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good results with Easy Composites XCR CF skinning.

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Tim51

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I know we don't really do build threads here on the UK section of TRF , so this isn't one.. nevertheless, I've been working with Stafford based company Easy Composites' improved XCR CF skinning kit, and I’m very pleased with the results, so I thought I’d post up some pictures by way of recommendation. For this build I’ve been wrapping 3” PML phenolic tubing with one layer of 2/2 3K twill. The materials are relatively easy to work with, particularly given that the resins are very low odour. I bought the larger 1.5 x 1m roll of the 2/2 3K twill, and bought the 1kg can of top coat, although the 500g base coat bottle was needed. Suffice to say I didn’t use up the entire amount of either. Skinning is the simplest form of lay up, involving allowing the initial base coat to go to tack, then applying the cloth, then successive layers of top coat, which have to added at specific (and varied) points during the curing process, so you need to make sure you set aside sufficient time. It also involves progressive flatting, which is pretty laborious. The first few flatting sessions 120 – 400 grit are dry sanding (professional masks and goggles essential) and then after that, and the final layer of top coat, it’s wet sanding from 400 – 1200. However, the results are very pleasing. The instructions are very detailed and easy to follow, and there’s also videos on the company website. They also run a very helpful technical advice line staffed by a very helpful actual real person. With careful measuring beforehand the seam can be kept straight and flat, and there were very few pin holes.


The only point of departure I made from the instructions was the very last stage, where I didn’t use the NW1 polishing compound (not sure why you’d name a polishing compound after Camden Town’s postcode but there you go..). Once I’d finished wet sanding with 1200 grit I masked off and sprayed the roll pattern (a can of Fiat Red-Orange from Halford’s), lightly sanded that once it was dry, then glossed it all with two coats of clear lacquer.

The fins are 3mm ply sandwiched with the same CF, set in fin pocket ‘dams’. The thrust plate was made from 3 rings of laser cut ply, clamped and glued, then drilled for metric threaded inserts to hold the flanged retainer.

I hope to scratch, scuff or otherwise ruin all this fancy finish at this year's Big Ears...

cf wrap without resin.jpg

cf with first coat.jpg

thrusplate1.jpg

thrustplate2.jpg

thrustplate3.jpg

booster section wet sanding.jpg

seam.jpg

complete.jpg

complete retainer fitted.jpg
 

Tim51

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As I'd hoped, I flew this rocket for the first time Saturday 29th at Big EARS on a CTI J270 to 3282 ft:
[video=dailymotion;x5kelnc]http://www.dailymotion.com/video/x5kelnc[/video]

As I started out that morning the Stones' 'Start Me Up' was on the radio, so I decided to name the rocket accordingly.
A successful flight in general, though the booster sustained slight easily fixable damage which I think was probably a strike by the FWFG nosecone during descent. I'll fit a plastic NC for future flights on this size of motor, and keep the FG one for K motor flights. I thought I'd switched on the on board mobius at the pad...'thought' being the operative word here, so my son's iPod footage is the only record of the flight.

I'm curious about the wobble visible shortly after leaving the rail. It straightens out as the rocket gathers pace.

At rest after first flight.jpg
 
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