Fiberglass Filler

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Hospital_Rocket

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I was wondering if when using chopped or milled fiberglass, do most of you use the powdery stuff that comes in the squeeze bottle or do any of you use the various grades of chopped lengths like those sold by US Composites
 

lalligood

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I bought one of the little bottles of milled fiber from BSD back when I ordered my Thor. It's a pretty fine grade of the stuff. It almost looks like a powder until you spread it out thin on a dry surface. Based on the packaging I'd say that BSD purchases a large quantity of the stuff & then puts it into their own containers (not that it really matters). What does matter is that I have used the stuff quite a bit & it indeed makes a difference in my epoxy fillets! Much, much stronger. It also means that you better get the fillets looking like you want them before the epoxy cures because they're impossible to sand the milled fiber infused fillets!
 

aksarben10

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I use the milled fiberglass and kevlar on a regular basis. I would not use the chopped fiber as you would end up with a rough surface and possible fibers sticking up. I use it because it adds strength to the epoxy but mostly because it thickens it into a paste that does not run.

I find it much easier to get good fillets when using it. Just add enough to milled product to thicken the epoxy to make a nice paste, then put it on using a popcicle stick creating a nice fillet and smooth out the epoxy mix by dipping your finger in rubbing alcohol.

Scott
 

lalligood

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Originally posted by aksarben10
I use the milled fiberglass and kevlar on a regular basis. I would not use the chopped fiber as you would end up with a rough surface and possible fibers sticking up. I use it because it adds strength to the epoxy but mostly because it thickens it into a paste that does not run.

I find it much easier to get good fillets when using it. Just add enough to milled product to thicken the epoxy to make a nice paste, then put it on using a popcicle stick creating a nice fillet and smooth out the epoxy mix by dipping your finger in rubbing alcohol.

Scott
That perfectly mimicks my experiences & technique of using milled fiber in epoxy.
 

North Star

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I use chopped strand/mat a lot for high (HPR) strength apps like CR to motor tube to airframe. I use the 1/2 hour epoxy so I get plenty of time to work the mat into the resin and the fibres sort of come apart and blend in with the resin. I then apply it to the relevent parts. It certainly does dry very uneven so is not good for external use but it is VERY strong. I bought a small plastic jar of the stuff about 5 years ago and still have most of it. I bought a bag of milled fibre from the West Systems dealer - there's over 2 pounds in weight so it'll see me out, as they say.
 
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