Motorhomer

My Feedback: (4)

WOW! OK guys, I do believe you!!!! Thanks a bunch.
Motorhomer, Ken McCormack

Gray Beard

My Feedback: (-1)

Yellow base is chinakote, I saw maekjus bipe and wanted to try it, Rickstubs gave me a roll. Red is mono and the logo of the meanie is all done with ultra. The chinakote goes on as easy or maybe easier then ultra and shrinks up tight as a drumb. Only question now is how it will hold up during the summer heat. Mono doesn't, it sags and wrinkles with a few bubbles thrown in. Ultra the sun has no effect on it at all. The red trim I put down with ammonia and water {doesn't work with the chinakote} then I tested my iron heat over a test piece until I got no bubbles then ironed it down, turned up the iron again then went around the edges of the mono. The articles I have read on ARFs show the covering getting put on a bit loose then it went through a heat shrink oven like used in our heat shrinking for packaging. Most the ARFs I have assembled for people have very saggy covering by the time it gets here and a lot of it won't shrink tight. I'm not too impressed with there covering but I do like a lot of there designs.

AndyW

My Feedback: (1)

I received your samples of Hobby King's Kote, (thank you) and I promptly put them to the test. Both had the adhesive soften when dunked in 35% nitro fuel. I could easily scrape off the adhesive with an Exacto blade. The interesting thing is, is that the blue had a clear film, with the blue as the colour and the adhesive. The red was white on the backside and IT had a clear adhesive. ??? I can only assume that each came from a different manufacturer.

I've been in the hobby over 50 years and have tried many Kotes. It was in the late 60s that Monokote came out. It had a sticky adhesive and you had to be very careful that you didn't let the sticky sides touch each other. It didn't take a lot of heat to stick it down on wood, or to itself. The trouble was, it melted pretty easily when raw fuel got on it. After a season, the covering was trashed, falling off, real bad news, all around. And it SAGGED, badly.

I forget when "dry" Monokote came out, it may have been only the very next year. To distinguish the new stuff from the old, it was called, Super-Monokote. And super it was. The colour/adhesive wasn't sticky and it was far easier to apply and handle. When I got my first few rolls, I naturally wanted to test how the new stuff would hold up to nitro fuel, before I used it.

Back then, (the mid 60s) there was no iron on film. I learned to apply tissue and silk (or silkspan) with clear and coloured butyrate dope to seal and fuel proof. LOTS of work, sanding after three or four coats, with 15 or more coats till we got that glossy shine we wanted. So I didn't want to waste time with this new fangled stuff and have to do it all over again, after only one season of flying. Happily, the new Super-Monokote tested with flying colours, sat in a jar of fuel for hours with nary a whimper.

Fast forward to today. Today, I tested a number of brands I had collected over the years.

I tested the HK-Kote, Ultracote, TowerKote, EnglishKote, Oracover and samples of MonoKote purchased some 2 years ago and some I salvaged from a plane covered some 15 years ago.

To my surprise, ALL of them were affected by the high nitro fuel. ALL of them, including the Mono-Kote samples, some 15 years apart. And most needed only 5 to 10 seconds of exposure to the 35% fuel. The exception was TowerKote, which I had to soak for 5 minutes. Even then, the colour/adhesive didn't melt in a solvent fashion, it lifted off as a film.

The Ultracote red, however, came through without a scratch, although when left in the fuel for ten minutes, it curled up into a tight, little tube. This means that although it didn't melt, and couldn't be scrapped off, the adhesive expanded. But still, it would not scrape off. A sample of Ultracote clear however, could be scraped off after only a few seconds in the nitro soak.

My conclusion is, is that MK has changed several times over the years. The very first year that the Super, (now just called MonoKote) came out, it really was bullet proof. The ONLY thing that would melt it was MonoKote trim adhesive, when that came out some years later.

But it did sag in the sun, or for me, over the winter in a cold basement. That had been my experience. I say had because I learned eventually, that it all depends on how you put it on. You have to put it on drum tight at the get go and then shrink it. It's possible, it takes technique and a fair bit more time. It's easier to just apply your Kote with no struggle and depend on the shrink factor to finish the job. This is why the higher shrink competitors came along. Having said that, I will admit that on occasion, I have had to reshrink small sections of MK, now and again. Rare, but it has happened.

That's not to disparage those who don't like MK and prefer the Ultra. Put out by Carl Goldberg a highly respected maker of kits and stuff, it was/is a quality product that suits many. Why when I use it, the trim lifts, is going to be investigated. It may be the high nitro content. If I recall correctly, nitro was originally developed AS a solvent. Diluted in methanol and oil, it may not be so potent. I should clarify too, that back in the late 60s, we were flying .40 and .60 sized planes and the fuel was at the most, 10% nitro with an all castor oil content at 25%. I hope I have some of that and will be doing more tests in the coming days.

I'll also be testing adhesion to itself. I DO know that most brands won't stick to their competitors. At least, that's been my experience. This could be the subject of a winter project and grist for a magazine article. We'll see.

I did do several for Flying Models over a decade ago but I haven't seen that mag on the stands for many years now. Maybe I'll start a brand new post on the subject.

Here's a question. Just HOW, does heat, shrink a covering? Where does the excess go? I know the answer, just wonder if anyone else has figured it out.

Gray Beard

My Feedback: (-1)

It's just a plastic covering and heat tends to melt it for the shrink. The term used is Hot Fuel Proof meaning the exhaust. The nitro in the fuel will remove the backing, color and adhesive if dunked in it. The HK covering can be activated with acetone and mono can be activated with ammonia for trim work. When the covering is laid down it should seal the wood and keep the oil away. If you have a loose seam then the oil will start the covering to lift. It can do that to paint too. First time I used the iron on mono was in the early 60s, I used my mothers iron, not the best idea and never get caught doing it. So far I haven't found any plastic covering that won't stick to any other. My trim coverings are left overs from several decades, all different brands, when I find enough of a color I need it gets used and doesn't lift. Even the Tex coverings stick to the plastics. The red on the plane in the photos is an old roll of mono I found in the trim box. Not sure of the age or where I got it but it stuck very well, I can't peel it with a fingernail. I haven't found a problem getting mono to stick but it is hit and miss if it will shrink or not.

LesUyeda

Granted, not recently, but transparent red Monokote, and white Ultrakote, because at that time, Monokote was high temp, and Ultrakote was lo temp.

Les

I'd get rid of that Stearman photo, if I could figure out how:-(((((((((((((((