- Mar 18, 2009
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So I thought I accomplished this with my Estes Crossfire. But I got lots of gaps and bubbles. Any tips on how to best do this? Secrets? Tools?
The tape sounds like a great idea and the smaller tipped bottles...I think we sell those where I work.People do this differently, so take in the ideas and then play around with what works best for you.
I have kids building with us and here's what I have them if they're interested in making neat glue fillets. Works for big kids too.
1) Put a strip of blue tape along either side of the fin, leaving about 1/4 inch of space where the glue fillet is going to go. This takes some extra time but it keeps the glue from running or smearing onto the rest of the body tube.
2) We use yellow wood glue as it's less runny--this is my personal preference--others like all-purpose white glue. I transfer glue into smaller bottles with narrow tips because it's much easier to handle and apply to small areas. In fact I got some bottles at Hobby Lobby today in the paint section but I've used bottles I've emptied paint or glitter from as well.
3) Practice running a glue fillet smoothly along a piece of cardboard or paper just to get the feel for it.
4) Run a bead of glue along the fin, keeping it as steady as you can. If you have a spot with missing glue or a big air bubble use the small nozzle on the glue bottle or a toothpick to fill it in or rub it out.
5) Swipe it carefully with your finger. Remove the tape when you're satisfied you don't need another fillet and the glue is dried.
UfO, just plain glue fillets are functional and with some practice can turn out decent. Some--like Brian just pictured--do like to take extra steps and use wood filler to really make them look good. Not necessary but if you want more info on that, the techniques board is a good place to ask.
Spackle is something I've never thought to try! That would be the perfect thing to put over an ugly, structural fillet to make it look nice.Spackle fillets are light, fast, easy to repair, and plenty durable for low-power and mid-power. Try them and I'll bet you switch from epoxy fillets immediately.
Or maybe you've managed not to glue yourself to that part, you smile, you're proud of yourself, only to find out your fingers are glued together.I have resorted all too often to wiping my glue laden finger on the lower edge / underside of my work table..
What about the "CA face cringe"?!
(The fumes of CA wafting up, hits your eyes & nose, causing both to shut & water profusly! You can't run away, because you're holding said part in place or you're glued to said part.. Usually both!)
I have a bunch of 20cc syringes I bought that I'll part with reasonably. No needles.And, if you can get them.. a 10cc syringe..
I use teh yellow carpenter's glue, althoug it does tend to shrink when curing..
Several beatings from my wife broke me of that habit....Numerous ruined jeans & shirts from the "glue on finger looking to wipe it off on something" dance..)
I tried using the Fixit epoxy and found it to be too stiff for getting smooth fillets. When mixed it's more like clay than a caulk. Once cured it's very hard (like granite) making sanding difficult as well. Needless to say my fillets using this technique are strong but visually imperfect.I've yet to try the Epoxy Fixit available through Apogee. I've seen fillets done using this and they look great!
You can avoid all this if you use Titebond Trim and Molding Glue -- no bubbles.If you are doing white glue fillets:
Lay the glue in the fin / body tube joint - slowly. This will help keep air out of the joint.
Keep an eye on the fillet as it dries. Air bubbles will not show up when the white glue is first laid down. You can pop the bubbles when the glue is fairly wet. Use a toothpick, the wood tip will pop the bubble easier than trying to use the tip of your hobby knife.
If the glue is still very wet, it should flow in and fill the hole. If it doesn't, I'd wait until it's completely dry to lay in more glue. You can't add more glue on a half-dried fillet and smooth it out with a finger. Let the first fillet dry, then go again. I typically do three fillet layers.
Be warned, anytime you fillet a launch lug you are bound to get bubbles. That tight angle is nearly impossible to fill without bubbles.
I've yet to try the Epoxy Fixit available through Apogee. I've seen fillets done using this and they look great!
Second that... great stuff. It's very thick and stays put very well, but smoothing it is kind of a chore, because it would rather stick to you than to the rocket, but it's all a matter of technique I've found. Also, being a water solvent glue, I've found I can leave the fillets 'humped up' (convex) and they'll dry 'concave'.You can avoid all this if you use Titebond Trim and Molding Glue -- no bubbles.
Read the Product Features on this page -- it really is great for filling gaps and small cracks, which lends itself to fillets. While it says it is sandable, I have not tried this, but heard others state that it is.