Laminate, Fillet, Tip-to-Tip, Surface Coat

Well shoot, I had a much better write-up for a theoretical TtT over FG-fin through FG-BT to FG-MMT, but clumsy me closed the draft tab.

In short: have you better recommendations for a more ridiculously over-strong system than PTM&W ( blenders of Aeropoxy )?

My thoughts:

• Bead blast fillet area, cut fin slots, clean with acetone
• ES6296 glue fin roots through wall into dams, wait an hour
• PT2846 tie layer
• HT2C fillets
• PT2846 glass laminate x 2-4 layers
• peel ply + breather + bag + vacuum, wait a day
• strip, trim as necessary
  
• PT1995 surface coat x 2, wait an hour
• 4 hours at each of 150 , 250, 350

Should ( maybe? ) give a minimum Tg of about 300F ... what have I completely missed / failed to understand / gotten exactly backwards?

Anything BUT fillet.

Problem solved.

Fillets are not only ugly, but they do not appear on REAL Missiles, which means they are performance robbing, so even if you are doing LPR, to hell with Fillets!!!!
That's the last thing you want on your rocket.
That said, how is the cloth I sent you working out for tinkering with?
You obviously have gone way ahead of me with your research, so you must have some lofty goals???
I don't even understand the terminology you are using in your post. Are you actually now set up to heat cure Epoxy products?
You've gone way above and beyond anything I can fathom apparently.

I'm going to be using foamboard and .5 oz. to tip to tip a mini BBZ soon, but you should probably contact the manufacturers of the mediums you are working in to see if they can give you what you need for Data.
I just play with model rockets.

Someone had to post an answer, and this post has been haunting me all day, but with so many irons in the fire I can't afford to fall down another rabbit hole!

I need to start honing in on my own project, and not going hog wild for hours at a time trying to find answers that can only be learned by experience, as the internet is still in it's infancy, and I hate having to use it anyhow.

Just make a Through the wall design, and then if you really are going mach 78, tip to tip it.
Seems to work just fine for everyone else.
If you are going beyond Mach 78, you already have access to the alien technology that you seem to seek, so don't waste our time.
People go above mach with no glass at all all the time.

You could always get really crazy, since you already have access to the motor technology to push materials like this to the brink, and just do some experiments and share your findings with the rest of us.
There is no rule against innovating in this hobby, but for the velocities we all assume you can achieve on any given motor, even certified HPR, you really don't need to get too crazy when the FG can do the work for you.
Build something, don''t hurt your head over it.


So many builds are stopped dead in their tracks do to the rampant availability of computer simulations and CRAP.
Go above and beyond it all and launch rockets by yourself to see what works. You should even find clandestine launch sites and windows for your larger stuff, so you can shoot them off in a truly "No harm no Fowl" fashion.
Then, when the thing the Computer did not believe in actually works, we'll all be quite impressed.

Only thing limiting me right now is dollars over time ( AKA 'not buying it all this month' ); can't-sleep-read-TRF is basically free

Oh, and this -is- all TopRamen's fault for sending me a really excellent bag of glass , by the way.

I had to do some research to figure out which laminating epoxy to order....

TopRamen said:

they are performance robbing

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Not looking for speed, this baby won't break mach ; looking for practically indestructible.

TopRamen said:

you must have some lofty goals???

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Can't sleep, sims will eat me.

TopRamen said:

Are you actually now set up to heat cure Epoxy products?

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TopRamen said:

Anything BUT fillet.

Problem solved.

Fillets are not only ugly, but they do not appear on REAL Missiles, which means they are performance robbing, so even if you are doing LPR, to hell with Fillets!!!!
That's the last thing you want on your rocket.

Click to expand...

Fillets have an important aerodynamic purpose. They reduce interference drag.
https://en.m.wikipedia.org/wiki/Parasitic_drag#Interference_drag

dhbarr said:

Not looking for speed, this baby won't break mach ; looking for practically indestructible.

Can't sleep, sims will eat me.

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Holy Cow!!!!:y:

TopRamen said:

Holy Cow!!!!:y:

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For the record, that picture is not of me ; but one can easily tune the heat on a setup like that with a number of exhaust ports which are covered or opened as appropriate, same as my forge.

watheyak said:

Fillets have an important aerodynamic purpose. They reduce interference drag.
https://en.m.wikipedia.org/wiki/Parasitic_drag#Interference_drag

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Ok, good point, but I still don't like them.

TopRamen said:

Ok, good point, but I still don't like them.

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Not only do they improve aerodynamics, they greatly add to strength. Form follows function.


[emoji1010] Steve Shannon [emoji1010]

Steve Shannon said:

Not only do they improve aerodynamics, they greatly add to strength.

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That's why I'm thinking about using hi-temp tool-making clay-type epoxy

Make your fillets with laminating resin and Kevlar pulp.

markkoelsch said:

Make your fillets with laminating resin and Kevlar pulp.

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I see people recommending this or other fillers a lot. What I was going for with this system was not having to measure out different kinds of fillers.

Pointers to any comparisons on strength of pre-filled vs. fiber-added-later methods?

And yes, this is all serious overkill. If it's worth doing, it's worth overdoing

dhbarr said:

Well shoot, I had a much better write-up for a theoretical TtT over FG-fin through FG-BT to FG-MMT, but clumsy me closed the draft tab.

In short: have you better recommendations for a more ridiculously over-strong system than PTM&W ( blenders of Aeropoxy )?

Click to expand...

I have a three inch Punisher built with injected West fillets that I have dropped on drogue from 10-15k apogee without notable damage. It is plenty strong.

I only laminate on minimum diameter rockets or repair jobs.

dhbarr said:

I see people recommending this or other fillers a lot. What I was going for with this system was not having to measure out different kinds of fillers.

Pointers to any comparisons on strength of pre-filled vs. fiber-added-later methods?

And yes, this is all serious overkill. If it's worth doing, it's worth overdoing

Click to expand...

I have no numbers to share. That said, I have used this method for 16 years. I have also used chopped carbon, but have repeatedly come back to the Kevlar pulp.

If doing injected fillets I use a small portion of pulp. Too much and it would not inject. For external fillets I am evolving to something close to a 60/40 epoxy to pulp by volume. It is very thick, and I apply it with a combination of spoons, putty knife, and a dowel rod. As the epoxy starts to form up I work on shaping it with the dowel and either wax paper or parchment paper.

Once set do not sand Kevlar ever. It is a mess. Get an epoxy based filler, and sand that for final shape.

You can do a tip to tip over this as well.

dhbarr said:

I see people recommending this or other fillers a lot. What I was going for with this system was not having to measure out different kinds of fillers.

Pointers to any comparisons on strength of pre-filled vs. fiber-added-later methods?

And yes, this is all serious overkill. If it's worth doing, it's worth overdoing

Click to expand...

Tons of research and pubs on laminate design. Filler comparison; maybe start with page 21 in this Google doc: https://books.google.com/books?id=HYppudlMIrEC&lpg=PA21