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roll pattern question ?

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bobby_hamill

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It has been a while since I masked off and painted the roll pattern for my 4 inch
Black Brant 2 ( 4 fin version ) . And now I am attempting the same thing but on a BT-55 airframe .

My question is, could it be possible to cut the fin slots on the airframe and then finish the airframe with primer and roll pattern before installing the fins ?

The fins will have internal fillets under the BT-55 airframe and be attached to the BT-50 motor mount tube.

Thanks

Bobby
 

Nytrunner

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You could leave a small (~1mm or >) strip next to each slot and touch that up later once glued.
That should allow you to put a tiny fillet in.
Unless you don't want any glue on the external side at all.
 

ECayemberg

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You could leave a small (~1mm or >) strip next to each slot and touch that up later once glued.
That should allow you to put a tiny fillet in.
Unless you don't want any glue on the external side at all.
Absolutely! I do the same concept every time I cover a rocket in r/c airplane film (Monokote or Ultracoat). It's way easier to cover the airframe, fins, prior to assembly. So the rocket gets it color and then gets assembled. Mid-High power no issues.

Love the BB2 with the roll pattern...make sure to post photos!
 

bobby_hamill

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Eric

I thought masking roll patterns on airframe and fins was a pain on a 4" black Brant
now trying it on a 1.3" BT-55 airframe . 2-3 nights on the airframe roll pattern and just marked the fin
roll patterns and started to mask them . 1 section per night as the neck and eyes get tired quickly :)

The sections I am masking over will be painted white

I will post a build soon as I am waiting on an airbrush to come in and for it to get warmer outside

Bobby

BB roll pattern.jpg
 

bobby_hamill

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Eric

Here is the BB ready for a coat of black paint after the roll pattern has been taped off
I didn't use a primer coat as this is just for "training" and technique down pat again

Bobby

roll complete.jpg
 

mpitfield

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Are you painting the white then masking and painting the black?
 

bobby_hamill

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the white is covered up at present as I will be using black first . Let the paint cure for about a week then mask off and spray the white.

The way I use to paint the roll pattern was to do the primer in gray. And after I was satisfied with the primer then shoot the complete model in white and after the white had cured mark and mask off the white and shoot the black.

This way would leave a "raised" black roll pattern on the white . A layer of clear coat would make the complete surface smooth.

This time I will mask off for the black first. shoot the black then set the model aside for 1 week to allow the paint to cure, then mask off the black and shoot the white this way both roll patters will be "level" with each other . After another 1 week cure time shoot with clear coat

Bobby

Bobby
 

mpitfield

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the white is covered up at present as I will be using black first . Let the paint cure for about a week then mask off and spray the white.

The way I use to paint the roll pattern was to do the primer in gray. And after I was satisfied with the primer then shoot the complete model in white and after the white had cured mark and mask off the white and shoot the black.

This way would leave a "raised" black roll pattern on the white . A layer of clear coat would make the complete surface smooth.

This time I will mask off for the black first. shoot the black then set the model aside for 1 week to allow the paint to cure, then mask off the black and shoot the white this way both roll patters will be "level" with each other . After another 1 week cure time shoot with clear coat

Bobby

Bobby
I think you will find that you will get better results by spraying the entire rocket white, wet sanding with 600, masking for black then spraying the black. Once the black is sprayed remove the tape when it is still a bit soft but not too soft let dry for a day or two then block sand with 600.

If you plan on laying down a top coat of clear then don't block sand too much, just cut the edges down a bit, lay down a couple layers of clear then block sand until flush and lay down your final clear. If you want to get that mirror finish then use progressive grit from 600-800-1000-1500-2000, then you could use an automotive polishing compound or ideally a 3 step system followed by a final wax.

Of course this represents quite a bit of work so it may not be something you're interested in, however laying down the white on the entire rocket, masking off the white and spraying the black should give you better results.
 

bobby_hamill

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mpitfield


Thanks for the paint tips as I am always open to new ideas
I am working on a 6" 4 fin BB 2 with the same roll pattern.
Fins will be scale airfoil type cast in alumlite resin and I have the antenna
and launch lugs 3d printed but not cast yet

this is what the roll pattern looks like.

Bobby

BB 2 x 2.jpg
 

bobby_hamill

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Here is BB with tape off . since this was just a test at painting and masking I did not seal the fins so there was some paint bleeding past the tape. Plus this was my first time using tamiya tape. .

I may go back using regular old masking tape

tape off.jpg
 

TangoJuliet

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bobby_hamill, did you use any sealer on the fins? It appears that the paint has followed the grain of the wood under where you had it masked. Tamiya Tape is normally highly praised, but your surface preparation needs to be up to the task.
 

bobby_hamill

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TangoJuliet

I didn't use any surface prep as this was just a practice for me on masking the roll pattern.
I have not done a roll pattern mask in over 5 years so some practice was in order. I knew the birch fins were gonna bleed through.
This rocket also has an E motor mount so I can test it with an D motor and a E motor

Bobby
 

bobby_hamill

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I finally got around to masking off the black roll pattern and painting the white roll pattern.
Any masking and painting practice I can get will help.
The birch plywood fins were not sealed on this build

And speaking of sealing fins I grabbed a scrap fin section and tried a new sealing process ( to me it is new )
I used some Elmer's Carpenter's Wood Filler placed a small bead of filler on the fin and wet my finger
and rubbed the filler into the wood grain. I used my finger to smooth the filler and take of the excess and applied
the excess filler to the other fin. The filler spreads very easy when you keep it slightly wet. After the filler dries
I will see how it sands out and how good it takes the paint :)

I will get the fins done later on

roll pattern.jpg


Elmer's WoodFiller.jpg
 

bobby_hamill

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after using the ECWF I sanded the 2 fin sections with what I think is 230 grit but it has a 150 on it to so I dont know which it is
then 3 light coats 4 minutes apart
sand with 600 then 1000 grit paper
finally 2 more mist coats 5 minutes apart

after each sanding make sure you wipe ALL of the dust off before painting !

grit.jpg


sand with 600 grit.jpg


sand with 1000 grit.jpg


2 light coats after sanding.jpg
 
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