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Building Tips and technical articles. => Paint and finishing => Topic started by: Douglas Ames on April 14, 2015, 06:42:37 PM
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What are you using to thin out Super Fil? I have some that is the consistency of cookie dough and needs to be a little smoother to work with.
Alcohol or MEK?
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I use water.
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To me it seems really thick out of the containers but then thins out decently once the two parts are mixed thoroughly. From there I'll apply it to the model and then use the finger dipped in alcohol trick for smoothing things out. Using some light reflection down the sight lines also helps you decide how you're doing during the smoothing process. If done well about all you'll need to do after it cures it scuff sand and feather it in prior to your finishing routine.
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Yeah, I use the wet finger technique. It just goes on pretty thick.
Makes very nice fillets though!
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The general rule of thumb that I know is -- don't let epoxy stay thinned. Epoxy doesn't harden by drying, so if you thin it and the solvent doesn't have time to escape it just prevents the molecules of epoxy from bonding together.
You can thin epoxy, but only if you use it in a thin film (like painting a tank compartment) and only if the thinner will flash off before the epoxy gets serious about setting.
I suppose that it doesn't matter much for fillets, because they don't need much strength, but I'd just use it out of the can, and if the stuff in the can is thickening, I'd get new.
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When the Super-Fil gets too thick in the containers, I apply a small amount of water and stir to a good consistency. I then mix how ever much I need. After I have applied the Super-Fil, I then wet my finger with water and proceed to smooth the fillet. I have been using this method for several years and it works great. Love this stuff, easy to sand.
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I might be thinking of something else here, but it seems like I heard just recently somewhere that you could also microwave the separate containers for a few seconds to soften it up. As far as the original post question above, I wouldn't try thinning it with anything.
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personally I would never thin any two part system with water unless it was directed by the manufacture ( do as you see fit,, its your plane),, I throw mine in the micro for 10 seconds, just enough to feel it warm a touch,, then as was mentioned,, it becomes less viscous as you mix the two parts,, I started warming it when after sitting for a couple years ( yeah,, Wayne,, I know build more right),, it started to separate resin from filler,, warming it allowed me to re-blend the components and be more workable,, I resist adding solvents,, thinners or any viscosity modifying agents unless specified in user instructions,,
as to fillets not needing to be strong,, I am not sure I agree here,, the wing fuse joint,, and the stab joint are high stress areas,, weak fillet material can allow all sorts of nasties,, cracking,, and so on,,
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I use Mark's method. Throw the two containers in the microwave for like 15 seconds and you can remix the resin and filler together pretty easily (it does tend to separate in the container) then just mix it up and off you go. Works well for me.
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I started warming it when after sitting for a couple years ( yeah,, Wayne,, I know build more right)...
Actually Mark, you got me on that one. I've had my batch at least two or three years and it's not even half gone. I did use some recently though and it mixed up and worked just fine.