RadioBanter - View Single Post

Lostgallifreyan · October 31st 14, 08:47 PM posted to rec.radio.amateur.homebrew

wrote in :

Making these flexible boards is an arduous process and requires a LOT of
capital outlay, so you have to make a LOT of boards or they will be
very expensive.

Maybe true if they're made of mylar or kapton, which most are, but I already
posted that very thin FR4 exists, and can be processed in exactly the same
way as any other copper clad FR4, and possibly it may even accept laser-
printed toner directly on to it, as it will roll just fine through the
printer. I don't know where to buy it, but I was given some by a guy who
would not have done that it it was particularly expensive or hard to come by.

As to what uses it has, I can't think of many, other than what I used it for,
namely mounting high power surface mount LED's in very tight spaces, by
epoxying it onto aluminium, then soldering LED's to the copper tracks. Its
thinness makes it a very good heatsink method that saves using more awkward
and expensive parts, and includes nice routing of high current conductors in
a very flat plane. THAT may be useful in a large number of situations, and
cheap too. The main weakness of thin FR4 is a need to avoid a minimum bend
radius because it will break abruptly and easily if pushed.