Author Topic: Polyspan by any other name......... (Read 16439 times)

Terry Caron · « **on:** November 30, 2015, 09:27:42 PM »

I read in another thread on polyspan that it's the same stuff used as "interfacing" on clothing.
Anyone know if it's the same as Pellon interfacing?

Terry

Perry Rose · « **Reply #1 on:** December 01, 2015, 04:45:28 AM »

I believe pellon is thicker. I looked at that several years ago I may be mistaken, no that's impossible.javascript:void(0)

john e. holliday · « **Reply #2 on:** December 01, 2015, 08:45:03 AM »

I have not seen any thing in the fabric stores that comes close to Poly-Span.

Gordon Van Tighem · « **Reply #3 on:** December 01, 2015, 01:18:43 PM »

Check the bottom of your bed's box spring. Similar material?
G

Terry Caron · « **Reply #4 on:** December 01, 2015, 01:43:30 PM »

I haven't gotten any yet, just researching.
Fabric stores sell several weights, sew-on, iron-on.

Terry

Keith Renecle · « **Reply #5 on:** December 01, 2015, 10:15:37 PM »

Hi Terry,
I've been through the same kind of research and even managed to email the first guy to use this for free-flight....Klaus Salzer (hope the spelling is right). It is Polyester non-woven fleecing tissue that weighs 18 grams per square metre. It's used for many things, one being interfacing as you mentioned. It was also used for something in fiberglass moulds and insulation in big fat electrical cables. I managed to source one called Dacmat here in Darkest Africa that came from somewhere in the USA. It was a bit thicker but took less dope to fill it. It was also 500 mm wide and I used it for years. I believe that Tom Morris has a certain type as well that is a better price than Polyspan.

They all have the same problem because the fibres are sort of hot pressed together and the thinners in the dope tends to cause fuzzies that are a real pain in the butt. There are however many threads on this amazing forum that help to do a good job with poly tissue. My source of Dacmat dried up unfortunately. What I found works better for me right now is to use medium weight tissue over thin laminating film. It comes out lighter mainly because it is a lot easier to finish. Good tissue here in South Africa is not something you can buy easily from any hobby shop, but I got hold of some teabag tissue and it is identical to medium weight tissue. It also weighs 18 grams/sq.metre. The laminating film is iron-on-heat-shrink stuff and is dead easy to use. Most print supply shops keep the stuff. I believe that this is an old free-flight trick and many use light weight tissue with very thin Mylar under it to stop the tissue from puncturing. A good friend and member of SAM in Canada also told that for the cabin type models, you also get free "glazing" this way!

The laminating film however is easier to use because it has the heat sensitive glue on it already.

Keith R

tom brightbill · « **Reply #6 on:** December 01, 2015, 10:45:28 PM »

I decided to try some locally available dress lining, what appeared to be almost as light as that which Tom Morris sells. It did not have a smooth, shiny side. It also did not take dope the same as Tom's. Heat shrinkage was similar. But without the smooth initial surface (like Tom's) it required much more final finishing. Not worth it in my opinion. As long as Tom carries his version, that's what I'm going to use.

Terry Caron · « **Reply #7 on:** December 01, 2015, 10:59:08 PM »

A local fabric shop has it for <$1.00/yd.
I'm going to check it out in a day or two, a shiny side is one of the things I'll look for.

Keith - lack of success w/iron-ons is why I'm looking at this stuff - I cut my teeth on silkspan but I have little of it left.

Terry

Steve Helmick · « **Reply #8 on:** December 01, 2015, 11:14:54 PM »

Mike Haverly used the lightest "dress liner" from the fabric stores for several years, but finally gave up on it for weight reasons. Cheap isn't always a good deal.

Steve

john e. holliday · « **Reply #9 on:** December 02, 2015, 10:29:10 AM »

Poly-Span from Stunt Hanger Hobby or Tom Morris is the only way to go. Patience, and the right tools do the job.

dave siegler · « **Reply #10 on:** December 02, 2015, 10:42:13 AM »

I would not expect that Polyspan is made for modellers. I would expecet it is some kind of fabric that is re-purposed.

I showed polyspan to my boss who is a fabric artist ( quilts, fabric dyeing) and she said Oh I know what that is.

She got me a sample of Pellon p45JAS. it looks like the real thing to me.

see this for product selection there may be lighter options

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwiuwsqQ3L3JAhUCUT4KHQxTBR0QFggkMAE&url=http%3A%2F%2Fforum.missouriquiltco.com%2Fattachments%2Fquilting-questions%2F37896d1359317011-pellon-product-guide-pellon-product-guide-printable-version.pdf&usg=AFQjCNH6WlNW9Zmjp8QcKWBYTHzIVIDQ8A&sig2=O_dIU4nyQVUHDsUAJcIM5w&bvm=bv.108538919,d.cWw

Fredvon4 · « **Reply #11 on:** December 02, 2015, 01:53:36 PM »

Thanks for that Dave

My wife is a machine quilter and sewing hobbyist and I do most of the on line ordering for her supplies. We actually share quite a lot between the hobbies. She looked at my Poly T from Tom and came back to my shop with a scrap that I swear is the same stuff (have not tested, just look and feel)

When I told her how much my roll from Tom was she asked me to get her some cuz his price was better than she pays JoAnn fabric for the stuff

Terry Caron · « **Reply #12 on:** December 02, 2015, 02:28:00 PM »

Fred, do you know the stock number of the material your wife uses?

Terry

Fredvon4 · « **Reply #13 on:** December 02, 2015, 03:52:04 PM »

Terry sorry brother her dad is in the hospital recovering from by pass surgery and she is out east helping her mom with him. May be a few weeks before she returns and I can get that info (I doubt she knows it off the top of her head but I will ask tonight when we talk

It is material she buys locally on sale from JoAnns or Hancok fabricks.... we rarely keep the receipts so I have no trail to follow right now

Terry Caron · « **Reply #14 on:** December 02, 2015, 03:57:15 PM »

Thanks Fred, no prob.
Best wishes and prayers for your family.

Terry

dennis lipsett · « **Reply #15 on:** December 02, 2015, 06:27:44 PM »

Go to google and type in p-45jas sew in interfacing material. This took me to the closest store in Reading carrying the product. It is $0.99 a yard. I have someone who is familiar with Polyspan and she has a sample. I'll see how my source pans out. Meanwhile you can check and see where you can get it at using the above procedure.

Dennis

Brent Williams · « **Reply #16 on:** December 03, 2015, 12:42:31 AM »

I stopped by JoAnn's this evening ad took a picture of the Pellon P45 JAS interfacing.
I don't have any Poly-Span to compare it against, but I could do so later this week.

john e. holliday · « **Reply #17 on:** December 03, 2015, 09:11:35 AM »

Will have to recheck my local Jo-Anns. That is where I get the colors of poly-eater cloth. It is a heavier material more like the heavy weight silk span.

Motorman · « **Reply #18 on:** December 03, 2015, 12:58:28 PM »

The thrill of sourcing something for models other than at a hobby shop.

Kieth, if I was covering a model in deepest Africa I'd just put lion skins on it.

MM

Terry Caron · « **Reply #19 on:** December 03, 2015, 01:06:55 PM »

For me, the benefit of stretching very scarce hobby dollars.
Also, some don't live near a LHS.

Not living in Africa, I tried deer skin - too heavy.

Terry

Tim Wescott · « **Reply #20 on:** December 03, 2015, 02:23:25 PM »

http://www.dharmatrading.com/fabric/silk/silk-habotai-fabrics.html?lnav=fabric_silk.html

Two yards of 55" wide material should cover a whole lot of planes for $10.

Terry Caron · « **Reply #21 on:** December 03, 2015, 02:55:22 PM »

I've never used silk before, didn't know it was so (relatively) inexpensive.
To weight in a sense no doubt, but to what does the metric designation refer specifically?

Terry

Tim Wescott · « **Reply #22 on:** December 03, 2015, 03:05:06 PM »

Quote from: Terry Caron on December 03, 2015, 02:55:22 PM

I've never used silk before, didn't know it was so (relatively) inexpensive.
To weight in a sense no doubt, but to what does the metric designation refer specifically?

It's not a metric number (not millimeters or meters). It's some weird measure of the weight of silk: https://en.wikipedia.org/wiki/Units_of_textile_measurement#Momme. 8mm is about 1 ounce/square yard (according to Wikipedia).

I haven't personally used their silk (I should have said -- sorry), but those who have recommend the 8m.

Terry Caron · « **Reply #23 on:** December 03, 2015, 03:23:01 PM »

Thanks for the clarification, Tim.
So 8mm silk would be heavier than the lightweight Pellon.

BTW, the relative inexpense I referred to above is "relative to my previous notion".

Terry

Tim Wescott · « **Reply #24 on:** December 03, 2015, 03:56:24 PM »

Quote from: Terry Caron on December 03, 2015, 03:23:01 PM

BTW, the relative inexpense I referred to above is "relative to my previous notion".

Well, yes.

The free-flight guys use laminating film (web search on laminating film and on Doculam^TM). Look for PET films (no, I don't know what "PET" means in this context). Some use tissue over laminating film. I haven't tried it.

Motorman · « **Reply #25 on:** December 03, 2015, 08:57:16 PM »

What thickness of laminating film is good for open wing bays on our planes?

Thanks,
MM

andy borgogna · « **Reply #26 on:** December 03, 2015, 09:23:31 PM »

Polyester Film (PET)

PET or polyethylene terephthalate film is a thermoplastic polymer commonly referred to as polyester film. Like most thermoplastics, PET films can be biaxially oriented or bubble extruded. Polyester film is one of the most common substrates used in the converting industry because of its balance of properties in relation to other thermoplastic polymers. PET Film is comparable or better then other thermoplastics in the following categories:

Dan McEntee · « **Reply #27 on:** December 04, 2015, 06:24:02 PM »

Quote from: andy borgogna on December 03, 2015, 09:23:31 PM

Polyester Film (PET)

PET or polyethylene terephthalate film is a thermoplastic polymer commonly referred to as polyester film. Like most thermoplastics, PET films can be biaxially oriented or bubble extruded. Polyester film is one of the most common substrates used in the converting industry because of its balance of properties in relation to other thermoplastic polymers. PET Film is comparable or better then other thermoplastics in the following categories:

HEY!! CAN HE SAY THAT ON THE FORUM?

? What ever it was he said! Hey Andy, speak English! What is it and where can I buy it easily?

Learning the ins and outs of this interfacing material ought to include the different weights of the different "sizes." I can see using something a bit heavier for a model that you might expect will take a bit of abuse and punishment. I'm thinking of trying it under Monokote. I think John Miller has a method of covering with Monokote over a layer of silkspan, and using the polyspan type stuff instead might be pretty bullet proof for a balloon bust airplane. A larger scale model might call for a heavier weight material. I'll be watching for other people's results, and maybe get some of my own!
Type at you later,
Dan McEntee

john e. holliday · « **Reply #28 on:** December 04, 2015, 06:38:55 PM »

I just bought some of the material at Jo-Anns Fabric Store. They all kinds there on the shelf. Some of it had a weave to it. Found the Pellon P45 JAS and got 2 yards of it. It does look like Poly-Span and silk span. It also tears very easily with the grain but not across it. Will be putting it to the test on a stab/elevator in a day or two. 99 cents a running yard. About 20 inches wide.

Terry Caron · « **Reply #29 on:** December 04, 2015, 06:42:07 PM »

Doc, does it have a shiny side like polyspan?
Can you give us a weight/sq yd?

Terry

john e. holliday · « **Reply #30 on:** December 04, 2015, 06:54:09 PM »

Both sides looked the same in the store. In the shop one side does have a slight sheen to it. The package the material came off of said 100% poly ester. So it should shrink with care.

Mark Knoepfle · « **Reply #31 on:** December 04, 2015, 07:39:32 PM »

Good job Doc! I'm waiting on your report.

BTW there is another material called stabilizer for embroidery that is also very similar...

dennis lipsett · « **Reply #32 on:** December 04, 2015, 09:20:09 PM »

Quote from: Dan McEntee on December 04, 2015, 06:24:02 PM

HEY!! CAN HE SAY THAT ON THE FORUM?? What ever it was he said! Hey Andy, speak English! What is it and where can I buy it easily?

Learning the ins and outs of this interfacing material ought to include the different weights of the different "sizes." I can see using something a bit heavier for a model that you might expect will take a bit of abuse and punishment. I'm thinking of trying it under Monokote. I think John Miller has a method of covering with Monokote over a layer of silkspan, and using the polyspan type stuff instead might be pretty bullet proof for a balloon bust airplane. A larger scale model might call for a heavier weight material. I'll be watching for other people's results, and maybe get some of my own!
Type at you later,
Dan McEntee

Dan,
I've posted this before but putting film over silkspan is relatively easy. The edge 540 wings/stab and elevator were covered with silkspan and then all of the other colors were applied with individual cut pieces. Not too difficult to do and as a side benefit film sticks tenaciously to silkspan so there is no wrinkles. The fuselage was painted to match

Fredvon4 · « **Reply #33 on:** December 05, 2015, 08:13:57 AM »

My wife confirmed last night that the JoAnn's Pellon P45 JAS interfacing is what she showed me and to my 60 year old eyes looks and feels identical to RSM

After thinking about it I think she and I were incorrect about RSM's was cheaper 15" x 20 feet @$18 I think is $2.79+/- a yard

I had told her the roll was 20 yards...my bad

Shawn Lenci · « **Reply #34 on:** December 05, 2015, 08:32:27 AM »

You guys got me all excited reading this thread. I went to JoAnn's last night and bought a 1 lineal yard of P45 which is about 18"-20" wide. At the register was a 40% off coupon for any 1 non sale item. Price out the door was $.43. I guess I could do some experimenting for $.43.

Shawn

Terry Caron · « **Reply #35 on:** December 05, 2015, 09:51:34 AM »

Can you weigh your piece accurately Shawn?
A quick calculation would give the weight/sq yd.

Terry

Motorman · « **Reply #36 on:** December 05, 2015, 10:05:19 AM »

Does the RSM polyspan tear easy one way and not the other? Don't you want the fabric to be strong in both directions?

MM

Fredvon4 · « **Reply #37 on:** December 05, 2015, 10:18:13 AM »

I took the piece of JoAnns stuff my wife gave me and cut a 12x36 inch piece...weighed 11.3 grams on my powder scale...so mine is 33.9 grams a sq yard or 1.16 Oz /Sq Yrd

Terry Caron · « **Reply #38 on:** December 05, 2015, 11:10:32 AM »

Weighing a piece of heavyweight silkspan, it's an RCH (an old machinist's term meaning "insignificant") over 1 oz/sq yd.

Terry

john e. holliday · « **Reply #39 on:** December 05, 2015, 11:57:33 AM »

Silk span, Poly-span and this new P45 will tear easily with the grain but not across it. I've already tried it.

Terry Caron · « **Reply #40 on:** December 05, 2015, 12:33:10 PM »

So if our calculations are correct (SGM silkspan @ 1 oz, 8mm silk @ 1 oz and Pellon @ 1.16 oz per square yard), material weight difference is perhaps less significant than the weight of paint necessary for a filled finish on each.

Terry

john e. holliday · « **Reply #41 on:** December 05, 2015, 08:22:04 PM »

I would say that is where most weight comes from is the finish, especially the under coats that are not sanded enough.

Mark Knoepfle · « **Reply #42 on:** December 05, 2015, 09:10:09 PM »

Doc - perhaps you can answer this... why is polyester better than silk (if it is)? Is silk that much stronger? Can silk be heat shrunk or is it all in the dope to make it tight? I am asking because it looks like we have a choice of both cheap habatoi silk and polyester interfacing.

Mark

john e. holliday · « **Reply #43 on:** December 06, 2015, 03:16:44 PM »

It has been so long since I used silk, but I do remember it had to be put on wet and pulled tight. Almost all my combat wings had some kind if dihedral because the bottom was covered first and the top side of the wings. Never used an iron or heat gun. It was always air dried. At the time nylon was what we used for absolute strength. But nylon was only as tight as you could get it. Yes, some times the butyrate would cause a little shrinkage. By the way silk is stronger than poly-span in my opinion, but harder to apply for me. Also it has gotten very expensive.

How many remember the Sil-Ray covering. If put on the wrong direction it would sag between the ribs.

Terry Caron · « **Reply #44 on:** December 06, 2015, 03:32:52 PM »

From SAM (so maybe more for rubber FF?), this link is on covering with polyspan:
http://www.antiquemodeler.org/sam_new/covering/assets_2/polyspan_covering_myers_nystrom_jan_2006.pdf

Same source, on covering with silk:
http://www.antiquemodeler.org/sam_new/covering/assets/covering_with_silk01.pdf

Terry

john e. holliday · « **Reply #45 on:** December 09, 2015, 12:50:35 PM »

Well I don't have a picture yet, but I have the top wing of the Vagabond covered with the Pellon P45 JAS. It reminds me of the heavy weight silk span that I have. The big difference is it has no sizing which is what I think gives Poly-Span it sheen on one side. Also thicker than Poly-Span. Had to thin the dope and put on more coats on the TE & LE. For the wing tips I used Elmers White Glue and my sealing iron. The sealing iron also helped stretch it around the tip. For some reason the dope was taking longer to set up. Maybe the multiple coats I put on. By the way don't drag the iron across the grain. Once I get it shrunk and some dope on the open area will try to get a picture.

Target · « **Reply #46 on:** December 09, 2015, 10:13:27 PM »

Quote from: dennis lipsett on December 04, 2015, 09:20:09 PM

Dan,
I've posted this before but putting film over silkspan is relatively easy. The edge 540 wings/stab and elevator were covered with silkspan and then all of the other colors were applied with individual cut pieces. Not too difficult to do and as a side benefit film sticks tenaciously to silkspan so there is no wrinkles. The fuselage was painted to match

Dennis-
Not sure I follow you on this.
The individual cut pieces are film, like monocote?
I read in the 1/2a forum where the poly span is put on, then thin SLC over it to give it a shine and toughness.
Is that how you did the plane in the picture? Was this SLC that was pre painted then applied over the fabric on the airframe?
I'm a bit confused here.
Thanks,
Chris

Mike Lauerman · « **Reply #47 on:** December 10, 2015, 06:31:24 PM »

Doc: Excellent report on the application/selection, as usual...

But, in which direction did you lay the grain? Concern is twofold:

First, you mentioned that it 'tears' with grain, but not across;

Second, which direction on wings, so as not to sag between ribs?

Following this thread with much interest, as I had tried something that resembled silkspan in the '70s.
Went on nicely...but after the 3rd coat of Nitrate, the stuff literally shredded!
I know it's not the same stuff, but lessons are learned hard.

Thanks!

john e. holliday · « **Reply #48 on:** December 10, 2015, 07:07:19 PM »

Okay, like silk span and poly-span the grain needs to go span wise, not chord wise. Shrunk the covering today and applied a coat of dope. As usual the first few coats take time to set. Had one spot the gun got to. By the way I use only butyrate after a bad mix up.

dennis lipsett · « **Reply #49 on:** December 10, 2015, 08:21:49 PM »

Quote from: Chris Behm on December 09, 2015, 10:13:27 PM

Dennis-
Not sure I follow you on this.
The individual cut pieces are film, like monocote?
I read in the 1/2a forum where the poly span is put on, then thin SLC over it to give it a shine and toughness.
Is that how you did the plane in the picture? Was this SLC that was pre painted then applied over the fabric on the airframe?
I'm a bit confused here.
Thanks,
Chris
[/quote

Chris,

It is MonoKote applied over silkspan. The pieces are cut from patterns and applied individually to the surface. You won't have problems with air bubbles getting trapped and as I stated you cover the wing with silkspan but you do not dope the open framework. Your applied Monokote wont ever pucker. Overlap is minimal and overlaps are not overly obvious. This is actually a lot easier than using a lot of tape to mask off your design. Since I painted the fuselage I can attest that it was a lot of work to get it done compared to the flying surfaces.