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littlemisterbig

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Hello,
I flew my Arcas HV this weekend on a G115WT, this was a test flight before my L1 cert attempt. Unfortunately on landing, two fins broke off so i was unable to do my cert flight. Anyways, the Wildman Blackhawk 38 is going to be my next rocket, some people that i have talked to have suggested doing t2t on it. Alot of the times i have seen t2t being done, they put it in a vacuum bag to help cure it. What type of vacuum bag and vacuum pump is best? I am going to be using plain weave cf and aeropoxy.

Thanks, Littlemisterbig
 
You dont need vacumm bagging to cure it. It is only used when you need minimal epoxy in the cured laminate.

Just using peel ply will help in not having to sand a rough surface.

I will say it requires patience, prepping, and planning. Overall not that hard and can be done.

Loose plain weave conforms pretty easily, so you went with a good choice.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet
 
Whats peel ply?
Should i cut the cf to the exact shape or can i trim it afterwards?
And is aeropoxy good for this?
 
You need something to hold the rocket at the proper angle. Any right angle surface with some tape will hold it steady while you apply the epoxy and such.
 
Whats peel ply?
Should i cut the cf to the exact shape or can i trim it afterwards?
And is aeropoxy good for this?

Trim afterwards, I have used aeropoxy and it works great. Hint: I recommend PH3663. The mix makes a really low viscosity that makes it really easy to laminate the carbon.

Peel ply is a fabric that is applied to the carbon/fiberglass, which later you can remove once the laminate has cured.

Soller composites has the Airtech Superlease peel ply. It is now my favorite and I recommend it.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet
 
Yes i see, do i need the jig or is it possible to do without?

I would recommend a jig. It could be done without, but once your done I'm sure you dont want to be holding the rocket in your hands until the epoxy reaches a gel state. The gel state can depend on the hardener.




Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet
 
Do you guys use a breather ply on over the peel ply to soak up the excess resin?

I'm think about doing a T2T job on a small 2.6" diameter project (to start). Have the 3 oz plain weave cloth, porous peel ply, breather ply, and waxed paper to cover the whole works and apply pressure with baggies filled with sand. Going to use West Systems...it's what I have.

Forgot to mention the fin jig I've already constructed. Much less sophisticated than John Coker's but a bit more than TimRo's foam board and 1/4" ply jig.
 
Thanks, Jim. Now I know what it feels like to take a drink from a fire hose! LOL!

Added your article to my dreaded "Rocketry Files" folder on the computer.

Beautiful carbon rocket at the end of your article...I'd be afraid to fly it.
 
Was your HV Arcas of the Aerotech variety? If so, the styrene fins won't take too kindly to the resin used in fiberglassing; it probably won't stick very well, leading to further broken fins down the line. If that's the case, I'd suggest increasing the chute size for your landing surface.

If that's not the case, then glass away! In addition to the excellent resources posted, I also did a pictorial of a tip-to-tip job a long time ago at the USCRPL blog. This sequence includes bagging. I've used this method on rockets up to 7.5" with good success. You can also skip the bagging step (optional things begin with peel ply, but peel ply sure does make the surface nicer) and it'll work fine. Bagging is more important in performance-oriented applications where you need maximal fiber density with minimal resin content, air bubbles, and bulk.

Good luck on your cert flight!
 
Do you guys use a breather ply on over the peel ply to soak up the excess resin?

I'm think about doing a T2T job on a small 2.6" diameter project (to start). Have the 3 oz plain weave cloth, porous peel ply, breather ply, and waxed paper to cover the whole works and apply pressure with baggies filled with sand. Going to use West Systems...it's what I have.

Forgot to mention the fin jig I've already constructed. Much less sophisticated than John Coker's but a bit more than TimRo's foam board and 1/4" ply jig.

Hm, never thought of that and your concept is good, but I see one issue and that is getting lots of sand to put pressure on the laminate. I'd recon you need a lot of pounds to put any good pressure on it.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet
 
Thanks, Jim. Now I know what it feels like to take a drink from a fire hose! LOL!

Added your article to my dreaded "Rocketry Files" folder on the computer.

Beautiful carbon rocket at the end of your article...I'd be afraid to fly it.

Thanks OD! I post those articles every now and then (I think it's been at least a few weeks now).

That fin can survived a high speed shred on it's first flight, but has since flown many times. I recall I had to pull it out of a tree after a flight at Asa (upper half not recovered) and then I lost it at Hearne for a while. It was found a week later, but a cow had crushed it just above the fins. That forced a conversion to 54mm. Now, it's getting pretty short, but it still flies fine. I flew it on a K-2045 a few weeks ago. It still cleans up OK.

Jim

LCY Mini 1.jpg
 
Yeah, i fixed the fins on the field. The fillets had split right down the middle it landed on frozen ground.
 
Hm, never thought of that and your concept is good, but I see one issue and that is getting lots of sand to put pressure on the laminate. I'd recon you need a lot of pounds to put any good pressure on it.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet

I picked up a small bag of terrarium sand at Walmart that weighs 6 pounds. I will have to transfer it into a baggie of greater volume so that the sand can spread out and "mold" itself to the surfaces involved. The rocket in question is 2.6" diameter so it's not particularly large.
 
Thanks OD! I post those articles every now and then (I think it's been at least a few weeks now).

That fin can survived a high speed shred on it's first flight, but has since flown many times. I recall I had to pull it out of a tree after a flight at Asa (upper half not recovered) and then I lost it at Hearne for a while. It was found a week later, but a cow had crushed it just above the fins. That forced a conversion to 54mm. Now, it's getting pretty short, but it still flies fine. I flew it on a K-2045 a few weeks ago. It still cleans up OK.

Jim
Yes it does. Nice work, Jim.
 
I picked up a small bag of terrarium sand at Walmart that weighs 6 pounds. I will have to transfer it into a baggie of greater volume so that the sand can spread out and "mold" itself to the surfaces involved. The rocket in question is 2.6" diameter so it's not particularly large.

Basically what you were suggesting was using a bleeder ply and then a bag of sand on top of that to keep the laminate clean? If so I see why not.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet
 
Basically what you were suggesting was using a bleeder ply and then a bag of sand on top of that to keep the laminate clean? If so I see why not.


Alexander Solis

TRA - Level 1
Mariah 54 - CTI RedLightning- I-100 - 6,345 Feet
I've never done any fiberglass lamination. Ever.

Checked all the various fiberglass forums (glider wings, surfboards, skate boards, etc.) in addition to TRF and watched countless videos on youtube (a couple of yours!) about bagging and general epoxy work. Timro's LOC Weasel MD build inspired me to do a tip-to-tip treatment on my own rocket. He laid down his fiberglass plies and covered it with a porous peel ply and waxed paper, then weighted down the fins/plies/waxed paper with baggies of sand to provide compression. I've seen his rocket close up and it turned out very nice. John Coker used the same method in one of his videos.

From what I read in other places about vacuum bagging, the suggested method was to place a breather ply on top of the porous peel ply and then hit the project with vacuum compression. The breather ply allows for complete evacuation of the bag and also soaks up the excess resin.

I'm not planning to do any vacuum bagging so maybe the breather ply is unnecessary. My question was do you use breather ply in your lay ups?
 
First off you should have had a L1 certification before flying a G115WT because it is over 80 Newtons average thrust and you need an L1 certification to fly any motor over 80 Newtons average thrust. So yes you would need an L1 certification to even fly something like the Pro24 F240VM or AeroTech G138NT. But that is beside the point. Just wanted to let you know.

Second you don't really need tip to tip carbon or glass on the Black Hawk 38 just good strong external fillets will get the job done. Curt Von Delius's 38mm minimum diameter flying on a AeroTech J510W that went 23K only had external fillets. Also if you have a hard landing with T2T and delaminate the carbon or glass it will be a hard repair job. Not impossible just a bit more work. But if you want to add T2T Carbon or Glass it could be good practice.

Best of luck on your L1 certification attempt.
 
[youtube]PtYYsX3VEmc[/youtube]

Tony A has a fantastic T2T method that he demonstrates in this video. Peel ply is a release fabric that absorbs excess epoxy, leaves a nice lightweight finish, smooth, and easy to sand/polish for that nice CF look. You can usually get it where you ordered your CF from.


Braden
 
Before you go down this rabbit hole I suggest you do a failure analysis on your fin failure. Your fins did not fail due to flutter. T2t is mostly for high preformance rockets with surface mounted fins. For your rocket T2T is not needed. My guess is your fins broke clean from the epoxy. Post some pictures of the failure.
 
If the fins broke upon landing it sounds like you need a bigger chute...not more fiberglass.
 
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