Saturday, December 20, 2014

Secrets of Estes Modeling, Part 2

And more from the same article:

Now you can attach the fins. Here you do use Titebond. do not use epoxy. The Titebond will make a better bond here because you want the water in the glue to pull the resin into the wood of the fin and the paper of the tube. Sorry, but epoxies won't do this and contrary to popular belief among rocketeers, epoxy is the poorer of choices for attaching fins.

Apply a bead of Titebond along the root edge of a fin. Wet the end of your finger and rub along the corner edge of both sides of the fin to make a nice straight glue bead. Don't dilly dally. Carefully attach the fin to the tube between the alignment lines. Do your sighting to make sure it is straight.

Note how the fin bonds to the tube within a few seconds using this technique. You have to have it straight, guys, when you put it down. Now hurry and look from the rear of the tube to be sure the fin stands straight out. You have just enough time to tweak the fin alignment before it sets. This may sound as though this technique is tricky, but I can tell you once you use it you are going to really like it. It just works.

You need to learn from experience just how much glue to put on the fin edge. If you put too much then of course it is going to squish out when you put he fin down on the tube. That's okay as long as you get to it before it dries. I keep a damp Q-Tip at the ready to drag along the fin-body tube joint to clean it up. You DO need to add a small fillet to complete the fin attachment and you can get this at the same time you attach the fins if you have learned the correct amount of glue to put on the root edge. The fillets we want are where the fin-body tube joint is just 'blurred' by the fillet. Anything larger just doesn't look professional.

We pre-finish blow-molded nose cones by dragging a razor blade along the seams to clean even out the joint, sand the entire surface, putting on a coat of the gray primer, and sanding smooth with 400 to 600 wet or dry. At this point the entire model is in gray primer. If not, then make sure it is. The reason is that whatever base color you put on, it will look the same over the entire model. Now, sand everything again using the finest sandpaper you have and wipe it down. A tack-rag is okay as long as most of the goo is gone out of it. It's waxy by nature and if it gets on the model your paint will bead like water on a waxed car.

But wait, there's more. You make this next choice, but we like to put on a coat of flat white Krylon on the entire model followed by a nice even coat of gloss white Krylon. At this point the model is ready for whatever final finish it needs. Note here that the Estes R&D group uses Krylon almost exclusively for all models. We have just never found anything else that works as well over the last twenty years. We do use Pactra or Testors on injection molded plastic parts because Krylon attacks them. Every model you see in the Estes catalogs have been painted with Krylon almost exclusively. BUT you guys can use whatever you want as long as the models come out okay.

What do you know, Estes uses Q-tips too!
I've read a few forum posts where people recommend tack rags. I don't use them for the same reason Mr. Dorffler mentioned: It's waxy by nature and if it gets on the model your paint will bead like water on a waxed car." 
Personally, I like smooth fillets. The larger the model, the wider the radius of the fillet. Smaller models get Titebond M&TG, larger models get epoxy. I guess my fillets aren't very professional!
This article was written a few years back, before Krylon changed their paint formulas. Don't bother with the new Krylon spray paint!

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