Covering with EkoBond

[mlachow]

Well it is the middle of the winter and the Bocian is ready to cover. Normally I like to put a real fabric finish on a wood sailplane. My Orlik and Pirat are both KlassKote over Nitrate on Koverall. Not a chance of using dope in the middle of the winter. The last two covering jobs were really nice weeks around September that were warm and dry and low humidity.

One of my local club members just recovered his Citabria, 1:1 scale. He used Stewart Systems for the covering. It is all water based so the smell factor is way down. I picked up the end of the bottle of EkoBond he had so I am going to do some sample pieces to see how it works out. I will stick with Koverall and I want to finish it up with KlassKote. I already have the can of paint for HA-3433. The only question is what to use to apply the fabric and seal the fabric.

I covered the trim tab on the Bocian first. Nice little surface with enough challenges for how things wrapped around. I also have a flat piece of ply with a square hole in it to see how things work around spoiler cutouts and servo openings. So far, the results seem good for just doing the covering.

Using it for applying the fabric is a little bit different. You apply the EkoBond around the edge where you want to attach the fabric. Then you let it dry. It is tacky enough when dry that you can press the fabric into the film of EkoBond applied to the edge. A little ironing around 200F sticks it a little better. The odd in the covering steps is that after you trim the edge and stick it down, you have one more step. Brush some more EkoBond over that edge and then wipe it off almost immediately so that only the EkoBond that penetrated the fabric remains. If you put too much on and leave it dry it remains rubbery and that junk is going to show in the finish.

On the second side, you want to apply EkoBond on the edge and up tyo wherever you want your overlap to finish up. The nice part is you can work the fabric in place around the edges and round pieces and then mark where your trim line will be. Then you can pull off the edge so you can do the trimming. After that stick it back down, and iron the edge. Finally, brush on and wipe off over the edge with some more EkoBond.

The only negative so far is you can't use it if you want a clear finish since you get the tint from the glue. The nice part is you know if you missed gluing anything.

https://www.youtube.com/watch?v=rl9I3FOA6Bc

https://www.stewartsystems.aero/

[mlachow]

I now have a couple of clear coats on the fabric to seal it. The fabric edges present some new challenges. Of course, they are always interesting getting sealed and flat and filled. the EkoBond is flexible so it really doesn't sand. So drips and fuzzy bits of fabric edge require some consideration. I had some edges where the fabric was a little rough or a thread or two was loose from the edge. After sanding a bit of the surface, where yoiu start getting some fuzz from the fabric, I put down some thin CA and wiped that onto the surface to harden it and make it smooth. It seems to be working fine to smooth the edges and overlaps a little before going to primer.

I also did some testing on a piece of wood to see how well this stuff sticks things. If you just go with the EkoBond on the wood and press into that is sticks OK. Once you do the second step of brushing some more through the surface, the bond is a lot better.

[lenb]

Hi Mike,
I've also been reading up on the eco bond system for the past year or so and recently saw a quick video from Balsa USA demonstrating the system. I was sure I heard hm say its available in clear, but my searching doesn't show clear, however there is a LINEN color.

https://stewartsystems.aero/product/ekobond/

I plan to use the system also so Im real interested to read about your experience.

thank for posting.

LEN

[mlachow]

They do have linen color. I could see using that and using a coat of ekobond to seal the fabric. That way it would all be the linen color. If what you want is a fabric and not painted finish.

I still plan on painting this model with klasskote. Nice part about epoxy paint is you can still spray that at cooler temperatures. The tails have three coats of minwax water based poly on them now to seal them. The next step willl be the klasskote filler. Hoping for something in the 50's in another week to spray the filler if possible. The fuse should be glassed by then. I'm holding off on the wings and ailerons until after I get the tail primed and sanded so I can see what it looks like. I already have the KlassKote so no need to try the water based stuff.

I did find the Balsa USA thing you referenced. https://shop.balsausa.com/v/vspfiles...structions.pdf
I did a little searching and never found any references to using it on model airplanes. If you do go the EkoFill approach, the current way guys are doing it is to first coat the entire fabric with EkoBond which provides a better bond to the fabric. The system was updated to go with a coat of EkoBond first, then EkoFill.

[mlachow]

So far things are progressing on the project. I put three coats of polycrylic on to seal the surface. It was warm Monday and I had a chance to spray some more primer. The elevators look good. I had some problems with the rudder structure. The outline pieces from the kit are plywood and these had the bow that you sometimes get in sheets of 3-ply. Because of this, the rudder was a little warped near the bottom. I stripped the fabric off the rudder. I didn't have that much of a problem stripping it from the rudder Now after some carbon strips, the rudder is straighter and it has been recovered.

I covered the wing ailerons. I have them split so there are four ailerons. It is kind of wierd working with glue that you paint on first but it is not sticky when it is dry. Brushing and wiping some of the Ekobond on the fabric before final cutting is handy. It just adds enough to keep the fabric together so you get a minimum of stray threads from the trimming. The edge seam is nicely cut and wraps around the edge. Things are sticky enough that you can wrap around the end of the control surface, Then use a pencil to mark the exact surface outline, pull it back and trim perfectly.

[mlachow]

As with any heat activated covering work, you eventually end up with some of the junk on your iron. Goo Gone worked fine at cleaning up the iron. Only one wing panel remaining to cover.

[mlachow]

Eventually things get covered.

[mlachow]

I managed to run into a few problems. Like always, you have to be careful sanding the covering after sealing. The results are a little different with Ekobond. You get another kind of oops. The stuff really does not sand/ You can end up with little rubber like bits sticking up. The best solution if you do that is to use some thin CA and wipe it over that spot to get things all glued together again.

The stuff can dry out a little when working with it and wiping over the top. You need very little water to thin it back out . A spray bottle to just mist the glue a little and mix in the water thins it out where it works nicely.

Be patient waiting for the stuff applied to the frame to dry. The pieces I left dry overnight were the easiest to get the covering on nicely.

Make sure you avoid having some runs or heavy spots on the frame. before applying the covering. It just makes for using more primer to get things smooth.

I can't believe the warm weather in early March. I managed to paint the entire airframe of the Bocian in RAL4005 already. Now for some time doing the masking to paint the bits of red on the modfell.

[mlachow]

Out in the sun.

[mlachow]

Masking things for the red paint on the tips. I found some nice stuff from 3M. It is masking tape with folded up plastic already attached. The roll there actually has about an 18 inch wide piece of plastic and it clings really well to the paint being covered. Definitely worth the $9 a roll on amazon.

[Swiss1]

We carry the Tamiya Brand Tape with film, 150mm or 500mm, less than Amazon




The Model Box 205 978 8787

Jeremy

SCC AAA TT TN

[mlachow]

Thanks for the info. Mine was about $9 for 20 meter roll, 2ft wide. It was someone using the Amazon platform, not actually from Amazon.

I also picked up Oracal white striping on the Amazon platform.

[mlachow]

Everything ia painted now and white striping added. Stilll waiting for numbers to show up.

[mlachow]

I did my first covering with the Linen color Ekobond. The color matches balsa pretty well. So you really don't notice it on the covering like the normal stuff. So the good news is the Linen would work if you wanted to have part of your open areas in clear to show the fabric. The bad news is that it is much harder to see the stuff when you are working with it. Did you coat all the wood? Did you wipe off the excess on the outside? Did you get any drips on the covering? It is much harder to see. I thinik if you intend to prime and paint and want a nice finish, then go with the standard color. You will be sure that you did things correctly and didn't miss any spots.