calebdevries

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I am looking at trying to build carbon fiber spinners and was wondering if anyone else has tried this. Do you have any tips or the process you used? Did you balance it? Any help would be appreciated. Thanks.

Roderick-RCU

Hello

Did you think of the mould already?

regards, Roderick

whstlngdeath

My Feedback: (15)

I worked with Mark Brown in San Antonio on his Pulsar kit shop
and had the pleasure of hand-laying spinners. We used 10 oz.
cloth wet-layed in a female mold. Since the builders of these kits
painted the spinners to match the plane, we never considered
using more exotic reinforcements like carbon fiber or Kevlar. The
price was also a factor. A 1 yard package of fiberglass cloth is
about $10 as opposed to $50 for the carbon fiber! If it is the look
of the carbon fiber you want, then it would be a good option. As
I understand it, it is easy to handle and lay up but you do need a
mold of some kind. Go to this site and check out all of the info that
they have on composites:

http://www.fibreglast.com/index.php?...93214be2536c69

They sell books and videos and all the product you need. Here is
a shot of the Pulsar that was such a good flyer, really aerobatic
at a + or - 6G rating! Used a Rotax 912 engine on pump gas.

ptxman

My Feedback: (2)

A few comments:

50 $/yd for CF cloth is very expensive. Plain weave can be had for 12-15 $/y range, satin weave about 20$/yd in the 4-6 oz weight, small yardage cuts, USA sources.

You didnt mention the size of spinner but my guess if its under 3" dia, carbon will require a bit more finesse to lay down in the mold cavity. If its larger than that, it shouldnt be a problem. CF is stiffer than glass by nature & any weight under 4 oz is hard to find and/or very expensive. If you obtain satin weave CF (aka crowfoot) it will conform a bit better. If any combination of [weight, balancing, cloth conforming or resin drain-off] becomes an issue, vac bagging would definately help.

Consider how the finished CF spinner layup is to be mounted to the backplate. Examine a Tru-Turn-like system for ex - the edge of the spinner actually has a step that engages in a groove machined on the backplate so the net outline is flush & the spinner is secured by a center bolt into the prop nut. Both the spinner edge & bolt entry area would have to reproduced on the mold & layup, somewhat finicky details here. Some larger dia CF spinners Ive seen are attached radially but to custom machined backplates with extended ears jigged & tapped I imagine. Also consider some sort of jig to make accurate prop cutouts.

Personally, I would start by making a female mold off an existing spinner just to bypass the plug making & get the layup technique & details nailed down. The specific shape & dimensions will dictate what the cloth pattern(s) look like. It may go in as one piece, or it may have to be segmented or seamed along a compound curve. Start with lighter weight & less expensive glass to get the hang of it & work up to CF if all goes well. Test your resin system against the intended fuel type.

If the layup is a reasonably consistent lamination & light weight, I wouldnt expect balancing to be a big issue because the weight * radial distance is relatively small. Send us some pics!

calebdevries

My Feedback: (8)

If all goes well, I am planning to make them from about 3" on up. I am trying to stay away from having to but a bolt through the tip of the spinner due to the extra work in the mold and layup process. I have a vacume bagger and I am thinking about using that because I would think it would kind of smooth out any extra resin and make the whole spinner more uniform. This should hopefully solve any balancing problems too. If you guys have any recommendations on where to get the different CF's and where the prices are good, please let me know. By the way, what kind of CF is most comonly used for looks, like on heli's and other things that use carbon fiber? Thanks.

ptxman

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Here are 2 links with descriptions, pictures & prices. Im not sure if these names all refer to the exact same weave (they seem to be used loosely among suppliers) but I suspect the 'look' CF you are referring to is called twill, basket weave or satin weave or crowfoot. Anyway, plain weave is the basic 90 deg cross over & under.

http://www.carb.com/index.html

http://www.shopmaninc.com/carbonpage.html

rsieminski

ptxman,
Where can I get "Plain weave can be had for 12-15 $/y range, satin weave about 20$/yd in the 4-6 oz weight, small yardage cuts"

Everything I find, is way expensive. Are those figures for 50" material, or narrow cuts. Please show me the way. I'm dying to make some CF LG.
Thanks,
--Rick

ptxman

My Feedback: (2)

For relatively small orders, plain & satin weave, I like these guys, FSI: Fiberglass Supply Inc.

homepage is here
http://www.fiberglasssupply.com/default.asp

link to catalog with glass, carbon etc is here
http://www.fiberglasssupply.com/Prod...orcements.html

Cattle_Prod

My Feedback: (1)

http://www.geocities.com/CapeCanaveral/Cockpit/3328/

peruse this wonderful aussie site.

calebdevries

My Feedback: (8)

I started on my first spinner plug for a carbon fiber spinner today. I filled in the prop and screw holes with automotive body putty and sanded it down to the spinner every where that I didn't want the putty. The first one is only 2" because I had it laying around and figured I just need the practice. I still have a little more putty work before I make the mold. It is going much faster than what I had originally thought it would. That's always good. I'll try to keep you posted.

rsieminski

calebdevries,
Can you post any pictures? You are using putty or RTV, for the mold?

calebdevries

My Feedback: (8)

I am making the mold of fiberglass because that is how I was told to do it from a guy I know who has done molds before. I will try to get some pics as soon as possible. What kind of putty are you thinking of? I am planning on putting automotive body putty on the outsid of the mold as a base and a support. Please let me know where to get the products you are talking about. Thanks.

rsieminski

RTV. . . expensive stuff, instant mold?
Plasticene Clay? Never used it.

http://www.shopmaninc.com/moldmaking.html

Probably other places as well.

Traxxas_Tech

My Feedback: (22)

I have aquestion: I'm trying to make CF plates and get a good imperfection free gloss face. I dont have anyone local to ask how. The epoxy finish seems to pick up rub marks etc from the wax.. I know I'm not doing something right.

What is the best mold release and method for getting an easy release, that gives me a fine, glossy surface? A spray? Frekote? Carnauba paste wax? Pleas tell me how to properly apply the product. Thanks in advance

SCALECRAFT

My Feedback: (13)

I have made a 109G6 spinner for my platt 109.

It was made by turning MDF/HDF particle board into the shape i needed.

Layup is in 3.75 and a 6oz "E" glass. Must also be layed up in sequence of overlaping triangle shapes to minimize balace problems. Practice, practice.

Keep it cheap, its frequently damaged part of a plane. I have a pic of it in one of the forms somewhere. Click onto Scalecraft posts, its there.
Good luck.

Steve

SCALECRAFT

My Feedback: (13)

The Carbon plate question.

layup on a flat piece of thick non porus material and clamp it together, as if a pressure mold.

Thick clear plexiglass is ideal. Experiment with cheap glass first.

I use "Partall" non silicone wax,along with PVA liquid mold release on top of the waxed surface. Silicone in waxes will cause the PVA to "fisheye" it will also cause any paint on the slicone surface to fisheye.

You may not need PVA on such a flat surface if you need a perfect image of a flawless surface, however, I always use PVA in my molds.

Steve

ptxman

My Feedback: (2)

On flat panels its actually pretty easy. I made CF/balsa/CF firewalls this way: apply ordinary drafting mylar, shiny side down on the epoxy wetted cloth & then pressed or (better yet) vacuumed bagged between 2 pieces of glass plate or similar hard smooth surface. The mylar will give an almost mirror finish & its transparency allows you to squeegee the resin a bit to ensure no trapped air bubbles. The pressure ensures a resin lean composite & the fibers will tend to flatten a bit so you dont see any underlaying core material. Vacuum of course applies much more pressure than weights.

Once cured, the mylar is then just peeled away & either disposed or re-used if you used releasing agent. Peeling the mylar away from the surface is much easier than trying to detach the lamination from a glass 'mold' especially on larger layups.
Any of the mold release agents you mentioned are ok, actually with mylar they are even overkill as it has inherant releasing properties, but I would still use an agent. I suspect you are applying too much wax and/or not buffing it off completely between coats. I have used a similar product to Frekote & it worked just as well with just a bit of haze on the part which is easily wiped off. Always check with a test piece that a solvent based agent is compatible with the mylar (most are).

If you are after a stunning aesthetic finish like some auto performance parts, this is usually acheived by clear coat paint applied either on the mold or on the part once removed.

Traxxas_Tech

My Feedback: (22)

There we go! Thanks for the info, I'll experiment...

calebdevries

My Feedback: (8)

Well.....
It didn't quite work. It got stuck on there pretty good. I cut around where the spinner plate would go and put the knife between the mold and the plug and got it loose all the way around as deep as I could. It wouldn't even start to come the rest of the way. Good thing I didn't spend much time on the plug. Please let me know about other molding materials that you have used. Thanks.

rsieminski

ptxman,
The epoxy will not bond to the Mylar? Are there other films that the epoxy wont stick to?

ptxman

My Feedback: (2)

Im not a plastics expert but this is my take on it. Mylar tends to have inherant properties that allow it to release nicely from epoxy more so than other materials & that seems to be why its favoured as well as other qualities: shiny surface finish, stiffness, thickness, availability, price. I think other materials will work, just a matter of experimentation & whether the cost & effort justifies it. Ive played around with what I think are non-mylar bagging materials, peel ply, perforated bagging materials etc & they release exceptionally well. Actually, so do the bagging tubes sold by ACP & CST for that matter. But these films are only a couple thou thick & more prone to crinkling which may not be suitable for flat panel aesthetics & especially molding wing surfaces. That seems to be where more rigid mylar sheets come in. What I was suggesting as a compromise for flat panels is drafting mylar which Im guessing is about 0.003" thick backed by a glass plate. The 0.014" mylar sheet favoured for bagging foam wings is definately good stuff but not that easy to obtain in my neck of the woods so Im going to pursue some similar thickness & shine 'other' plastics in combination with a releasing agent.

ptxman

My Feedback: (2)

Its kind of hard to tell what went wrong without seeing your part, materials & finish. Sounds like you made a 1-piece mold off a spinner from a handmade plug? Some thoughts: if the spinner is not 100% symetrical (circular) or has any surface roughness other than glossy & smooth, that would probably present enough resistance so the plug/mold cannot be rotated against each other to part. For example, if you left an outline for the prop, that little ridge would present enough of a step to prevent rotation assuming the mold & plug is rigid. If the mold is polyester vs epoxy, I would suspect the higher shrinkage during curing might be gripping the plug a bit more. You may have had a failure of the releasing agent, whatever that was. Pulling the spinner plug straight out of the mold is probably not easy because there is a lot of mold/plug contact area.

Depending on how bad you want the parts, its probably worth getting forceful with the parts at least to find out what went wrong & chock it up to experience. We've all been there. Try knocking the mold periphery & on the nose with a rubber hammer in attempts to break the contact area. You might find (eventually) that it was a tiny little area that was causing all the headache & you will pay attention to that detail next time. Thats a reletively small part to have it locked up so there is something fundamentally wrong.

You ca go to flexile molds like urethanes, they will flex more & yield the plug, but that same flexibility works against you for making nondistorted symetrical layups - bad news for a rotating spinner.

SCALECRAFT

My Feedback: (13)

Hi

This is what works for me. I have a mold of a 5.25" spinner I made for a 109G6. It has rivet and scale section recessed scribe line. I wax the mold with partall and PVA it before layup. To remove the part I push one edge of the part away from the mold and use air pressure to pop it out. It jumps out at you. I've done this with a 109E spinner also that has a negative angle at the end of the spinner, and still it comes out

calebdevries

My Feedback: (8)

How do you get the air pressure in the mold? What is your mold made of? How did you make the plug? Do you attach the spinner to the backplate with screws around the perimeter of the spinner rear? Thanks

SCALECRAFT

My Feedback: (13)

Hi

There are 2 ways I can get air into the spinner mold. At the tip of the spinner mold there is a hole I plug with clay before layup.

Also i can push away the back edge of the spinner from the mold and blow air down there. I use a rubber tipped blow gun.

Mold is 100% west system resin and glass.

Plug is a High density particle board glued together and turned to shape. it is then primed with laqure based primer. will yield a new car type finish once waxed.

This particular spinner mounts to the back plate just like a TRU-Turn type of spinner, a bolt through the front. The spinner is layed up of a 3.75 "E" glass cut in triangles and placed as evenly as possible. Then a circle of 5.75oz "E" glass small circle at the front where the bolt will pressure. Then a layer of 5.75oz "E" glass in triangles to finish.

Minimal balance problems if you take the time to layup evenly.

On this spinner i put a seam tape a the insde outer edge of the spinner for additional support.

Hope this method works for you. I can post a pic of the plug if you like.

Steve