fabric covering results

Robbie,

Looks very good !

On Mon, 11 Sep 2006 20:51:32 -0500, Robbie and Laura Reynolds wrote in :

Nice work, Robbie!

And thanks again for the feedback. It's nice to know what works and what doesn't.

I may try the Polycrylic in place of epoxy on the utility plane I'm designing and building. Sounds like Polycrylic would be a lot easier to work with. I want to practice spray-painting with latex for the top coat.

Marty

You know what my favorite thing about Polycrylic is? Not only can you clean up with water, but it comes out of the brush almost instantly. You can spend 5 or 10 minutes getting all of the latex paint out of a brush, but this stuff comes out in about 10 seconds.

On Tue, 12 Sep 2006 08:21:45 -0500, Robbie and Laura Reynolds wrote in :

I'm sold!

Thanks again for the report from the field. Your speaker cabinet looks magnificent!

Marty

I can ship you some photos of what happens to MinWax Polycrylic over latex when you then get alcohol on the polycrylic.

Not pretty.

Polycrylic is not resistant to alcohol or methanol.

On Tue, 12 Sep 2006 09:58:52 -0500, the-plumber wrote in :

OK.

I was thinking of going the other way: latex over polycrylic. And it's primarily for a gasser, though I can't swear that I'll never put a glow engine on it. ...

Thanks for the warning.

Marty

Polycrylic isn't fuel proof or gasoline proof as I recall.

I guess that's the difference between "resistant to fuel" and "fuelproof". Maybe you could take advantage of the benefits of Polycrylic by using one or two coats to seal the fabric, and then put some kind of top coat over it.

In that case you'll need to sand the polycrylic 'cuz it's pretty slic stuff if you get enough on the airframe to do any worthwhile fue proofing.

Latex is gas proof, according to Vaillancourt and others, and s doesn't need a clear coat.

You could always shoot the poly later if you swap in a glow motor. Th stuff isn't the cheapest thing in the world. Half pint around here i close to six bucks; I needed a quart to cover the 140" L-4, so th polycrylic was more expensive than the custom blended latex I used.

One last thing - if you spray it, and it does spray quite nicely out o the can without thinning, it _really_ atomizes, meaning that a cartridg type respirator and fairly serious filters on whatever shop a/c an powered air filtration system you might have are pretty much mandatory It's almost as bad as the worst balsa dust you ever made with a powe sander.

The white overspray dust was very noticeable in the shop air for quit a while, and I've got a 450 CFM powered air filter with 5 mic filter in a 10'x10'x18' shop (major overkill on air changes per hour).

The only model application I've heard of where polycrylic shines is i glassing electrics - it's used in place of epoxy and purportedly does good job at scant weight gain.

Personally, I'm all done with polycrylic

-- the-plumbe

----------------------------------------------------------------------- the-plumber's Profile:

Latex does an admirable job of sealing fabric.

The polycrylic was intended to protect the latex from glow fuel, and used it based on the MinWax propaganda which clearly states ". . resistant to . . . , alcohol, and other household chemicals.". Th MinWas rep explained that their notion of "resistant" means if th alcohol is diluted (as in a cocktail) and is wiped up immediately (no ten minutes later at the end of a flight).

Having to seal the latex against glow fuel was irritating.

Having to seal the sealer is irritating-er, but I don't have a lot o options if I want to avoid stripping the covering off a brand new 140 L-4 and starting over.

Stripping the model down to bare fabric (acetone) would solve th polycrylic problem, but I'm not anxious to replace the 3700-odd fak stitches that will certainly come off in the process.

I'm gonna experiment with a couple of polyurethanes which are suppose to be fuel (in this case alcohol) proof.

If I hadn't spent the $1100 for the O.S. Pegasus engine for this mode I'd swap in a G-38 already and get on with detailing, like installin the 23 window panels

-- the-plumbe

----------------------------------------------------------------------- the-plumber's Profile:

Ted shuffled out of his cave and grunted these great (and sometimes not so great) words of knowledge:

From my own experience, Polycrylic is fuel RESISTANT provided you follow the following caveats :

1. Let the polycrylic dry for a MINIMUM of 7 days before exposing to fuel.

1. Do not let the residue remain on the plane/finish for over 4 hours or the poly will soften.

If you want/need fuel PROOF, you need an epoxy paint or one of the other types of 2 part paints.

I shoot poly-u on my planes when I need a good seal for seams and such. Yep, it can yellow in the sun if you leave a plane out. It can be heavy too if attention is not paid when applying. All in all, I like it for the toughness and the shine.

wrote in :

Yeah, but, how's it *sound*? That's what counts.

Tejas Pedro

I already worked out the details on the sound. If I hadn't done that I wouldn't be trying to figure out how to make it look good. It sounds good enough that a guy from Vancouver gave me a downpayment for one after playing through it for 20 minutes at a blues jam.

I found this thread interesting as I am in the process of building a gas powered 1/4 scale NE-1 Navy Trainer (military J3 Cub) from a Balsa USA kit. The covering will be Ceconite sealed with MinWax Polycrylic. The weave will be filled with a solution of MinWax and corn starch as outlined in

I have ran all the tests on an old wing section and everything worked fine with only 24 hours of drying between MinWax and the Rustoleum coat.

the-plumber wrote:

I guess that's the difference between "resistant to fuel" and "fuelproof". Maybe you could take advantage of the benefits of Polycrylic by using one or two coats to seal the fabric, and then put some kind of top coat over it.