Stacking them up

Nothing new, but last night I gathered up all 47 full ribs and stacked them up, carefully aligning the cross pieces for the main spar, aft spar, and nose spar.  I was a little concerned about the amount of variation I might find, considering the ribs came out of two jigs over a period of 20 months.  I was very happy to see that there’s no more variation than could be attributed to wood thickness.  Less than 1/64″, probably under .025″ anywhere along any of the ribs.  Then I stacked up the dozen false ribs I have done so far, same story. 

Wait – 47 full ribs?  Yes, it seems somewhere along the line I must have lost count and built one extra aileron rib.  I’ll either keep it around as a wall hanger/test piece, or maybe stick it under the wing walk for a little extra support.  I’m not sweating it.

This exercise has also reinforced my idea to build a sled for the table saw to lop off the ends of the ribs for the leading and trailing edge pieces.  They are very highly consistent, as they should be, so I think that will save time and make subsequent assembly steps easier.

The bad news is — my T88 epoxy is junk.  I refilled the dispensing syringes and the resin looked a little “off”, not perfectly smooth and clear as it usually is.  Maybe a little cloudy and with a different texture.  I mixed up a small amount and glued up some test pieces.  Where I glued the flat sides two sticks of capstrip together, the joint held well and pulled apart well into the wood.  However, where I had glued a couple pieces of geodetic brace into the slots, the glue joints failed allowing the braces to pop out without breaking.  The glue also was not clear and hard, as it should be, but had an almost grainy or mealy texture to it.  I don’t have any trust in the remaining glue in those bottles.  I’m certainly not going to risk using substandard adhesive to save about $20 worth of epoxy!  Into the trash it goes.  I have two new bottles here, and half a dozen new 60cc syringes on the way from Amazon.