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Best light weight filler

Stewbronco

Well Known Member
.....getting ready to start paint process.....a few " hangar rash " dings ( NOT CONTROL SUFACE ) .....looking for some real world experience with light weight fillers . I have used Poly Fibre Super -Fil. Quite like it but West system 105 with flox or micro perhaps an option ? Adhesion AND Flexibly are the major considerations....sand ability also of course .Surface prep ??? Please not looking for conjecture or anticdotal opinion,just real world experience based opinions.
Have of course dressed out the depressions as much as prudent ( where access to back side was possible and all of these ( maybe half a dozen ) are very small and fairly inconspicuous but now is the time
Many thanks in advance. Stew
 
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Epoxy and a bulk filler (microballoons, talc, etc) provides the best adhesion, but given small imperfections (rivet smileys, rock dings), practically any of the polyester-based commercial "glaze" products will do. And they are fast and easy.

It's a lot like the primer debates...not much evidence, lots of belief, plenty of "My buddy said". I did some shop tests years ago...

https://vansairforce.net/community/showthread.php?t=24991

...and it hardly settled the matter.

Speaking of primer, for best adhesion the auto body world tends toward epoxy primer under their polyester filler. Think about that.
 
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Evercoat

First if you're filling something to sand smooth, you do not want to use Flox. Extremely hard to sand. Thick micro epoxy blend is good.

Sand the area with 220/320, clean thoroughly before using anything.

I personally use Evercoat 416 for small fill and finish fill work. It is a catalyzed material that cures quickly and sands like balsa, yet is quite hard. Apply with credit card type plastic. (I save all my hotel room keys for this purpose.)

I also used is as the final fill on edges of glass like the windscreen. It is also great for weave fill that the epoxy didn't completely fill.

Works great, easy to use. Used it all over in areas on my plane and it turned out pretty good!!
 
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I personally use Evercoat 416 for small fill and finish fill work.
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I was JUST at my paint shop today and I paid $80 for the Evercoat Glazing Putty (ultra smooth), that I like to use after the epoxy/micro for the rough smoothing.

Almost triple what I paid about a year ago :eek: Holy **** it's getting expensive to build an airplane!

I like the idea about using old hotel card keys as a cheap applicator. I'll have to try some Evercoat 416....maybe my airplane will looks like RV7Guy's ;).

Laird
 
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If I have something big to fill I like Evercoat Rage Gold. For small things or scratches I like Evercoat 417. Both are easy to find and are easy to sand. I avoid Bondo brand filler at all costs. It doesn’t sand easy. After I do any filler work I always come back and spray high build primer over my filler. It will show me if there are any pin holes and if I sanded my edges good enough. My current primer of choice is PPG K36. It’s super easy to spray and dries in 90 minutes.
 
Micro

Since we are sharing...
I use micro. No magic. I measure epoxy by weight and add 10% denatured alcohol then add micro. The alcohol allows more micro. It evaporates really fast so you have to lay the stuff down quick. Since there's more micro, it sands really easy. I knock it down optically flat with whatever tools. Sureform file, PVC pipes, etc.
Then I brush on two coats of Kirker EnduroPrime mixed neat.
Wet sand to a flat surface.
Apply glazing to any remaing imperfections.
Wet sand
Spray primer
Wet sand
Spray paint
Cut&buff
Here's what a part looks like ready for spray. Looks like a bad Pollack painting but actually very smooth. I wish we could post vertical photos. :D
20220917_151035.jpg
 
Should have specifically said for ALUMINUM

Thanks folks …..should have specifically said for the aluminum skins …..pretty good with what seems to work on fibreglass…but all comments are appreciated
 
Specifically aluminum skins

Good point regarding fiberglass vs aluminum suggestions. West 105 sticks annoying well to aluminum when you don't want it to. Since it does sometimes “Pop off”, I don't get confidence in it is a “go to “ filler. My impression is a good bond is achieved by one of the following :
Acid etch and epoxy primer, then fillers of any preference.
Etch primer then 2K primer then filler of preference.
Aero adhesives like 2216 or Hysol, the fillers of your preference.

Just my observation of this forum and my experience. Hope this helps.
 
Adhesive micro

Good point regarding fiberglass vs aluminum suggestions. West 105 sticks annoying well to aluminum when you don't want it to. Since it does sometimes “Pop off”, I don't get confidence in it is a “go to “ filler. My impression is a good bond is achieved by one of the following :
Acid etch and epoxy primer, then fillers of any preference.
Etch primer then 2K primer then filler of preference.
Aero adhesives like 2216 or Hysol, the fillers of your preference.

Just my observation of this forum and my experience. Hope this helps.

2216 or Hysol mixed with micro? There's an idea.
I've mixed West G-flex with flox. Pretty aggressive. Never tried micro. I may try a sample on some scrap aluminum.
 
whether it's just me or it actually works when i use epoxy/micro mix if it is mixed really ''dry'' i put a few drops of uncut epoxy on a gloved finger and smear it on all surface to be bonded. i feel it gives a better bond to the filler.
 
You're right!!

Almost triple what I paid about a year ago :eek: Holy **** it's getting expensive to build an airplane!

I like the idea about using old hotel card keys as a cheap applicator. I'll have to try some Evercoat 416....maybe my airplane will looks like RV7Guy's ;).

Laird

Hi Laird,

The price of things is off the chart. We have a supply house here in the Phx area that you get everything needed for painting and they will mix custom paints. They have a generic version of 416 that is about half the price of Evercoat. The manager told me it is packaged by Evercoat. EXACT same properties in mixing, use and finishing. Saved a little that way.
 
Hi Laird,

The price of things is off the chart. We have a supply house here in the Phx area that you get everything needed for painting and they will mix custom paints. They have a generic version of 416 that is about half the price of Evercoat. The manager told me it is packaged by Evercoat. EXACT same properties in mixing, use and finishing. Saved a little that way.

Could you let us know what the product name for that is? I wouldn't mind trying it out. I'll see if I can find it around Chicago.
 
I think I've eaten a mushroom and fallen down the rabbit hole. This thread has a good builder wiping discount polyester filler on aluminum and epoxy, and another is talking about $30K+ paint jobs.

Oh, the colors, the colors....
 
Thanks folks …..should have specifically said for the aluminum skins …..pretty good with what seems to work on fibreglass…but all comments are appreciated

I found that when the aluminum surface is alodined, most everything will stick to it. I spray epoxy primer on top of aluminum and everything sticks to a top coat of epoxy primer, including all kinds of fillers, polyesters and micro, and I used both so far.
 
Grace Slick

I think I've eaten a mushroom and fallen down the rabbit hole. This thread has a good builder wiping discount polyester filler on aluminum and epoxy, and another is talking about $30K+ paint jobs.

Oh, the colors, the colors....

Like the lady says, "One pill makes you larger, and one pill makes you small. And the ones that mother gives you, don't do anything at all."
 
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