So I'm working on 4 paddles. Ordered fiberglass and varnish from Northwest Canoe in St Paul so I should have good materials. Last coat of fiberglass went on last Wednesday, week ago today. Sunday I did final sanding, washed, dried, and varnished. Did not thin varnish but have never done that before. Tonight, Wednesday, the varnish is still tacky. I don't think I could sand it. The paddles have been in my basement at room temp the whole time. It is not a damp basement either. Don't think humidity is a factor. One of the paddles is for my sister's birthday next month so I need to figure out what to do. Any ideas?

What resin did you use? Was it thinned at all? I've had varnish not harden when placed over resin that wasn't fully cured. You'd think a week would be long enough for a good cure but it can depend on the resin and hardener. Or if the mix ratio of the two wasn't correct that will slow cure time.

I'd put the paddle in the warmest place you can find for a few days and see what happens. If it still doesn't set up you're probably looking at sanding the varnish off and waiting longer for the resin to cure. One way to tell is to wipe the resin with acetone or alcohol. Fully cured resin will be unaffected while uncured resin will get a little tacky. Uncured will also load up sandpaper while cured won't.

Alan

I am assuming you used epoxy resin for the glassing. Depending on the type of hardener used, your epoxy may have had what most folks call "blush". This is a waxy film that floats to the surface of the resin as is cures. This needs to be cleaned from the paddle sanding. If you did the process in the order you stated, wash came after sanding.

If you sanded the waxy blush your paper would have gotten gummed up real fast AND you would have entrained that blush into the surface of the resin where the after-sanding wash would not have cleaned it.

Regardless of the reason. It sound like your varnish might not cure hard enough. If you have to remove it I would recommend a scraper. Sanding soft varnish will just entrain more uncured stuff into the surface. A cabinetmakers scraper can be found that has some curved edges if there are any concave surfaces. Scrape it down into the epoxy'

Also, I always try to heat up curing epoxy well above room temperature for at least a day in a weeks total cure. I try to get 80-85 with a space heater.

Here's an update. I put a space heater close to the paddles and it seemed to work in spots. I then moved them into a closet with the space heater and that worked pretty nice. Then put them in the sun for a day on each side, glad we are still having this nice weather, and the one that is the birthday present is good. The others are prolly 99% dry but since it's November, I'll just let them sit a while longer. The birthday present needs 2 more coats on the top foot of the handle and it is done! Thanks for the advice, I think I'm good.

Glad it seems to finally be hardening up. I'm still curious what resin you used.

Alan

It is the Ad Tech Pro Build from Northwest Canoe. I think the pumps I got are defective so it didn't mix right. The one for the hardener was weird so I am using an old one. The one for the epoxy spits air a lot but my old one is broken. That's why I got a new set. Wondering if I should start measuring? What do you do to mix?

Probuild should probably have been ok. It does seem to cure a little slower than some other epoxies at lower temps but I had a lot of trouble with the Adtech 820 series. I saw no mention of it on their spec sheet but read later, on another site that sells their product, that it doesn't cure below 80 degrees. That's a problem when building boats around here in the winter.

I don't use pumps. I'm sure they can be fine as a lot of people use them successfully but I have a hard time trusting what I can't see with my own eyes. The 2:1, 3:1, 5:1 ratios given my the epoxy manufacturer are for volume measurements. So that's what I used to do and it worked fine. I'd use graduated mixing cups or else sometimes make my own (use a sharpie to make marks on blank cups). For small batches syringes work well.

Then I started doing it by weight instead and I like that a lot better. If you look at the manufacturers spec sheet it will tell you what ratio to use if weighing it out. It will be different from the volume measurement. I mostly use Raka resin, which is 2:1 by volume, but the ratio for weight is given as 100/43. That means 43 parts hardener for every 100 parts resin. A 2:1 ratio would be given as 100/50.

Anyway, it's easy enough to measure out with a calculator on the bench. Pour out how much resin you want, let's say 1.3 ounces, and then multiply it by .43 (for Raka) to get the amount of hardener; which would be .56 ounces. Mixing small batches by weight is a lot easier than by volume and you can use whatever container you want instead of needing something with graduated measurements.

A decent kitchen scale is only about $14 from Amazon. I like this one. The different scales come in handy for measuring different amounts. Using grams is nice for small batches and unlike some scales it gives you the option of showing 20 ounces as "20" rather than "1lb 4oz".

Alan

This say's it should be 3:1. I was thinking of the syringe as I usually mixing small amounts for the paddles. Where do you get your syringes?

quote Rustycards: "This say's it should be 3:1. I was thinking of the syringe as I usually mixing small amounts for the paddles. Where do you get your syringes? "

I was using Raka as the example, it's 2:1. I couldn't remember what the Adtech was for sure. I get syringes from the vet department of the local farm store.

Alan

I use cheap clear cups from Walmart, and a sharpy.
Pumps are problematic ! They spit, and clog. but when they go bad you not only waste epoxy, you can ruin what you are making. I know everybody sells you pumps, They are good for dispensing, not so good for measuring !
Just go old school, you'll be happier !
Either go with a graduated cup, or make your own, as Alan suggests !