I'm no medical Dr but thats a slight mis-reading. Sun tanning is not cancer in any way, its a cell response to the UV that produces more of the exact same chemical that makes coloured people brown, melanin. Excessive exposure causes cell nucleus DAMAGE which leads to cancer eventually.sun tan is mild skin cancer
Yes it does. And sun cream is just a partial filter, full block DOES leave you untanned.UV does not cause a sun tan. If it did then going on holiday twice a year would cause skin cancer or using sun cream would leave people untanned.
Certain glasses do to a great extent, but I've ended up with sunburn from behind a closed car window before now. More modern cars have better UV filtering to make car interiors last longer. House windows also use the same barrier technology.i always thought glass blocked UV, thats why you cant get sun-tanned sitting inside.
I genuinely don't know about the absolute even spread of light.Yes, fair enough. Its a good test.
And a flash exposure would certainly save time. Can you hang things around a flash tube (or tubes) to get a dead even spread?
Obv. with a bit of electronic (PICAXE controlled?) jiggery pokery you can adjust flash energy. (Or just move the tube further away ).
You may be onto something there. See you in Dragon's Den ?
I'm suffering Shrudlu today.Sorry, you've lost me.
Why do you want to use that great pile of stuff?
Why not a few flash tubes (+gubbins) in a box with a glass top and fold down lid?
I'm sure we can think of something better than crumpled foil for a reflector
Check out the refelctors used in proper boxes.
Maybe in conjuction with a diffusing thing.
It could look like a proper exposure box. Instead of a timer on the front you could have a knob to set the energy.
But feel free to fit a brolly on the top and inside a tent if you want .... hee hee.
A portable, fast exposure box - now that appeals. No mains. Nice. (Assuming it works).
@AICHi all,
just wanted to remark that I successfully etched a small PCB using some kind of incandescent light bulb for exposure. No UV tubes were used..
- for exposure I used 10cm distance PCB to bulb for 18 minutes
- development was done using 1.5g NAoh / 120 ml water
- etching was done using some grams of persulfate in some water (didn't measure)
I'm very pleased with the results, although I did just cut out the traces by hand using a sharp knife... (of course you cals also print your layout onto some transparent laser printer paper but I wanted to be ghetto about it! )
I'm in a hurry so thats all now but I think you can see that UV light isn't needed for exposure...
cheers
I think 40 is the optimum working temp, I believe it breaks down at temps above 45 deg C...i'm sure I read that somewheredid you ever try etching with persulf at 60°C?
David. How much money have you got?Right, sorry I haven't replied for a while...
I still haven't ordered the LED's but am wondering if I should in light of eclectic's discoveries using them.
As suggested though by MartinM57, I could just drill or cut off the tips of them to get rid of the directionality. Should I still stick with the LED's or move back to the light tubes?
You really need to remove the dome on the LEDs, not just "squidge" it down. Where will the excess material go? Also, you'll probably end up with 100 LEDs stuck to a hot piece of metalHeat up some scrap, sheet metal on the hob and press the tips against it it should flatten them all without danger of breaking the dice.
Also, you'll probably end up with 100 LEDs stuck to a hot piece of metal
even more if you wanted to "Burn" them.And three different power rails