Vacuum forming paper

[Bionic Modeler]

I was going through my old stuff and ran across this experiment I tried back The 1/4 merc project was underway. I was searching for a realistic way to form the heat shield and the Shingles for the skin. So i though I would post it again for any who might be interested

VACUUM PAPER FORMING by Tim Hinds

OK here is my method. You can go all out and build a vacuum former or you can simply use a plastic bag, which will work but not as well.

To build the vacuum former make a 4” deep box at least 12”x12”. Glue a piece of pegboard to the top. Drill a hole in the side for your vacuum hose. Use a shop vac if you have one. I don’t recommend your house vac as the airflow cools the motor. Once you pull a vacuum there is no more airflow and it will overheat (Your wife will be very angry with you). Shop vac’s cool separately.

If you use a plastic bag make a platform about 12”x12” out of pegboard and place inside. When you place your mold inside in the middle of the platform insert the vac hose as close to the work as possible. Tape the bag closed around the hose and turn on.

You can use whatever you want for a mold I made mine out of plaster and formed them from the actual card model part . Then with a little tooling and you have a pretty good mold. I also used Scott’s Plastic shingles and made molds from them. Once your molds are ready depending on the amount of relief (depressions, curves 3’d impressions) you might be able to use card stock. Wet it overnight to loosen the fibers or boil for a few minutes. Use a piece of plastic food wrap to cover the mold then place your wet card stock over the top. Then cover with a smooth fabric (T-shirt works good). You don’t want any pattern, as it will show up in your product. Then cover everything with a large piece of food wrap. Turn on the vac and it will suck the air out forming your paper to the shape of the mold. Work it in to the depressions with your fingers and fingernails for any creases you want to show up etc. and roll out any wrinkles using a hard wooden roller. Do this for a few minutes with the vac running. Then uncover and Walla you have your part. Let dry then spray with clear coat or paint.

For more demanding parts like those I made of the Mercury Fairing, use Viva Super absorbent paper towels. Wetting one piece, forming as above then coat with a layer of white glue while wet. Follow this same procedure three more times for a total of 4 layers vacuum forming each layer as you did in the first. Then let dry. The plastic wrap under the paper will let it release from the mold. When it is almost dry remove it from the mold and remove the saran wrap from the bottom so it will dry thoroughly. Then when dry you can repeat the process dry forming it to re-define the reliefs a little more as it shrinks a little when drying. You can also paint the final product with a final layer of glue for a smoother finish. Paint to desired color and clear coat. The more clear coat you use the smoother the finish will be as there is a little texture from the paper towel and the T-shirt combination. But it isn’t bad. You can try different papers but the ones I suggest worked best for me especially when forming tricky curves. I practiced on a light bulb (for you helicopter enthusiasts) and got a near perfect smooth bubble. You can break the light bulb when finished to remove it from the mold.

You can also use plastic parts for molds as well. However there are limits to how much you can form it. For really detailed parts cast paper mache’. That is another whole process. I have little experience with that but maybe others can help.

[Isaac]

sounds interesting. Pictures please of examples.


Thanks

Isaac

[Bionic Modeler]

I had pics beck when I wrote this but can't find them I still have the molds though maybe if there is enough interest I can re-create them

[spaceagent-9]

plumbers epoxy is a grey squish and dry stone. great for mold making and stuff.

absolutely great thread you started here. paper can replace plastic as far as model kits and parts go!!
really great stuff you did here.
jim

[Paperwarrior]

This is quite interesting. I must admit I never thought of doing this, plastic yes, paper no. It will be interesting to see more.

Jeff

[Leif Ohlsson]

I will follow this with interest as well. Good thing of you to preserve your rich experiences with this method, Tim!

Let's watch this with Ron's saved instructions for the Vac-Former in mind!

Leif

[Gil]

Hi Tim,

Great post!

The method you described works well. I've used it to make fuselage shells though I ended up leaving the vacuum forming part out of the process. The build up shell, after being burnished into the mold shell half, stayed firmly in place. The problem with wet paper and vacuum molding is the lack of ventilation to remove moisture.

What's needed is a slow setting [<30 min.] glue that does not require air as part of the cure - a "green" epoxy like, water based compound. One that comes to mind is plaster of paris [PoP]....,

+Gil

[Isaac]

this looks like a negative mold. For vacuforming I have used positive molds ( like for a canopy ). A negative mold is harder to make and require extra steps.

That is why I requested more photos and detail.


By the way, that is a Mig-17 you made.


Isaac

[GaryPilsworth]

Watching this one too very interesting

[grimpirate]

@Gil: If it wouldn't be too much to ask (I realize it takes your time and effort) could you post (on a different thread so as not to change the original premise of Bionic Modeler's post) how it is you made that curved shell you've shown in the photo in more depth or a step-by-step? Being able to produce double-curved paper surfaces would be great.