Model Rocket Building Blog

Semroc IRIS Build Part 1 Parts
Here's all the parts from another of the Semroc Deci-Scale kits, the IRIS. I hope to show an alternative way to paint the black/white separations down the body tube. Some of the more interesting parts: That is one long, beautiful nose cone, 8" in length! In the center of the the centering rings, ...
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Semroc IRIS Build Part 2 Engine Mount
There is nothing out of the ordinary with the engine mount. The centering rings are a little thinner than I would have expected, but should work fine. I wanted to explain a way I use to wrap the retaining tape. This method insures two full wraps around the body tube and over the engine hook. I use ...
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Semroc IRIS Build Part 4 Fin Taper
This leading edge will be tapered down to almost a knife edge. With balsa being a light color, it's hard to see how thick the leading edge is. This idea was taken from how a luthier levels worn guitar frets. The frets are blackened with a permanent marker. When the top of the fret is filed down, ...
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Semroc IRIS Build Part 5 Fin Taper Fill
Using 400 grit on a block, lightly square the top of the edge taking off the remaining black ink. NOTE: My fins don't actually taper to a real knife edge. the leading edge is squared off a little. If the fins were to go to a very sharp edge, the leading edge is weakened. For now, leave the tape on ...
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Semroc IRIS Build Part 6 Paint Plan
Looking ahead, this is going to be a tricky mask. The IRIS picture is from the Semroc.com website I've decided to take the easy way out to get the split between the black and white sections of the main body. Sure, I could mask it and cross my fingers, but this method will give you a very clean ...
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Semroc IRIS Build Part 7 DIY Making A Coupler
Making a coupler has been covered before, but this one and it's application is a bit different. I've made them out of body tubes but not from stiff, black fish paper before. There was no Series 11 coupler in my parts box. I do have a BT-55 coupler. It's slightly bigger so it'll be cut down to ...
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Semroc IRIS Build Part 8 DIY Making A Coupler
Sand the joint edges with a block and keep them straight. The other half of the coupler is around the back of the sanding block edge. After a little sanding, here's the fit in the Series 11 IRIS tube. To hold the joint together, a glue tab was made from card stock and glued in place. Don't glue in ...
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Semroc IRIS Build Part 9 Nose Cone Shoulder
The nose cone was filled at the same time with the fins I mask off the base to keep the filler away from a good fitting nose cone shoulder To get the best fit at the shoulder, I'll lightly rough up the body tube end (just the flat edge) with 220 grit sandpaper on a block. I don't want to take too ...
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Semroc IRIS Build Part 10 Primer Band Mask
In this step, the tube will be marked for masking before spraying the primer. There will be a strip mask for both bands and the fin root edges. The bands will be glued on after the primer is sprayed and sanded. Later on, the fins will be glued on after they are painted red. The fins are even with ...
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Semroc IRIS Build Part 11 Gluing Bands
The fins, body tube and nose cone were sprayed with gray primer and sanded. The tape was removed before sanding the body tube. (You'll have to add back more tape strips before painting the white and black on the body tube.) I layed a thin bead of white glue to the flat finish side of the band. ...
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Semroc IRIS Build Part 12 Band Gluing
Here's the doubled band at the top of the body tube. Note there is a raised edge where the band ends. While gluing the band on the fin side, I was double checking the fit with the fin recess. Here, the first wrap is glued down. I've yet to add glue to the second narrow wrap and smooth out the glue ...
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Semroc IRIS Build Part 13 Engine Mount Gluing
The launch lug location had already been marked and masked on the tube. The engine hook will line up with the launch lug. The engine mount in now glued in place. Some instructions will have you place a bead of glue inside the tube, 1" from the end. Because these centering rings are thin, I tried ...
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Semroc IRIS Build Part 14 Fin Tab Gluing
Looking very close, there are some extended corners on the square tabs. Each tab was stood on end and the small extended corners cut square. The laser burned sides were sanded and cleaned up a bit with 400 grit on a block. A small glue line was set into the recesses with a sharpened dowel. Not ...
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Semroc IRIS Build Part 16 Color Separations
You can see how the wrap strip overlapped itself and left a ridge. It'll take some careful sanding and a little filling to make it less noticeable. Now, on to the black / white body paint pattern. This was first explained in post #6. Instead of a difficult mask, I wanted to try something a little ...
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Semroc IRIS Build Part 17 Color Separations
It's hard to see in this picture, but Scotch tape was used over the white area separation lines. Masking tape covered the area between the thinner Scotch tape lines. Here, the Scotch tape is removed. The mask line is looking clean so far. With all the tape removed, here's where the tube stands ...
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Semroc IRIS Build Part 18 Color Separations
The tube is marked halfway between the upper and lower bands, around 7 1/2" from the top. I wrapped card stock around the tube for an edge to cut against. Use a sharp knife and cut carefully. The paint will chip off if cut to quickly. Use a sanding block with 400 grit sandpaper to clean and square ...
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Semroc IRIS Build Part 19 Rear Color and Lugs
I used some aluminum Monokote trim material for the silver area behind the rear band. I used aluminum because the silver Monokote looked a little too metallic and shiny. The lower launch lug was wrapped with the same trim material. I didn't wrap it all the way around, but left a narrow open strip ...
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Semroc IRIS Build Part 20 Fin Mask and Gluing
All four fins have been sprayed red. The root edge on the left still has the thin masking tape strip in place. On the right, the tape has been removed. I used a sanding block over the root edge to remove the paint "step" and to take off most of the red down to the bare wood. A thin strip of ...
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Semroc IRIS Build Part 21 Oops!
This is what can happen when you take pictures for a blog by yourself. I dropped it! The IRIS fell hard and broke off two fins. The fin on the left has a pretty good ding in the trailing edge. Sure, it's all repairable. I used CWF (without thinning it with water) right out of the tub. For filling ...
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Semroc IRIS Build Part 22 Fin Fix and Decals
After the filler was sanded just the side with the dent was hit with gray primer. Then the obligatory white undercoat. Red followed and the two fins were re-glued again. Looking ahead at the decals: I didn't realize it, but the rear decals don't have a clear background, but are black printed on a ...
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Semroc IRIS Build Part 23 Decals
Between the IR and the IS is a very light pencil tick mark. This is the measured center of the IRIS decal. The body tube also has a very light pencil tick at the center of the upper white rectangle. This makes it easier to center the decal by matching up the two tick marks. Sometimes a drying ...
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Semroc IRIS Finished!
Here's the finished Semroc IRIS I did have to hit the model with a dull clearcoat to match up the dull surface of the rear black decal. Before hitting it with the dullcoat, the rear Monokote aluminum trim piece was masked and the nose cone was left off. TIP: A dull clearcoat (or any clearcoat for ...
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