Horizontal Stabilizer

Tonight marks the start of the KR-Super2 build. I completed glassing the first side of a 2’x4′ 1/4″ Last-a-foam panel and one side of two 3/8″ panels for h-stab skins. Work was done according to Chapter 2 as per instructions. 

I was initially going to use Ecopoxy for this build because it was described as odorless and non-toxic and ok for structural parts. I purchased a gallon kit. Later I became worried that is may not be a good substitute. Aircraft Spruce was not able to provide a mechanical properties of the Ecopoxy resin system and I also read that the Aeropoxy does not contain the cancer causing substance MDA and is tested by Rutan for all structural use. I switched back to the Aeropoxy. Ordered a gallon kit from Spruce 3pm Thursday and it showed up 5pm Friday with UPS ground. Not bad. That allowed me to get started tonight.

All-in, tonight’s work used about 1/4-1/3 of a 1 gallon kit. About $30-40 worth of resin.


I laid out a sheet of 1/2″ ply to provide a flatter surface than my garage floor. The plastic is to protect the wood.


I cut the BID for the first two sheets as per instructions. The final piece I straight cut. When following the instructions I only had the small triangles as waste. Straight cut definitely has more waste, but the large leftover rectangle can be used elsewhere in the future. The bias cut method proved very hard to keep the cloth weave aligned as I was rolling out the cut sheets on the micro’ed foam. It took forever to get the weave aligned again. The overlap of the two pieces of cloth is also heavier. For future glassing, I think I’ll stick to straight cut and accept the waste to make a better, light part in less time.


Above, 45 degree cut cloth laid out and trimmed to size.
Overlap of 1.5-2″


Straight cut cloth trimmed to size.


Cut BID rolled up and ready to go.


Mixing station set up. I would pour out the amount of resin needed, weigh it. Divide that by 100 and multiply by 27. That gave the exact weight of hardener to weigh out. Tonight’s project used about 1/4-1/3 of the Aeropoxy that came today.


I printed and bound the. Hold manual for easy reference.

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My first attempt at mixing micro. It was a bit hard to spread. I mixed subsequent batches thicker and it spread on much easier.

Edit – the next time I mixed the micro 1:1 by volume with catalyze resin and this consistency was much easier to work with.


1/4″ foam nearly done with micro. I used an extra large scraper to speed things along. Just had to be careful to keep it flat and not let the edges dig into the foam.

Edit – the next time I used my yellow plastic squeegee to spread micro. Though it’s smaller, it seemed to work much better and faster.


Rolling the glass on to the foam was so easy with one big single sheet. Smooth by hand to eliminate air gaps between glas and foam.


Completed side 1 of the 1/4″ panel that will become various structural parts for the horizontal stabilizer.


I did the 3/8 panels with two glass pieces cut at a 45 degree angle. This was much less wasteful on the glass, but hard to align the two pieces of cloth to get the right overlap while keeping the weave pattern intact. 


Closeup of a finished panel.


Three panels with glass on one side. The 1×2 strips will give the wing skin panels a small curve that helps them conform easier to the airfoil shape of the h stab. 

Total time start to finish, about 4 hours.