epoxy cure time prior to sanding

[mark mcfarlane]

I was curious how long people have to wait prior to sanding small defects filled in with dyed epoxy? Also, what type of epoxy are you using to get your specific result?

I'm currently using Gorilla epoxy (readily available) and while it works fine for filling in small knots, etc, it takes at least 24 hours to get hard enough to sand. I'd like to find something that can be sanded in 8 or fewer hours.

thanks,

[Derek Cohen]

Mark, I used tinted 15-minute two-pack epoxy. It takes about 8-10 hours to be hard enough to chisel and sand. Until that point it is chewy and will simply gum up sandpaper.

Regards from Perth

Derek

[Ole Anderson]

Until that point it is chewy and will simply gum up sandpaper.

"Chewy", that tickled me as funny for some reason. Good choice of words Derek! Chewy, gum...

[Mike Cutler]

Mark
My experience with epoxies is that 24 hours for a liquid type is going to be about the norm. I'm sure there are others through that I'm not aware of.
The only epoxy products I know of that can be sanded in the time frame you're looking for, would be the epoxy sticks, like "Quik-wood", and the Mohawk Finishing product lines.
https://www.mohawkproducts.com

[johnny means]

We use a variety of stuff available at the box stores. The 5 minute and the 15 minute stuff both seem to work as advertised. Pigments and dyes don't seem to be a problem. We just discovered StarBond. It dries instantly with the spray and can be built up very quickly for smaller voids and cracks.

[Martin Siebert]

I agree with Mr. Cohen, it might say 5 or 15 minute...but it always takes much longer. I just surrendered to the fact that I will glue something up with epoxy, of any kind or brand and leave it until the next day. I have had zero luck with the Gorilla brand epoxy. I mostly use Devcon. It works pretty good if you can find it. One thing you might want to try, but I don't know if it works with epoxy. They make a stuff called "surface agent" and it is mostly liquid paraffin wax. it is an inexpensive additive that you mix in with whatever you are working with. It floats to the top in a very thin layer and denies air contact. Air apparently causes the very surface to not cure and stay sticky...it's this stickiness that gums up sandpaper. Works great for all kinds of adhesives, I just don't know if they have it for epoxy. Another thing to try is wipe the surface with acetone or MEK to remove that sticky layer, but you cant do that if you have some other finish near.

[mark mcfarlane]

FWIW, my Gorilla epoxy fill of some checks and knots is at 24 hours, and the thick parts (up to 1/4") are still chewy. The epoxy syringe was first opened probably 14 months ago. Hopefully I won't end up scraping it out.

It seems like the last time I used this same syringe (4 months ago) it took closer to 48 hours to be ready to sand, so no panic yet.

How about the West Systems epoxies, are they '24 hours to sand'? I use so little I hate to buy the big bottles, I probably only use one-two ounces per year.

[mark mcfarlane]

For the record, my '18 month opened' Gorilla epoxy was fine to sand after 30 hours. It was still a little soft after 22 hours.

[Kyle Iwamoto]

Have you tried Super Glue? I use sanding dust, fill the crack/defect, hit it with thin CA, wait a few minutes and sand. Repeat until the defect is flush. Starbond sells medium thick colored CA glue. Brown and black. Try googleing them, I love their products. Be careful though. CA will wick into the wood and discolor it. If at finished stages, you will see it. Works really well when you are sill at working stage, prior to finishing stages. Sealing the wood prior to hitting it with CA helps prevent wicking, but not always.

[Dan Baginski]

It hasn’t been above freezing here for a few days and I filled in a knot hole a few days ago. It’s slowly getting there but still a little tacky in one spot. My garage doesn’t get below freezing but pretty close.