Fellow blues guitarists: What is the best type of slide for an Acoustic Guitar? Whaddabout an electric?

Also if you could tell me the differences in tones between ceramic, metal, glass etc. that would be very helpful, Im new to slide guitar.

I have experience with many slides over the years …

Here is what I think …

1) Brass. Definately the best. I play acoustic slide (mostly) and use a heavy, thick piece of brass on my third finger. Smaller brass pieces never seem to fit over my entire finger, nor give the mass ans sustain from a serious piece of brass.

Here is a link to me playing my dobro with a heavy brass slide:

If it didn’t give the whole link (Y!A tends to chop the url’s) then try:
http://www.youtube.com/macegill and click on one of the slide tunes like “last fair deal gone down” or “crossroad blues” etc.

2) Glass – I have tried glass over the years and find that for acoustic playing, it always sounds a little like playing under wate (particularly since I tend to play finger style with slide).

Glass is better for electric playing as it seems to give a good combination of control/cosistency/subtlety. HOWEVER … and this is a ‘bonehead’ practicle piece of advice … every time I would crank the amp to “11″ and play, I would then place the slide on the amp to play something else, and the glass slide would vibrate off and shatter.

*sigh* stupid, I know …. so I stopped using them.

3) Chrome – Never could find one to fit my finger.

Slide Guitar in D major with a glass (Tuned down to D from E.)