I am Tosk wrote:
In article ,
says...
I am Tosk wrote:
In article ,
says...
I am Tosk wrote:
In article ,
says...
mx wrote:
Will all epoxies bond to one another? I have some West GFlex, which I
want to use thickened to fill a gap between two loosely-fit fiberglass
parts, and some System Three laminating resin (Clear Coat, I think, I
don't have it with me right now) that I then want to use with glass
tape to reinforce over the surface of the joint. Will the epoxies
bond well to each other, if the glass is applied within a few days of
the first resin?

Also, is colloidal silica and microballons the same? I have an old
bag of house-brand microballons from Fiberlay, and colloidal silica is
recommended as a thickener. I feel like I used to know the answer to
this...but, apparently, I'm an idiot!

Thanks,
Mike

epoxies are a universal primer and epoxy will stick to epoxy, but watch
out for amine blush. Some/most venders (like the ones you mention)
sell the bushing epoxies because they make more profit/ Blush can affect
the bond between layers.

fumed silica is a common thickener... microspheres are tiny hollow
spheres, very light and fine (comes in different densities) - thickens
the epoxy but acts like tiny ball bearings in the epoxy

paul oman - progressive epoxy polymers inc. www.epoxyproducts.com and
www.epoxyusa.com
Has anyone mentioned that Balloons are more for filling and fairing,
Silica is more for structural work?

SmallBoats.com
Micro balloons come in two flavors - Phenolic and Glass.
Glass should not be used with Polyester resin.
But either can be used with epoxy.

I believe silica is just a thickening agent to help prevent
sagging on vertical surfaces.

Cotton make a great structural additive. Milled or stranded as needed.
Or even cotton balls sometimes.

Or wood flour, if you are working with wood.

Then there are the exotic fillers.
Aluminum dust, steel powder, carbon powder, etc.
When I was building, I used the silica for everything. I always tried to
use as little as possible to get the job done though. It is hard to sand
once finished too. When I needed more strength in a bond, I would layer
in glass fabric, or chop some glass fabric into strands and mix it in. I
don't remember ever using the balloons.

Warning, tangent below

When I was working with wood that was going to be clearcoated I would
pigment the epoxy with two colors, pine and maple, wood flower. The pine
would end up about the color of commercial peanut butter and worked for
corners on lighter wood, the maple would turn a rich brown with the
epoxy. You can also mix the two to match colors. Note, your own homemade
sawdust is not the same as wood flower, it can be used, but it is not as
smooth. I suppose the stuff your sanders save at 100 grit or smaller
might be good too.

SB

I had some really old West resin.
The catalyst had turned really dark.
It still worked fine, just made a beautiful darker finish.

another tangent:

I found that if you take that last coat of resin and wipe it OFF -
ALL OF IT!, just keep wiping it off (use lint free cotton rags rather
than paper towels) you can get a gorgeous satin finish.

The only downside is the danger of leaving any small puddles of
resin which will still be shiny and quite obvious.

But if you stay at it and get it clean, it makes a really pretty finish.
And way tougher than varnish.

I would still cover it with UV protective clearcoat as UV breaks down
epoxy pretty quickly.

sorry.
I should have added that I only use this for interior finished.
You are absolutely right.