Question: What to use for fillets on balsa to plastic

[Dseter]

Not much action from the mid-power thread for this one. I'm building that Estes V2 which has the TTW balsa fins and the plastic tail cone. I'm wondering what you guys would recommend for the fillets where the balsa meets the plastic tail cone. Would need to be sandable and paintable and offer some adhesion to both if possible. Thanks in advance! Dave

 

[Peter Olivola]

Thick CA with micro balloons.

 

[rharshberger]

Not much action from the mid-power thread for this one. I'm building that Estes V2 which has the TTW balsa fins and the plastic tail cone. I'm wondering what you guys would recommend for the fillets where the balsa meets the plastic tail cone. Would need to be sandable and paintable and offer some adhesion to both if possible. Thanks in advance! Dave

Any epoxy commonly used in making HPR fillets will work, however I might consider using the "epoxy rivet" method on the plastic side along with heavy scoring of the plastic. Another thought is to use small #1 or #2 wood screws threaded into the plastic then filleted over. Of course on a V2 that adds weight at the wrong end.

 

[fyrwrxz]

Not much action from the mid-power thread for this one. I'm building that Estes V2 which has the TTW balsa fins and the plastic tail cone. I'm wondering what you guys would recommend for the fillets where the balsa meets the plastic tail cone. Would need to be sandable and paintable and offer some adhesion to both if possible. Thanks in advance! Dave

Rocketpoxy. A little more flexible than Proline. +1 on the surface prep actions above. Straight smoke and good chutes!

 

[dixontj93060]

I like Loctite Plastic epoxy...

 

[Dseter]

Thanks guys, guess I'll be leaning toward an epoxy over traditional glues. I'm fresh out of the micro balloons I think but will check for those, otherwise, I'll be sanding the Holy Hannah out of the epoxy to avoid future yellowing.

 

[BEC]

In the model airplane realm there is something called "canopy glue" - it's an alphiatic resin that sticks well to both plastic and wood. The original is the (no longer available?) Wilhold RC-56. But there are two similar products now sold for the same purpose - Pacer Formula 560 is one. This is what I use in E2X kits and anywhere I need to glue plastic to paper or balsa. When I get to my Estes V-2 that's what I'll use in the joint you're interested in.

CA's make brittle joints though I have to defer to Peter with respect to using it with microballoons - have never tried that combo.

Epoxies will certainly work if you want to deal with them (and the added weight in the back of a model that probably should be as light as possible in the back....)

 

[Boosterdude]

Epoxy mixed with micro-balloons.

 

[impulse09]

Building a V2 also, and I went with 30 min epoxy and micro-balloons. However, I am also building a Black Brant II, and I used carpenter's glue to fillet between the fins and boat-tail. The length of the plastic/balsa interface is only an inch or less, so I'm not worried about strength. Seems to work fine.

 

[jahall4]

I like Loctite Plastic epoxy...

View attachment 278900

Yes, does seem to work better than anything I have tried to date, but beware there is a 5 minute product from Loctite in a similar package that is NOT a "bonder" and not the same thing.

 

[Micromeister]

Just about any good 30minute epoxy with added Micro balloons or 3M Glass Bubbles did a wonderful job on my V2 Balsa fin to styrene tailcone. Using a gloved finger dipped in 70% Isoproply Alcohol to smooth and round the fillets they have stood the tests of Time & Launches. My old V2 is now retired as it has the signatures of both G. Harry Stine & Vern Estes on it. That said Model 026- BT-80 V2's fin/body joints are as strong as they were when built back in 05-03-1989.

I personally perfer DEVCON 5 & 30 minute epoxies for most of my Model rocket building but any decent 30 minute will make excellent fillets. I'm still using the gallon jug of 3M Glass Bubbles sent for FREE as a sample from 3M more than 10 years ago.

 

[Incongruent]

I'm still using the gallon jug of 3M Glass Bubbles sent for FREE as a sample from 3M more than 10 years ago.

Are they still sending out samples?

 

[Micromeister]

Are they still sending out samples?

I have no Idea.