Body Work - Cut Exhaust Hole Too Big - Repair

[Padawan]

I cut one of the exhaust holes too big on the passenger side. I would like to big out the edge about an inch.

The body is made out of glass and vinyl ester resin, can I use glass mat and epoxy to build out the edge?

Example: https://www.autozone.com/sandpaper-and-body-repair-tools/fiberglass-material/p/evercoat-fiberglass-repair-kit/1178018_0_0

Pic of exhaust hole with Pipes attached: 173913

I'm a novice so trying to make sure this repair doesn't snap off in 3 months.

Thanks

[Scott L]

Back in the day I ordered vinylester resin and mat from TAP Plastics -

https://www.tapplastics.com/product/fiberglass/polyester_resins/tap_marine_vinyl_ester_resin/34.

This worked great on my MK 3 - not sure about the chemistry on a MK 4 - I would ask Jeff K, or the Bat

I used this with a thin vale to cover holes (trunk hinges, side mounts) and with real mat to repair a thin spot on the inner door edge.

Use the surface activator to accelerate the cure time. Good luck.

[egchewy79]

once it's primed and painted, the only person who'll notice is likely going to be you. keep in mind that you never see both openings at the same time, so most will not notice any asymmetry. food for thought.

[Padawan]

I cut one of the exhaust holes too big on the passenger side. I would like to big out the edge about an inch.

The body is made out of glass and vinyl ester resin, can I use glass mat and epoxy to build out the edge?

Example: https://www.autozone.com/sandpaper-and-body-repair-tools/fiberglass-material/p/evercoat-fiberglass-repair-kit/1178018_0_0

Pic of exhaust hole with Pipes attached: 173913

I'm a novice so trying to make sure this repair doesn't snap off in 3 months.

Thanks

Is it correct the Polyester Resin is compatible with vinyl ester resin? From what I read online polyester works better with vinyl ester resin than epoxy?

[Jeff Kleiner]

I don’t mix dissimilar materials. My go-to sources for Vinyleters resin are USA Composites or Fiberglass Supply Depot.

Jeff

[Scott L]

Captain O ring to the rescue. ;-) I knew you would know.

[Hoooper]

TAP plastics also carries vinylester resin and the needed cloth, convenient if you have one nearby

[Padawan]

TAP plastics also carries vinylester resin and the needed cloth, convenient if you have one nearby


I called TAP Plastics and they walked me through the order... I'm buying the cloth locally not sure how much I'll need.

TAP Marine Vinyl-Ester Resin
Marine Vinyl-Ester Resin, 1 quart

TAP MEKP Liquid Catalyst
MEKP Liquid Catalyst, 2 oz

Vinyl ester resin vs Polyester resin
Vinyl ester and polyester resins are chemically compatible but:

The cross bonding of vinyl esters is superior to that of polyesters. This means that vinyl esters bond to core materials much more effectively than polyesters and delamination is less of an issue. Vinyl esters are less sensitive to ambient conditions (temperature and humidity) than are polyesters