Cub_Boy

My Feedback: (6)

Hey Guys,

I have a little arf that long since lost its cowl, I just refurbished the ARF and would like to make a cowl for it. Any ideas on materials or common supplies I could use?

saramos

Sounds like a job for 'Vacuumform Man'. Theres a book titled 'Do it Yourself Vacuum Forming', by Douglas E. Walsh. It provides instructions on building your own vacuum forming machine, molds, forming and finishing parts. Do a google search, and you should be able to find the book in stock somewhere.

Scott

Denis49

A google search found this:
http://www.ares-server.com/Ares/Ares...oduct&ID=80868

Flyboy Dave

My Feedback: (21)

Another way to do it is to make a nice piece like what you want, shaped
out of foam....then fiberglass a couple layers over the foam. Then rip out
the foam, and you have a nice fiberglass cowling. Just sand it down smooth
and paint it.

Dave.

Kaos Rulz

Dave's got the right idea with the foam and fiberglass.

Try the green foam that florists use. It shapes and sands easily. If it doesn't pop away from the fiberglass, just pour a little gas into it and dissolve the foam.

Campy

My Feedback: (1)

If you decide to go with the foam, I usually cover mine with scraps of LOW TEMP film. Depending on the foam and the resin used, the resin can eat the foam.

If you want to try to save the plug for the future, put about 10 - 12 coats of wax on the film covering the plug (seriously ) and/or use PVA release liquid.

I usually do any sanding of the cowl/part prior to removing it from the plug. When you remove the part from the plug it will be VERY flexible. Do any minor shaping at that time, then put it aside and let it sit for 3 or 4 days - it will harden right up.

ecmiller

FYI, the foam florists use is called OASIS.

glen9032003

Small plant pots

AlphaWhisky

I`ve made a few one-off glass cowlings generally as described above and although they came out OK, it can be a messy exercise, moreso for the smaller items as the strips of stiff glasscloth seem difficult to get to lay down neatly.

By chance I came across an article in RCM magazine, May 2004 issue, on making these using pantyhose in lieu of glasscloth. That must be one of the most useful 'how-to' articles I have ever read. I thoroughly recommend you track it down.

The job is approached similar as for a one off glass cowling over a male foam plug. Casually wrap kitchen film around the plug and then fit 4 separate tubes of nylon pantyhose cut from the leg of a pair of pantyhose. Unlike glasscloth, these cling to the plug and readily hold their shape. It is a simple job to massage out the occasional wrinkle and tie the open ends off with a strip or two of masking tape. The resin is applied as for the glasscloth item.

It is a simple exercise to separate the finished item from the plug. I give mine a good coat of sanding sealer prior to painting. in my opinion the finished item is lighter weight and a finer finish than the average glasscloth equivalent and therefore ideal for the smaller project.

The largest one I have done so far was for my 80" span Spitfire and in this instance I applied a few strips of glasscloth around the inside to beef it up.

Try it - you`ll like it.

Alan W

Cub_Boy

My Feedback: (6)

Guys,

Those are some great tips... and it gives me more than one option to try!
I appreciate all of the input on this subject


Rick,

kdheath

A real old fashioned method for making small parts and cowls involves making the buck and layup as already described, but mount the buck on a healthy piece of dowel. Clamp the dowel and the plug in a vise. Layup the glass or whatever, then inflate a large toy balloon and press it down on the buck, slowly letting the air out until the balloon is turned inside out over the piece. Let dry and peel the baloon off. Makes a pretty slick finish and reduces the amount of after-work.

Jimmmaaa

I dont know how it would hold up, but I shaped the cowl out of a solid piece of wood (4x4 fence post??). Then I cut off the top of a soda bottle and placed it over the wood, and melted it to the form with a heat gun (for covering). It turned out pretty good but a little flimsy.

bingo field

Ok, kill me now. I couldn't find the URL for the article, but here is the text and the more important pictures.

How to Articles Index Make A Pop Bottle Cowl
Its easy, inexpensive and environment friendly!
By JOE BESHAR


I NEEDED TO MAKE a thin cowl, and carving one out of balsa just wasnt practical. A modeler friend suggested that I pull one out of a clear plastic soda bottle. This sounded interesting, so I found a few clear bottles in the recycling bin and developed this simple, inexpensive procedure to make a very satisfactory cowl.

1.
Make a plug of the cowl out of balsa, hardwood, plaster of Paris, etc.
2.
Use a clear plastic soda bottle into which the plug will fit as tightly as possible.
3.
Cut off the bottom of the bottle and remove the cap. Insert a long dowel into the bottom of the plug.
4.
Put the plug inside the bottle. Direct a heat gun at the bottle while you turn the assembly.
5.
The plastic has shrunk tightly against the mold plug. After it has cooled, trim the plastic and slide it off the mold.
6.
Paint the inside of the cowl with plastic-friendly paint and, if you like, add a decal or two to the outside.

You can also use this procedure to make canopies and other model accessories out of plastic bottles. Good luck and happy landings! j

Stripes

My Feedback: (19)

The plastic should be folded over the bottom of the plug and stapled on before heating.

The top can be screwed back on and a hole put in it to use compressed air for removing it from the plug.

Top-Flight paint is too tranparent and you can see right thru to the underlying color of the bottle so use clear bottles if possible otherwise paint with Rustoleum.

Contrary to a previous post about being flimsy I find them very tough and resilient just like the pop bottles they come from.

http://www.theflyingknights.com/phpB...topic.php?t=72

.

Charlie P.

Great ideas here!

I don't know if it will adhere well to the polystyrene (?) plastic or whatever soda bottles are made of, but I have used coffee filters saturated with epoxy (fiberglass resin, too) to internally repair or reinforce cowls at the attachment and stress points. Used drier sheets & epoxy work well, too.

Cub_Boy

My Feedback: (6)

Hi Guys,

I have to say, you guys are full of wonderful ideas!
I needed to do some FG repairs on one of my scale contest planes and you just
offered up a couple of methods to help with that as well... BONUS!!!

I really appreciate everyones input... thats what I like about this hobby/sport
everyone is into sharing their great ideas and experiences.



Thanks again guys....

Rick,

ballgunner

My Feedback: (1)

This one goes a long way back but it works. As in most prodedures it requires a form made of whatever is handy, balsa, hardwood or whatever will hold shape. Cut some of the old fashioned paper grocery bags into strips and soak well in thinned elmer's white glue. apply to the form in several layers. Make it thick enough to sand to shape when dry. Works well for compound curves but cannot be relied on for strength. A layer of fibreglass on top will help make it stronger. Cheap and easy, which is a major requirement for me.

Balsa Master

glass is a much nicer solution... though messier and easier to make mistakes on... if its not really that large of a plane then i recomend the bottle method previoulsy explained... i make cowles and nav lights that way works good...

only down side to your method ballgunner is its not very water resistant or fuel resistant... but i have used the peper machet method and it does work though not my favorite...

BillS

Great method. Use another cowl as the plug.

I had a Kougar/King Cobra cowl that had not been cut (afraid I would mess it up). The cowl slipped inside of the coke bottle and inside of ten minutes I had a new plastic cowl for experimentation. Forgot the Vaseline. Now if the original cowl will come out. But if it will not come out I have not lost anything but an empty coke bottle.

What a nice solution.

Bill

BillS

Wow! Ten minutes of effort.

Bill

krazycdn

ya get a chunk of wood and carve a cowl Foam wood be easier but you have to glass it anyways wood is the cheaper method. Once you have the right look and size find a clear plastic pop or water bottle that will fit over the carving. align the opening with the prop opening on the cowl and secure it there with a screww through the opening with a washer to hold the bottle in place on the wood plug. take a heat gun and start shrinking the bottle down onto the wood plug try and do this evenly to avoid wrinkles once the plastic is shrunk let cool for a bit then cut rear edge fluch with wood plug and remove wood plug then cut neck off of bottle for prop hole and there you go

pirit4

My Feedback: (1)

That's the best freakin' solution I have seen yet! People spend hundreds of dollars on vacuum forming machines for this!!! I havent tried it yet, but I cant wait!!

And the cowl is stronger than any of the ones you would get with a kit!

Insane

giffordbilt

My Feedback: (1)

Hey Stripes, over on the blue knight site a fellow named warren has a couple of planes forsale, do you know if he still has them?