TLP Indigo Build

The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
I thought about how to apply pudding-like filler to the low areas, and I came up with this.
m_2171.jpg
It's a maybe 3/8" wide piece of can, kinked for strength. I used it to apply filler to the low points length-wise first. After it dried a little, I used the concave part of the tool sideways to smooth it out a little more. Then I used a dampened finger for final smoothing. I was debating whether to put a coat of dope on what I had done up to this point, but I chose not to. I might have gone too far on the previous application when I used my wet finger, dope might prevent dissolving the previous layer. It worked well for a first try, I'm waiting for it to dry.
m_2172.jpg
 
I cleaned off the can block with alcohol again, and sanded the tail cone joint. Mostly I was turning the BT with the block held in place with my hand, trying to have the load distributed equally. Kinda like a really slow lathe. There were a few low spots yet. I used a half inch wide aluminum smoothing tool like in the above post to apply latex-like filler. I didn't use my finger this time.
m_2173.jpg
With practice this tool seems pretty cool. It needs to be wiped off often. I'm hoping this will be my last application of filler back here. I'll need to replace the sandpaper on the can block before what may be the final sanding.
 
I replaced the 320 on the aluminum block. The old stuff peeled off easily. I sanded, and it's still not there. Here's the new worst spot.
m_2174.jpg
I also sanded the BT joint, and applied filler to the two low spots. Here's one of them.
m_2175.jpg
I used that aluminum tool to apply filler to the rear again. It is so close except for a couple spots, mostly where I am trying to feather it to the BT. I'll get this right eventually. Practice, practice, practice!
m_2176.jpg
I'm playing the waiting game now, at least the humidity is low.
 
While I was waiting for filler to dry, I thought I'd try to improve my aluminum block design. I had the other half of the can I cut way back when, and cut it to about half the circumference of a BT-80. It's what fits in my hand comfortably. I scored just inside the ends lightly with my heavy-duty X-acto, and bent them along my ruler. I then CA'ed popsicle halves to each bent-up end. 320 was then Duco'ed to the inside. Pictures of both sides, I hope you get the idea of how I did it. I'll have to wait until tomorrow night to see how it works.
m_2177.jpgm_2178.jpg
 
It didn't take long for one of the handles to snap off at the aluminum joint. It still worked well, and it slid over the fin slots better than the other side.
m_2179.jpg
I sanded the areas. It's pretty doggone good, and I am debating whether to do anything else. Maybe a coat of dope over everything, and then a thin coat of filler with a brush.
m_2180.jpgm_2181.jpg
I need to paint one of my other rockets with primer to see what happens before I proceed further. I still need to get some sheet metal. My days off lately have been Sunday, and I can't get any then. There isn't much else to do except cut out the forward fins, and make a new rear fin to replace the guinea pig.
 
Last edited:
I cut out the forward fins from that 1/8" stock I bought a while ago. It's kinda medium hardness. These fins will be surfaced mounted, as I don't think they will hit the ground first in most circumstances.
m_2182.jpg
I also cut out a replacement for Guinea Pig from the stock provided in the kit. I can screw up two more and then I run out of stock.
m_2183.jpg
I then taped together the fins along the leading edge.
m_2184.jpg
I sanded the root edge, and taped that together too.
m_2185.jpg
I sanded the rest of the edges so the fins are the same size. Here they are.
m_2186.jpg
 
Doggone it, camera needs recharging again. All I did was sand the tip of the Guinea Pig Replacement so Arbitrary Fin Tip Dowel #2 would fit well. I did it like a post long ago, but this time used 220 wrapped around a mini engine case. It is now Arbitrary Fin #2.

I found some 26 ga. sheet metal at Ace Hardware, but I'd need to cut it myself. I need it to be non-deformed, so I'll call a couple places to see if they can cut me a 5x5 inch square piece of 28-30 ga. steel. Hopefully I can get that done tomorrow.
 
Here's what I did to get Fin #2 to fit the dowel.
m_2187.jpg
I stopped by Don's Sheet Metal here in town, and asked for a 5"x5" piece of 28 gauge. The thinnest he had was 26, and he cut me off a piece, free of charge. Mighty nice, thanks Don! It would have been over 20 bucks for that one at Ace with a snips, that wouldn't have been as perfect.
m_2188.jpg
Oops, I reduced this picture twice by accident, but there isn't much to see really. I figure as it wears down I can just turn it to a new edge.

I'm kinda beat, but I'll see how it works to get Fin #2 up to the others at least tonight.
 
Here's the fin rigged up. Balsa spacers are still needed along the fins to support the clamps. I applied thin coats of rubber cement to the board and the steel, after it was washed to remove the coat of oil. This is much more stable and prone for more precision than aluminum.
m_2189.jpg
I soon realized that the steel would have to be moved way back, as it is thicker than the aluminum.
Here's halfway through sanding with 150 on a rubber block.
m_2190.jpg
I made a new shim as rubber cement is involved now, it is seven layers thick. Here it is after sanding, still on the jig.
m_2191.jpg
The fin after sanding. It's almost where the others are.
m_2192.jpg
 
Last edited:
Fin #2 surpassed the others, as I applied latex-like filler to most of it. At least a little past the place where the back bevels will start.
m_2193.jpg
I applied filler to the rest of the fins to that point, and here they are drying.
m_2194.jpg
I have a plan to finish sand the fins on the jig. I can't think of any other way to keep a defined shallow bevel, and I'm hopeful after my experiments that this will work. At the worst I think it will look nice still from a few feet away.
 
I thought I'd post a picture before I put the steel shield on. I broke off a piece of the scrap balsa I cut the fins from, and it fits nice for a clamp support. The rubber cement holds things in place if you don't get too crazy.
m_2195.jpg
Shield in place.
m_2196.jpg
I sanded with 320 on one of my rubber blocks. I had to inch the shield back a little twice until I was hitting the line. Here's after the first time.
m_2197.jpg
I put masking tape on the sanded bevel.
m_2198.jpg
I then strictly sanded side to side so I wouldn't curl up the edge of the tape. I tried up and down once, and the tape curled up.
m_2199.jpg
The middle of the fin is smooth and filled, the bevel needs one more coat. I'm leaving the fin on the jig through all this. I put pretty thin filler on the bevel being careful to keep it off the middle part, and it is drying now.
 
Last edited:
I put the shield back on, and lightly sanded the bevel. Front of this side of the fin done.
m_2200.jpg
I did the other side of the fin same process. I added filler to the beveled area. I'll sand that tomorrow.
m_2201.jpg
It only took about 10 minutes now that I have some practice under my belt. Three more fronts of rear fins to go, and then on to the rear bevels the same way. It will also go much faster now that I won't have to take pictures and stuff. Well, I might throw a picture in here and there. I'm happy how it's turning out so far.
 
Just an update. I have to overcome some burnout, get some stuff out of my landlord's way for further painting, and plan for a vacation. It's not the launch at Bong in September, it's a family reunion in Gatlinburg, TN at the end of August. Family comes first, especially since I haven't seen any of them in almost two years. After all that I hope to get back on the Indigo.

Bradycros, I'll be in your neck of the woods. I'll be on the look-out for Hobbes.
 
Back
Top