Author Topic: Using Polyspan without dope (Read 2669 times)

Scott Bauman · « **on:** December 04, 2012, 06:52:54 PM »

I am about to start an electric Vector 40 project and currently finishing up a freeflight model for the upcoming King Orange competition down here in Florida. Since both models will not need fuel proofing and I prefer not to work with dopes I deceieded to cover both models using polyspan and use waterbased paints.
I have read about using waterbased Minwax Polycrylic to stick the polyspan down with. On my first test panel using polycrylic and the waterbased paints everything is fine. But the next step is to fold the polyspan around a small 90 degree corner such as the trailing edge of a wing, elevator etc.

How the heck do you get polyspan to go around a 90 degree bend and have it stick while the polycrylic is drying?

Yes it's a freeflight Gee Bee and no I do not expect it to fly very well. But every modeller should build at least one Gee Bee. I'm just getting it out of my system so I can move on to other good projects.

-Scott

Scott Bauman · « **Reply #1 on:** December 04, 2012, 07:07:36 PM »

Here is the first parts covering in polyspan....not my usual quality.

Mike Haverly · « **Reply #2 on:** December 04, 2012, 08:45:11 PM »

When using dope I use my monokote iron on medium to high heat. I would think it would work the same way with polycrylic. Stretch it as you go and be sure to keep the iron moving. I have done conave curves using the same method.

Scott Bauman · « **Reply #3 on:** December 04, 2012, 08:49:25 PM »

Ok will give it a try.

wwwarbird · « **Reply #4 on:** December 04, 2012, 10:43:24 PM »

The easiest way to get Polyspan around a tight compound curve is to substitute it with Silkspan.

Scott Bauman · « **Reply #5 on:** December 06, 2012, 07:01:40 PM »

Other than silkspan is using a heat iron to get it to stick the best method? I think I'm going to just use the polyspan on the wings and tail of my Gee Bee. The rest of the model will be tissue which I know how to use.
-Scott

Avaiojet · « **Reply #6 on:** December 07, 2012, 04:54:14 AM »

Quote from: Scott Bauman on December 06, 2012, 07:01:40 PM

Other than silkspan is using a heat iron to get it to stick the best method? I think I'm going to just use the polyspan on the wings and tail of my Gee Bee. The rest of the model will be tissue which I know how to use.
-Scott

Scott,

I never used a heat iron on any model I covered in tissue. We didn't have them then.

IMHO, I personally would use tissue on the entire model.

Ultrakote?

Kudos on your choice of modeling, I have interest in the Gee Bee's.

Outstanding!

Charles

jfv · « **Reply #7 on:** December 07, 2012, 12:24:58 PM »

When I use polycrylic and polyspan, I attach the polyspan with balsarite just like you would attach any film covering. I generally use a trim iron on the edges. Seams almost disappear. I apply the polycrylic after shrinking. This wing was done that way.

Gene O'Keefe · « **Reply #8 on:** December 07, 2012, 12:59:20 PM »

Nice framework on the Gee Bee !

Scott Bauman · « **Reply #9 on:** December 09, 2012, 07:02:38 AM »

Thanks for the build compliment. It got a couple hours worth of sanding after the bare bones picture was taken.

I have not tried balsarite yet. I will give it a try.

One of my goals is to find a Polyspan glue that does not react with Auto-Air paints. Auto-Air paint is a "waterbased" solvent type paint for airbrushing. It is light weight and seem to fill the gaps in Polyspan very well. I have several hundreds of dollars invested in Auto-Air paint for my jetski/helmet airbrush side hobby. Most of the dopes I have tried on test pieces seem to keep the Auto-Air from fully curing. But the polycrylic as a glue seems to let the Auto-Air paint fully cure.

Here is the website for Auto-Air paint http://www.autoaircolors.com/

-Scott

Paul Smith · « **Reply #10 on:** December 09, 2012, 11:10:22 AM »

With Polyspan I cover the tips with several narrow strips wrapped from the top side of the tip rib to the bottom of the same tip rib. The seams take some doping blend in, but it beats wrinkles when you do it another way.

A little bit of overlap in is not enough to get Polyspan to stick when you bend it over an edge. Whenever you wrap Polyspan around an edge, give it at least half-inch of overlap.

Scott Bauman · « **Reply #11 on:** December 09, 2012, 09:10:05 PM »

I've had pretty good luck with the polycrylic so far this weekend. With heat it seems to bend around 90 degree corners and holds on 1/16" squares. Also, the paint seems to be working out ok. We'll see how it actually looks when it's finished.
-Scott

Scott Bauman · « **Reply #12 on:** December 09, 2012, 09:17:15 PM »

One more picture.
p.s. this is more of an experiment to learn to use Polyspan and to see if Auto-Air paint will work with polyspan for when I build my Vector 40 so yes this thread is control line related.
-Scott

Roger Vizioli · « **Reply #13 on:** December 09, 2012, 09:25:41 PM »

Lookin' good Scott.

As this is your warm up for finishing procedures for the Vector 40, I cant wait to see the Vector.
Roger V.

john e. holliday · « **Reply #14 on:** December 10, 2012, 09:54:37 AM »

Can I send my planes to you for covering??? That looks great.

Scott Bauman · « **Reply #15 on:** December 10, 2012, 08:32:23 PM »

Here's tonights quick 10 minute paint... Looks ok so far but it's not done till it flies....or not...
I hope it flies further than I can throw it to the garbage can.

Roger-Next time you are over I will show you the technique I used to do the covering using the trim iron and polycrylic. I'm sure on a big structure like a CL wing the margin of error is much greater and it will look better. On the small 1/16" square sticks of the freeflight model there is little room for error for the covering.

Yes you can send your models to me for covering...I will work for money

I've done a little bit of building for "hire" in the past.
Honestly I don't think this looks as good in person as it does in the photos.
-Scott

Scott Bauman · « **Reply #16 on:** December 11, 2012, 09:08:41 PM »

Here is the model after some red paint on the fuse and some decals. The Auto-Air looks like it might be an ok paint for an electric model especially after a 2 part clearcoat is sprayed on top of it. For this freeflight model I am going to leave the paint bare (I think).

I included a detailed picture of the red/white paint border as well. There is a couple spots in the picture where there was some blow under. I did not really press the vinyl stencil down very hard and also keep in mind the sticks are 1/16" square so it is really quite minor.
-Scott

Scott Bauman · « **Reply #17 on:** December 11, 2012, 09:09:37 PM »

For some reason I get an error if I try and upload more than 1 picture at a time. Here is the fuse with paint and decals.

Scott Bauman · « **Reply #18 on:** December 11, 2012, 09:11:02 PM »

one more. This one shows the wing N number has yellowed some with age. I didn't realize the yellow would show up as bad as it did

Roger Vizioli · « **Reply #19 on:** December 12, 2012, 06:35:15 AM »

Scott,
Looking very good!
If you want, we can go to the club field and we can "test glide" / trim it before the KOI FF event (not to be confused with the CL KOI @ Whitehouse).
I was out there yesterday, the high grass acreage beyond the mowed areas should work well.
Roger

Roger Vizioli · « **Reply #20 on:** December 12, 2012, 06:37:24 AM »

Quote from: Scott Bauman on December 10, 2012, 08:32:23 PM

Roger-Next time you are over I will show you the technique I used to do the covering using the trim iron and polycrylic. I'm sure on a big structure like a CL wing the margin of error is much greater and it will look better. On the small 1/16" square sticks of the freeflight model there is little room for error for the covering.

-Scott

Great!
Okay, we can setup a time for this.
Roger

Scott Bauman · « **Reply #21 on:** December 12, 2012, 05:43:42 PM »

I'm pretty sure I can take the model out to a nice soft field for some test flying this weekend. I"m wondering if I should fly it with the giant wheels and wheel pants and just put those on for static display. I'm afraid they will tear up the wings in the event of a crash.

Sure thing Roger I'm going to be around all weekend. The polycrylic seems to be holding up pretty well so far. The only thing I need to do this weekend is a little bit of an alignment on my car using a stick, my eye and a couple wrenches. Are you good at eyeballing alignment?

-Scott

Roger Vizioli · « **Reply #22 on:** December 12, 2012, 06:01:36 PM »

Scott,
Rotary Park has short grass but it should be okay and it is 18 miles closer.

Did some alignment work at night when in college. s/b able to help.
Dog trial this Fri/Sat. will know schedule later this evening.
Roger

Scott Bauman · « **Reply #23 on:** December 12, 2012, 07:59:34 PM »

Roger-KK re-this weekend.

Here it is 95-98% complete. I realized I forgot to paint the landing gear struts last night. Not sure what color the spinner is supposed to be so it is still bare. Carbon fiber shaft for the rubber band holder in the rear. Oh yea I think the prop needs a little bit of balance work.

The paint has taken to polyspan quite well. Plus the decals are attached very well from the looks of it. So far I'm happy with this polyspan experiment but it does look much better in the pictures than in person....but that's just me.
-Scott

Scott Bauman · « **Reply #24 on:** December 12, 2012, 08:01:16 PM »

A couple more

john e. holliday · « **Reply #25 on:** December 13, 2012, 08:52:12 AM »

If that flies as well as it looks in the pictures, I hope you have your running shoes on. I have always had a little fondness for the Gee Bee racer. Used to have a little plastic model that I did as much to scale detail as I could. Don't know what ever happened to it.

Scott Bauman · « **Reply #26 on:** December 13, 2012, 10:09:26 AM »

I hope it flies ok. I have always likd the Gee Bee as well. I know the rc models fly ok but are a handful. Most end up crashed due to stalls so instead of spending a lot of money on an rc model gb i went for a freeflight one. Im sure this model will cure me of wanting another Gee Bee.
Scott

Scott Bauman · « **Reply #27 on:** December 20, 2012, 09:33:16 PM »

I won the model of the month at our club meeting. Now I just have to get the darn thing to fly and start on my Vector 40.
Scott

john e. holliday · « **Reply #28 on:** December 21, 2012, 10:08:09 AM »

Congradulations on the award. Now don't go bruising the grass with it.