Monday, May 8, 2017
Estes Photon Probe #3026 Build, Part 8, Tube Prepping
The launch lug was glued on in line with the engine hook side.
A painting wand is slipped in the back. Rolled up paper towel is pressed into the engine mount recess to keep paint out of the inside.
Primer coats followed.
There is a light difference in the nose cone shapes. The original plastic nose cone (on the left) is slightly broader at the tip.
Here's a strange photo edit:
TIP: To prevent yourself from sanding over and thinning the end of the tube, slip your left thumb into and against the tube end. The skin at the base of your thumb acts like a "bumper" and prevents the sandpaper from rolling over the tube edge.
The original kit fin marking guide was off! I would expect the older kit to be more accurate. I could tell it wasn't correctly spaced by rotating the guide after initially marking the tube.
While the newer kit guide didn't quite meet at the ends, the fin spacing was accurate.
After the primered tube was sanded down and the fins lines marked, the fin positions were scraped to remove the primer right down to the bare tubing.
The scraped area are a little wider than the 3/32" thick fins to allow the fillets to bond to the tube.