Better adhesive for estes PSII plastic fins.

[Back_at_it]

I've never found a "plastic" glue that would stick to whatever plastics Estes uses. It all fails and generally peels right off. JB Weld Plastic bonder was the best of them but even that didn't hold when pressure was applied and the bubbling was a deal breaker.

I've found that pretty much any medium CA will work better then the best plastic cement but I prefer epoxy. Scuff up the mating surfaces where you can, clean the surfaces then apply epoxy and clamp.

For thin areas, I've warmed epoxy to the point where it's almost water like then brushed it over the joints and let it soak in. Wipe away the excess with alcohol.

 

[kjhambrick]

<<snip>>

For thin areas, I've warmed epoxy to the point where it's almost water like then brushed it over the joints and let it soak in. Wipe away the excess with alcohol.

@Back_at_it --

How do you warm your epoxy to thin it ?

Thanks

-- kjh

 

[neil_w]

@Back_at_it --

How do you warm your epoxy to thin it ?

Thanks

-- kjh

A warm or hot water bath is the most controllable approach.

 

[Back_at_it]

@Back_at_it --

How do you warm your epoxy to thin it ?

Thanks

-- kjh

If you mix in small plastic cups you can sit the cup in hot water for a couple of minutes. If you are mixing on a flat surface like a board or wax paper, use a heat gun on it's lowest setting.

Epoxy will get really thin pretty quickly. You don't need to get it much above 100F for most of them to be really thin. BSI 30 min is like water at those temps.

 

[kjhambrick]

A warm or hot water bath is the most controllable approach.

If you mix in small plastic cups you can sit the cup in hot water for a couple of minutes. If you are mixing on a flat surface like a board or wax paper, use a heat gun on it's lowest setting.

Epoxy will get really thin pretty quickly. You don't need to get it much above 100F for most of them to be really thin. BSI 30 min is like water at those temps.

Thanks @neil_w and @Back_at_it

So does warmed epoxy also cure more quickly ?

And ... thanks again !

-- kjh

 

[SolarYellow]

Epoxy will get really thin pretty quickly. You don't need to get it much above 100F for most of them to be really thin. BSI 30 min is like water at those temps.

I'll have to try that for small layups. Normally, the heat would kick it off very quickly, but with the working time of BSI 30 and the cooling when its spread out, maybe there would be enough time to get something done while having the thinness of a laminating resin for a little while.

 

[Back_at_it]

Thanks @neil_w and @Back_at_it

So does warmed epoxy also cure more quickly ?

And ... thanks again !

-- kjh

It will cure in faster in warmer temps but I have not noticed any real change in the working time of the epoxy when warmed. Most epoxies warm a bit as part of their curing process but I have not see a noticeable difference in "working" time.

I will tell you that I absolutely take advantage of these nice sunny warm days to help cure the epoxy. Once it has set enough that I'm sure it won't move around (generally about 90 mins or so). I'll move the project outside and place it in the direct sun

 

[Back_at_it]

I'll have to try that for small layups. Normally, the heat would kick it off very quickly, but with the working time of BSI 30 and the cooling when its spread out, maybe there would be enough time to get something done while having the thinness of a laminating resin for a little while.

I've warmed BSI 30 min. and T-88 epoxies and had more than enough time to use it to paint on layers to coat fins and even a couple of complete rockets. If you look back at my F-32 and Mega Mosquito builds you'll see what I mean. The entire rocket was coated in T-88 epoxy as a finish coat on the F-32 and the fins of the Meg Mosquito were also done with thinned T-88. I had enough working time with the T-88 to do all three fins before it was too stiff to brush on.

 

[SolarYellow]

I glued up the edges with the Plastruct Plastic Weld this weekend. Used a single edge razor blade to separate the edges and make a gap for the solvent to wick into, moving around the perimeter in steps, about a half inch at a time. Masking tape along the edges kept any overflow/sloppiness with the brush from running down onto the flat of the fin and making an ugly lump. The root and tip flats will have to be sanded and there's just a little bit of squeeze-out along the LE and TE that I'll dress with a large flat file and then some 400 grit to blend. But the fins are rock solid and very clean looking. And straight. I'm feeling confident.

 

[cwbullet]

What leads you to believe that this would be better than CA?

CA glue is hit or miss on 3D-printed plastic. For PLA, it is brand dependent and may require an activator. The two-part plastic epoxy is a better bond that is less rigid in my book. Plastistruct is a good choice also.