Fixit epoxy clay

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Unless you have exceptionally long fins you should have more than enough! A little bit goes a long way. No need to go overboard ... so as you roll it out think "less is better" ... just enough for a smooth transition from airframe to fin.
 
I used this on a Aerotech mid power kit. Maybe I applied it wrong - did not sand before putting it on? I had it as fillets for all four fins, but set it aside for several months as I went to work on other kits. I came back to it to work on some sanding, and quite by accident - applying a little bit of force to the fin caused the seal to break and I was able to wiggle the fin off. So..I took off all the fix it, sanded it and went back to epoxy. Will look forward to hearing how yours goes. I am glad it happened to be during the building stage instead of after it was all painted and it was during a landing!
 
The clay is not really what you want to use for fillets. You are better off with other techniques. The clay is heavy, brittle and does not adhere to many surfaces.
 
1+ on not the best application for this. I've had rockets where the adhesion was not sufficient to keep from breaking loose easily. Proline 4500 is my epoxy of choice for fillets, but about any similar epoxy should do the trick.

Doug
 
I have used this product and it works "ok".

But, I have two problems with it.

The first is that while it is has the word "epoxy" in it doesn't mean that it is a great product for structural applications. You are better off with using better epoxies (such as Aeropoxy, WEST System, or Rocketpoxy) and adding your own filler to suit the need.

The second is that it is heavy and you are adding mass to one of the worst places to add mass, at the end of the airframe. Epoxy mixed with microballoons (and a bit of fumed silica doesn't hurt) is a balanced adhesive solution that is both lightweight and easy to sand.

Greg
 
I have done beautiful fillets with epoxy clay. I have yet to test past mach one and it is something I want to test. For certain bonding needs to be properly done as this is not a liquid and will only adhere to the top layer.

I do not agree with others that it is heavy. Never felt like if it was a brick.

I do agree on the part where it is brittle. You know what, screw my comment about it not surviving mach 1. I have tested it close to Mach 1. When I took my Mariah 54 on a J381 skidmark it was expected to go past mach 1. My rocket survived and it had epoxy clay fillets.

All it takes is applying it correctly. I do not know of any confirmed tests past Mach 2 so dont take the project that far. I will also say that it is not best for hard landings only if your fins are not going to impact the ground first.

Hope this helps.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet
 
I've used it twice, here are my results:
Madcow 4" Patriot: Small fins that do not extend past the airframe, no where near mach flights (full internal West Systems epoxy fillets) - still holding on
Mega Der Red Max: Very large fins that usually take the brunt of the landings (15 minute BSI epoxy internal fillets) - have had to repair 2 of the 3 fins, both have cracked and pulled away from the top layer and looked like they were barely attached.

Oh and as always, take into consideration your landing area, even on the nice soft grass of the sod farm where we fly and land, the Mega Max still developed cracks on fillets.

I would say on the DX3 you would'nt have a problem as long as you go with strong internal fillets on the MMT and airframe. But, if it were me I would go with Proline or something similar.
 
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+1 on the proline.


Sent from my iPhone using Rocketry Forum
 
Ok, thanks for all the advice. Ill probably go with proline or rocketpoxy, what filler would you recommend?
 
Honestly anything besides the clay would work including 5 minute if your a fast worker...(not advised) but you get the point. Any real epoxy will work fine.
 
Rocketpoxy...... no filler needed. Easier to learn with than Pro-Line.

Already has filler in it. Mix it just like JB weld on cardboard or paper, spread out 2 equal lines.

Add color then blend, spread out and let sit 20 minutes so air bubbles surface and epoxy thickens [for fillets]

place into V-groove , then pull fillet smooth with correct size tool for the job. [meaning diameter] usially dowel, PVC pipe, etc is used from 1/2in. to 1.5 in


Good luck.
 
Depending on what you use you may not need a filler. I use collies silica. But there are many others. I've successfully used flower in small amount and the results were great. You can see them in my JR L1 DX3 build thread.
 
blackjack2564 said:
Rocketpoxy...... no filler needed. Easier to learn with than Pro-Line.

Already has filler in it. Mix it just like JB weld on cardboard or paper, spread out 2 equal lines.

Add color then blend, spread out and let sit 20 minutes so air bubbles surface and epoxy thickens [for fillets]

place into V-groove , then pull fillet smooth with correct size tool for the job. [meaning diameter] usially dowel, PVC pipe, etc is used from 1/2in. to 1.5 in


Good luck.
Click to expand...

I'll have to most agree with CJ here. I like rocketpoxy. It is strong and simple to use as CJ described it.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet
 
I have used fix it. I would stray away from the clay. I flew it on a 4" to M0.9 some time ago and it held up…. it was the landings that it could not withstand. It adhered fine with proper surface preparation (albeit on phenolic/cardboard) but it is slightly brittle.

No filler needed for the proline fillets unless desired. You can use silica, west systems 404 adhesive filler, graphite, milled glass, etc. My vote is for the proline over the rocketpoxy. I have used both and honestly either will work for what you are doing.
 
You guys have no clue how to use the clay so therefore you feel its inferior to other epoxies when in fact you lack the necessary techniques to produce a flawless fillet using clay. You can fillet a complete rocket in a couple of hours verses several hours or days ... Really

Oh yeah and you don't have to mask or deal with the epoxy running over your rocket. The problem a lot of people on here is they seem to think one way is the only way to do something when in fact there's more than one way to skin a cat.
 
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AfterBurners said:
You guys have no clue how to use the clay so therefore you feel its inferior to other epoxies when in fact you lack the necessary techniques to produce a flawless fillet using clay. You can fillet a complete rocket in a couple of hours verses several hours or days ... Really

Oh yeah and you don't have to mask or deal with the epoxy running over your rocket. The problem a lot of people on here is they seem to think one way is the only way to do something when in fact there's more than one way to skin a cat.
Click to expand...

Thank You, most agreed here. Like I had stated it works fine. None the less the annoying part is the hard landings that will crack the fillets. I believe the key here though is tacking on the fins with a strong adhesive. In my experience using JB weld and then use the clay fillets. I'm confident that wont budge nor suffer any damage.

Here is another great story. My transonic rocket flew to Mach 1.21 The epoxy clay was so strong that the blue tube was ripped apart. The clay fillets held their own from the flutter that it ended up shreding the tube. If the clay fillets had failed. I am sure there would have been raining fins and not body tube pieces.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet
 
AfterBurners said:
You guys have no clue how to use the clay so therefore you feel its inferior to other epoxies when in fact you lack the necessary techniques to produce a flawless fillet using clay. You can fillet a complete rocket in a couple hours verses several hours or days ... Really
Click to expand...

Why are you so emotional? You are making a lot of assumptions mate. No idea how to use the clay? Really. All this coming from a guy who didn't know JB Weld IS epoxy. The epoxies I use ARE superior to fixit epoxy and rocketpoxy is also better. Why? They are more validated than fixit epoxy, but don't take my word go and look on the datasheets and what projects use what (HPR+ of course)! BTW all of this is coming from a guy who has used all of the above mentioned epoxies AND dislikes the maker of rocketpoxy.

Hmm :/ A flawless fillet and doing fillets rapidly??? Fillets are not all about the appearance and doing them quickly.


Edit: Obviously there are different ways but there are also better ways. When you start launching bigger and faster rockets you tend to want to use the better ways.
 
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JB Weld works fine for fillets. If you're in a hurry you can even use JB Quik. I wouldn't recommend it for anything very large, though, because it sets up too quickly, and once it starts to "skin" you're not going to get a smooth finish.
 
I'll just say this: When I see some really bad fillets on a rocket, they are usually done with fixit. I'm not saying that good fillets can't be done with the stuff - I have managed it myself and there are situations where I find the stuff useful - but it is definitely easier to produce a really bad result with the stuff. Furthermore, it cures very, very hard and is more difficult to sand than most things.

I have used a lot of different things to make fillets. Titebond molding and trim Glue, 5-minute epoxy (Blob Smith), 30-minute epoxy (Bob smith), West sysetm with colloidal silica, Aeropoxy 6209, RocketPoxy, Proline 4500, and Fixit Epoxy Clay.

My favorite for external fillets is Proline 4500 by a fair margin. Next would be RocketPoxy, which just seems a little more prone to running in directions you don't want it to go.

My favorite for internal fillets is RocketPoxy - easy to mix, strong as hell, has a good consistency for working into tight spaces, and cleans up easily.

I have found Fixit somewhat frustrating to work with, requiring a lot more effort to get right. The one application where I would recommend it would be if you have a cosmetic need for fillets that are not a simple radius in the natural shape of a meniscus. A case in point would be the tube penetrations around a canted cluster rocket (see below):

IMG_0684.jpg

IMPORTANT POINT:

You should ask yourself why you are doing external fillets and choose your weapon accordingly. If you are doing the fillets for structural reasons, such as when larger fillets are required because you are attaching surface-mounted fins and internal fillets are not possible, then I think you want something stronger, easier to work with, and easier to sand than Fixit. As I mentioned above my preference is for Proline 4500 or RocketPoxy. If your fillets are purely for cosmetic reasons, such as cleaning up the look of the fin-to-airframe intersection, then you should be minimizing your fillets for aerodynamic reasons (hint: fillets generally increase drag unless they are combined with a corresponding dillet in the airframe). In that case, I especially recommend something other than Fixit as it is a real pain in the butt to produce small fillets with it.

To summarize:

  1. If your fillets are structural, Fixit is inferior to other epoxies as it is quite brittle. I have seen it crack and seen fins separate on rockets built by some very good craftsman who know how to prep surfaces for epoxy.
  2. If your fillets are cosmetic, they should generally be as small as you can make them for aerodynamic reasons, and Fixit is inferior to other epoxies for most of these applications because it is more difficult to get a consistent shape along the length of the fillet (It doesn't form a meniscus and gravity doesn't help you with the process).
  3. One can often tell when looking at a rocket that the Fillets were done with Fixit. This is not a good thing. It can be used to produce good results, but it's more difficult.
  4. Fixit is useful for unusual fillets that aren't in the shape of a simple radius.

That's my $.02. Some others seem to be quite emotional about this...so while I urge you to avoid the frustration of using the stuff for your own sake, let me assure you that I don't give a rats behind what you use. Happy Rocketing, and good luck.
 
AfterBurners said:
You guys have no clue how to use the clay so therefore you feel its inferior to other epoxies when in fact you lack the necessary techniques to produce a flawless fillet using clay. You can fillet a complete rocket in a couple of hours verses several hours or days ... Really

Oh yeah and you don't have to mask or deal with the epoxy running over your rocket. The problem a lot of people on here is they seem to think one way is the only way to do something when in fact there's more than one way to skin a cat.
Click to expand...

Yes, you can. I have used the stuff. I have also used a host of other products and find Fixit to be heavy, brittle, and difficult to work with. I have used Proline to make all six fillets on a 3FNC with a single batch in under an hour with no runs, drips or errors, and I'll choose that every time.

Feel free to use what you want; I really don't care. But I think I'm providing some good advice to the OP nonetheless. Your mileage clearly varies.
 
wfcook said:
Yes, you can. I have used the stuff. I have also used a host of other products and find Fixit to be heavy, brittle, and difficult to work with. I have used Proline to make all six fillets on a 3FNC with a single batch in under an hour with no runs, drips or errors, and I'll choose that every time.

Feel free to use what

you want; I really don't care. But I think I'm providing some good advice to the OP nonetheless. Your mileage clearly varies.
Click to expand...

Yep more than one way to skin a cat.
 
wfcook said:
I'll just say this: When I see some really bad fillets on a rocket, they are usually done with fixit. I'm not saying that good fillets can't be done with the stuff - I have managed it myself and there are situations where I find the stuff useful - but it is definitely easier to produce a really bad result with the stuff. Furthermore, it cures very, very hard and is more difficult to sand than most things.

I have used a lot of different things to make fillets. Titebond molding and trim Glue, 5-minute epoxy (Blob Smith), 30-minute epoxy (Bob smith), West sysetm with colloidal silica, Aeropoxy 6209, RocketPoxy, Proline 4500, and Fixit Epoxy Clay.

My favorite for external fillets is Proline 4500 by a fair margin. Next would be RocketPoxy, which just seems a little more prone to running in directions you don't want it to go.

My favorite for internal fillets is RocketPoxy - easy to mix, strong as hell, has a good consistency for working into tight spaces, and cleans up easily.

I have found Fixit somewhat frustrating to work with, requiring a lot more effort to get right. The one application where I would recommend it would be if you have a cosmetic need for fillets that are not a simple radius in the natural shape of a meniscus. A case in point would be the tube penetrations around a canted cluster rocket (see below):

View attachment 186713

IMPORTANT POINT:

You should ask yourself why you are doing external fillets and choose your weapon accordingly. If you are doing the fillets for structural reasons, such as when larger fillets are required because you are attaching surface-mounted fins and internal fillets are not possible, then I think you want something stronger, easier to work with, and easier to sand than Fixit. As I mentioned above my preference is for Proline 4500 or RocketPoxy. If your fillets are purely for cosmetic reasons, such as cleaning up the look of the fin-to-airframe intersection, then you should be minimizing your fillets for aerodynamic reasons (hint: fillets generally increase drag unless they are combined with a corresponding dillet in the airframe). In that case, I especially recommend something other than Fixit as it is a real pain in the butt to produce small fillets with it.

To summarize:

  1. If your fillets are structural, Fixit is inferior to other epoxies as it is quite brittle. I have seen it crack and seen fins separate on rockets built by some very good craftsman who know how to prep surfaces for epoxy.
  2. If your fillets are cosmetic, they should generally be as small as you can make them for aerodynamic reasons, and Fixit is inferior to other epoxies for most of these applications because it is more difficult to get a consistent shape along the length of the fillet (It doesn't form a meniscus and gravity doesn't help you with the process).
  3. One can often tell when looking at a rocket that the Fillets were done with Fixit. This is not a good thing. It can be used to produce good results, but it's more difficult.
  4. Fixit is useful for unusual fillets that aren't in the shape of a simple radius.

That's my $.02. Some others seem to be quite emotional about this...so while I urge you to avoid the frustration of using the stuff for your own sake, let me assure you that I don't give a rats behind what you use. Happy Rocketing, and good luck.[/QUOTE

I use a file then I sand.

As I mention a lot of people wontv ake the time to do that
Click to expand...
 
Post #26 is a good post for the OP.

SinfulDarkLord said:
Thank You, most agreed here. Like I had stated it works fine. None the less the annoying part is the hard landings that will crack the fillets. I believe the key here though is tacking on the fins with a strong adhesive. In my experience using JB weld and then use the clay fillets. I'm confident that wont budge nor suffer any damage.

Here is another great story. My transonic rocket flew to Mach 1.21 The epoxy clay was so strong that the blue tube was ripped apart. The clay fillets held their own from the flutter that it ended up shreding the tube. If the clay fillets had failed. I am sure there would have been raining fins and not body tube pieces.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet
Click to expand...

Simply using Jb weld for tacking on the fins and then using fixit for the fillets, will not prevent the fillets from cracking.
 
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