From: "Finn Lassen finn.lassen@verizon.net" <flyrotary@lancaironline.net>
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Subject: Re: [FlyRotary] Re: Radiator - A/C Evaporator core welding
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
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Date: Thu, 25 Feb 2021 09:02:52 -0500
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Thank Lynn.

But that would mean I'd have to get a Tig or Mig or ... welder and learn 
to weld :(

I have a Henrob torch but expect that won't work -- too long time to 
heat up area allowing heat to spread.

I really like my cores: new, cheap, square and very light. 3.875x7.25x7 
(8.5 with tanks) . Problem is tubes are welded to side of tanks instead 
of tank end plates making the holes too small. I may switch over to 
"Ford" cores: 4x6.375x9.125 (12 with tanks). They have tubes welded to 
tank end plates (the 1/2" tube would have to be replaced with 3/4" 
tube). But if I do that I'll have to re-make the intake duct. And if I 
do that I really should change the standard RV-4 cowl inlets to a round 
ones further out in the prop wash to improve (ground) cooling. See where 
this is going?

Finn

On 2/24/2021 10:27 PM, lehanover lehanover@aol.com wrote:
> The low temp "welds anything" filler rods, if I remember correctly, 
> contain Zinc. Which I believe sticks to aluminum but does not actually 
> form a weld.  Years ago I used big GM evap cores as oil coolers and in 
> one case as a water radiator. Came from a junk yard off of the 
> aluminum pile. One still hooked up and holding pressure would be 
> ideal.  But more expensive. Used they may have lots of oil in them. 
> (compresser lubricant)
> So clean extensively with Ketone of similar. Wrap with wet towel right 
> up to the edge of the top. Do not fill with water. Steam will ruin the 
> weld. I cut off the tubes and welded on AN fittings. Very nice look. 
> Pressure test to twice the expected oil pressure before use. Should 
> hold pressure over a weekend.
> I forgot the actual alloy number of the low temp filler rod from the 
> welding store. But it is actual aluminum filler rod. Wipe off each 
> filler rod with wet or dry 400 grit and clean with ketone rag. Use a 
> stainless wire wheel on the area on the evap to be welded.  Weld about 
> 1/4"  at a time and let cool to room temp. Lots of amps/short time.  
> This is welding on the thick flat end plates. Formed end tanks can be 
> very thin.
> No leaks. No distortion. Looks like a factory piece.  ..........Lynn 
> E. Hanover
> In a message dated 2/22/2021 6:26:16 PM Eastern Standard Time, 
> flyrotary@lancaironline.net writes:
>
>     https://www.alumiweld.com/
>     is one brand, but most local welding shops will carry some version
>     of the stuff. I used it to braze my intake tubes to  1/4" plate,
>     but I have no idea whether it will stand up to the intake pulses &
>     vibration with the engine running. I can tell you that the stuff
>     isn't the magically easy to use stickum that it seems to be, when
>     you're watching the carnival barker at SNF. The stuff I used was
>     marginal on thick stuff with a propane torch (might not be a
>     factor with the heat exchanger). You'll almost certainly need a
>     wood handled stainless steel brush to free the corrosion on the
>     base metal while the torch is applied to the molten brazing material.
>     Have you thought about hitting Barry up to take a look at it? ;-)
>     Charlie
>
>     On Mon, Feb 22, 2021 at 3:04 PM Finn Lassen
>     finn.lassen@verizon.net <mailto:finn.lassen@verizon.net>
>     <flyrotary@lancaironline.net <mailto:flyrotary@lancaironline.net>>
>     wrote:
>
>         Some time ago Ed Anderson recommended some (rather expensive)
>         DIY alum
>         welding or brazing rods that he had good success with.
>
>         I really need to add some alum tubing to the ends of the
>         evaporator core
>         tanks (and close off the existing tubes going into the tank
>         sides).
>
>         I'm worried that If I try to do that myself that I will
>         disturb (weaken)
>         the existing core brazing/welds.
>
>         I assume that if I take them to a (Tig?) welder he'll be able
>         to do it
>         so heat won't spread (or maybe submerged in water)?
>
>         Any advice?
>
>         BTW, I'm now unable to find the exact same cores on eBay and
>         would
>         rather avoid having to re-do the fiberglass inlet ducts. So
>         I'll have to
>         take the plane out of service to do it and to not mess up the
>         cores.
>
>         Finn
>
>
>         ---
>         This email has been checked for viruses by Avast antivirus
>         software.
>         https://www.avast.com/antivirus
>
>
>         --
>         Homepage: http://www.flyrotary.com/
>         Archive and UnSub:
>         http://mail.lancaironline.net:81/lists/flyrotary/List.html
>


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    <div class="moz-cite-prefix">Thank Lynn.<br>
      <br>
      But that would mean I'd have to get a Tig or Mig or ... welder and
      learn to weld :(<br>
      <br>
      I have a Henrob torch but expect that won't work -- too long time
      to heat up area allowing heat to spread.<br>
      <br>
      I really like my cores: new, cheap, square and very light.
      3.875x7.25x7 (8.5 with tanks) . Problem is tubes are welded to
      side of tanks instead of tank end plates making the holes too
      small. I may switch over to "Ford" cores: 4x6.375x9.125 (12 with
      tanks). They have tubes welded to tank end plates (the 1/2" tube
      would have to be replaced with 3/4" tube). But if I do that I'll
      have to re-make the intake duct. And if I do that I really should
      change the standard RV-4 cowl inlets to a round ones further out
      in the prop wash to improve (ground) cooling. See where this is
      going?<br>
      <br>
      Finn<br>
      <br>
      On 2/24/2021 10:27 PM, lehanover <a class="moz-txt-link-abbreviated" href="mailto:lehanover@aol.com">lehanover@aol.com</a> wrote:<br>
    </div>
    <blockquote type="cite" cite="mid:list-1252302@logan.com">
      <meta http-equiv="content-type" content="text/html; charset=utf-8">
      <div>
        <div class="userEdit" style="font-family: arial, helvetica,
          sans-serif; font-size: 10pt; color: #000000;">
          <div><span style="font-family: arial, helvetica, sans-serif;
              font-size: 10pt; color: #000000;">The low temp "welds
              anything" filler rods, if I remember correctly, contain
              Zinc. Which I believe sticks to aluminum but does not
              actually form a weld.  Years ago I used big GM evap cores
              as oil coolers and in one case as a water radiator. Came
              from a junk yard off of the aluminum pile. One still
              hooked up and holding pressure would be ideal.  But more
              expensive. Used they may have lots of oil in them.
              (compresser lubricant)</span></div>
          <div> </div>
          <div><span style="font-family: arial, helvetica, sans-serif;
              font-size: 10pt; color: #000000;">So clean extensively
              with Ketone of similar. Wrap with wet towel right up to
              the edge of the top. Do not fill with water. Steam will
              ruin the weld. I cut off the tubes and welded on AN
              fittings. Very nice look. Pressure test to twice the
              expected oil pressure before use. Should hold pressure
              over a weekend.  </span></div>
          <div> </div>
          <div><span style="font-family: arial, helvetica, sans-serif;
              font-size: 10pt; color: #000000;">I forgot the actual
              alloy number of the low temp filler rod from the welding
              store. But it is actual aluminum filler rod. Wipe off each
              filler rod with wet or dry 400 grit and clean with ketone
              rag. Use a stainless wire wheel on the area on the evap to
              be welded.  Weld about 1/4"  at a time and let cool to
              room temp. Lots of amps/short time.  This is welding on
              the thick flat end plates. Formed end tanks can be very
              thin. </span></div>
          <div> </div>
          <div><span style="font-family: arial, helvetica, sans-serif;
              font-size: 10pt; color: #000000;">No leaks. No distortion.
              Looks like a factory piece.  ..........Lynn E. Hanover</span></div>
          <div><span style="font-family: arial, helvetica, sans-serif;
              font-size: 10pt; color: #000000;"> </span></div>
        </div>
        In a message dated 2/22/2021 6:26:16 PM Eastern Standard Time,
        <a class="moz-txt-link-abbreviated" href="mailto:flyrotary@lancaironline.net">flyrotary@lancaironline.net</a> writes:
        <div> </div>
        <div class="quotedReply">
          <blockquote style="padding-left: 5px; margin-left: 5px;
            border-left: blue 2px solid;">
            <div id="yiv3716412891">
              <div dir="ltr">
                <div class="yiv3716412891gmail_default"
                  style="font-size: small;"><a
                    href="https://www.alumiweld.com/" target="_blank"
                    rel="nofollow noopener noreferrer"
                    moz-do-not-send="true">https://www.alumiweld.com/</a></div>
                <div class="yiv3716412891gmail_default"
                  style="font-size: small;">is one brand, but most local
                  welding shops will carry some version of the stuff. I
                  used it to braze my intake tubes to  1/4" plate, but I
                  have no idea whether it will stand up to the intake
                  pulses &amp; vibration with the engine running. I can
                  tell you that the stuff isn't the magically easy to
                  use stickum that it seems to be, when you're watching
                  the carnival barker at SNF. The stuff I used was
                  marginal on thick stuff with a propane torch (might
                  not be a factor with the heat exchanger). You'll
                  almost certainly need a wood handled stainless steel
                  brush to free the corrosion on the base metal while
                  the torch is applied to the molten brazing material.</div>
                <div class="yiv3716412891gmail_default"
                  style="font-size: small;"> </div>
                <div class="yiv3716412891gmail_default"
                  style="font-size: small;">Have you thought about
                  hitting Barry up to take a look at it? ;-)</div>
                <div class="yiv3716412891gmail_default"
                  style="font-size: small;"> </div>
                <div class="yiv3716412891gmail_default"
                  style="font-size: small;">Charlie</div>
              </div>
              <br>
              <div class="yiv3716412891gmail_quote">
                <div class="yiv3716412891gmail_attr" dir="ltr">On Mon,
                  Feb 22, 2021 at 3:04 PM Finn Lassen <a
                    href="mailto:finn.lassen@verizon.net"
                    target="_blank" rel="nofollow noopener noreferrer"
                    moz-do-not-send="true">finn.lassen@verizon.net</a>
                  &lt;<a href="mailto:flyrotary@lancaironline.net"
                    target="_blank" rel="nofollow noopener noreferrer"
                    moz-do-not-send="true">flyrotary@lancaironline.net</a>&gt;
                  wrote:</div>
                <blockquote class="yiv3716412891gmail_quote"
                  style="margin: 0px 0px 0px 0.8ex; border-left: 1px
                  solid #cccccc; padding-left: 1ex;">Some time ago Ed
                  Anderson recommended some (rather expensive) DIY alum
                  <br>
                  welding or brazing rods that he had good success with.<br>
                  <br>
                  I really need to add some alum tubing to the ends of
                  the evaporator core <br>
                  tanks (and close off the existing tubes going into the
                  tank sides).<br>
                  <br>
                  I'm worried that If I try to do that myself that I
                  will disturb (weaken) <br>
                  the existing core brazing/welds.<br>
                  <br>
                  I assume that if I take them to a (Tig?) welder he'll
                  be able to do it <br>
                  so heat won't spread (or maybe submerged in water)?<br>
                  <br>
                  Any advice?<br>
                  <br>
                  BTW, I'm now unable to find the exact same cores on
                  eBay and would <br>
                  rather avoid having to re-do the fiberglass inlet
                  ducts. So I'll have to <br>
                  take the plane out of service to do it and to not mess
                  up the cores.<br>
                  <br>
                  Finn<br>
                  <br>
                  <br>
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