Low viscosity epoxy question????

[john51277]

I ordered some epoxy from US Composites. I did not realize it is a low viscosity/thin. It seems to run out of the cloth on a vertical lay-up. It will still stay! Can I thicken the epoxy with glass bubbles and use it? If I do this will it weaken the epoxy? Or should I order new epoxy?

 

[fishingdan]

Re: Low viscosity epoxy question????

A couple of things:

- After you fully wet out the glass, you want to squeeze as much epoxy out of the glass as possible. In this situation, less epoxy = better strength.

- Not clear if you are wanting to use this resin for other than laminating. Assuming yes, you can use any epoxy filler you like for the intended purpose. The key is to use the correct filler for the intended purpose. For example, glass bubbles are used when you want to use epoxy as a filler for fairing work. Glass bubbles make epoxy easier to sand. You wouldn't use glass bubbles in an application that requires strength.

 

[john51277]

Re: Low viscosity epoxy question????

Well, It seems that when it does run down from the cloth/mat it leaves voids in the cloth between the fibers. I would not think this is good. Can I mix with glass bubbles and then wet out the cloth? Just a little to keep it in the cloth until it sets up? I do not want to wait a week for more epoxy. I do have a few quarts of glass bubbles at the house. The glass is wet, but there are very small voids/bubbles in the glass. I think it can be filled in with the next layer though. Thanks for the help so far guys!!!

 

[jonesg]

Re: Low viscosity epoxy question????

You can fill the weave with a second coat.

 

[ondarvr]

Re: Low viscosity epoxy question????

You can add some fumed silica to thicken it.

 

[oops!]

Re: Low viscosity epoxy question????

Well, It seems that when it does run down from the cloth/mat it leaves voids in the cloth between the fibers.

The glass is wet, but there are very small voids/bubbles in the glass. I think it can be filled in with the next layer though. Thanks for the help so far guys!!!

glassing can be a bear at times......use the fumed sillica as ondarvr suggested........

a really good wet out is crutial in glassing......that does not mean gob on the stuff till it pours off....it means take the roller and really rub it into the sub straight....several different directions........

micro bubbles can occure if it is not wet out properly...........vertical OR flat surface.......

that might help with a SMALL part of the problem

 

[john51277]

Re: Low viscosity epoxy question????

fumed sillica??? I will google and find some. I did one layer of CSM 7 oz last night to the inside of the old bilge outlet hole on the rear side(as a test) and it held VERY strong. I filled the hole, from the outside with glass bubble thickened epoxy and I will be wrapping the transom with a layer of glass and wrapping around the sides about 6 inches, which I will feather out and fair. I hope the layer of 1708 will be enough!

Can I use some of the microspheres to thicken it?

 

[ondarvr]

Re: Low viscosity epoxy question????

Fumed silica goe's by a few names, Cabosil and Aerosil are some brand names, it's used to thicken resins and other liquids. It can be found at the same place you bought the epoxy.

 

[john51277]

Re: Low viscosity epoxy question????

Can I use some of the microspheres/ bubbles to thicken it?

 

[ondarvr]

Re: Low viscosity epoxy question????

Sort of, but it won't work as well as silica. Silica acts a little like velcro, in that it bonds together and holds the resin in place, when aggitated these bonds are broken, but they rebuild when the liquid (resin in this case) stops moving. At rest it has a higher viscosty than when moving, so it can be sprayed or poured, then worked into the glass, but not drain out on a vertical surface. The spheres will thicken it, but will let it flow at rest easier than silica, so it may still drain out.

 

[john51277]

Re: Low viscosity epoxy question????

Gotcha, So it kind of acts like sand would as far as flowing through it rather than stacking up and staying! Or round vs. square. Thanks for that bit of info!