I have an old foam plane on which I used some epoxy to glue the vertical and horizontal stabilizers to the fuselage. I noticed the epoxy has a strange brownish-yellow color, which looks terrible on the white foam. Is this coloration normal after the epoxy dries? I thought epoxy is supposed to dry clear.

SAF

I think mine is yellowish too..... AFAIK, that is normal

too much hardener,it will yellow after a good while year or so.when it is still workable use rubbing alcohol to remove the excess from the visible areas,and use colormatch paint if you can find it.

One thing I found out . . . the thirty-minute epoxy always dries yellow . . . but the five-minute epoxy always dries clear. If you want or need your foam plane to look neater and if you can do the work in five minutes or less, I would recommend using the five-minute epoxy to have a clear dry finish.