[R-390] Home made IREC style tube shields

[Perry Sandeen]

Yo Bubba Dudes!
A reasonable substitute for the IREC tube shields can be home-brewed if one is interested in performance but not crazy about good looks.
This can be done in one of two ways.
Method 1.
Go on ebay and find aluminum 7 and/or 9 pin tube shields which can be found in black.  It will take a lot of searching do to the extreme competition for the audiophool market so all sorts of combinations and deals are offered.
What your looking for is the type that has the twist lock to match the *A* tube sockets.
When you get them, go to or buy from Harbor Freight the set of tapered reamers they sell for about $10.
The nest step is tricky as shield thickness varies on the thin side, the idea is to ream off the top lip so one ends up with a tube. So with a wooden dowel on the inside, the shield can be held in a vice.  An alternative if your hands are steady enough (mine aren't) a Dremel (sp) tool with a carbide cutter works well.
Then at your local Big Box store but the smallest amount of aluminum possible as you'll have lots left over. What I've found came in a roll which is what one needs.  Wrap at least 6 inches with  two layers of duct taped.  DO NOT use masking tape.
Measure the tube height and add an additional 1 inch and make a mark. (If too long for a location it can easily be trimmed down later.)

Now comes another tricky part.  We want to cut off the measured piece. The simplest, but not neatest, is to use a hacksaw with at least a 32 tooth blade.  With care, a chop saw with a fine tooth plywood blade cutting slowly through will work and give a clean cut.
Then remove the tape and unroll the screening.

Next using a bad or weird downer tube start wrapping the screening around the tube tightly until it's about the width of the tube shield.  This is a judgement process.  One needs a little slack so when it's used it will fit over the tube with a little compression so the heat can be conducted away.
After a good trial fit, unroll the screen and measure its length for reference.

Re-roll the screen and put about 3/4 inch above the bottom of the shied. 

Do a trial fit and adjust up or down as necessary.
With the screen fitted properly use super glue to bond the screen to the shield.

Next about 3/8 of an inch above the shield top, run a tiny finishing nail horizontally from side to side and super glue. This keeps the screen from spiraling up or down. Now you're done.
The downside: repeated insertion and removal will rub off the painted tube info.
Method 2.  Instead of using ebay shields go to the Big Box Store and buy a 3/4 inch copper pipe. Five feet if you can get it. Ten feet is about $30 OR they sell 3/4 inch copper pipe  couplers.
The trade off is that for buying just what you need the are a bit shorter than than what you get with the aluminum shield and will use a longer length of screen wrapping.
Withe the copper pipe or couplers there may need a bit of fitting on the bottom tube socket locking pins.
Otherwise use the same steps as the aluminum shields. 

I think I covered it all.
Regards,
Perrier