Here's the Boosted Bertha before decals.
Orange overall, one white fin on the booster, one white fin on the second stage.
That seam fill at the joint of the booster centering ring and body tube came out well, it's not noticeable.
The new 18mm retainer ring was glued on with the Beacon Fabi-Tac glue.
Here's the second 18mm engine retainer in the sustainer or second stage.
You are usually told to glue the tri-fold shock cord mount far enough inside the tube to clear the nose cone shoulder.
The Boosted Bertha instructions say to glue it 2" in.
TIP: Measure and mark the shock cord at 2". Use that mark as a "depth gauge" against the tube top end before pressing the glued mount into the body tube.
Will the Fabri-Tac hold up to the heat of the motors? Out of habit, even for low and mid power, I use JB Weld.
ReplyDeleteHi Metal,
DeleteI only do low power launches and builds. All of the plastic to tube joints done with Fabri-Tac have held up well over the past few years. I don't think 18mm BP engines develop the heat that a larger composite engine would. These 18mm retainers should hold well with the Fabri-Tac glue, much better than the "safe" plastic glues available now. For larger than 24mm BP engines you should probably stay with the JB weld.
Fabri-Tac is a fairly “hot” adhesive - it should melt the plastic retainer enough to get a good bond with the paper engine tube. On Estes E2X kits I’ve had body tubes fail from hard landings but never a Fabri-Tac plastic to paper joint.
ReplyDeleteThanks Openroad!
DeleteA good affirmation of the same results I've had.
Definitely going to have to pick up a bottle of the Fabri-Tac glue to try out. I do remember back in the 1970s trying out that (supposedly) safe lemon-scented plastic model glue, and finding that it didn't bond polystyrene to polystyrene very well.
ReplyDeleteHi Naoto,
DeleteThe Fabri-Tac is great for plastic to Kraft tube joints, like a plastic adapter to a body tube. It isn't good for assembling a escape tower or other small, tight projects.
I used the "safe" plastic glues once. Can you imagine how many Mercury Redstone and Apollo towers have fallen apart using that crap? I think Estes should give more specific glue descriptions in their instructions.
For polystyrene to polystyrene I'd use liquid model cement (basically it's a solvent that'll "melt" the adjoining parts, creating a "weld"). On subject of plastic model kits, sometimes you have to be careful about what plastic is being used -- I recall back when Polar Lights issued the 12" Jupiter II (from 1960s Lost In Space TV series) kit, it was molded in ABS (same plastic used in LEGO blocks) rather than polystyrene -- so the standard liquid plastic model cement wasn't going to work, and you had to use something that was a bit more chemically active (which unsurprisingly would be a tad more toxic).
DeleteNot sure what sort of contact cement was in those ampules in the Estes Star Trek kits, but I do recall it worked quite well in sticking the plastic parts to the paper and balsawood.
I did the 'tube along the motormount' kevlar shock cord trick instead of the 'teabag'. Other than that, mine was a stock build. Didn't have time to paint it before the launch but it went up beautifully on a C6-0 to B6-6
ReplyDeletehttps://photos.app.goo.gl/QrMH7MZxEXG9qRNy6