Metal Spikes

Step 1

First just fill your base layer with the color you want it to be, in my case I picked a boring brown color.

Then create a new layer and apply a drop shadow to the layer.

Drop Shadow: color:#FFFFFF

Next you'd have to use your airbrush tool and make the area through which the spikes would come through the base material. Using a one pixel brush with color black and a pressure of 50%. I have a Wacom tablet and that makes it easier for me compared to using a mouse. 

Mine came out looking like this:

You'd notice how the drop shadow is applied to the layer for each brush stroke, this is really helpful in getting it just right.

Step 2

Hide the layer you just created for now and create a new layer then use your vector or marquee tools and create a spike that looks something like this:

Apply a drop shadow to this layer:

Drop Shadow: color=black

Which should make it look like this:

Step 3

Select the layer transparency of your spike and create a new layer  then fill with white. Keeping the selection in tact more it up 1pixel then right by 1 pixel then delete the white within the selected region. If this method does not work feel free to airbrush the edge if you please. Then set the layer transparency to about 79%. This layer is where the light shines against the raw edge of the metal so I'd make it more shinny later. For now leave as is.

When your done you should have something like this:

Step 4

Select the layer transparency of your spike and create a new layer  then fill with white, set the layer blending style to Dissolve then set the opacity to around 11%. This should give it a slightly speckled look. Create a new layer and merge it with this one so that the Dissolve look does not change the next time you open the file (which I think it may).

Now create a new layer and select layer transparency of the spike again. Fill it with white and move the selected area to the left by 1 pixel. Delete the area within the selection and set the layer transparency to about 31%. Lastly make the layer you first made visible again (the airbrushed crack). 

When your done you should have something like this:

Step 5

Got back to Step 3 and duplicate the layer and set the layer transparency to about 53%..... this should give it more shine. I erased a little of the top left portion of it and let more of the white shine be at the tip of the metal.

Now it should look like this:

Now your spike is done.

Additional Step:

Link all the layers that make up the spike, so that they would move as one group from now on and were going to rotate it 3 times by 90 degrees clockwise and make 4 spikes from one image. So after linking the layers go to Edit > Transform > Rotate 90 CW.
Now you would have 4 spikes that looks like these babies:

Note that the drop shadow is consistent for all 4 spikes, which is great if you trying to have global lighting in the entire image.

Doing this is a valuable time saver to avoid redoing stuff, you can also rotate by smaller amounts but doing that would most likely make the image blurry. You can however rotate them by smaller degrees then shrink the spikes to make the blurring less visible which is another small trick.

You can see how this style was used in version 3 of my site, here is another example of how it was used in my one of my old signature images. Note the 3 shrunken spikes are all from the same image.