Proper use of epoxy

[davidpm]

I've never used epoxy before so I'm trying to get the rules down.

This is what I think i have so far.

Thicken if:

Needed for gap filling for example chine joints or tabbing.

For Fillet or mini fillet for tacking chine

When clamping two pieces of wood so it will not squeeze out.

Straight (unthickened)

For:

coating plywood

Painting on tacky fillet so fiberglass tape can be pressed into it and whetted out.

I'm not sure what to use to for:

Filling the weave of the fiberglass tape

whetting out the tape and wood for the but joint.

Any advise would be appreciated.

[Scott Dunsworth]

I have tried a lot of different ways to wet out the tape and keep coming back to the way Devlin suggests in his book. I clear a flat area and cover it with plastic then I wet out my tape and take it to the boat. For longer pieces you can roll it up as you wet it out. Now you must already have the area the tape is going to be layed wetted out.

You get just enough epoxy in the tape that it isn't starved and not so much that it floats.

Scott

[Peter HK]

David

My 2 c worth is this:

The thickening of the epoxy varies depending on the job. If gluing large, flat, well mated surfaces eg a butt join then slightly thickened epoxy that flows nicely and won't get too dry from epoxy soaking into the surfaces is the go. If making fillets especially on vertical surfaces or filling large gaps then it needs to be fairly thick so it doesn't run (better to coat with straight epoxy beforehand and let it go tacky).  Standard gluing eg inwales is in between. Descriptions like ketchup/mayonnaise/ soft putty are sometimes used to describe the gradient in consistency. A little practice and you'll be right.

For filling the weave and wetting out tape use unthickened epoxy.

I agree with Scott that wetting out tapes on a bench is the easiest. I have a piece of ply about a metre by 30 cm that is affixed to one wall of the garage - I no longer use plastic on it- just smooth off the epoxy with the spreader used for wetting the tapes at the end and let it dry. When the epoxy gets too thick/uneven on the ply, I hit it with the belt sander.

Peter HK

[davidpm]

That makes complete sense, thanks.

[Tom Lathrop]

I also agree with Scott about pre-wetting the tape on a plastic covered board.  I find that using a "Z" fold instead of rolling the already wetted tape is much easier to handle  though.

[Dale Niemann]

Along with Devlin and other books, System Three has a very good pamphlet about Epoxy which is entertaining as well as informative.  I used it a lot in my early days of epoxy work.  I think they still have it and I imagine the cost for it is very low, although I have not checked lately.

Dale