Sanding/Painting: Filament wound fiberglass nosecone

[Alby]

So I've purchased a filament wound fiberglass nosecone from Wildman Rocketry.
My question is what's the best technique to sand and paint this nosecone?

I'm going to assume Eye Protection and Lung Protection, because fiberglass in your eyes or lungs is not good.
I'm curious about what grit sandpaper should I start with and end with? I'm also wondering, will sanding impact the
wound fiberglass integrity?

Thanks,

 

[Hobie1dog]

I would spray 2 to 3 coats of high build primer that you can get at Advance or AutoZone made by a company called SEM. It is expensive at $25 a can but it will actually build up pretty good instead of the very thin normal primer that is really cheap. Then you can sand lightly with 320 to see what you have, and then go from there.

 

[Alby]

I would spray 2 to 3 coats of high build primer that you can get at Advance or AutoZone made by a company called SEM. It is expensive at $25 a can but it will actually build up pretty good instead of the very thin normal primer that is really cheap. Then you can sand lightly with 320 to see what you have, and then go from there.

Thanks. I'll buy that primer today, spray, then sand and paint..





Thabks

 

[David Schwantz]

Make sure you wash NC first, then sand with 220, prime, scuff with maroon scotchbrite pad, then paint. These are of course just my 2 cents.

 

[Alby]

Make sure you wash NC first, then sand with 220, prime, scuff with maroon scotchbrite pad, then paint. These are of course just my 2 cents.

Thanks. I'm ordering those scotchbrite pads and on Amazon they have 4 cans of the build primer for $59.70, effectively $14.92/ea

SEM 42003 Black High Build Primer (4) https://www.amazon.com/dp/B07Z9NWLJD/ref=cm_sw_r_apan_glt_i_684Y2JHQWC7BYBQCS1EZ

 

[David Schwantz]

Although I have never used that primer, I am sure it is good stuff. I like to use the Rusyt Auto fill and sand stuff. Have had great luck with that for 40 years. God I am old

 

[Hobie1dog]

There are many standard primers in aerosol cans that are very thin in nature with a low solids content, and that basically doesn't do you a whole lot as far as filling in small imperfections and building up a nice uniform layer of primer. You want to eliminate all of those extremely small crevices, so just stay away from the cheap stuff. You will usually notice as you spray it on, if you get a run, then you know it's the real low solids formula. So you kind of get what you pay for with primer.

 

[manixFan]

For primer, I use Dupli-Color automotive primer, which works well over fiberglass, followed by their high temp brake-caliper paint for rockets going over Mach. It's held up better than the other high temp paints I've tried. Dupli-Color makes a true high-build primer-surfacer that they also sell in cans so you can thin it yourself and brush it on. It works very well for filling weave and heavy sanding scratches. I've even had good luck with it filling 3D printed fin surfaces.


Tony

https://www.duplicolor.com/product/filler-primer/
https://www.duplicolor.com/product/professional-primer-surfacer/
https://www.duplicolor.com/product/caliper-paint/

 

[SkyFire]

I just painted one like it. No need to sand the fiberglass. Applied 4 coats of Duplicolor primer filler and 4 coats of Rusto 2X. Sanded with 400 then 600 grit after primer. Nose cone surface is pretty rough and takes quite a bit of paint.

 

[Alby]

I just painted one like it. No need to sand the fiberglass. Applied 4 coats of Duplicolor primer filler and 4 coats of Rusto 2X. Sanded with 400 then 600 grit after primer. Nose cone surface is pretty rough and takes quite a bit of paint.

Awesome. Thanks for the tip. Any time I can get away with less sanding, I'll take it.

Awesome.

 

[manixFan]

I just painted one like it. No need to sand the fiberglass. Applied 4 coats of Duplicolor primer filler and 4 coats of Rusto 2X. Sanded with 400 then 600 grit after primer. Nose cone surface is pretty rough and takes quite a bit of paint.

Wait, the surface was pretty rough and took a lot of paint? Isn't that why you sand things - so it's not rough and paints easily? Somehow 8 coats of paint is better than a couple of minutes with sandpaper? You don't need any protection if you wet sand it - I do mine in a utility sink, there is no dust to worry about that way.

Interesting perspective.


Tony

 

[SkyFire]

Wait, the surface was pretty rough and took a lot of paint? Isn't that why you sand things - so it's not rough and paints easily? Somehow 8 coats of paint is better than a couple of minutes with sandpaper? You don't need any protection if you wet sand it - I do mine in a utility sink, there is no dust to worry about that way.

Interesting perspective.


Tony

Other fiberglass nose cones I have are smooth like the body tubes and required little sanding before paint. The Wildman nose cone is rough because the filaments are on the surface. I was leery of sanding it because of the risk of breaking loose the filaments and creating a big mess. I have another Wildman kit that I haven't started yet. My plan is to apply some finishing resin to the nose cone before paint.

 

[Alby]

Other fiberglass nose cones I have are smooth like the body tubes and required little sanding before paint. The Wildman nose cone is rough because the filaments are on the surface. I was leery of sanding it because of the risk of breaking loose the filaments and creating a big mess. I have another Wildman kit that I haven't started yet. My plan is to apply some finishing resin to the nose cone before paint.

I support this theory because I had another Wildman nose cone which I wrapped in blue painters tape (can't remember my reason why), but when I pulled off the tape off it caused the fiberglass fibers to come off like little hairs. It made handling the NC unpleasant (think little fiberglass fibers embedding into you skin).

Because of that experience, I'm all for the idea of not sanding, priming, then sanding the primer prior to painting.

 

[afadeev]

Wait, the surface was pretty rough and took a lot of paint? Isn't that why you sand things - so it's not rough and paints easily? Somehow 8 coats of paint is better than a couple of minutes with sandpaper? You don't need any protection if you wet sand it - I do mine in a utility sink, there is no dust to worry about that way.

I've never run into any fiber-glass tubes or nose-cones that required any preparation before painting. The picture above looks a lot like one of Wildman's nose-cones. It should be perfectly well formed.

Other fiberglass nose cones I have are smooth like the body tubes and required little sanding before paint. The Wildman nose cone is rough because the filaments are on the surface. I was leery of sanding it because of the risk of breaking loose the filaments and creating a big mess.

Strange, all of my WM nose cones have been smooth and ready for paint. I'm looking at 2 painted and 3 un-painted ones right now (last one purchased 2+ years ago). All 3 unpainted ones will not need any prep before painting. Perhaps there was a quality degradation recently?

1). I wash the FG/CF materials, wipe them with alcohol (to remove oily finger prints I may have introduced).
2). Then spray it with a primer layer. For me, that would also be a DupliColor automotive primer:
https://www.amazon.com/gp/product/B000B6DG7M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=13). 2-3 light primer spray cycles usually get the job done. I sand only if I screw-up, and get uneven primer coat (or a run).
4). Wait for primer to fully cure (read the instructions on the can, to avoid frustration).
5). 2-3 light coats of paint, then 2-3 coats of clear coat. Done.

a

P.S.: Repeat, as desired, after each flight, cause I always nick something on an airframe either during landing, or transportation. Or not.

 

[manixFan]

I've never run into any fiber-glass tubes or nose-cones that required any preparation before painting. The picture above looks a lot like one of Wildman's nose-cones. It should be perfectly well formed.



Strange, all of my WM nose cones have been smooth and ready for paint. I'm looking at 2 painted and 3 un-painted ones right now (last one purchased 2+ years ago). All 3 unpainted ones will not need any prep before painting. Perhaps there was a quality degradation recently?

1). I wash the FG/CF materials, wipe them with alcohol (to remove oily finger prints I may have introduced).
2). Then spray it with a primer layer. For me, that would also be a DupliColor automotive primer:
https://www.amazon.com/gp/product/B000B6DG7M/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=13). 2-3 light primer spray cycles usually get the job done. I sand only if I screw-up, and get uneven primer coat (or a run).
4). Wait for primer to fully cure (read the instructions on the can, to avoid frustration).
5). 2-3 light coats of paint, then 2-3 coats of clear coat. Done.

a

P.S.: Repeat, as desired, after each flight, cause I always nick something on an airframe either during landing, or transportation. Or not.

I think you quoted the wrong post - I didn't say anything about the nose cone being rough or even that it needed sanding, that was Sky Fire. I was simply pointing out the contradiction in his statement. I haven't bought any Wildman kits so I don't know how they look. On the other hand, sanding any surface before painting will improve paint adhesion. Every single can of Dupli-Color primer or paint I have says to sand the surface before painting.


Tony

 

[SkyFire]

Finished nose cone; 4" Wildman Interceptor AAD-98

 

[Alby]

Finished nose cone; 4" Wildman Interceptor AAD-98
View attachment 507636

Love the look. This is the Nosecone with the 4 coats of primer, 4 coats of paint, and 400/600 sandpaper to finish it up?

 

[SkyFire]

Love the look. This is the Nosecone with the 4 coats of primer, 4 coats of paint, and 400/600 sandpaper to finish it up?

Yep! Painted 2 coats of primer, let it cure, sanded with 400. Painted 2 more coats of primer, let it cure, then sanded with 400 and 600. Then 4 coats of paint. After the top coat cures (just painted this week) I will follow up with some Meguiar's 210 polish then a bit of wax.
As others mentioned, it's important to clean the fiberglass well before painting. I normally use a mix of alcohol, water and dish soap. Rinse this off then wipe down with 90 percent alcohol.
When handling the clean fiberglass parts I use latex gloves to keep off oil from my hands.
Before painting I wipe down with a slightly damp microfiber cloth. Don't use tack cloths!!!!

 

[manixFan]

Yep! Painted 2 coats of primer, let it cure, sanded with 400. Painted 2 more coats of primer, let it cure, then sanded with 400 and 600. Then 4 coats of paint. After the top coat cures (just painted this week) I will follow up with some Meguiar's 210 polish then a bit of wax.
As others mentioned, it's important to clean the fiberglass well before painting. I normally use a mix of alcohol, water and dish soap. Rinse this off then wipe down with 90 percent alcohol.
When handling the clean fiberglass parts I use latex gloves to keep off oil from my hands.
Before painting I wipe down with a slightly damp microfiber cloth. Don't use tack cloths!!!!

That is a great cleaning procedure, especially the gloves and no tack cloth. I have to ask though, in the photo it looks like there is a noticeable step-up in diameter between the aluminum tip and the rest of the nose cone - is that real? For a Mach+ flight, that would not be good. But I can see how 8 coats of primer and paint could create that step.


Tony.

 

[SkyFire]

That is a great cleaning procedure, especially the gloves and no tack cloth. I have to ask though, in the photo it looks like there is a noticeable step-up in diameter between the aluminum tip and the rest of the nose cone - is that real? For a Mach+ flight, that would not be good. But I can see how 8 coats of primer and paint could create that step.


Tony.

In the photo the tip is just sitting on top of the nose cone (not centered or tightened).
It's close enough for government work!
Won't be going Mach+ because the club I belong to can only get a 4500' AGL waiver due to the proximity of Tucson International Airport.