About enmels, acrilics pastel chalks and others...

Hector,
The chalks used for weathering are the dry pastel type, get them at an arts supply shop - try to stay away from the oil based ones, they're difficult to apply and almost useless for this purpose. The ones you want are dry like the white chalk the teachers use at school on the blackboard. They usually come in a pack that has a whole bunch of colors. Take a chunk of rough sandpaper, then rub the dry pastel chalk stick (whatever color you need) on the sandpaper to make a little pile. Then using a brush, q-tip, fingers - whatever - apply the chalk to the model wherever it needs it - exhaust, dust, dirt, grime etc.
Some paints are enamel based, (Testors, Model Master etc) being a petroleum product, requiring an enamel type thinner to thin the paint.
Some paints are water based acrylics (like Tamiya and Gunze Sangyo) and can be thinned with water or isopropyl alcohol.
Other paints (like X-tra Color) are enamel based (I think) but need white spirit to thin them - white spirit is a refined type of turpentine.
You generally can't mix one with the other, and you should always follow the manufacturers directions if you're unsure.
To do a "wash" to weather something, take a little amount of paint on a pallette or in a small container and add a whole bunch of thinner to it, then apply to the corners and engraved bits on your model using a fine brush. Some wipe off the excess, some leave it on. It makes the corners and recesses darken up and gives depth to the model.
VERY IMPORTANT - make sure you use a gentle type of wash over your paintwork because some types of paints will EAT others!!!! If you paint your model with enamels, and then use an enamel wash, the thinners will just eat away the original paint color, making a mess and breaking your heart.
I have painted models with enamels and done a wash with enamels, but I spray the model first with Future floor was, protecting the original paintwork - the Future provides a protective "barrier" between the paint and the wash.
Hope this helped - I'll have a look again soon to see if you have any more questions - there's also about 16,000 users who will help, so don't be shy about asking. That's what we're here for, mate.
Cheers,
LeeTree

Hey mandrake. Well there are lots of pigments you can use to paint and weather Armor, Aircraft etc. Acrylic paint is water based and therefore must be thinned with either water or alchohol. Enamel Paint is oil based and needs to be thinned with mineral spirits or turpentine (miniral spirits is best). Artist Oils are of course Oil based and thinned with Turpentine. Laquer based paints need to be thinned with Laquer thinner. As for Pastels, they come in sticks and there are two types..hard and soft. Hard pastels are the best and the ones to use. You have to shave down the stick with either sand paper or a Xacto knife.

I model Armor almost exclusively and use Acrylic paint 99% of the time. After I give my model it's base coat or camo pattern, I then wash my vehicle with oil paints thinned with turpinoid (turpentine). By washing the vehicle in oil pased paint, it will not effect the water based base coat. If you base coat your model in Enamels, you have to give it at least 48 hours to cure, apply a coat of Future or Acrylic vanish, if you are to use Oil based washes. Pastels are used as a shadowing technique mostly, and can be mixed with thinner or applyied staright to the model to add depth to detail etc.

I guess you can go on and on on techniques with all the types of pigments, and I am sure there will be some more posts explaining it. I hope I was able to help.

Rob

This site has some good information about weathering kits. I use it a lot when I am having weathering problems:

http://www.missing-lynx.com/rareworld.htm

Mandrake,

The other answers have generally covered your issues, but I'll say a few things about paint (I've been learning alot about this lately and so far I still don't totally understand them...so if anyone spots something I say as incorrect, please let me know!)

Basically, paints are primarily defined by two major things:
1. How they dry (evaporation, or chemical reaction/curing)
2. What type of 'carrier' is used with the pigment (water based or petroleum based)
When you get into automotive type paints it gets quite a bit more complicated, so I'll ignore that...

I'll tell you a bit more, but firstly you need to know that we (ie. everyone in this hobby) has adopted some terms and definitions of paints that aren't 100% correct. For instance, we often refer to any paint that is 'water-based' as an 'acrylic', however you can get acrylic paints that are petroleum based as well. The definition is complicated and not worth going into, other than to just let you know that the term is used differently in this hobby than it would be by paint 'professionals'. The term 'enamels' is often used to describe paints that are 'petroleum based' when the reality is that many water-based paints are actually enamels in a technical sense. We all know what we mean when we say 'acrylic' or 'enamel', but understanding this is a little bit important if you really want to know about paints.

Back to my definition:
1. How they dry:
a. Some paints are just a pigment suspended in a liquid. When the liquid evaporates, the paint pigment is left on the surface. Not many 'hobby' paints are like this but examples would be like children's water paints, etc where you just add some sort of liquid (water in this case) and the pigment is transfered with the liquid. The liquid could be water based, or petroleum based.
b. Most hobby paints we use go through a chemical reaction when they are drying that is called 'curing' (essentially the paints chemicals are reacting with the air that initiates the 'reaction'). These types of paints are called 'enamels'. It really doesn't matter if they are water based or petroleum based. If they 'cure', then they are and enamel. The most common type you'd be familiar with are Testors or Model Master paints which are essentially petroleum based enamels. However, the Tamiya and Gunze type paints also go through a 'curing' process and essentially then are also enamels, but in their case they are 'water' based. The unique thing about an 'enamel' paint is that once it is fully cured, the process cannot be reversed (the type of paints in 1.a. can be re-dissolved in their thinners and reapplied in the same manner). Enamel paints can be dissolved, but they will not go through the same 'curing' process a second time.

2. The second item that defines a type of paint (and probably the most important to the hobby user) is the type of carrier. (you've probaly heard that oil and water don't mix... well you can likely guess what the two main carrier types are:)
a. water based paints are essentially made up of a carrier that is either water or soluble in water. You'll often hear that people use alcohol with these types of paints and that's because alcohol is generally soluble in water. The actual carrier is usually some exotic mix of alcohol and other mysterious ingredients, but they are designed this way so that younger modellers can just use water to mix their paints (ie. ease of use). However, the closer you can get to the actual chemical used, the better the paint will mix and dilute. That is why many people use alcohol. You will also hear of people using things like Windex, windshield washer fluid and other bizarre things. They all do basically the same thing, but some just seem to do the job better and/or cheaper. Tamiya, Gunze, and ModelMaster Acryl paints are all in this category. You'll notice that they all sell 'thinners' that chemically match their paints. 'Cheapskates' like me prefer to use an alternative that does 95%+ the same job, but is much cheaper and easier to get (ie. alcohol or water).
b. oil based paints have a petroleum based carrier. The same rationale applies here. Any 'petroleum' based item (ie. Turpentine, Varsol, Mineral Spirits, etc, etc) will essentially work to thin the paint, but the closer it is to the actual chemical used by the manufacturer, the better. Some paints work better with Turpentine, and others work better with Lacquer Thinner. Personally, I use Lacquer Thinner for EVERY oil based paint I use. It does the job for me and I don't have a single complaint about using it. Some of these thinners/carriers are very exotic and hazardous to your health. Chemicals like Xylene and Toluene are usually the main ingredients used, but these things are very BAD for your health. That's why we often recommend using a respirator when using these types of paints. The fumes can cause your brayn ot ddo crasy thinks and nnot evn no bout itttttttttt!!!! NO I don't want a sandwich!!

So, now that I've confused you, here's my recommendation:
- when you're using "acrylic" paints (ie. water based), try alcohol as a thinner. It seems to be the most common and gives good results. You can use just plain water as well, but I think that most people prefer to use alcohol.
- when you're using "enamel" paints (ie. oil based), use whatever petroleum-based thinner you choose. Turpentine, Varsol and Lac.thinner will all work reasonably well
- if you're not sure which category it is in, try mixing a little bit on a palette with each thinner and you'll be able to tell pretty quickly. They'll either mix, or not. This is also a good way to determine which thinner works 'best'. ie. try mixing some Tamiya paint with water. Then try alcohol. Then try their thinner. They should all mix, but I expect you will see that the alcohol will blend more 'smoothly' than the water will.

The magic of all this is that you just need to know that these two 'types' of paints don't mix. So, if you're going to do a 'wash' or something like that, make sure that the base coat is one type, and the wash is another type. This way they won't dissolve into each other and make a mess.

Sorry for the long winded post. I didn't cover all the possibilities, but likely 90% of the things we'll run into in this hobby. I didn't mention lacquer paints, which are basically a petroleum based paint where the carrier 'evaporates' instead of cures. Future itself is essentially a water-based enamel, but it behaves in some ways that put it in a category all it's own.

Good luck


Murray

Wow, that was a long post. Someone smack me...

Murray

Good info though, thanks for that.

Hey thanks a lot, this info is very helpful, i feel more confident about mixing paints and stuff, now i understand the difference much better, but i´ve never seen the Turpentine neither Varsol nor Mineral Spirits or Pastels, can any one suggest me a good brand of this material? any brand that may be cheap and "good" for my inexperience..

Thank you LeeTree, Rob, kaleu and Murray :-)

This post will be shorter... I promise:
- Turpentine, Varsol, Mineral Spirits, and Lacquer Thinner can usually be bought at any hardware store or a big-box store like Home Depot.
- Pastels can be bought in any art supply store and I've also seen them in office supply stores like Office Depot or Staples. Make sure you get 'chalk' pastels and not 'oil' pastels...

Over-and-out.

Murray

Roger that, wilco, that will help a lot, thank you very much!

over and out.

Well done Murray!
Thats the type of info I like. Understand the subject and you will have less problem in the long run.

Mike