Im Interested in using Ampreg 21/22 or Sicomin 8500 for composite repairs in glass/carbon and how well they stick to polyester gel.
Does anyone have any reviews on these.
The before race car shop I worked, we used ampreg22 with duratec PE primer and it bonded well. We did not use with gelcoat though. As always you should test your materials, as every combination will have different results.
I would struggle to believe that any epoxy would bond to a regular polyester gelcoat… Given that regular polyester gelcoat doesn’t cure hard, there can be no mechanical bond, and the two chemicals don’t play well so there is no chemical bond either.
The only way I know epoxy bonds to polyester, is for it to be an unwaxed coating that isn’t air-inhibited so that there can be a mechanical bond there.
Interested to hear if anyone has experience to the contrary, but that is my basic understanding of the issue.
only have experience on ampreg 22 with a iso npg gelcoat and vinylester/csm skincoat. No problems there. I know there are some tie-coats available to skip the vinylester or polyester skins
In the past I have used sp110 and it surprisingly sticks well to gelcoat. I spoke to the Sp dealer and they said Ampreg 21 is taking over/susperseed ampreg 22.