West System epoxy filler...

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bsexton

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OK, I've read most of the threads on TRF that I can find and I've read most of the information on the West System web site about epoxy fillers. I know fillers fall into two general categories -- adhesive and fairing.

So my question -- If you could have one (and only one) filler to use with West System 105/205 epoxy to thicken, add strength (or at least not make it weaker) but still be fairly easy to sand what would you choose?

The West System 406 Colloidal Silica seems to be the most versatile, but what say the rest of you?
 

Missileman

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I cant pick just one, but fillers are not expensive and go along way.
I use 406 silica all the time for internal fillets and anywhere I want extra strength. 406 is very hard to sand.
I use microballoons for external fillets or were I need lighter weight and easy sanding.
 

Stymye

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Ive been using the 403 for thickening, it looks like fluffy flour..
I haven't tried the 406 but I'm sure it's good as well for thickening

the only thing from West that makes it easier to sand is the 407 or 410

(I use Prather brand Phenolic microballoons instead from ehobbies)
 

DumasBro2

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I use 410 for filling where I will need to sand and milled glass for internal fillets where I can't uses a piece of glass. I have also used a combination of 410 and milled glass.

steve
 

wyldbill

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DON'T use the 404. Way dense and impossible to sand. very strong tho...
 

Ted Cochran

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I use 407 for thickening, fillets, and the like. It's not exactly easy to sand, but it's certainly easier than West alone.

Mostly I use West by itself. I'm no huge HP rocket builder, but I've probably used a gallon of the stuff over the past few years. I still have more than 3/4 of the one can of 407 I bought, and more than that of 406 and410.

FWIW,

--tc
 

airwolfe1

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West System 406 Colloidal Silica I think is the lightest weight of them all and I've had really good luck with it. When you make your fairing, mix the epoxy to a consistancy of peanut butter. "Butter" it along the root, then use a plastic spoon, dip it in denatured alcohol and run it along the joint. This will smooth it out and make every fillet the same size. The alcohol smoothes the surface so virtually no sanding is required. Go to Jon Cokers web page for this tip it's at the bottom of the page. https://www.jcrocket.com/quicktips.shtml
 

airwolfe1

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West System 406 Colloidal Silica I think is the lightest for strength vs. weight of them all and I've had really good luck with it. When you make your fairing, mix the epoxy to a consistancy of peanut butter. "Butter" it along the root, then use a plastic spoon, dip it in denatured alcohol and run it along the joint. This will smooth it out and make every fillet the same size. The alcohol smoothes the surface so virtually no sanding is required. Go to Jon Cokers web page for this tip it's at the bottom of the page. https://www.jcrocket.com/quicktips.shtml
 
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