SW Enamel Won't Harden

So I painted the J Head of my bridgeport with SW Kem Bond Primer. And top coated with SW Urethane Alkyd Enamel. After 7 days I can still wrinkle the paint with my thumb in a couple areas. I will admit I may have sprayed one of the coats a little too heavy. The cure time of this paint should be 7 days. It has been 7 days. At least 2 of those I have had it sitting out in he direct sun. Am I SOL and need to start over? I had some orange peel show through so I need to sand and add another coat. Is there anyway to salvage this?

I have painted several other item, and the paint has hardened ok. Will still take a fingernail print after 7 days though.

Unless you are in a hurry just let it sit for another week and see what happens. It was many years ago but I seem to remember using the same product on some lathe accessories and it took a couple of weeks to fully harden. IIRC, which as I get older gets somewhat questionable.

Steve

What did you use for reducer..that makes a big difference in dry time. I have painted many things with all sorts of enamel, Sherwin-Williams included, and I always use a synthetic reducer, a off the shelf hardener and a dropper full of Marson fish eye remover. Dry time is hours, flow out and gloss are perfect.

I know this 'boast' doesn't help your present situation, but it may change your procedure for the next paint job. Your current paint will eventually harden, but it will probably take a lot more than 7 days..for sure.

Stuart

Hey Stuart thanks for the info. I used Xylene for my reducer as it was recommended in the data sheet for enamels. Can you recommend a specific hardener? I am quite new to painted metal with something other than a spray bomb. I did recently paint my arbor press with rustoleum and Majic Catalyst Hardener that seemed to work pretty well. Would that work with a Urethane Enamel?

mvernon said:

Am I SOL and need to start over? I had some orange peel show through so I need to sand and add another coat. Is there anyway to salvage this?

I have painted several other item, and the paint has hardened ok. Will still take a fingernail print after 7 days though.

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Heat. Maybe. Since UV can no longer penetrate very far.

Artists "watercolors" aside, most paint vehicles don't "dry" - as-in shed solvents by evaporation - so much as polymerize or "cross-link". "Become" a different chemical - a stiff solid rather than a liquid, IOW.

It may become more leathery-flexible than gummy, given time. Months and years, not days or weeks before you can sand it, if-even-ever.

That is not always a "bad thing", as it should be chip-resistant.

thermite said:

...Artists "watercolors" aside, most paint vehicles don't "dry" - as-in shed solvents by evaporation - so much as polymerize or "cross-link". "Become" a different chemical - a stiff solid rather than a liquid, IOW.

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To add a bit- this is how urethanes cure, and it's the exposure to air that makes it happen. The OP laid a thick coat on, and it skinned over. This inhibits the polymerization process.

It will cure but it will just take more time. High humidity will also increase the curing time.

mvernon said:

Hey Stuart thanks for the info. I used Xylene for my reducer as it was recommended in the data sheet for enamels. Can you recommend a specific hardener? I am quite new to painted metal with something other than a spray bomb. I did recently paint my arbor press with rustoleum and Majic Catalyst Hardener that seemed to work pretty well. Would that work with a Urethane Enamel?

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I haven't used the SW urethane's so I'm hesitant to recommend a hardener that is compatible. The Xylene is plenty hot enough in my opinion to give you a short dry time. As you mention, maybe you piled the paint on too thick in several places.

Stuart