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Speeding up cure time of Enduro-Var with heat lamps
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Author:  Bill Higgs [ Tue Aug 24, 2021 2:45 pm ]
Post subject:  Speeding up cure time of Enduro-Var with heat lamps
I am trying to duplicate John Greven's technique of using heat lamps to shorten the cure time of Enduro-Var.
The problem is I don't know any of the details.
From talking with the System 3 folks about their Silvertip, I know that every 18°F rise in temperature decreases the gel time in half. System 3 tests Silvertip at 77°F and 50% humidity.
Extrapolating from this, I am assuming (and I know this is a mistake) that the set time would be cut in half as well at 95°F and 50% humidity.
Now to extrapolate even further, I'm assuming that Enduro-Var might be pretty close to this. In other words, if I hung an instrument in a closet with heat lamps on both sides and maintained a temperature of 95°F the Enduro-Var curing time stated on the can would be cut in half.
What are your thoughts on this?
Have any of you tried using heat lamps to speed up curing times?
What is your setup?

Thanks
Author:  J De Rocher [ Tue Aug 24, 2021 4:47 pm ]
Post subject:  Re: Speeding up cure time of Enduro-Var with heat lamps
For clarification, are you wanting to reduce the cure time after all the Endurovar coats are on the instrument or reduce the time between coats?
Author:  J De Rocher [ Tue Aug 24, 2021 5:02 pm ]
Post subject:  Re: Speeding up cure time of Enduro-Var with heat lamps
John Greven described his method in American Lutherie issue #118. He puts the guitar under a heat lamp for 30 minutes between coats. Six coats per day. The article doesn't have details about his heat lamp setup, but it says "curing thirty minutes between coats under a heat lamp". He says "a heat lamp" twice in his description of his process so it doesn't sound like a complicated setup.
Author:  Bill Higgs [ Tue Aug 24, 2021 5:26 pm ]
Post subject:  Re: Speeding up cure time of Enduro-Var with heat lamps
Jay, I want to reduce the time between coats.
Author:  Stuart Gort [ Tue Aug 24, 2021 6:08 pm ]
Post subject:  Re: Speeding up cure time of Enduro-Var with heat lamps
Not just heat...but airflow. Not too much...but guarantee that the air is moving above the curing surface.

Also light....could be UV is all you need. The more intense whatever light band proves to be effective...the more you may be able to crank up the light intensity in certain bands without producing so much heat. It's probably not HEAT that cures the glue but rather a specific frequency of that heat lamp. Isolating that frequency and cranking it up probably results in even faster curing.

Simple test...three panels....regular heat lamp...UV light (try to match the wattages)...and your oven. Same wood and film thickness. Have a look every ten minutes to see how they cure. Use about 175F in the oven.
Author:  J De Rocher [ Tue Aug 24, 2021 8:01 pm ]
Post subject:  Re: Speeding up cure time of Enduro-Var with heat lamps
Stuart Gort wrote:
It's probably not HEAT that cures the glue


Is "glue" a typo?

Since Endurovar is a water-based urethane finish, I'm thinking that the heat lamp speeds up the curing by evaporating the water faster.
Author:  Colin North [ Wed Aug 25, 2021 3:06 am ]
Post subject:  Re: Speeding up cure time of Enduro-Var with heat lamps
Curing is technically a misnomer then, GF quotes 1 week to dry EV, plus another 2 weeks to cure, which is by crosslinking.
And 1 coat can be sanded after a hour or less.
Author:  Jeff Rey [ Wed Sep 01, 2021 12:43 am ]
Post subject:  Re: Speeding up cure time of Enduro-Var with heat lamps
John uses a 250 watt white bulb to speed drying between coats.
Author:  Alan Carruth [ Wed Sep 01, 2021 11:53 am ]
Post subject:  Re: Speeding up cure time of Enduro-Var with heat lamps
I don't know the chemistry of Enduro-Var, but the oil-resin varnishes I use cure faster under UV. These cure by an oxidation reaction after the 'vehicle' (thinner or turps) evaporates. UV reacts with VOCs to produce ozone and smog, and ozone is much more reactive than regular oxygen. This does reduce the time between coats, and can also help when non-drying oils in the wood inhibit the cure. Again, this is the stuff I've worked with (Behlen's old 'Rockhard' varnish, and now Murdoch's Ure-alkyd 500); I can't say whether it will work with Enduro-var.
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