Discussion in 'Low Power Rocketry (LPR)' started by scadaman29325, Oct 28, 2019.
I'll make a note of that. Thanks.
Looking for verification... The Estes logos supplied with this kit are about 1.44" long (1 7/16"). That doesn't fit (well) on the sustainer fin, compared to the one seen in the facecard.
Yup. That would certainly be a tight fit on the fin.
I just keep messing up. Glad this is just 2nd build since returning and my first bash. According to my own directions, I was supposed to glue 3.5" to 12", I glued 2.75" instead, just like the kit instructions said. Need to print my instructions out and refer to those. I'll just have cut the long tube down for the booster.
Also, super glued myself to everything around my strengthening the fins. My typing finger feels like I have sewing thimble on it.
Anyways, this is what I did tonight. Strengthened the papered fins. Glued a set of fins to the 3.5" BT. Cut a trench in the coupler for kevlar. Also notched the end so the knot would be recessed against engine. Glued 2.75" BT to 12" BT.
And I've did the spirals with CWF and sanded those down. I got a little messy with the fin papering, will have to clean that up. Used Qualman's fin alignment tools, those worked very well. AND I did not glue those to the BT! I'll claim that as a victory for not screwing that up. Baby steps.
Well, I've turned this into another learning project! I shouldn't be so hard on myself, but I'm not used to being such a dork about things.
After sticking on one set of fins on a booster, I thought I'd go ahead and prime everything before sticking on the two sets of fins. Sanded everything with 220 grit first. Got the spirals fairly filled and leveled. Scuffed up the entire BT a little more than I would have liked in the process. The papered, CA strengthened fins got the same treatment. I may have taken to much CA off the fins, because later sanding revealed paper too quickly. May CA before papering next time and use 400 grit for the pre-prime prep. (As in airfoil, CA, sand with 400, paper, CA again, sand with 400, then prime.) Wiped everything down with a very lightly dampened wash rag, then dried with another.
Bought some Rustoleum Gray Primer because the BT was white. I wanted to see where the primer stopped and BT began when sanding. Resisted the urge for full coverage on the first pass with the primer, waited a minute till it no longer glistened in the sunlight, then did another layer of primer. I was surprised how quickly the glossy finish went away before making another layer. I tried to keep the painting angle away from the root edge and did address the other three edges. Also I had made little (blue) masking tape loops and stuck the fine to cardboard, let it dry for 30 min, pulled them off, flipped them and painted the other side. I was fully expecting to see the tape lift the primer when I done, but not so, it did very well, no lifting, no residue left behind. I thought I had put the primer down pretty thick, but when wet sanding the fins with 400 grit and the paper showed up fairly quick. I was also a little afraid of wet sanding the papered fins. Just didn't seem like a good thing to do, but I said f--- it and went to town on them.
First thing I did was sand at the wrong edge/angle. I thought I was at the top of the airfoil with a slight angle on the sand paper. A few swipes revealed wood. Went straight through the paper. Then I realized I angling down on the root edge side and the crown of the airfoil. Crap what a dummy. Anyways, worked my way around all sides, angles and edges leaving shallow areas with gray primer. Some wood showed up, some paper rolled up... Aggravating. Some areas feel slick as glass, some areas as rough as it was before I did anything.
I'll hold off sanding the BT for now. After that I'll shoot them with white primer. And see how many different ways I can screw that up.
Oh well, I'm having fun. Ra, ra, ra... (raspberry).
BTW, went to the auto parts store for a headlight cleaning kit and cruised the paint section. I found some spray cans of filler primer for deep scratches, I thought hmmm, maybe I'll try that next time.
Probably more to blab about, but it's time to go.
As I continue this build, it's like I continue to document my screw ups...
Well, I primed the BTs with gray primer, did ok with that I think. I started sanding with 400grit. That's slow going and eats up a lot sandpaper. Still trying to get most of the primer off and just now the paper started rolling up.
So, when I sprayed the white BT with gray primer, I wanted to take it almost all off like I see on Chris Michielssen blog. Then I was going to spray white and take most of it off....
Now I'm thinking I should have sprayed with gray primer and just smoothed it a little, then white, then start painting.
Well, now I'm going to try to fix the mess I made and spray again with gray primer.
Ummmmm...I hope I am reading this wrong, are you saying you primed the other tube BEFORE attaching the other fins? If so, that’s a potential problem.
IIRC it is fine to use CWF over surfaces you glue. Glue will work right through CWF. PRIMER and PAINT are another story. If you either mask your attachment points or sand off the primer and or paint, that’s okay too, but otherwise primering over attachment points BEFORE attaching makes for weaker adhesion.
Don’t feel alone papering fins and then sanding the wrong edges. I have gone to using light pencil marking on the fins right after papering them to keep track of which edge is which (and STILL messed it up a few times!)
Especially good to mark the direction of the GRAIN after papering fins, depending on how you paper them it is easy to loose track. Adhesive papering adds a little strength. GLUE papering adds a LOT of strength, but is messier. Neither however helps you if you get the grain direction wrong. I have proven this by accident.
I am enjoying your posts and efforts, please continue.
Oh yes, that's what I did and am doing that right now. I am going to scrape the BT area before gluing.
This is my 2nd build since returning to the sport and am using these "simple" builds as learning tools before getting into the more difficult rockets. In the past, I would sand fins and BT glue them on then prime...
I've been doing a lot of reading and watching vids, and felt that there were other, possibly better ways, and was going to play with those ideas.
I hope you are laughing at my calamities, I'm laughing and whining at the same time. Like sanding down to the paper, OMG, I should have been using a sanding block, not that it would have stopped my over zealous sanding, but it may have helped me not dig in so deep and concentrated. I've got one of those rubber ones that you have to lift up the ends to get paper on, what a pain. I'm looking for another, but think that I may have to find a HARD 2x4 and cut it down to a usable tool.
Anyways, it raining and cold, and will have to wait for the weather to break to lay down another coat of primer. And then I'll move onto screwing something else up.
Thank you for your input. It is highly valued!
been doing this for 40 years now - always learning a little something new, or how to do it better or more efficiently either on my own, or here on the forum. can't wait to see how this turns out.
As someone replied on another thread,
I'm getting great advice from all the experts, this will most likely fail spectacularly in some unforeseen way!
Best thing I've ever heard. Sounds like my job.
Network Maintenance tonight, 15min I.T. time, 3hrs normal people time, or until I fix whatever it is that I break.
Please keep posting.
Always good to have someone looking over your shoulder, whether you are a beginner or level three.
Pretty much all mistakes can be corrected if you catch them BEFORE you hit the LAUNCH button!
Oh crap, that sounds like my job too. "Mistakes are great in training, so we'll learn how to fix in a live system"
I'm doing this to get my mind off work! LOL
Well, here's some more screw ups.
What's wrong with this picture?
I scraped the primer off to glue the fins on. Not a big issue, but will probably glue them on first next.
How about the card stock angled straight edge included in the Qualman fin alignment tools, nice, except I glued the numbers to the inside vs where I can see them on the outside! (Insert very colorful language).
And to top it all off, then I broke the top off my glue bottle!
Oh, that was the booster that was too long. I was happy with cutting the extra 1/2" off. I laid it in the angle braced my razor and did a saw action. Couldn't rotate the tube because the fins were in the way. Had to sand it down a bit. No problem.
Well, how far can your rubberband stretch, vs flat, vs round?
My super scientific method indicated 3x for all three.
The 5/32"(?)rubberband supplied with the kit, the 5/32"(?) flat elastic from Hobby Lobby, and the 3/32"(?) round from HL were tied tightly to a 16oz water bottle, marked at 12", then lifted the bottle and measured.
The rubberband measured 35", both the flat and round elastic were 33".
Hmmm, I was expecting more variance.
The pic doesn't show it well, the above numbers were measured carefully. Which means I most likely messed that up too.
I'm attaching the shock cord.
Ain't this some crap! Just stop reading please. I saw a post a build straight from hell, I thought, it couldn't be that bad. He has company now!
I fed the kevlar that's attached to engine block the the forward end and marked it at the edge. Worked it back through aft and tied that to elastic. Nice! Fed it back through the forward end. Was VERY happy!
Until I gave it tug, and an extra two inches came out and exposed the kevlar out the forward end! (Insert MUCH more colorful language)
I had already put glue on the knots. Well, I fed it back through the aft and tied a loop in the kevlar as close as I could to the BT. Then fed it back forward. It's where I wanted it now.
Hmmm, what's next? There's not much more that I can screw up.
Do they make a 18mm H motor for this thing? I don't think I want to see it again.
I continue to struggle with prime and sand. First gray, where it got a little to deep and rolled up some paper fuzz, smoothed some CA in the area and sanded it down, primed in gray again. Sanded and repaired areas again still not completely happy, but went to white primer sanded, still not completely happy, but am getting tired of working on this one.
I put on a light coat of white, followed by two medium coats. There are areas that really turned out great, and others not so much. For some reason it showed a couple 1/16 wide round pits. I don't think those were there. It almost looked like a paint bubble popped, but I didn't see any bubbles. Anyways, I worked on those and a few other areas and have decided to reprime in gray.
Since I've turned this into training project went ahead and made a baffle. I took 2 of the thin walled yellow measuring tubes, split one lengthwise, trimmed an ⅛, inserted it into the other yellow tube. I cut three disc from some cardboard centering ring stock, sanded those down to a decent fit. Cut them so they were a little more than half circles, glued one in the middle of the tube and then both ends. I didn't want fire getting to the chute. Next time I will use my new hole puncher instead of cutting the disks. Glued the baffle in the lower bodytube, tape fitted it into upper bodytube, VERY tight fit. I want to be able to inspect it later on. Went ahead and filled the seam. I may regret that later when I rip it apart to see how the baffle is doing.
It's ready for priming again, but it's raining. I think there will be sunshine soon.
Oh, and I forgot the launch lug till after the first coat of paint. Duh. I loaded it with a C6-0, A8-0 & A8-5 to find the center of gravity which was way back at the fins on the bodytube. I may need to add some nose weight.
Try to keep your full stack launch weight under 113 grams
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