MAC BlackFly build thread

TangoJuliet

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For whatever reason, your photos don't show up when I check this through the server at work, though I can when I go home (I haven't noticed that elsewhere).
I have a similar issue on my work server, though not in this particular instance. Our IT department has many websites blocked, including YouTube :facepalm: and some photo hosting websites due to content.
 

mpitfield

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For whatever reason, your photos don't show up when I check this through the server at work, though I can when I go home (I haven't noticed that elsewhere).

I have a similar issue on my work server, though not in this particular instance. Our IT department has many websites blocked, including YouTube :facepalm: and some photo hosting websites due to content.

I upload my photos to flickr then embed them using BBCode, which is just a link back to flickr. It is common for companies to block multimedia sites such as flickr, either knowingly or because they are classified as multimedia which just gets turned on with the content filter. Same reason the pornography category filter can block lingerie shopping, and the same reason the gambling category filter can block lottery websites. Both seeming innocuous and innocent activities but they often get blocked and the administrators would have to create exceptions.

Anyway, on thing to watch with the canvas tube is that the phenolic can be porous in spots. Sometimes these spots hold sanding dust, so you don't see them until after you've moved on in the process. I just found that with the PAC-3 that I'm building; I thought I'd finished the filling and priming phase, so I wiped it down and sprayed the first coat of color. Once it dried, I found that there were several spots I missed filling that weren't noticeable while I was sanding and priming. So now, I'm waiting for it to dry enough to fill, sand and respray. If the MAC canvas tube has one drawback, its that. But I'd much rather contend with some spot filling than spiral grooves! And the tubing doesn't really get fuzzies, though the beveled edges on the fins do.

Rick you have to post some progress pics of the MAC PAC :) I will try to get some time this evening to prep the nosecone, and if I do I may just mask it up and give everything a shot of prime. If I do I will post the results.
 

EXPjawa

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Well, that makes it especially odd, since that's the same method that I post pictures on this site. And I can still see my pictures. And I can still pull up my flickr account without issue. Actually, if I couldn't, it would be a problem since all of my photos are on this computer (I've got 20 years of photos on this computer!), and this is where I upload them to flickr from...

I haven't taken photos of the PAC-3 as I built, with the exception of the occasional odds and ends (like when i posted the photo showing the airfoil button earlier). I've gone off the idea of build threads generally speaking; the documentation slows the process down and I don't think anyone really reads them anyway. The last one I did was my 3" Scorpion, mainly because I wanted it documented in case I decide to use it for a L2 cert someday... Anyway, you can see the thing in a couple weeks at URRF4. Mike might have it at his tent, though I do hope to test fly it there at some point.
 

mpitfield

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Well, that makes it especially odd, since that's the same method that I post pictures on this site. And I can still see my pictures. And I can still pull up my flickr account without issue. Actually, if I couldn't, it would be a problem since all of my photos are on this computer (I've got 20 years of photos on this computer!), and this is where I upload them to flickr from...

I haven't taken photos of the PAC-3 as I built, with the exception of the occasional odds and ends (like when i posted the photo showing the airfoil button earlier). I've gone off the idea of build threads generally speaking; the documentation slows the process down and I don't think anyone really reads them anyway. The last one I did was my 3" Scorpion, mainly because I wanted it documented in case I decide to use it for a L2 cert someday... Anyway, you can see the thing in a couple weeks at URRF4. Mike might have it at his tent, though I do hope to test fly it there at some point.

As far as the image break issue. There could be many reasons for this, which could be anything from flickr having an issue on their end, the forum having an issue, to an end user issue. And technically every network inbetween. It is hard to tell but in your case Rick, content filtering does not sound like the issue. I know the images do not use the flickr.com domain but in my case use the sub domain c1.staticflickr.com, here is one example "https://c1.staticflickr.com/5/4208/35235989406_2aa680e71a_b.jpg". I have not done any testing to see if c1 denotes Canadian but it would not surprise me. Bottom line the reasons people are having issues can vary from person to person.

I look forward to getting my hands on the PAC, you always do such a good job on your builds. I am thinking of bringing my BlackFly but it depends on the stage it is in paint. If it has not been cleared, or the clear is still soft then I am likely not going to bring it, we will see. To complicate this, as I get closer to painting I am leaning more towards using the masking vs. decals, and this may add time between masking and laying down the next colour. I will have to get more info on the paint.
 

DavidMcCann

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I know the images do not use the flickr.com domain but in my case use the sub domain c1.staticflickr.com, here is one example "https://c1.staticflickr.com/5/4208/35235989406_2aa680e71a_b.jpg". I have not done any testing to see if c1 denotes Canadian but it would not surprise me. Bottom line the reasons people are having issues can vary from person to person.

one of mine - https://c1.staticflickr.com/1/262/32025129224_d679592027_b.jpg



I've had weird issues with forums embedding photos too. For example, about half of Riley's photos are red X's to me.
 
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watheyak

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Thanks for the insight into the "fuzzies", I will have to pay closer attention. What primer are you using? Did you wick the CA in before priming or after priming?

I don't appear to have a lot of fuzzies right now, but as you know stuff shows up after that first coat.

With cardboard, PML Quantum tube, and the plastic nosecones I have had the "fuzzies" However so far I have had good results by taking a dry 320 (cardboard builds), wet 400 (everything else) and block sanding the initial prime coat relatively smooth, then just laying another light prime coat down. I guess we will see if that works on the canvas phenolic.

I've been using Duplicolor Filler Primer. There were 2 coats that were mostly sanded off before applying the CA, but applying the CA before the priming would probably be best. I've had fuzzies on cardboard that a few subsequent primer coats took care of, but this kept fuzzing up. It reminded me of how Kevlar fuzzes any time it's anywhere near sandpaper. The CA is actually a Kevlar sanding trick.

The actual paint will be Klass Kote epoxy paint primer and color.
 

DavidMcCann

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The sharp corners and crisp edges looks great on the shelf but the plan is for this bird to see a lot of flights. So I always try to take the sharp edges and corners off my fins before they get compressed with a tough landing, even on my carbon fiber rockets.

I like the rounded look, and don't disagree with taking precautions. However..... my villain had quite the life.... sadly only 4 flights, but one was a half mile drag plowing the field, and the last was...catastrophic.... and this is the worst the fins took. these fins cut me when I was building it, lol.

34484573173_6bd4f0e3ae_c.jpg
 

mpitfield

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I like the rounded look, and don't disagree with taking precautions. However..... my villain had quite the life.... sadly only 4 flights, but one was a half mile drag plowing the field, and the last was...catastrophic.... and this is the worst the fins took. these fins cut me when I was building it, lol.

34484573173_6bd4f0e3ae_c.jpg

Ah Dave, nothing you can't buff out...you really need to build a a Villain Due!
 

mpitfield

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So I took a bit of a shortcut with the nosecone. I washed it thoroughly with soap and water, then took 100 grit on my trusty sanding block, and sanded down the seams within 15 min. That is the good news. The bad news is that I took 100 grit to it. I have used 100 grit, and even lower grit, on plastic nosecones, however it typically results in a lot of plastic fuzzies. 150 is the better choice but it takes longer to sand and requires more effort. The good news is that it is an easy fix.

I applied 3 light coats of the Dupli-color adhesion promoter on both the nosecone and tailcone, with 3 min between each coat. Then within 10 min I laid down a light prime coat on everything and let it dry for 10 min. This was followed by another light coat, followed by 10 min and the last light coat for the evening. From here I will let her dry overnight and then block sand with 400 wet, which will take the plastic fuzzies away. I will also deal with any other imperfections I discover, and a quick look did reveal some.

Here she is fully assembled and with a uniform coat. I always look forward this stage because it is the first time you can see the rocket instead of assembled parts. She is one good looking bug!

34908344720_311d95cf0a_b.jpg


A close-up of the plastic fuzzies. They look dramatic, but they will be gone next round, and she will be as smooth as silk.



Here is one imperfection that I need to deal with, the seam in the canvas phenolic tube. I knew this was there but I thought the filler primer would do a better job in hiding it, and it still may once I sand it. If not I will just fill it with my spot putty and it will be gone.

You may notice that I painted over that red tailcone, after Mike took the time and effort to make it a simple no paint required add-on. You can certainly do that, however I wanted the tailcone finish to blend better with the paint, and after priming it looks great. I will take a better pic of it tomorrow.

34908345130_88a770923e_b.jpg


I can see some more blending I need to do on the fillets, but this filler primer is good at hiding small imperfections like this with the appropriate sanding. One of the fins has a minor amount of the fuzzies Rick mentioned, but I am pretty sure it will go away without much more effort than sanding. If not I will use Rick's CA method of dealing with it.



Here is a pic of my sanding block, for reference. If I take a piece of sand paper, cut it into quarters, then fold one of those quarters in half, the piece fits perfectly on the block and over-wraps by one full width of the block. This allows me to almost fully use the piece of sand paper, and it is very easy to grip. The flat side I use when I want the block sanding to count as it is harder, and the dimply side I use when I am not as concerned because the dimples make it feel a bit more soft. The edges and sides work really well in the fillets and other hard to reach places. It is roughly 1.25" W by .625" D by 3" L.



Up next is 400 wet sanding and hopefully everything blends. If not I may have to fill and possibly prime, sand, and inspect again. Once the priming/filling stage has taken care of the imperfections, I will finish my last prime coat off with 600 wet, then start to lay down my base coats. I had a look at the directions this evening and it said to re-coat within 24 hours, or after 7 days. However if I mask I need to make sure that the paint is dry enough to not lift when I remove the masking film so I will need to do a bit more digging as I have not masked with this paint before. I also need to have a closer look at the masks to figure out the painting order as I cannot recall if I ordered negatives, positives or a combo. Normally you want to go from light to dark, but that is not always the best choice.
 

mpitfield

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So priming is done.

I had to deal with the plastic fuzzies on the nosecone, some minor bubbles in the canvas phenolic body tube, that Dave mentioned, and some minor fuzzies on one of the leading edges of the fins that Rick mentioned. However it was minor and took minimal effort to rid myself of them.

Once the first primer coats dried I had a good look at everything and block sanded the entire airframe with 400 wet. The imperfections that were left were minimal and I used 3M spot putty to fill them, then let dry and block sanded again. This is what the nosecone looked like once that process was complete. Still some very fine fuzzies but they were so small I couldn't feel them to the touch. These visibly disappeared after the next prime coats and sanding.

34983800780_c8d9334361_z.jpg


The imperfections (bubbles) in the body were minor and mostly concentrated around the seam. A single application of the 3M spot putty, followed by block sanding, and the final primer coats, visibly eliminated these.



After the block sanding with 400 wet this is what I was left with, and how I went into the final prime coat.



All masked and sitting on my lazy Suzanne spray table. I applied 3 light coats of filler primer, with 10 min rest between each coat, then after 3 hours I wet sand everything using 600 grit and she is now ready for base coats. Overall the surface is uniformly covered in primer, albeit thin after the final sanding, but it is fully covered and acceptably smooth.



My paint scheme used a red that was red/orange. However the paint that I decided to use is the Krylon camo, which does not have the same red. Instead the colour is more on the orange side, so below is the adjusted mochup of the final paint scheme. I will also be masking everything instead of using the decals.



The paint will be laid down as follows: Orange tailcone first with a soft mask on the rest of the rocket. This will be done this evening. I am doing the orange first because it will be easier to mask on the orange side of the line vs.the gray side of the line, due to the narrow masking line in relation to the fins. The rest of the masking gets complicated due to the black fins. As I said, ideally you want to lay down you colours from light to dark, however in this case I will be laying down the black then gray then orange eyes in the black fly.

Having said that I was not thinking when I had the masks cut so the black mask is a negative and it should positive. At this stage my plan is to lay down the orange, mask it off then spray the rest of the rocket black and order the positive black masking from StickerShock. This will also provide me an opportunity, while I am awaiting delivery of the new mask film, to de-mask and inspect the paint as well as resolve any defects. It will also allow the paint to cure for a week before I resume painting, which I have had some experience with using this paint and it is not an issue.

Once I lay down all of the colours and fully de-mask I will block sand with 600 wet just to knock down the edges between the colours. This is not a full sanding as you can easily cut into the different layers but it is more of a very light overall sanding with some attention focused on the edges. I have found that this quick step helps when you clear, especially if you are not planning on block sanding between clear coats, which I will not be doing with the chalky matte clear.

Below is a link to the colours and paint I am using. I have used this paint now on 6 rockets, all with great results. Recently I refinished my Aerotech Arreaux and used the black camo then topped it with the "Chalky Clear" which dried to a nice matteish dull finish. I really like the look. The chalky clear seems to be a nice durable, and very practical finish for a rocket. On the matte side the camo on it's own is a bit too dry and the grease from your fingers shows up, as do very slight scratches. However on the opposite end of the spectrum the gloss finish looks great but picking up the rocket, putting it on the rail and launching it damages the finish. I am hoping that this finish is a nice compromise.

https://www.krylon.com/products/camouflage-paint-made-with-fusion-for-plastic-technology/

The colours I will be user are: Orange Camo 4301, Gray Camo 4304, Black Camo 4290, Chalky Finish Clear 4117.
 
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mpitfield

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Time to resume building or I should say painting.

Last week, while at URRF4, I was speaking with Rick, AKA EXPJawa, and I told him that the week before I had given the tailcone a few light coats of the Orange Camo 4301, however the colour swatch on their site is nowhere near the colour in the can. The colour on the lid is much closer and that would be a florescent looking very bright and dry orange. Rick mentioned that there was a darker orangeish red in the Rusto 2X. So this evening I hit Canadian Tire, and they had it in stock. However Krylon also had a good looking dark red, "2328 Red Pepper". This Krylon red is also the same paint formulation, fusion for plastic, as is the camo. So for the sake of compatibility I picked up a can.

Here is the new red beside the previously painted camo orange, over 12 days now. It is sanded and ready for a repaint with the new red, which I will mask and do tomorrow night.



Here is an edit of the rendering with the new red, beside the last rendering using the orange camo, which in real life is a lot more bright orange

34780981264_49994b3337_k.jpg


I should have some pics with more paint by the end of the weekend.
 
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EXPjawa

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Good deal, Mike. Smart to stay with the same family of paints as to what's already on the cone; even if you've sanded it, you still could get a bad reaction to the new paint if its different. Paint can be weird sometimes...

I had some sort of odd reaction (or something) when I was putting last coat of paint on my PAC3. I used Rustoleum 2X (satin Oregano), but after the first coat found I hadn't sufficiently filled all the little voids in the tubing. So after doing that, I reshot it. It had been about a week from the first paint. On the nose cone, though, some weird bubbles or blisters lifted up. It wasn't a fish-eye situation, where the surface wasn't clean. They were more like little bubbles. I was able to wet sand them off and mostly smooth it out, and there was enough color underneath the voids that I didn't have to reshoot it again with color. So, after that, the decals went on and I shot a gloss coat over everything. You saw the result...

BTW, any significance to the numbering on the aft end of your rendering? TRA #?
 

neil_w

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I had some sort of odd reaction (or something) when I was putting last coat of paint on my PAC3. I used Rustoleum 2X (satin Oregano), but after the first coat found I hadn't sufficiently filled all the little voids in the tubing. So after doing that, I reshot it. It had been about a week from the first paint. On the nose cone, though, some weird bubbles or blisters lifted up.

Chris Michielssen has mentioned numerous times recently about how the paint dries a lot slower on the plastic nose cones vs. the wood or paper parts. Dunno what materials your rocket is made of but if it's a plastic nose cone it doesn't sound farfetched that it could be related.
 

EXPjawa

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Maybe, though I think the age of the paint and humidity level may have also played roles. The rocket in question is basically of the same construction as Mike's above (MAC Performance canvas-phenolic). In fact, they have the same nose cones.
 

mpitfield

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BTW, any significance to the numbering on the aft end of your rendering? TRA #?

My twins were born on December 17th, and 14579 is my TRA#. The rendering has a 6 by mistake, which I just noticed, I will have to flip that number.

Chris Michielssen has mentioned numerous times recently about how the paint dries a lot slower on the plastic nose cones vs. the wood or paper parts. Dunno what materials your rocket is made of but if it's a plastic nose cone it doesn't sound farfetched that it could be related.

That is something I had not considered before, do you have a link to the discussion?
 

snrkl

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Chris Michielssen has mentioned numerous times recently about how the paint dries a lot slower on the plastic nose cones vs. the wood or paper parts. Dunno what materials your rocket is made of but if it's a plastic nose cone it doesn't sound farfetched that it could be related.

I use rustoleum - a lot.

Long story short: recoat inside an hour or Waiiiiiiit.

For cardboard / balsa I've found 48hrs can be the minimum. 3-4 days is better.

Plastic in particular - if you're layering with masking or sanding - wait at least a week between coats. It takes *ages* for bonding to plastic.
 

Nytrunner

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I use rustoleum - a lot.

Long story short: recoat inside an hour or Waiiiiiiit.

For cardboard / balsa I've found 48hrs can be the minimum. 3-4 days is better.

Plastic in particular - if you're layering with masking or sanding - wait at least a week between coats. It takes *ages* for bonding to plastic.

I hear that. The nose of my L1 is still giving me problems a year later.

My problem is I do masking a lot so that drags things out.
 

EXPjawa

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I hear that. The nose of my L1 is still giving me problems a year later.

My problem is I do masking a lot so that drags things out.

I hear that! When I built my Estes D-Region Tomahawk, I think I had 5 colors on there, all paint, in an as close to scale correct color scheme as I could make. Took weeks, especially when I had to redo part due to impatience. All to have the rocket become sacrificed to the tree gods on flight #1...
 

snrkl

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I hear that! When I built my Estes D-Region Tomahawk, I think I had 5 colors on there, all paint, in an as close to scale correct color scheme as I could make. Took weeks, especially when I had to redo part due to impatience. All to have the rocket become sacrificed to the tree gods on flight #1...

Yeah. It's funny - I'm so particular about the finish on my rockets.

Then I fly them once and they get normal wear and tear or a bit dirty and suddenly I don't care anymore...

¯\_(ツ)_/¯
 

CzTeacherMan

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Just ordered my Black Fly and thought I'd be clever and do a build thread... Oh well! Good thing I checked first.
I have to say, I'm pretty stoked about the build. My L3 was a 5-fin Gizmo XL-DD, and though it was a little wonky to build with 5-fins, I LOVE the look of 5-fins. I'm weird, I guess...
Anyway, after meeting Mike at URRF 4, I decided that I had to give Canvas Phenolic a shot... After a week of debating on which kit, I decided to start small and go with the Black Fly. Shopping on Mac Performance website was a SNAP! Super easy interface, quick updates on shipping, and a built-in link to the tracking number. Great way to buy a rocket. Once it's all built, maybe I'll even post a picture or two...
Thanks for the thread!
-Cz
 

mpitfield

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Just ordered my Black Fly and thought I'd be clever and do a build thread... Oh well! Good thing I checked first.
I have to say, I'm pretty stoked about the build. My L3 was a 5-fin Gizmo XL-DD, and though it was a little wonky to build with 5-fins, I LOVE the look of 5-fins. I'm weird, I guess...
Anyway, after meeting Mike at URRF 4, I decided that I had to give Canvas Phenolic a shot... After a week of debating on which kit, I decided to start small and go with the Black Fly. Shopping on Mac Performance website was a SNAP! Super easy interface, quick updates on shipping, and a built-in link to the tracking number. Great way to buy a rocket. Once it's all built, maybe I'll even post a picture or two...
Thanks for the thread!
-Cz

I was telling Mike he should use the tag line "once you fly Mac you never go back", but he seems a bit gun shy on that one :)

I would love to see what you do with the color scheme and I hope you do a build-thread. I will post more on mine tomorrow.

I hear you on the 5 fin look, although as you know we are not totally weird as there are 5 fin rockets/missiles out there in the wild. I like the look plus I liked the challenges it posed from a design point of view. 5 fins over 3 fins moves the CP back, if I recall correctly, about 2 inches so it does come with a cost. I just did my nose weight this week and initially I was going to ad 75g but I ended up adding about 100g in total weight, just for the extra margin with the bigger motors.

BTW I totally missed officially meeting you at URRF4, although we may have talked, my apologies for not introducing myself.

You made another sale for Mac Performance.

2 more sales and I can mail in for my x-ray glasses.
 

CzTeacherMan

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I would love to see what you do with the color scheme and I hope you do a build-thread. I will post more on mine tomorrow.

I hear you on the 5 fin look, although as you know we are not totally weird as there are 5 fin rockets/missiles out there in the wild. I like the look plus I liked the challenges it posed from a design point of view. 5 fins over 3 fins moves the CP back, if I recall correctly, about 2 inches so it does come with a cost. I just did my nose weight this week and initially I was going to ad 75g but I ended up adding about 100g in total weight, just for the extra margin with the bigger motors.

BTW I totally missed officially meeting you at URRF4, although we may have talked, my apologies for not introducing myself.

I'm still debating on color scheme... But... I've wanted to do a two-tone black rocket for a long time (matte-gloss), so this might be the one. Then grab the decals in red lettering. Just where my head is at for the moment.

I'll hold off on nose weight until I have the final build. Few differences: 1) I'm planning on foaming the internal fillets, 2) I grabbed the Wildman FWFG nosecone option, and 3) I use Chris Attebery's nosecone sleds in my 54mm rockets, one of which I mounted an RRC2, 9V, and 3ozs of tungsten weight so I should be able to balance fairly easily.

As far as meeting you, I'm sure I did at some point. I met so many of you guys that I lost track by the end of the day on Friday. Saturday I was rocket hunting and hanging out in Tim's trailer helping some young flyers so I didn't get around much. If Tim didn't mind me as a travelling partner, I'll be back! Next year, with a Black Fly and a big 29mm motor.
 

mpitfield

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Some more progress.

First up, as per my previous post I did not like the florescent orange paint and wanted something a bit more on the red side and I got it. After repainting it twice with the new red, below is the current state. I had to paint it twice because I tried to take a short cut which did not pay off, so because the repaint time after 24 hours is 7 days, it set me back a week. I should have laid down the grey and be on the black at this stage...live and learn.



Currently un-masked and sitting on my lazy Suzanne painting stand drying. It will sit here until a min of a week as I will be traveling for a bit. Once I get back I will very carefully block sand it just to cut the masking line, take the shine off and remove any orange peel, then it will be masked off and I will lay down the grey.



Next up I started working on the nosecone. First thing was to mock-up the entire rocket, take the CG and weight, then run some calculations to settle on my nose-weight. Initially, in post 8, I estimated 75g, however I added a little bit extra for a bit more margin with the bigger motors. I normally mix up some thicker epoxy and pour the clump into the cavity, however I was doing a T2T layup for another rocket and had some Aeropoxy PR2032 mixed up so I used that instead. After using it I personally prefer the thicker epoxy for this application as you can tap it down and compress it much easier. With epoxy it added about 100g. I used #9 lead shot for this as I recently picked up a 25lb bag, which packs nice and tight and the bag should last me a while.



One important step I almost forgot, scuff up the nosecone cavity so it has something to bite into. To do this I first pored the weighed lead shot into the nosecone to get an idea on where it would sit. Then I grabbed two dowels, a 1" dowel, which is the diameter that sits just at the top of where the shot would be, and the other was a .5" dowel. I wrapped and taped a piece of 80 grit paper on one end then inserted it into the nosecone and simply spun it around a few times, then repeated with the smaller dowel to get a bit deeper.



Then I mixed and poured the mixture into the nosecone and let it dry for 24 hours in the vertical position.



Nosecone before lead weight



And after



I also had a bit of fun with setting up the altimeter bay and sampling holes, which I will post tomorrow night.
 

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Are you going to foam the cone at all to maybe help hold the weight in, or are you expecting the epoxy to bite where you scuffed it well enough?
 

mpitfield

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Are you going to foam the cone at all to maybe help hold the weight in, or are you expecting the epoxy to bite where you scuffed it well enough?

The pic with the red circle is not the best pic, but in person it was scuffed up relatively deep, so much so that I am confident that the epoxy is not going anywhere. Having said that I wouldn't bet my life on it. So my plan was to just move it forward as is but I may consider scuffing it up a bit more and adding a small layer of foam.

What are your thoughts?

My only other experience with adding nose weight and having flown the rockets, was on my BaddAzz Mini-Missile line. The weight is added into the base of the nosecones, which are either wood or CNCd Delon. I also added some nose weight to two Rocketry Warehouse Mouse 38 nosecones, which are the thin wall FW glass, but those rockets have never flown.

In all cases the process was the same, mix lead with epoxy and pour, except the epoxy used was the Aeropoxy ES6209 structural adhesive, although with the ES6209 you can really pack it down nicely with a dowel.
 

EXPjawa

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Well, getting stuff to bond into the tip of a cone like that can be tricky as I understand it. The geometry is working against you; your tapered epoxy/ballast slug is essentially trying to be pulled away from the tapered cone by the forces acting on it at launch. All that's counteracting it is whatever grip the epoxy has in the scuffed area. If the walls were straight (cylindrical) like at the motor mount, then its being pulled in shear and the epoxy can resist that well. But on the back of the taper, its being pulled away from the surface. That's why a lot of folks cross-drill the tip and glue a dowel in prior to pouring the ballast in, as a sort of anchor. My thought was that if you foam filled, at least up to the bay centering ring, then the bay structure will back up the foam and the foam will make sure that the ballast has no place to go.

With that said, I haven't had to ballast a cone like that yet. For the couple of rockets I've built that needed some nose weight, the nose bay assembly was enough. I have, however, foamed a few of the cones that I've put the bay kit into. This wouldn't be much different, since the ballast is already in place.
 

CzTeacherMan

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Whenever I add nose weight to a plastic NC, I drill a hole straight through and slide a skewer through... Drop in nose weight... Cut off skewer ends. Basically, it creates a little bridge to grab the weight
 

mpitfield

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Well, getting stuff to bond into the tip of a cone like that can be tricky as I understand it. The geometry is working against you; your tapered epoxy/ballast slug is essentially trying to be pulled away from the tapered cone by the forces acting on it at launch. All that's counteracting it is whatever grip the epoxy has in the scuffed area. If the walls were straight (cylindrical) like at the motor mount, then its being pulled in shear and the epoxy can resist that well. But on the back of the taper, its being pulled away from the surface. That's why a lot of folks cross-drill the tip and glue a dowel in prior to pouring the ballast in, as a sort of anchor

Whenever I add nose weight to a plastic NC, I drill a hole straight through and slide a skewer through... Drop in nose weight... Cut off skewer ends. Basically, it creates a little bridge to grab the weight

I forgot about that technique. I recall a thread showing it and they used brass rod. I even purchased some small brass rod several years ago for another project that is still on the bench. I know exactly where it is and I think I will attempt to drill through the nosecone and lead weight, and insert it in. It should be soft enough to do this without any issue.

My thought was that if you foam filled, at least up to the bay centering ring, then the bay structure will back up the foam and the foam will make sure that the ballast has no place to go.

With that said, I haven't had to ballast a cone like that yet. For the couple of rockets I've built that needed some nose weight, the nose bay assembly was enough. I have, however, foamed a few of the cones that I've put the bay kit into. This wouldn't be much different, since the ballast is already in place.

Based on what I have already done with the AV bay, it is likely going to be easier for me to try your "anchor" idea first.

I will give it a shot this evening, worst case I will really screw it up and need a new nosecone.

Thanks guys!
 
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