The risks of oven drying finishes

[scott spencer]

For the past couple of days I've been spraying the final coats of my guitar project with poly, letting it skin over, then setting in the oven at ~ 95F to dry for a couple of hours to speed the drying process. (getting a bit chilly at night around here)

Tonight I walked into the kitchen to find my wife with a concerned look holding the guitar body with oven mits! :eek: You guessed it, she had started to preheat the oven to cook without checking. Fortunately, the aroma caught her attention quickly and she rescued it before any visible damage had occurred. It was pretty hot to touch but did not bubble....it ought to dry even quicker than I planned, but geez is that a risky venture! :rolleyes: I hate to even think about how many hours I've got into this so far!

Next time...if there ever is a next time...there'll be a note!

Anyone know what heat can do to a polyurethane spray finish?

[Matt Warfield]

Wow!! You got a concerned look? I'm jealous!! :rolleyes:

Suggestion as notes tend to fall off - remove the knobs for the oven and put 'em out of the way. This should immediately raise the question "what's going on?" :D

[Tyler Howell]

You should get some lightening hot licks out that baby.
Rock on!
I thought I could make an axe smoke now and then :cool: but.....You win:o :D

[scott spencer]

You should get some lightening hot licks out that baby.
Rock on!
I thought I could make an axe smoke now and then :cool: but.....You win:o :D

We definitely have the technology to make it smoke...just wish we could get one to "Howell" like you do! :D

[Howard Acheson]

You are probably OK. Urethane is added to vanish ot make it more heat resistant.

That said, I'm not sure I would heat cure a finish that was not designed for it. Oil based finishes "dry" in two steps. The first is the evaporation of the solvents. When these evaporate, the finish feels dry--no longer tacky. But, the real curing is just beginning. It's the chemical oxidation of the varnish. This process goes on for a long time. It can take 3 to 4 weeks for an oil based varnish to fully cure to ultimate hardness and scratch resistance. While it takes some warmth for the oxidation to occur, overheating can cause some funny things to happen. I would check with the finish manufacturer to see what their position is on heat curing.