Doc O'Briens Powders

Welcome to the forum Bob.  For $20 you can get a set of chalk pastels, not oil... the oil ones are more crayon-like, with more than the 12 colors that set will give you and probably find you are going to use few of those as well.  I got a set of about 20 coclors for about $13.  Yopu can either scrape them across sandpaper to makes a little pile or scarpe a sharp blade dowm the legth of the chalk.  Why pay someoen else extra just to have them powdered all ready.

Bob,

I have used both the chalks, and just recently MMP powders. I have better results with MMP. Mixed with Future, or alcohol, makes great mudd, crudd or whatever. If you over do it, just remove to your taste. It can also be applied dry as  dusting or fading effect. It 'bites' more on flat paints that chalks.

Well-- I have to disagree with Marc.  I was given them for Christmas last year and will never go back to pastels.  The set of them is under $20 and I have barely used any in a year of modeling...they seem to grab much better than pastels- not sure if they added anything to the powders or not...I have attached some pics of some of my builds to show their use-- for exhausts:

And for dust and such in a desert environment: