Hello from France, I am in the process of applying a first layer of resin to the background after having installed the glass mat. before sanding, it was transparent and we could not see the 2 superimposed layers on the edge of the tear. there was no cloud effect. I apply a layer of resin to fill the frame and in some places on the counter there are areas that are no longer perfectly transparent. This only happens in certain places but they are very visible. I have a thin white line which follows the limit of the superposition and where I have 2 layers of glass mat superimposed I have a cloudy effect even after having put a layer of resin on top. Where I wonder is that before sanding we didn’t see any limits. how can I fix the problem? Is it possible that I sanded too much and that this altered the resin (due to the effect of heat for example)
Try wiping it with denatured alcohol. If it disappears while it’s wet, there’s no problem. The varnish coat will make it permanently disappear. If it stays visible while wet with alcohol, it’s a permanent feature.
White areas like that are caused by sanding into the glass fibers, not by sanding the epoxy. The way to avoid it in the future is to sand very lightly. Do not try to smooth everything at once by sanding down the hills. Instead, fill the valleys with more epoxy (thin layers!) and smooth the transitions.
Good luck,
Laszlo
As usual, Laszlo has it right. And I hate it when this happens and becomes permanent. I continue to struggle to find the right technique to minimize it. I suspect leaving a raw edge of glass instead of cutting off the “leather” along a taped edge might be better to avoid this but I would struggle with leaving that kind of irregular edge. I strongly suspect that leaving the glass on the tape until as late a possible would help avoid the light piping from the cut fibers that loosen up if the leather is too raw.
~Ron
Bonjour, Rurk!
If you are interested in removing the blemished fiberglass and redoing it, Nick Schade shows how in this YouTube video:
-Rich
Thanks you for your information.