13brv3@bellsouth.net writes:

<< BTW, I still haven't officially decided if I want to use AN hose, or just
 good quality "heater hose".   I'll certainly keep AN hose for oil, but I
 think heater hose is probably fine for water, especially with all my
 possible plumbing methods.   
  
 Thanks,
 Rusty (evap cores temporarily in place)  
 
  >>

I once added a core as additional cooling on a GTP Jr Lola. The dash 16 hose 
end took up too much room and was too heavy. So, I made up two short pipes in 
6061-0 to weld to the core. I cut two shallow grooves in the hose area so as 
to get a good grip. Then used two 1/4" hose clamps. One over each groove for 
redundancy. The connection was made with a formed 90 piece of hose I found at 
NAPA. It was about 1" inside and dirt cheap. For aircraft I would use the blue 
silicone stuff. Pricey but great performance. Much lighter and more compact.

People that repair auto air conditioning often have cores that are faulty. 
Get a couple of these, or off of the core pile at the wrecking yard. That is 
just aluminum parts to get melted. These are damaged and useless as parts, but 
are generally sold for the price of scrap aluminum.

I clamped the cores between two pieces of 3/4" plywood lined with sheets of 
1/4" filter foam. One piece of plywood was longer than the other so as to work 
as a handle to clamp in the vice. Mine won't open far enough to grip 
everything together. 

Then Saw off the fittings with the core inverted. Drill a hole through a 
piece of 3/4" plywood with a hole saw. Clamp that piece of 3/4" plywood across the 
area where you want the fitting hole and fasten that piece of plywood to the 
clamping sheets with drywall screws. Drill through the plywood and into the 
land area on the core. The plywood will guide the hole saw. 

Slip the hose of a shop vac over the other end fitting on the core and blow 
air into the core while you drill into the core. You do the same on both ends. 
Not a flake of aluminum will end up inside the core. Then debur the holes 
inside and out. Running the shop vac the whole time. And holding the core inverted 
the whole time. 

If you make the fittings from scratch, you can leave a little welding flange 
on the one end. Also, radius both inside ends to improve flow. 

Wrap the end of the core with a few layers of soaking wet towel while welding 
on the fittings. 

Practice on the junk cores. Get good at it.

The cores will have oil in them that circulates in the system to lubricate 
the compressor. Let them drain for a few days and the rinse them out with ketone 
or similar and then soap and water. Blow it out to get it as dry as possible 
before welding. If you short cut this step, be aware that the jet of orange 
oil vapor flame that shoots out of the proposed fitting holes is about a foot 
long and will blow your welding helmet clean off of your head.

These things work well for water or oil cooling. They are tough as nails. 
(the GM stuff). If you have room, you can cut one side off of a bulkhead fitting 
and use the hex as a welding flange. Better for oil cooling where the fittings 
hose ends are going to be heavy anyway. For water service, the AN fittings 
and hose ends will be too big (dash 16 or 20) and too heavy.

Mount the core in foam lined brackets. Don't let anything rub against them 
(but a foam seal strip).

Lynn E. Hanover