Bob's Painting Tips
For Mammoet models I use:
Completely disassemble the model. Most truck cranes are two parts, the chassis and the crane. There is usually a screw that holds them together attached from underneath or from the top. You may have to pull the boom up as far as it will go if the screw is in from the top. With the chassis, you have to figure out how the wheels and axles come off. Some Conrad stuff you usually wind up breaking the pins that hold them in as they are crimped in after assembly. I epoxy them in during reassembly or you can drill a hole through them and run a piece of solid brass rod, cut to length. Other manufacturers are held with screws making it easier. If they are riveted, be prepared to drill them out and re attach with epoxy. Remove any screws you see, remove out riggers, pop cab off, pull off any exhaust stacks, most are pushed in with pins. As for the crane you will need to drill most of the rivets holding the hydraulic piston/ram as well as where the boom attaches. You will need to drill out rivets on the mast head pulleys as well as any jib pulleys. Some masts are held with pins and just need to be pushed. Remove the counter weight it may be screwed or press fitted, again drill and epoxy. Pull out extensions be careful to note that the little safety keeper is spring loaded and if you loose it the section will not be able to hold its position. These springs and little metal keepers are the key to the whole boom operation. Crawler cranes are roughly the same, just keep disassembling the unit to the most base componets-remove the tracks, pull rotating wheel off, drill out rivets etc.. Removal of winch droms is roughly the same for either of the crane types, the either have a shaft or are fixed mounted between rails, however they all have springs inside them to keep the drums tensioned. As with any spring, during removal they can fly anywhere, so keep your hand over the assembly and move slowly-or you will be on your knees looking for parts!!
- The next step is to strip the crane to bare metal. You can use a stripper or a glass bead sand blaster. I use both. I start with the sand blaster which depending on the model can remove the paint quite easily. If the blaster is having trouble and the paint being stuborn, then its time to break out the chemicals. A word of caution-strippers melt plastic so be careful. I start with Laquer Thinner and soak the parts. In 95% of all cases that I have encountered so far, 30 minutes or so in this stuff lossens the paint where it can be scrapped off with a brush. Then return to the sand blaster to get those last few areas clean. If Laquer Thinner does not work, thens it is time for the real strippers to come out, Bix Stripper or any grade carried by the home center/hardware stores will do the job. They are messy and sometimes not environmently friendly so read the labels and choose carefully. I take and remove every bit of paint from all metal items. Do not strip or blast plastic. I then go over all parts with 0000 steel wool cleaning up edges and smoothing the surfaces. Then a quick wash in a mild citrus acid and blow dry with compressed air.
- Hang all the pieces from there painting hangers so you work out all attachments points before you paint.
- Before painting the pieces you need to primer the pieces. The color of the underlying primer can affect the final color, believe it or not. I have a small piece of sheet metal that I cut into 2 x 4 inch squares and then spray red, white and gray primer. And then I put two coats of the end color on it and compare-make sure you write on the back which color primer was on the sample. You will be amazed at how a color will look with the different primers.
- Before laying down the primer you want to mask off any areas you do not want painted. I do the mast ends on telescoping cranes where the spring clip goes in. I also stuff the areas on the chassis where the out riggers go in. Painting inside the out rigger raceways and then out riggers will be too much paint. The outriggers will bind, stripping paint off or not come out at all. I roll up paper towel into a cigarette looking tube and stuff it in the out rigger raceways, then trim the ends off.
- Spray your primer coat, very light coat, get all the corners etc. Most primers dry in 12 minutes or less these days. I usually let them go an hour or so before handling. I also spray in a small booth made out of an old bed sheet and I wear a respirator and disposable latex gloves bought at any hardware store paint department.
- When I do the Mammoet’s, I under lay the red stripe on the crew cab and operators cab. After primer I then spray the red area where the stripe will be seen, making sure to do a wider area than needed. Lighter colors go under darker colors. After its dry (24 hours) I then use model masking tape to mask off the area I want red. I buy the tape at the hobby shop that sells the radio controlled planes and cars. I rub the tape into all the corners and cracks using tooth picks and q-tips because you do not want the next color to bleed through. Then spray the whole area with Testors dull coat top coat spray. It comes in a can and when dry helps seal the edges of the tape and prevents bleed through. I then spray the black over the piece one or two coats as needed. Wait 24 hours-no mater how tempted you are before removing the tape. Remove the tape and you should have a real great stripe. I do the same thing with the boom tips top get my red and black on them. On latice cranes in Mammoet, I hand paint the boom tips black as masking would take forever!
- I have painted with spray cans, for a first time it was good and might be a good idea to try. But after that I bought an air brush. I started with a Testors Aztec internal mix. Cost about $50.00. I have a compressor so I have an air source, if not they sell air in cans for use with these air brushes. I have since moved up to a GREX Genesis.XT airbrush, professional level model, internal mix which offers me more control. Always get an internal mix airbrush, not an external. When using the air brush it is important to thin the paint, even if the paint says not required. It is easier to control everything if you thin, but do not over thin or it will run! I use a ratio of 2/3 paint 1/3 thinner and I get pretty good results, sometimes I use a 60/40 on thicker paints and 50/50 on metallic paints. You have to play around with the paint and sometimes your compressor air pressure to see what works best. Make the paint go on in thin layers, making multiple passes to build up to a solid color. You may go over a piece two to twenty times before the layer is done. To much to fast will cause a run-and than means back to square one, strip it!
- Plastic pieces I rough up with very fine sand paper 320 grit. Depending on the color of the plastic and the color it needs to be determines if primer is needed. When painting black, I do not use primer. Other pieces that need to match, I use the same primer as on the metal pieces. These are usually little pieces I hang from hobby/florist wire and give them several coats.
- I let the pieces dry 24 hours when all have been given their final coats. Handling with gloves I wipe down every surface and then bake the finish on. I either place the pieces out in the sun for a day, when its over 80 degrees or I use the oven. With the oven, I preheat the oven to 350 degrees. I place all the METAL (never ever plastic) pieces on a cookie sheet lined with foil, leaning the parts on the lip of the cookie sheet so air can get on all sides. I turn the oven off and place the cookie sheet in the oven and keep it there until everything is at room temperature-about 2 hours. Bakes on the finish and gives a nice glossy shine. Recently I started to use a toaster oven which I use currently heat to 150 degrees and again place only metal pieces inside for ten minutes and then let cool to room temperature.
- Re assemble the model wearing gloves when practical. You will need to sand any pins, or file out any holes that parts attach with to remove paint if they do not fit. Epoxy part back where solid rivets were used as part of the castings. Fabricate new brass rivets from brass tubing of similar size. I have found that most of the time I can find just about the right one, and sometimes may have to drill out the holes to make room from my slightly bigger rivet. I use a home made flaring tool made from a C clamp with a pointed end on the screw. Others use a self centering punch for the same result, to flair out the end of the tubing to keep it in place. And a new method taught me is to use hollow tubing and super glue brass brad nail heads in the holes creating a perfect round head. Whenever possible I try to reuse the rivets pulled out.
- Print your decals on model decal water slide paper, spray with a gloss clear coat and let dry. Cut out decals and trim as small as possible. Before applying the decals I wipe the entire model down using McGuires Speed Detailer-its an automotive cleaner and wax. Spray on wipe off. I use Slovaset to help place all decals and to help them adhere to the surfaces, especially if uneven.
- I replace all thread/cable with the Musky Master Line from Cortland. Looks and works the best.
- Take picture and post!!
A red fast dry primer
Testors Model Master Enamel Guards Red
Testors Model master Enamel Gloss Black
Testors Air Brush Paint Thinner
I make my own red and white stripped decals with hobby decal paper bought at the hobby shop, white paper and I make the red lines and then cut with scissors to the desired size. Angled ones I cut in opposite directions to get left and right hashed stripes for use on bumpers and counter weights. Print them out, spray with clear gloss coat and let dry 24 hours before using them
Back to Cranes Home Page