whatwheel

I would like some info about makeing a spare cowl useing the one that came with the kit that is no longer available, would like to have the new one out of fiberglass, the one with the kit thin lexon [ SPELLING] ? the plane is a goldberg bucker jungmann.

Thanks for any help, Glenn.

SoCalSal

My Feedback: (16)

Hi, go over to the Composites & Fabracation forum. You will be able to find much on how to make a spare anything out of fiberglass. Not hard to do at all.
Also check out Fiberglass Specialtes to see if they don't already have one made up for your needs.

whatwheel

Thanks for the info. I will check it out.

Glenn.

Campy

My Feedback: (1)

Your present cowl is most likely made from ABS plastic.

If it DOES NOT HAVE the rocker arm bumps making a duplicate cowl is easy. If it does have the bumps It is still easy to make a duplicate, HOWEVER, you will need to cut your cowl into 3 pieces to do it.

Making a plug is easy and so is vaccuum forming a new cowl. The new cowl would be from ABS (or a similar plastic ) though. If you decide to go this route pm me and I will give you directions on how to make the plug. There are several threads here on how to make an inexpensive vaccuum former using your vaccuum cleaner or a shop vac (cost is typically $10 - $30 depending on what you have available/on hand in your workshop/garage/basement.

whatwheel

Thanks Campy, when I get closer to this part I will take you up on your pm offer.

Thanks again, Glenn.

Kimhoff

My Feedback: (22)

You can make a perfect plug by filling your exsisting cowl with plaster of paris.

dhal22

great idea! i like the plaster of paris tip.

david

whatwheel

I have heard about that to, but I have also read on several post that its better to use some other type of plaster and not plaster of paris. I very well could have this backward.

Thanks all for the help, Glenn.

Campy

My Feedback: (1)

Plaster of Paris works fine.

A couple of things though -

1. Apply a LIGHT coat of vasoline to the inside of the cowl to prevent the Plaster of Paris from adhering to the cowl.

2. Let the Plaster of Paris dry for a MINIMUM of 2 weeks before using the plug. Some people say you can dry it in a 200 degree oven for a couple of hours. I have not tried that so I can not comment on whether or not it affects the strength/durability of the plug. Any sanding/touch up of "rough spots" should be done after the plug has dried (the best way is fix the inside of part before making the plug). I have used both lightweight spackle and Hobbico lightweight filler when "repairs" were needed to the plug.

3. Make a base out of 3/8" (1/2" preferred ) plywood. The base needs to taper as follows: the top of the base (the part the plug will be attached to ) needs to be 1/32" - 1/16" LARGER than the plug. The bottom of the base should be 1/8" larger than the top of the base. I attach my plugs using medium CA. The taper is to facilitate removal of the plug from the vaccuum formed piece. If need be, you can screw some screw eyes into the base so you have something to grab onto - at times it is "difficult" to remove the plug from the piece without damaging either. The lip provides a cutting mark.

4. If the part has a large diameter to it you should consider inserting some straws in the Plaster of Paris while it is wet, then CAREFULLY trim the straws flush after it has dried (you will need to drill out the base also). This allows the vaccuum to pull the plastic better on the top of the plug (most cowls have a lip that can be difficult to get right when vaccuum forming.

5. Make certain NOTHING protrudes. That will prevent removing the plug. Cowls with the rocker arm bumps are a prime example of this. Typically, something like that requires that the original cowl be cut in 3 or 4 pieces in order to remove the cowl from the plug (Notice I said remove the cowl from the plug, not remove the plug from the cowl).

Some people apply a thin coat of polyurethane to a Plaster of Paris plug to facilitate removing the plug from the part. With Plaster of Paris plugs I have had excellent results dusting the plug with talcum powder just prior to pulling the part.

Vaccuum forming is not rocket science, it is just using common sense and thinking it through BEFORE doing it.

TexasAirBoss

My Feedback: (22)

The Bucker Jungmann is a classic and there are aftermarket fiberglass cowls available that are much more durable than plastic. Plastic cowls tend to crack from vibration and stress after a couple of years. By then , your original cans of paint are lost or clogged up. I tend to go with a glass cowl right from the start . There are two great companies making fiberglass cowls and wheel pants. Fiberglass Specialties and Precision Fiberglass. I'll bet one of them has a cowl for your kit. They are a little pricey, probably around 25 to 35 for a Jungmann, but they are nearly bullet proof. Making a cowl out of fiberglass is a bit more involved than pulling a plastic one. The materials needed are expensive and it requires several products. I consider making my own cowls the last resort. The Jungmann is a nice airplane and certainly worthy of a professionally made glass cowl. My 2cents.

whatwheel

Thanks Campy and Pilotfighter. You have given me a lot of info I can use Idont feel as lost now.

Thanks, Glenn.