how thick?

how thick is the material you are using?

I have laminated 1/8" material together to make 1/4 or 3/8" curves just using wood glue.

kerf's

You can cut 1/8" deep Kerfs in the material to help it bend.

I would use a double layer of 1/8 material for the corners.

I've curved 1/4" MDF successfully

I'm making glacial progress on an N scale switching layout, which I used 1/4" MDF as fascia for.  There are a couple pretty tight curves at the corners, which came out nicely.  I wrote up what I did with pictures on my blog:

http://rices-rails.blogspot.com/2011/11/palmer-industrial-fascia.html

Basically, soak the section you want to bend thoroughly, make the bend a little bit at a time letting it soak at each stage, and then clamp in place on some sort of form that has the right curve - I clamped mine right to the layout.  Patience is key.  First one I did went fine, the second curve I got a little impatient and over ambitious at first (2 curves in piece section is hard to manage), and broke a couple pieces.

- Ken

MDF

I never thought of that, but then I get an occasional free supply of thin hardboard from my job, and have a plentiful stash for whenever I get around to actually doing my fascia.

Yeah, thickness is the key I would think.  Just my two cents from wood-working, wet-it as suggested or kerf-it as also suggested.  Maybe both.  If you have a table saw, even a really cheap one like I have you can set that blade depth at whatever is appropriate and make your parallel lines along the kerf.  If less that maybe 1/2" MDF I'd probably not kerf it, but who know's?  I've never tried to kerf MDF.

Almost need a layout

diagram.  You can use mixed-media as a fascia!  MDF for the straight-ish and thin hardboard for the curves.  Spackle is a wonderful thing that is nicely sanded smooth for a transition joint and of course it's all primed over/painted eventually, right??

Consider that.

Thanks all!

OK, I'll give a try to wetting the MDF and see how it goes.  Kerfing it is an option but I ain't that comfortable using a table saw yet so I'll pass on this...  but thanks for the trick.

Ok...  time to go and prepare my stuff for the Ottawa Train Expo this weekend...

Food... check!

Drinks... check!

Credit card... check!

Router

You could also make the "kerf" cuts with a router if you are not comfortable with a table saw. Actually, a radial arm saw would be ideal.

The expensive way...

If you want to go the kerf route but aren't comfortable kerfing, you can always spend your way out of the problem - there are several sources I found that sell pre-kerfed MDF, like this one:

http://www.roberts-plywood.com/neat-form-bendable-mdf.html

Cool stuff.  But wetting and bending my own was cheaper, plus I didn't have to fill in or cover up the kerfs on the top edge.

- Ken

You can also purchase kerfed MDF from Rockler

http://www.rockler.com/product.cfm?page=11206&site=ROCKLER

Ok...

...after thinking it through for a week, I finally decided to just make a 35 degree angle instead of curving it.

Picture are coming tonight as I don't have access to my pictures from work.

Thanks all for your advice,

Chris