I having trouble finding a good filler material. My “go to” filler was Sig Epoxilite. Yes I know know it dries like cement and difficult to sand, but it was easy to work with and I could shape it so that very minimal sanding was required. Now I’m using the blue stuff (aeropoxy light??) and I’m not digging it. I can’t seem to ever get it shaped right and it’s just as hard as expoxilite is to sand. Seems ok for wing fillets but around canopies or anything else I hate it. Isn’t there something out there more sandable than these 2 part epoxy fillers?

I was delighted to read of your rekindled enthusiasm.

Welcome to the ranks of Those Who Hate the Blue Stuff. Now there are two of us. I may look into getting T-shirts.

Size 3X please.

    I don't know if you are referring to Super-Fil and "the blue stuff" or not, as I have never used it. There have been plenty of posts praising it's virtues, so it must have some redeeming social value! Like Ty mentions, are you just wanting to fill dings and dents, or make fillets? I'll have to try the stuff he posted photos of to fill dents and dings. For fillets, I use finish cure epoxy mixed with micro balloons. finish cure epoxy, like the old Smooth-N-Easy, and the stuff Bob Smith Industries markets, is 20 minute stuff in normal use. But when you add the micro balloons, it slows down considerably, to more than an hour, so lots of time to work it. I apply as usual, with a pop cycle stick or similar, and carve it out to where it satisfies me. Then as it starts to kick off, you can dip your finger in alcohol and drag it smoother than a baby's butt. If you need to sand it, it sands just fine. It takes dope and any kind of paint I have used on it with no lifting in the fillets. I haven't been able to build much in the last ten years or so, so it never made economic sense to buy another product that may go bad sitting on the work bench. I sue the finish cure epoxy for coating engine and fuel tank compartments, laying up fiber glass, and other repair jobs where the thin viscosity come in handy, so I always have that around. It can be used to fill dents and dings also.I hope to get a lot of practice at this in the coming year or so!
  Type at you later,
   Dan McEntee

I have only had one Super-fil kit. It was too stiff. I asked Aircraft Spruce, from whom I got it, if it was a fresh batch. They assured me that it was. I’ll get a new batch before I try it on an airplane again. Where are you blue-stuff enthusiasts getting yours?

Super Fill is the blue stuff I referred to in my OP (I mis quoted as aeropoxy)

Most specifically, I'm having trouble with canopy fillets. They never seem to come out smooth and the Blue stuff just doesn't sand/shape worth a damn, but fillers like spackle have no strength and sometimes react to dope over them.

The blue stuff is fine for wing fillets as those are usually very uniform all the way around the wing where it's easy to just use an exacto handle or something to get your radius.

I like the Elmer's wood filler.  not the "plastiwood" wtuff.  you can get it in big 32oz tubs, or smaller ones as well.  you can also dial in how thick you need it by adding a couple drops of water before application.  sands like butter, and takes dope well as far as I can tell.  I wouldn't use it to fill larger holes or gaps, but for small ones, seams between panels, etc, works great!

https://www.acehardware.com/departments/paint-and-supplies/patch-and-repair/wood-filler/1011998

finishing resin and corn starch works great for me .sands great

There’s a few interesting ideas here, but the consensus seems to be that I just need more practice with the Superfil.
Perhaps I should buy a new batch to practice with, though. What I have was bought 7-8 years ago but the jars aren’t dated.

Epoxy of any kind used for filling dings and low spots is difficult.  That's because epoxy is hard, and balsa is soft.  Sanding will result in uneven surface.  Your filler should be the same density as balsa.  If you insist on epoxy, then mix lots of micro balloons to make it less dense.  Where mechanical strength is not required, then a type of spackling putty is easier to blend into balsa.

   Use alcohol instead of water, then it smooths out just like epoxolite.

    Brett

 Yep, and don't be afraid to use plenty, it'll evaporate off quickly and won't hurt a thing.

I have only had one Super-fil kit. It was too stiff. I asked Aircraft Spruce, from whom I got it, if it was a fresh batch. They assured me that it was. I’ll get a new batch before I try it on an airplane again. Where are you blue-stuff enthusiasts getting yours?

 
Spencer Aircraft, Thun field.

Yep, I get mine from Spencer Aircraft.

Hi gang,

I shot this photo some time ago, to remind myself just how nicely "Super-Fil" sanded.  The sanding
dust was left on the sample, and the sanding rod was 'tapped off" to show that there was no
clogging of the sand paper.

It was purchase a long time ago, so I don't remember the source, but I do remember it was
the most "user friendly" filleting material I have ever used.  If the mixture gets hot, or if it
is hard to sand after curing, I would suspect that it might not have had the proper ratio in
the mixture.

Cheers.

Warren Wagner