BalsaRite Carbon fiber and Monokote

[Bob Reeves]

Long story involving ST 46 but basically I am putting together a Nobler ARF that I stripped the covering off the fuselage and rebuilt the nose. Plan on going back with Monokote but would like to reinforce the nose before I cover it.

Was wondering if applying CF vail using BalsaRite would work, anyone ever tried this?

[Dave Shrum]

 Bob:
I just got an E-mail back from Roy DeCamera (who undoutably gets some of the nicest finishes around --bar none!!) Anyway,
"Basically, dope the bare wood three coats or so and apply the carbon --(( he does not mention to  putting on the carbon V. with dope where you want it)) Seal with 3 or more coats of dope and proceed as normal with the tissue (silk span) work" 
Now, you now have the "formula"--get out there and see if the judges think its as good
as Roy's.
R3C2--Dave Shrum

[Bob Reeves]

Thanks Dave, that is what I normaly do if I am going to paint but I am going to cover this fuselage with Monokote. Had a bad expierence trying to put Monokote over dope so thought of using BalsaRite.

[Steve Holt]

Bob,
I'm not sure that Balsarite is not just nitrate dope.  I would suggest that for the nose, you finish with nitrate and then paint with Lustercote paint.  There is one that matches the monokote color pretty well.  My experience with film covering around the engine area has not been good.  Best with Monokote, worst with either Brodak ARF film or the Sig Primary Force ARF film.  Ultracote is close to Monokote, but still not as good as Lustercote paint.
Steve

[Mark Scarborough]

POerhaps upon investigating the label on a can of balsarite you would find it is not Nitrate.

[Douglas Babb]

Make a test piece out of a small piece of sheet to check adhesion and fill before comitting to the whole nose.

[Steve Helmick]

Bob, I'd be interested in finding out how you rebuilt the ARF nose. Did you remove the engine bearers? That's where I'd like to start, but not sure how to get them out. Wish they'd send over some good Yankee maple for the purpose, but I might end up installing aluminum plates and DuBro brass inserts or just go with Keen-Serts. Post pics, if you would, please!  to all...  Steve

[Dave Shrum]

MMMMM--lets try this again--your right I did not read your post that well.  OK, I had similar situation years ago in that I repaired the nose section and the rest of the plane was covered in monocoat.  Sooooo, what I did was  make a nice pattern into the nose with the monocoat and then paint the nose, but going over the mono... about 1/8" so that it sealed the edge and it worked great-I guess it was the best of both worlds!!!!!
Dave S.

[Steve Helmick]

Thinking more about the BalsaRite part of the question, Nils Norling is the only guy I know who uses it to any extent. He uses it quite a lot, actually. I believe he puts something on with it, other than the usual Monokote. What I'm not sure of, is that CF veil or light FG, but I tend to think it's CF. It's gotta be better than clear dope, right? I believe he puts Rustoleum over the CF, on the fuselage. I don't think BalsaRite is particularly light.  Steve

[Mark Scarborough]

Steve, and others,
I jsut used balsarite to adhere the Micafilm to my P-40. Micafilm and balsarite came to just under an ounce by a few grams. Its like anything , easy to get to much! Kinda like brushing dope I had to play with the reducer to get it to brush on smoothly enough that I wouldnt have concerns about  the strokes showing through the covereing. Incidently, I am painting this, I will be posting a full report as soon as I get further along, whether the results are good or bad.
IMHO putting any type of composite on without completing the matrix is only going to give a marginal gain in strength. If you are after strength, then I suggest a layer or two of 3/4 glass cloth with finishing resin. and perhaps following the other advice earlier in this thread about lustercoat over that portion to match the monokote?

[Bob Reeves]

Bob, I'd be interested in finding out how you rebuilt the ARF nose.

Hi Steve,

What started this whole mess was my coming up with the hairbrained idea of putting a ST 46 in a Nobler ARF. At first I was going to try to replace the motor mounts but gave up. Tried heating the glue with a heat gun and all I did was almost set the fuselage on fire so went to plan B.

Had some 1/16 circuit board stock laying around so I cut strips and epoxied it to the engine side of the MM's. I then cut pieces of 1/8 aircraft ply for the outside and blind nut side boxing the mounts in. Hoping this will give it enough extra strength so the mounts won't crush.

Needing to set the engine as far to the rear as possible and wanting to use a 2 inch spinner to give me more options for props meant I couldn't use the stock cowl.  I just started building up the nose with balsa and ply figuring things out as I went..

Here are a few pictures as I was building the cowl, didn't get pictures as I was building up the nose but these should give you a rough idea of what I did.

[Bob Reeves]

And as it stands now... BTW: The stock cowl weighs 1.3 ounces this one weighs 0.2 ounces. Still have to finish and fuel proof it but don't expect that to add more than 1/4 ounce...

[Bob Reeves]

Back to the original topic...

I have the Monokote, CF and Balsarite, I don't have any sapphire blue Lusterkote and trying to use what I have on hand. After all it just an ARF 

Seems like no one has tried this combination so guess I'll be the ginnie pig and just do it. Will report back with the results...

[Tom Niebuhr]

Bob,

With all the great work you are doing to improve the ARF... why are you building an ARF?

[Bob Reeves]

Bob,

With all the great work you are doing to improve the ARF... why are you building an ARF?

Know exactly what you are saying, this just kinda grew out of what was going to be a quick experiment. I am still searching for the size airplane engine combination that I will eventually settle on for my competition stunt ship(s). ARF's (usually) give me a good fast way to try different  things.

[Bill Little]

Know exactly what you are saying, this just kinda grew out of what was going to be a quick experiment. I am still searching for the size airplane engine combination that I will eventually settle on for my competition stunt ship(s). ARF's (usually) give me a good fast way to try different  things.

Hi Bob,

You do fantastic work. 

Thinking this over, I would apply the CF veil with Z-Poxy wiping all of it off that I could (you know the drill) then apply Balsarite to that, after wiping it down with a cleaner (once it's cured), for adhesion purposes.

That ARF Nobler with an ST 46 should have enough power! 

[Bob Reeves]

Thanks for the complement Bill and Merry Christmas..

I tried a test piece with Balsarite/carbon (two coats of Balsarite sanded) and although I really believe it added the strength I was looking for when I covered it with Monokote the carbon weave showed through. Would take several coats of Balsarite and sanding to fill the CF enough to have it look good.

Here is what I believe will be the final answer.. When I was at Brodaks in 2003 I attended a seminar put on by Tom Dixon using light fiberglass and thinned 5 minute epoxy to fill the grain and give a smooth surface ready to finish. Covering a fully sheeted 60 size stunter using this method only added about 2 ounces. Basically here is the procedure...

- Mix equal amounts (ie 50/50) of 5 minute epoxy and acetone
- apply fiberglass (.5oz) to surface with above mixture.
- scuff surface with 240 when cured/dried
- Again mix equal amounts (50/50) of 5 minute epoxy and acetone
- Apply to epoxied surfaces.
- Scuff lightly and dry sand with 320 and 400.

I had almost forgotten about this even though I did experiment with it when resurrecting the Dancing Girl bipe. I did the nose of the bipe as it had several stress cracks from the old shaker Fox 40. It came out fantastic, didn't add any appreciable weight and it's been flying with the same Fox 40 for the last 3 years.

The great part is it's quick, the epoxy kicks off in less than an hour and you are ready for the next step. Should be able to do this tomorrow and will report back on how it goes..

[Crist Rigotti]

Bob,
With all my experience with Monokote, it does not still well to epoxy.  When building an R/C wing, I'd use epoxy and fiberglass on the center section for reinforcement.  If I used Monokote directly over the epoxy/fiberglass, it would not stick very well.  I then began covering the epoxy and fiberglass with silkspan and nitrate dope (just a couple of coats) and the Monokote stuck very well and the grain of the silkspan showed just a little bit.

[Bob Reeves]

Hi Crist,

Don't have any nitrate dope but thought I would follow what was suggested and put a  coat of Balsarite on the fiberclass before I tried to cover it.  Actually only going to have a fairly small area that will be covered with Monokote. Have decided to paint the forward portion of the nose, I am not good enough appling Monokote to even think of trying the to cover the font of that cowl.

I'll dig up this thread and post a picture when it's finished...

Merry Christmas everyone.

[Crist Rigotti]

Bob,
Let me know how the Balsarite works over epoxy only.  Thanks.

Merry Christmas

[Walter Hicks]

Great stuff guys,

  I have another method that I use when I need a quick repair. Not a cheap way but effective.

.5oz glass  cloth and foam compatable ca glue (thick) ,I belive Bob Hunt used this

years ago. I have done a whole plane this way. For some reason the Foam compatable

Ca glue sands very well. Sand it and fill it until no  more shine (flat dull surface)

spray with auto primer sand and paint with whatever you want . All in minutes!

It is very light if you sand it corectly. The downside it is not cheap.

[Bill Little]

Hi Walter,

I believe Bob Mentions him and Robby doing just that technique in the RD-1 article on the fuselage.  Man, it IS strong and EASY!  But that Foam Friendly CA is like "Liquid Gold" as far as price goes!   (maybe that's why Smith packages it in *GOLD* labels! 

Bill <><

[Bob Reeves]

Finlay got to the covering stage on the Nobler today.. The fiberglass/5 minute epoxy with Balsarite worked like a champ. You need to be a little careful laying the Monokote down so you don't get any trapped air but I wouldn't hesitate to use this process in the future. It really came out nice...

The thinned 5 minute epoxy worked just as advertised but it is a little hard sanding. I used open coat 100 and it still took quite a bit of work. had some old 30 minute epoxy I used for the second coat and wished I had used finishing resin. The epoxy was old so thought I would just use it up, it took two days to set and was very hard to sand but I eventually managed to get a smooth finish on the fiberglass. Finishing resin would have been much easier. Once I had a smooth finish using 100 grit paper on the epoxy I applied a coat of balsarite, let it dry then sanded it with 320. It ended up as smooth a finish as I believe is possible.

Didn't have any problem with the Monokote sticking to the fiberglass, you do need to be sure to start on one side and press out any air as you go. The fiberglass base is completely sealed and trapped air has no place to go.