(Yet Another) Der Big Red Max build
- Thread starter ep29030
- Start date
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PAINT AND FINISH
As I mentioned earlier, my approach is to fill spirals in the airframe, and get most of the fin imperfections out before I start assembling. It is just easier to sand down the parts when they can be laid out and flattened. I usually do 2 coats of sanding sealer on MPR/HPR kits followed by sanding it all off. This normally gets everything ready for a final primer coat, then on to final paint. If I find a deeper spot, my usual approach is to fill with spot putty, sand it down and hit it with primer to see if it needs more work. Switching sandable primer colors between coats (e.g. gray, then brick red) can be helpful to see how the finish is progressing. I fly most of my kits so I want it to look nice, but I am not obsessing over it. If I am not happy with something after 2 coats, I just repeat the process once more and that usually fixes it.
I wet sanded the nosecone with 600 grit at the sink, dried it off and painted it with a coat of Duplicolor self-etching primer. I had a couple of spots that needed some spot putty. They were filled, the entire cone was dry sanded with 400 grit and coated again with self-etching primer. Looks good, so on to the black paint.
For the rocket body, I decided to go with Duplicolor Ceramic paint (Chrysler Red). I used Duplicolor Ceramic gloss black on the nosecone. Once the decals and paint touch-up were done, I finished the paint with Duplicolor 1K Clearcoat High Gloss paint. These are all rattle can paints from the local auto parts store. For all paints, I spray a light coat to cover the surfaces, wait 10 minutes then hit it with a heavier second coat that gets the paint to flow and level (without getting runs).
After the Red coat dried for two days, I did a light wet sanding of the red with 800 grit wet sandpaper, followed with wiping down the surfaces and applying decals.
I did not like the small red gap at the top of the airframe so I touched it up with a gloss black paint pen I had. It looks bad against the flatter finish of the decal, but I knew the clear coat would make them have a uniform look at the finish, so I didn't worry about it. Turned out fine.
I hand painted the aft end of airframe with flat black before I used JB Weld to attach the motor retainer. The aft end always gets a burned look after 3-4 flights so the black just starts it where it will end up anyway.
I scuffed up the bottoms of the rail guides, cleaned them with acetone and glued them down with epoxy.
As I mentioned earlier, my approach is to fill spirals in the airframe, and get most of the fin imperfections out before I start assembling. It is just easier to sand down the parts when they can be laid out and flattened. I usually do 2 coats of sanding sealer on MPR/HPR kits followed by sanding it all off. This normally gets everything ready for a final primer coat, then on to final paint. If I find a deeper spot, my usual approach is to fill with spot putty, sand it down and hit it with primer to see if it needs more work. Switching sandable primer colors between coats (e.g. gray, then brick red) can be helpful to see how the finish is progressing. I fly most of my kits so I want it to look nice, but I am not obsessing over it. If I am not happy with something after 2 coats, I just repeat the process once more and that usually fixes it.
I wet sanded the nosecone with 600 grit at the sink, dried it off and painted it with a coat of Duplicolor self-etching primer. I had a couple of spots that needed some spot putty. They were filled, the entire cone was dry sanded with 400 grit and coated again with self-etching primer. Looks good, so on to the black paint.
For the rocket body, I decided to go with Duplicolor Ceramic paint (Chrysler Red). I used Duplicolor Ceramic gloss black on the nosecone. Once the decals and paint touch-up were done, I finished the paint with Duplicolor 1K Clearcoat High Gloss paint. These are all rattle can paints from the local auto parts store. For all paints, I spray a light coat to cover the surfaces, wait 10 minutes then hit it with a heavier second coat that gets the paint to flow and level (without getting runs).
After the Red coat dried for two days, I did a light wet sanding of the red with 800 grit wet sandpaper, followed with wiping down the surfaces and applying decals.
I did not like the small red gap at the top of the airframe so I touched it up with a gloss black paint pen I had. It looks bad against the flatter finish of the decal, but I knew the clear coat would make them have a uniform look at the finish, so I didn't worry about it. Turned out fine.
I hand painted the aft end of airframe with flat black before I used JB Weld to attach the motor retainer. The aft end always gets a burned look after 3-4 flights so the black just starts it where it will end up anyway.
I scuffed up the bottoms of the rail guides, cleaned them with acetone and glued them down with epoxy.
Attachments
RECOVERY SYSTEM
I used a 15 ft piece of woven Kevlar I had in my box for the recovery train. I used a small SS quick link to attach both Kevlar shock cord and parachute to the nosecone Kevlar loop I created. I decided to abandon the provided parachute and go with a 30 inch X-form from Top Flite. I'm a fan of X-forms because they have less opening force than flat round chutes. I have an old PML Tethys I flew several times without issue using a homemade 54" X-form; the first time I used a flat round chute, I got a zipper, so it's back to the X-form for me. BTW, Rocketman-style chute are just X-forms with tucked in gore ends. X-forms have a lower drag coefficient so you will need a larger one. Anyway, that completes this rocket. I'll probably break it in with an F motor, then try a G80 to see what it will do.
I used a 15 ft piece of woven Kevlar I had in my box for the recovery train. I used a small SS quick link to attach both Kevlar shock cord and parachute to the nosecone Kevlar loop I created. I decided to abandon the provided parachute and go with a 30 inch X-form from Top Flite. I'm a fan of X-forms because they have less opening force than flat round chutes. I have an old PML Tethys I flew several times without issue using a homemade 54" X-form; the first time I used a flat round chute, I got a zipper, so it's back to the X-form for me. BTW, Rocketman-style chute are just X-forms with tucked in gore ends. X-forms have a lower drag coefficient so you will need a larger one. Anyway, that completes this rocket. I'll probably break it in with an F motor, then try a G80 to see what it will do.
Nice job and thanks for taking us along!
that sure turned out nice 
That looks amazing. Duplicolor is about the best paint I've found over the counter without going to a custom mixed and filled can from an auto paint distributor.
I've sprayed a lot of Duplicolor in the very conditions that they tell you not to. I just now sprayed a red nose cone, a body tube with a few coats of primer, and another tube gloss black.
It's 40deg out, and raining. Everything came out perfect.
Hans.
It's 40deg out, and raining. Everything came out perfect.
Hans.
With recovery system it is 18.25oz. : Airframe w/o nosecone or recovery = 9.75oz, Nosecone = 5.75oz (mostly epoxy/coupler in the tip), recovery system (Kevlar+chute) = 2.75oz. There's probably 4-5 oz of paint on there. Can't wait for some nice weather to put a large G/baby H motor in it. Those fins are rigid and I believe the kit can handle it. By adding the coupler in the nose I have the ability to screw in additional weight or a GPS unit. The kit provides clay weight for the nose--I just replaced it with a 1/4" coupler set in epoxy. I put a coupler in just about all my MPR/HPR kits anymore. Just build a normal av bay, add a bolt at the front and it can be added and removed quickly.
Max is a heavy boy. Mine weights in at 20.3 with recovery minus motor with the plywood upgrade and a baffle.
Part of my intent for my build was moving the CG forward by my building choices, rather than just throwing clay weight in the nose. If you are going to take on additional weight, get something for it. The reinforced balsa fins came in lighter than plywood while giving me the added stiffness for larger motors and lighter fins keep the CG from moving rearward. I used a longer motor mount and used the middle centering ring as a baffle. The longer mount move CG forward by keeping the recovery system closer to the nose during flight. I could have moved it forward to the place that the nosecone shoulder sat flush on the top centering ring and the recovery system was inside the nosecone. That would have moved CG forward even more. My decision to use a plywood plug to cap the motor tube and be the recovery system attachment point also added more weight. That's the one part where I could have saved weight with a different recovery attachment design (such as Kevlar attachment to fin roots). The added weight of that plug/screw eye helped to move CG forward. And the coupler epoxied into the nose added about 3oz of weight, but adds the ability to screw av bays or weights into the nose and remove them, rather than just add nose weight.
Fantastic thread.
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