Cleanliness is going to be your most important factor in this process!!! Obviously being so close to the road, your wheels will not only pick up, but they will also be embedded with alot of road grime, so your most important part is going to be cleaning both your rims and tyres (that is obviously if you cant get the tyres taken off - which in the long run will not only make the job a hell of a lot easier, but will also give you a better final product). Look at getting yourself a good quality wax and grease remover or 'prepsol' (wherever you are buying your paint from should also sell this product)
I am not familar with the 'duplicolor shadow paint kit', but unless it is something special, I will give you a quick run down on how I paint a set of rims.
- Wax and grease (extremely thoroughly) both your rims and tyres - using one rag to wipe on, and a clean rag to wipe off. You may need to do this 2 or 3 times before you no longer get any dirt on your rags. (by cleaning your tyres this works in two ways 1. removes dirt and grime, 2. will allow for masking tape to stick later on in the process). Its also worth cleaning the inside of the rim. Dirt and grease particles can float in the air, so you dont want this to be dirty otherwise when you begin painting they will land and contaminate your fresh paint work!
- Use P800 wet and dry (by using water it will act as a lubricant, thus your scuff scratches will not be so deep, and fill up with paint and become invisible) to scuff up the rim. Be sure to sand the entire wheel, especially all the little nooks and crannies around the edge of the wheel (fresh paint will not stick to old, unscuffed paint work - and after a matter of time will begin to flake away.
- If possible use an air gun and dry rag to clean and dry the rim. You dont want there to be any water traces. If your tyres are still on you will really have to concentrate around the bead where they join the wheel, this may take a while, but you MUST get all the water out before you begin painting.
- Again wax and grease both the tyre and rim, using a dry rag to apply it, and a clean rag to wipe it off.
- Use 2inch masking tape to mask your tyres off. I have found the best way to do this is in small sections at a time (approx 10cm). Push it up under the lip of the tyre and then fold it back so it sticks to the tyre - continue doing this until the complete tyre is masked up, you can then finally use something such as newspaper to cover the remainder of the tyre that can be seen. I know its time consuming, but its a lot easier than trying to clean paint of your tyres at the end!! You will see at this stage how important it was to clean the tyre to allow the tape to stick, as well as to blow out all the water.
- Again wax and grease the wheel. This is your final stage now before you apply the paint, so whatever dirt or grime is left on your rim will then be in your paint work. If you are able to get hold of a tack cloth (a slightly sticky cloth that will pick up dirt particles - should also be available from where you purchased your paint from) use that at the end of wax and grease and wipe over the entire rim.
- You are now ready for the fun part. Begin spraying, again take your time with it - but most of all enjoy watching it transform before your eyes!!!
Another extremely important thing is the clear coat you will put on the rims. You will need a clear coat that is hard, thus protecting it from stone chips, scratches etc. I would only ever use a 2 pack clearcoat on rims (a 2 componant clear, where you physically need to add a hardener, and possibly a thinner as well), and would stay well away from acrylic, and especially spray can jobs - they just wont give you the protection needed, and after a matter of time (possibly weeks) you will need to redo the whole process again!!!
Unfortunatly with painting (anything, whether it be rims, a fender, an entire vehicle or even your bathroom wall) the time and effort you put into the preperation will show with the end product. I was a spray painter for 10 years, and a paint manufacturer technical consultant for 5 years and found there was just no way of getting around the importance of preperation (and yes unfortunatly I learnt that the hard way on more than one occasion!!)
I hope this helps a little - and would love to see both before and after pictures!!!