[Heathkit] Apache or Warrior panels

[Carl]

I havent worked with those panels but Ive patched up standard rack 
panels many times with a TIG. I dont recommend trying to fill the hole 
with welding..

Epoxy fillers such as Evercoat Rage, JB Weld and Devcon have different 
expansion coefficients than aluminum which makes for a failure at some 
point down the line.

If you cut an aluminum plug, tack weld with the TIG and then finish with 
exoxy, the warpage and bonding problems no longer exist.

Ive plugged holes from 1/4" to meter size that way; once finished and 
painted the repair cant be seen.

I suppose if one was very careful and installed the plug with a minimum 
thickness of JB Weld along the circumference it might work well.

Carl
KM1H

----- Original Message ----- 
From: "rbethman" <rbethman at comcast.net>
To: <heathkit at mailman.qth.net>
Cc: "John Hensley" <w5jv at hotmail.com>
Sent: Thursday, December 18, 2008 3:06 PM
Subject: Re: [Heathkit] Apache or Warrior panels


> John,
>
> Using EITHER Mig or Tig welding methodology would VERY likely cause 
> warpage.  The reason is the concentration of heat in particular areas.
>
> One way too deal with this would be heat treating the panel 
> AFTERWARDS.  Welding aluminum causes almost immediate expansion due to 
> its properties.  It coefficient for heat expansion is pretty high.
>
> To use one of those panels, consider using a hardening body filler. 
> You can always cut a piece of aluminum screen to occupy the hole, the 
> apply the body filler, IF you are having issues with RF.
>
> There is of course the possibility that welding being difficult 
> because we do NOT know what specific alloy of aluminum was used.  Most 
> likely it varied widely.
>
> Another thing to think about, plug welding WITHOUT a backing plate 
> increases the difficulty.  The individual performing the welding would 
> be trying to build up the weldment by adding molten metal to the edge 
> of EACH hole to bring the hole to a close.
>
> Bob - N0DGN
>
> John Hensley wrote:
>> Has anyone been successful wire welding hole inserts into the Apache 
>> or Warrior panels in order to reuse them for another purpose?
>>
>> I'm familiar with filling unwanted holes with various compounds and 
>> then refinishing to give the "appearance" that the panel is solid. 
>> I'm curious if in a project anyone has taken one of these 3/16" 
>> panels and been successful reclaiming them with wire welding ?  Part 
>> of the interest is to find out if they can take the heat without 
>> warping.
>>
>> I'm getting ready to build a homemade KS-1 power supply and will be 
>> using an old Apache cabinet to house it in.  By the way, if anyone 
>> has the same project on their "to do" list, Harbach is geared up to 
>> reproduce the original plate transformer.  If a few builders could be 
>> found, we might be able to get a better price on the xmfr.
>>
>> TIA, John
>>
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> -- 
> Bob - NØDGN
>
>