Blush??

[jdupre']

I put the Swamper in the bayou this morning for a little paddle and when I came back, I slid it up on the bank with a little of the stern still in the water. I looked at it a few hours later and this white deposit covered the area under water.

You can see it's an even coating on the bare epoxy as well as the graphite coating. The boat's been finished for over a year. Could this be a delayed blush? It's not mud or dirty water film. It is waxy and hard to remove like amine blush. I never did get around to varnishing over the epoxy. Could have something to do with it.

Joey

 

[hairymick01]

Joey,

I have never seen anything like it. How likely is it that there might have been a chemical spill in that bayou?

 

[jdupre']

Mic, this is the second time this happened. Two completely unconnected bodies of water. The first time the only thing that would remove it was 0000 steel wool. It's kind of waxy leaving a powdery residue when rubbed. I guess it could be some sort of chemical.


Joey

 

[oldsparkey]

It can't be a blush since it is on the graphite mix along with the epoxy on the boat. After a year that epoxy is set up , it was really set and cured after about a month but even more so as time rolled by. I'm betting it was something in the water that decided to attach itself to your boat while it set there.
The question I have is ........... Has this happen to other wood boats that have the same finish as yours , or has it even happen to boats with a different finish ?

 

[seedtick]

Friend Keith and I have seen something like this once before and, on discussing it with another old time boat builder from Mandeville, his belief was that it came from water penetration of the top of the epoxy layer. Sanding removed the haze

Epoxy is very water resistant but not completely waterproof. His experience and ours is that the slower curing hardners will tend to haze or cloud with water and sunlight under some conditions.

We switched over to West Systems special clear hardner and have not had a recurrence of the problem


The amines produced by blushing are water soluble, so i don't believe it's likely that you're seeing blush

 

[jdupre']

Seetick, the boat HAS been out in the sun a lot lately and I did use slow hardener. I'm figuring the top layer of epoxy has started to oxyidize, letting moisture penetrate and causing that haze. Maybe a good sanding and scrubbing and apply another light coat of epoxy, wait a month, and then varnish????

Joey

 

[swampwood]

I was just reading an article on (amine blush). This is a quote from that article
"This film is mostly water, one of the byproducts of the epoxy cure, and it's the very devil to stick paint or varnish to. You can wash it off, but the epoxy keeps curing, and blushing, for a long time."
They advise letting the epoxy cure for weeks or months before finishing.
I am presently using MAS epoxy, it is non blushing and you can finish it after 72 hours. Costs about the same as West Systems.
I have used West Systems and US Composites. Liked the West, US Composites is really bad about blushing, but it is the cheapest of the three.

 

[tx river rat]

I have been using US composite epoxy with no problems. I just use the 2 to 1 slow mixture.
Any more developments on the JD?
Ron

 

[jdupre']

Ron, piper came over to do a little pellet slinging and recommemded I use denatured alcohol. Took it right off. He said to clean it well and varnish. I guess I have to get off my lazy butt and do that.

Joey