Polyester Resin Tack-free Strategies

[Cal79]

First time poster here!

What is the best lamination strategy to have a tack-free cure for laminating with polyester resin? The method I use is to add 2% wax to the resin for my last layer of fiberglass. This works well for me, but I am worried it might be weakening the laminate in the long-term. Anyone know if using wax on the last ply weakens the lower plies long-term?

Should I switch to brushing a layer of PVA on the last ply and forget about the wax altogether? Any practical comments / suggestions?

 

[Blueknarr]

Welcome to the forum.

Wax can't migrate into previous layers of fiberglass, so it can't possibly weaken them. Residual wax may/usually interferes with the bonding of any additional layers after any waxed layer. Wax additives have a long history in polyester glass work. If there was an weakening issue, it would have manifest it long ago.

The decades I spent as a commercial painter made me biased against adding wax. I am now doing fulltime fiberglass and gelcoat repair. The gallon can of wax surfacing agent I bought three years ago is still well over half full. I do use a lot of PVA.

Almost all of the cloth I lay will require some grinding/sanding back to be fair with original surface profile. I accept the clogged abrasive disks on small repairs. On medium to larger ones, I'll use peelply. I don't PVA over cloth out of concern that it will be difficult to remove from the pits in the weave.

I almost never leave new cloth ungelcoated. Just the nature of repairs.

 

[ondarvr]

Don't over think it, if the wax works for what you’re doing then stick (pun intended) with it.


I will add that the average shop doesn’t use wax in resin very often, most never do.

 

[KD8NPB]

The ISO/DCPD I use dries tack free.

Ashland Aropol L67300-series. C1 churns out L67303T40 like water.