Storing guitar in a hot car when unavoidable.

The trunk will be a lot cooler than the passenger cabin on a sunny day ... no greenhouse effect.

The trunk will be a lot cooler than the passenger cabin on a sunny day ... no greenhouse effect.

Good point that needs clarification.
I drive a Jeep Cherokee. No trunk. (But it has dark tinted windows except front doors and windshield)

I think I found some reassurance to my situation. I'm talking about an Epiphone PR-150 guitar. Found two reviews on Musician's Friend by people who keep theirs in their cars and haven't had problems. That's about all a guy could hope to learn.

But I'd still like additional tips if anyone has any more ideas.

after removing the guitar from the vehicle, leave the gig bag or case closed till the outside of the bag/case temp stabilizes to the outside air before opening.
i even crack open the case/unzip the bag and let it set for a few more minutes befor taking out the guitar
this assures that there will be no quick change in temp that usually causes the problems you want to avoid

hmm maybe a humidifor in the case? i wouldent use a gig bag id get a hardshell case and maybe bring some light setup tools incase it gets that bad where it needs a minor setup. iv left my guitars in cars for the same reason (hiking) and didnt have a problem. but my friend brought this guitar along with us last time and his warped horribly. he had it in a gig bag. just trying to help :D

The principal concern is not about moisture changes in the wood. It's about the glue softening when it gets hot. My guitar teacher had a previous student who had an expensive Martin dreadnought completely come apart on being left in a hot car.

The principal concern is not about moisture changes in the wood. It's about the glue softening when it gets hot. My guitar teacher had a previous student who had an expensive Martin dreadnought completely come apart on being left in a hot car.
Bummer!

That's what I've picked up from the various luthiery websites. They use heat to soften the glue (for example - using a soldering iron on frets before removing them). Hide glue relaxes at about 140F. What I don't know is whether the elcheapo guitars use hide glue, Krazy Glue, epoxy, wallpaper paste, or swamp mud for adhesive. And then the question is what temperature their glue softens at.

I suppose I could drop an email to Epiphone and see if I get a useful answer before summer?

I was going to be snarky and say "maybe you can get a cooler big enough to fit the guitar into with some ice," but maybe there's some hope in the idea after all.

Keep it in a hardshell case and stick a couple of frozen "blue ice" packs in there - I would imagine it could stay cold for at least a few hours. They're sealed, so the worst they'd do to the guitar would be a paint crack from the cold if it was touching.

The only problem then is keeping ice packs handy... When we camp we can usually keep ice frozen in a good cooler for 2-3 days. On a weeklong trip without access to additional supplies, you'd run out of ice halfway through.

If you try that, definitely crack the case and let it acclimate before you open it...

Keep it in a hardshell case and stick a couple of frozen "blue ice" packs in there - I would imagine it could stay cold for at least a few hours. They're sealed, so the worst they'd do to the guitar would be a paint crack from the cold if it was touching.

It's a thought though I'd be concerned about such temp extremes from where the pack is to where the pack isn't. And don't those things sweat? Hmmm.

I dropped a note to Epiphone last night. Maybe someone will respond.

Car temps can get amazingly hot. I measured 175F on the outside paint of a black car mid-summer.

Put the guitar (+ case if it will fit) into a sleeping bag. If not cover the case with the sleeping bag.

I received a reply from Epiphone/Gibson along the lines of the glue not being hide glue but being more like "Titebond." While there were no numbers given in the email I checked to see what Titebond's website might say and found that the adhesion strength was rated at room temperature and after "overnight at 150F" The high temperature strength was half of that at room temp but still appears to my uncalibrated eyes to be fairly strong. (1500 psi)

Just working thru the logic of the situation it seems to me that slacking the strings somewhat and trying to avoid heating as much as possible is about the best I can do. An unstressed guitar wouldn't come apart even if the glue retained nearly no strength. (plus or minus built-in stresses)

One question that goes unanswered is whether the glue regains strength upon cooling.....I sure hope so!

I expect it does, but have no definite info. Hide glue certainly does.