From: John De Armond
Newsgroups: sci.engr.heat-vent-ac
Subject: Re: nail hole in a/c coil
Message-ID: <h83vbu40d69t0vmaveobdefbbk5eqdp8tt@4ax.com>
Date: Thu, 18 Apr 2002 23:27:08 -0400

On 15 Apr 2002 05:52:48 -0700, chris@krahe.org (Chris Krahe) wrote:

>A week ago I was tearing down my deck and carelessly knocked a
>baluster, nail first, into the side of my Carrier A/C unit (about 3
>inches from the ground, near the center of the front). Smooth. Within
>about 15 minutes the freon was out (i.e. I could no longer hear it
>fissssssssssing). That might give you an idea of the hole's size I
>suppose.
>
>The unit is a 6 year old Carrier 38TRA036330.
>
>Can something like this be repaired?


Sure.  You can either braze the hole shut or epoxy it shut.  I've had equally
good success with both processes.  To braze, simply cut away enough fins so
that you can get in with a micro-torch (a tiny oxy-propane torch) to braze it.
Works equally well with aluminum or copper coils.

HVAC supply houses sell epoxy repair kits.  I've had success with industrial
repair epoxy like Dexter Epoxi-patch.  Don't waste your time on the 5 minute
stuff - too weak.  The area around the hole must be thoroughly degreased.  The
epoxy is applied to the hole and then a light vacuum is pulled on the system
to pull the epoxy through the hole a bit where it expands out and forms a
mechanical lock as well as adhesive bond.  Either heat the epoxy to ~225
degrees after it gels to speed the cure or leave it for a couple of days.
Then evacuate and recharge the system normally.

If the condenser is copper and you choose to braze, use Sil-phos.  No flux
required so there's no problem with flux contamination.

John