Fiberglass

[theoldwizard1]

How do you get fiberglass and epoxy to stick when going around an outside corner ? (6" wide, 1708 fiberglass cloth)

The "edge" is horizontal. The 'glass is well saturated, but after wrapping over the edge, within a few minutes the horizontal portion lifts up making an air pocket.

(The only thing I can think of is 2 pieces a 1by about 2"-3" wide, screwed together to make a 90°. Coat with wax (or wax paper or something that the epoxy will not stick to). Screw it down through the fiberglass.)

 

[PCustoms]

Tape, stretch wrap, blocking etc.

I've never used screws through wet glass...

Your glass is compatible with the resin, correct? How old is the glass?

 

[Firebrick43]

Best is to vacuum bag it if you can.

Stretch wrap comes in a close second.

Peel ply and a bleeder layer keeps the epoxy from sticking and makes further bonding much easier and reduces excess resin.

1708 is extremely heavy layer for a corner, especially an outside corner. It would be much better to use (3) layers 6 or (2) layers 10 oz cloth instead of 17 0z cloth. If you make the layers different widths it makes it easier to taper out out for much easier finishing as well.

 

[Firebrick43]

Your glass is compatible with the resin, correct? How old is the glass?

I haven’t seen a 1708 that is incompatible with epoxy. The strand mat layer is retained via stitching instead of binders that are melted via ester resins.

It is somewhat incompatible with corners. That is the baffling part to me.

 

[Xti04]

1708 is biaxial cloth if I remember right. I used to use 1208 for jet ski repairs and k 1708 is even heavier cloth. Vacuum bagging the part might be of help to you to hold it in place while it cures.

 

[theoldwizard1]

Peel ply and a bleeder layer keeps the epoxy from sticking and makes further bonding much easier and reduces excess resin.

Peel ply does not let the epoxy bleed through ?

So if you lay down peel ply and put weights on the 'glass it will cure in place ?

 

[Firebrick43]

Peel ply does not let the epoxy bleed through ?

So if you lay down peel ply and put weights on the 'glass it will cure in place ?

Yes it allows resin to bleed thru and be absorbed by the bleeder layer. Even though it does bleed through it still allow the peel ply layer and anything above it still to release and be ripped off. It also causes a textured surface to allow secondary bonding.

If you want to deal with excess resin but have a smooth surface they have perforated release films

If you don’t want to remove the excess resin many use Mylar as a release film but because it’s not perforated it won’t let any resin through.

Just placing weights on things rarely work’s satisfactory as the weight is rarely spread out evenly. Vacuum bagging allows an even 14 lbs of pressure (at sea level) to be applied extremely evenly.

I have seen tubes and curved surface layups use 6” wide shipping stretch wrap pulled tight and several layers with good success but it doesn’t work correctly on flat surfaces.

 

[PCustoms]

I have seen tubes and curved surface layups use 6” wide shipping stretch wrap pulled tight and several layers with good success but it doesn’t work correctly on flat surfaces.

Used to do a lot of prototype/small run layup, got really good at cheap tools that could get bagged or wrapped.

@theoldwizard1 post a pic of your project

 

[Jeff Ivers]

Are you using cloth or mat and, if mat, what weight? The lighter weight mat is less susceptible to this in my experience.