Noob ESL builder looking for advice

[Shaunman]

Here's the 12" snips cutting the perf sheets. The sheets are not quite flat after the cut--hopefully I will be able to get them flat enough.

[CharlieM]

Originally Posted by pcb121055

In shopping McMaster-Carr for perforated metal, I noticed that one of the available patterns had the holes in straight rows rather than staggered ones. (McMaster-Carr) This would allow a cut to size between the rows for a single, straight clean edge rather than thru a bunch of the perfs. Is there a reason why noone uses this?

Typically, straight (non-staggered) holes are only used where the open area is below 40%. Most builders I've asked recommend 40%-61% open area. McMaster-Carr has great prices and fast shipping but last time I checked 40" was the largest dimension they sell. If you want taller panels for cheap, OnlineMetals.com has great prices and will cut to your dimensions. I bought some of their 20 gauge 48"x12" precut steel perf for $20 each.

[JAMESBOS]

Originally Posted by Shaunman

Cutting done. I used some 12" tin snips I got from Home Depot for about 20 bucks. The process did induce some bending. I also picked up an edge grinder, so either straightening or edge smoothing is next.

I started with scissors with plastic handles then the plastic broke on one of the handles, could have been nasty, that's why I bought all steel scissors, no chance of any accidents when cutting perforated sheet. Still, I don't think you will be cutting as many sheets that I have.

[Shaunman]

The scissors are steel with a thin plastic covering. How many panels have you cut? Sounds like a friendly challenge

[JAMESBOS]

Originally Posted by Shaunman

The scissors are steel with a thin plastic covering. How many panels have you cut? Sounds like a friendly challenge

That's safe then, about 50!! My 12 um mylar has just arrived so can carry on with rebuilds.

[geraldfryjr]

I think that you will have even more of a challenge getting those panels flat again.

The most tolerance of warpage tat you can ave for an ESL is about .010" and maybe up to .025" total for both sides if you are lucky.

Being slightly bent is not the same as having a panel with many large waves and creases.

Even some of the very slightest waves in a panel have been known to separate at the tape bonding.
One of Mavric's panel's did this there might be a picture of it in one of his threads back in early of the year 2010.

different ideas for ESL panels

different ideas for ESL panels

different ideas for ESL panels

Here is were it had separated,

different ideas for ESL panels

different ideas for ESL panels

Material for ESL

Start to Finish ESL Hybrid

And more,

Help needed with ESL

My ESL attempt

All of these treads are a must read from start to finish as there is a extreme wealth of info.
I have heard these panels and they sounded awesome and it took a lot of patients to get them done.
I do remember that they had a few quirps here and there, But were easily worked out as Charlie would know the details of what they were off hand.
For the most part they worked perfect on the first try.

Remember these are not the same as magnetic planar with the diagphram at least an 1/8" over the top of a layer of magnets.

The the tolerances are much much greater.

Only about 10% is about the max that you can have without worrying to much about stability problems.
At 10% that is only a 6mil (.006") difference with 1/16" D/S spacing.
As you have two Tremendous forces pulling on both sides of the diagphram and any deviations in the gap can/will cause an unbalance and unequal force to occur and cause the Diagphram to suck into one the the Stators and stay there until the bias voltage is removed and dissipated.
Not to mention the possibility of a slightly higher THD should they be stable otherwise.

I would hate to see you spend the money on coating them only to find that they may not work well or even at all.
I think that you might be able to salvage few pieces for some smaller panels or someting or maybe you will get lucky with A LOT of extra hard work and get them straight again.
But, all in all, They Must Be Flat!!!

Good Luck !!!

jer

[Shaunman]

So Jamesbos, when you cut your panels do they bend like mine did? How do you get them flat again?

[JAMESBOS]

No they did not bend they were quite flat, it must be the way I cut them! Even the small A4 size and the headphone sized ones.

[Bazukaz]

Why don't you use an angle grinder with steel cutting disc for that? Pretty fast and accurate.

[CharlieM]

Originally Posted by Shaunman

So Jamesbos, when you cut your panels do they bend like mine did? How do you get them flat again?

On my website (link below) view the "building the stators" link therein to see my method for straightening the stators by hand. I don't recommend using a metal hammer over a hard surface, as that would expand the metal and ruin the stator.