dots or strips for spacers?

[CharlieM]

Hello All,

I'm building some 12x48 perf metal esl panels assembled with 3/4 wide 1/16 thick double-sided foam tape. I'm trying to decide whether to use 1/4" width foam strips or 1/2" diameter foam dots for the inner spacers and would like to hear recommendations from the esl builders here. Bear in mind that my stators are less than perfectly flat (tack-weld one together from two pieces) so I will need to be conservative with the distance between spacers in order to keep the diaphram centered.

The attached sketch shows (4) dot layouts on a 12x48 panel-- should I use 1/4 strip spacers or one of these dot layouts? Please let me hear your opinions!

Chaz

[CharlieM]

OK...
No responses (yet) to the dots versus strip spacer query. Oh well, it's a moot issue for this project now, since I've already assembled one of the esl panels this evening using foam tape strip-spacers. Still, I would like to hear any opinions on sonic differences between dots and strips (resonant modes, resonant frequency, character of the sound).

I was alarmed and astonished to find that the 3-M foam tape didn't stick to the stators very well. I concluded the culprit was the satin clear poly topcoats on the stators rather than the tape. The stators were first spray-coated with about 7 or 8 mils of latex house primer, then black Krylon from an aerosol can, then three sprayed coats of some Minwax clear satin polyurethane left-over from another project. I'm thinking the satin filler in the poly (which dulls the shine) inhibited adhesion to the tape so I advise DON'T USE IT!

Anyway, (due to the poor adhesion) I was afraid the dots were not going to provide enough adhering surface to hold the stators together so I opted for two 3/8" wide vertical strip spacers 3.5" apart and I sanded and solvent cleaned the stator topcoat at those locations; which seemed to improve the adhesion somewhat and the finished panel looks ok.

LESSON LEARNED: Spring for powder coating :-)

Chaz

[moray james]

high gloss coatings have the most solid content in them so will provide greater dielectric insulatiom. 3M acrylic tapes require a couple of things to work well and to achieve full strength. They are heat and pressure. Get and keep your panels warm and get some weight on the joints. Does not matter how you go about doing either just so you do.