FETTLING
Check over the chassis and laser cut parts for laser cut splatter and small tags. The little tags are from where the laser cutters have left the part attached to the sheet of steel rather than drop it through the machine. They then punch out the parts and collect them up working away from the machine.

File and clean up all the steel to a standard you are happy with. Pay special attention to the axle keeps as rough steel or a tag can damage the Delrin axle box.

CLEAN

You do not stand a chance of getting your paint to stick with out cleaning the chassis - key areas -

1. Wire brush all the laser cut edges. The laser cutting tends to leave a dark layer of charred steel. This comes off easily with a wire brush and/or a course wet and dry.
2. Welding splatter/soot. It is obvious where it has been welded. Remove all the spatter and soot with a wire brush. Harder stuck on spatter may need knocking off with a screwdriver and a hammer (yes I know bad practice).
3. Wipe over the whole chassis with a solvent to remove the grease. Standard thinners or white spirit. Wipe over afterwards with a clean cloth and keep wiping until a clean cloth stays clean.
4. Be careful not to put the grease back on with your hands or using a dirty cloth. There are commercial pre paint wipes available which may help.

PAINT

There are those out there who have a far better knowledge and understanding of painting than we do. Below is a basic guide which will give good results using methods that are safe and with in the ability of most model engineers.

Always buy more cans than you need. Colours from different batches probably won't match. Cans can stop working for no reason so don't tempt fate.

Aerosol Paint - this offers a cost effective method of painting with the paint being easily obtainable locally.

1. Plan your painting. Clean work area - well vented, dust free and warm.
2. Warm up* the air and the item you are going to spray.
3. Roll up small paper tubes and insert in to buffer shanks to keep paint out. Buffers will not fit if you paint the inside of the shanks.
   
4. Try and suspend the item so it can be rotated or you can get around it. Drying time for handling is usually quite quick (10 minutes or so) so you can re hang or turn the item around to spray from another angle.Alternatively put on clean blocks or paint lids to lift it off the table, which is where the dust settles.
5. Do not over apply the paint. Better to build in thin coats - see can instructions. If you are not used to painting then paint on table where there is less chance of paint runs.
   
6. 1st coat should ideally be an etched primer that will help bond the paint to the chassis. Expensive but well worth the investment. Follow the instructions on the can - especially the health and safety ones. Some etch primers contain some pretty nasty chemicals, so wear the appropriate mask.
7. Leave to dry before re coating. Times will be listed on the can. If you want to accelerate drying time use a low wave heat lamp or a radiant heater such as a patio heater or put out in the sun. Do not heat with a fan heater. See notes below. Apply at least two coats.
8. If it is too hot (25 deg C+) you may find the paint dries in the air and it is very hard to get a wet lay on the item. Do not keep going, wait until it cools down.
   
9. Inspect in daylight before spraying next coat to help identify missed parts
   
10. Paint runs - not end of the world. If you can spot them when spraying then dab with a clean sponge while the paint is wet. Dab a whole area if necessary. Lightly over spray the dabbed area. This should leave an easier area to sand once dry as against paint runs that take ages to dry and are hard to sand with out removing the surrounding paint.
    

Before applying top coats - inspect the chassis. Rub down obvious areas + use filler if required. Recommend to use a two pack filler as it less likely to shrink over time. It also sets pretty quickly so doesn't delay the painting process. Cover filler and sanded areas with additional primer coat.

Acrylic Paints

1. These are easily available from car accessory shops in numerous colours and give a good quality finish.
2. Give the primer coats plenty of time to dry before applying the first top coats.
3. Follow instructions on the can except the turn it upside down to clean the nozzle. All you do is waste propellant and make a mess.
   
4. Plan to use the can in sessions. This reduces the chances of the nozzle blocking and wrecking the can. Swapping the nozzles rarely works.
   

NOTES

• * Do not dry paint with convected heat - ie a fan heater. This will cause the paint to skin over and may trap solvent in the lower layers. This can cause paint failure at a later date - especially if the item is taken in to a warm house.
  
• If you are intending to paint the buffer beam a different colour, paint at a later date. It is fairly easy to mask up and over paint with a primer and different colour. Putting masking tape on paint which has solvent in it will mark the paint. To be safe leave paint at least a week, use a low tack tape and keep it on for a short a period as possible.
• Minor blemishes in paint can be rubbed down and polished out once the paint has set. Leave it at least two weeks and use water or a water based cutting compound.