HVAC aluminum foil tape

[petey twofinger]

i saw this product , or something very similar at menards for 5 bucks . it was a large roll of this thick sticky tape that is made from aluminum "foil" , actually thicker than standard kitchen foil .

my question is this

any reason why this would NOT work as a substitute for copper tape , which i believe is 4x expensive ?

the idea is for rfi or emi shielding . i am getting a lil whine in one of my amps when i use high gain , this amp has a lot of powering stuff going on in it , it was dead silent till i added a 9 volt regualtor circuit . it only whines when in battery mode , not ac adapter mode , and the adapters are inside the amps chassis .

thanks !

[petey twofinger]

link ;

http://tinyurl.com/cb6vy4p

( havc aluminum tape ) although this is not the stuf i have worked with , it was duller , and seemed to be thicker as well .

would one need to run a ground wire to the tape as well ?

[CynicalMan]

I just shielded a strat with it. There are just two caveats:
- It's very difficult to solder to.
- The adhesive side is not conductive, so overlapping pieces will not be connected. I got around this by folding over the end of each piece, then taping it down with another small piece of tape to make a connection.

Edit: The tape you linked to looks like it has stuff printed on the top, so the top side of the tape might not be totally conductive either.

[John Lyons]

The adhesive side is not conductive, so overlapping pieces will not be connected.
I got around this by folding over the end of each piece, then taping it down with another small piece of tape to make a connection.

This is how I do it as well. Set your meter to continuity to check your, uh....continuity between pieces 

[R.G.]

Aluminum foil works as a conductive shield. Aluminum has a resistance that's 30% larger than copper for the same cross section.

The problem with aluminum is that it is so reactive that the surface grabs oxygen atoms out of the air, rips the O2 molecules into monatomic O, then eats the Os to form aluminum oxides, which are both nonconductive and form a continuous film. This happens even if it's covered up by X unless the oxygen just can't get to it, so even clean, bright joints corrode over time. This is what led to the aluminum-wire-burns-houses fiasco.

Aluminum tape may or may not make good contact, and it may or may not *stay* connected over time. If you can find copper tape, use it. I solder the edges of copper tape strips in spots to ensure that curling adhesive and so on do not destroy the conductivity even on copper.

[Mac Walker]

The problem with aluminum is that it is so reactive that the surface grabs oxygen atoms out of the air, rips the O2 molecules into monatomic O, then eats the Os to form aluminum oxides, which are both nonconductive and form a continuous film. This happens even if it's covered up by X unless the oxygen just can't get to it, so even clean, bright joints corrode over time. This is what led to the aluminum-wire-burns-houses fiasco.

The bigger issue relative to house fires involves the chemistry between aluminum and copper.  Without the correct use of specialized connectors to go between the two conductors, a galvanic reaction occurs, speeding up the corrosive process, increasing the odds of heat generation, which then leads to fire....

At any rate I'm kind of partial to conductive paint for shielding applications at this point, the time savings is definitely worth it.  It also goes a lot further than you would expect in my experience.....

[davent]

A while back I found a good deal on copper foil from a seller on ebay. Using 3M's Super 77 spray adhesive i was surprised to find i had continuity on all the overlapping pieces in the sheilded guitar cavities. Still spot soldered the overlaps just to be sure, with the copper foil that was easy.

[R.G.]

A while back I found a good deal on copper foil from a seller on ebay. Using 3M's Super 77 spray adhesive i was surprised to find i had continuity on all the overlapping pieces in the sheilded guitar cavities. Still spot soldered the overlaps just to be sure, with the copper foil that was easy.

Good one! Easy enough to make it adhesive.

I lucked out on a partial roll of 2" wide copper tape at a surplus store in Minneapolis back in 1992. Still have most of it. It was $5.00. 

[runmikeyrun]

I used the tape to shield my electronics cavity in my bass.  Still holding up after 10+ years. 

RG, how and why did you get the little "more" under your username??

[Paul Marossy]

I shielded my frankenstrat project guitar with that same aluminum duct tape. Works fine. I used staples to ensure continuity between pieces. I also shielded a jazz bass for someone with copper tape and I liked that you can solder to it. There's pros and cons for each side. Having done both, I'd rather spend the money on the copper tape.

[R.G.]

RG, how and why did you get the little "more" under your username??

! ? ...  ??

I have no clue. I had not even noticed it was there.

[Earthscum]

While this subject is hot, how is the magnetic paint supposed to work? I haven't tried it yet, but the test piece I did showed absolutely no conductivity through the paint, dry or wet.

http://www.muzique.com/lab/magpaint.htm

[Paul Marossy]

While this subject is hot, how is the magnetic paint supposed to work? I haven't tried it yet, but the test piece I did showed absolutely no conductivity through the paint, dry or wet.

http://www.muzique.com/lab/magpaint.htm

It's just conductive paint. It works, I have a couple of guitars that used it to shield the control cavities, and there is definitely conductivity going on with it. I suppose it's like everything else, there is good stuff that really works and there is poor quality stuff that might need multiple layers to get a sort of satisfactory result.

[Earthscum]

I'm going to use the stuff in my wood wah. Guess it's worth a shot, I can always get foil to cover it if it doesn't work, right? I got the same Rustoleum stuff pictured in that article.

[Paul Marossy]

I'm going to use the stuff in my wood wah. Guess it's worth a shot, I can always get foil to cover it if it doesn't work, right? I got the same Rustoleum stuff pictured in that article.

Sure, give it a try. You probably just need to do several layers of the stuff. And make sure you shake up the can REALLY good, too!

[petey twofinger]

thanks for the replies !

i am going to keep my eyes peeled for copper tape when i go re-saling , i honestly don't think i ever saw any , woulda grabbed it for sure .

the mag paint sounds doable , i am guessing its 10 a can , i did see it at michael$$ .... maybe i will monkey with the layout of the wires first , they are kinda squirley .

at this stage of the game i would gladly trade the use of radios to make whine and hum go away . ever since steve dahl and kevin mattews left terrestrial radio ,  i haven't found much use for it .

[wavley]

you can get copper tape at good gardening centers(snails and slugs hate copper), it's adhesive is not conductive so you need to solder it, but it works quite well and is a bit cheaper.

[petey twofinger]

sounds good !

besides i hate it when slugs get in thru the output .

[Paul Marossy]

you can get copper tape at good gardening centers(snails and slugs hate copper), it's adhesive is not conductive so you need to solder it, but it works quite well and is a bit cheaper.

Just a footnote: the copper tape from Stewart MacDonald has conductive adhesive.  

[.Mike]

I've used aluminum foil tape to shield guitars without any problem. I do the fold-over technique, but add a small thumbtack to keep the folds together and connect the ground.

I haven't confirmed it myself, but I have read that Rustoleum chalk board paint or Rustoleum magnetic primer can be used for shielding. Both are available at Home Depot for around $10 a quart. Apparently you need to do 2-3 coats. Anyone tried either of them?

Mike