Why Tubes Break: Debunking The Myths

After years of working with vacuum tube solar cookers and thousands of happy customers, we’ve become experts on the matter.

December 17, 2015 3 min read 7 Comments

GoSun Solar Vacuum Tube

After years of working with vacuum tube solar cookers and thousands of happy customers, we’ve become experts on the matter. In wake of our recent appearance on Top Chef, in which one of the cheftestants thermally shocked and broke their cooking tube, we’ve decided to address this matter head on.  

Properly made vacuum tubes typically break from only one of two causes: a substantial impact or thermal shock. To put it simply, These tubes only break with user error.  Furthermore, GoSun would not be in business if our evacuated tubes exploded.  Due to the vacuum's reverse pressure, GoSun's cooking chambers actually implode if they break, they do not send projectiles of broken glass.

The Top Chef contestants had absolutely no time to familiarize themselves with the product. Due to this oversight, and the fact that the production assistants opened the GoSun to the sun, one of the chefs arrived to the GoSun Sport pre-heated at about 600°F.  She then poured cool water inside creating Thermal Shock.

Solar vacuum tubes are nothing new and are trusted by millions daily for solar hot water heating. As an established industry, these tubes have been installed on rooftops across the world and are built to last the elements for decades. Cooking in the tube however, brings an additional factor into the mix: the human factor.

The following myths should help de-bunk the fear and misinformation about these magical vacuum tubes:


Myth 1: Vacuum tubes are fragile.

Solar vacuum tubes are almost exclusively made of borosilicate glass, originally made famous for its use by Pyrex brand bake ware. Borosilicate is unique in that it is extremely resistant to thermal stress and physical impact. Its superior durability, chemical and heat resistance finds excellent use in chemical laboratory equipment, cookware and lighting. You likely have a piece of Borosilicate bake ware in your kitchen right now, as all Pyrex cookware before 1998 was made with a nearly identical chemical composition to our vacuum tube.

These tubes are surprisingly resilient. If impact and thermal shock are avoided, you’ll be cooking with the same tube for years to come. 


Myth 2: Vacuum tubes can be easily thermally shocked.

Due to legal restraints, GoSun can not recommend pre-heating the stove before inserting cold food or water. However, the temperature differential needed to create catastrophic thermal shock is generally 200°C (392°F), which equates to inserting cold food into a 450°F tube.  Furthermore, thermal stress tends to accumulate in abused glass over time so it is generally forgiving the first few mistakes this size.   

Of the thousands of stoves in circulation, we know of only a handful of such cases in which a tube was broken by thermal shock. 

Think of the tube as a glass pot. No one would leave an empty pot on a lit burner for an extended amount of time. Likewise, one should not do this to their solar stove left in the sun pre-heating without food inside. 


Myth 3: Vacuum tubes explode when broken.

We would not be in this business if our products exploded. If broken, a vacuum tube implodes,due to the negative pressure of the vacuum. This means the glass stays put, posing no projectile hazard. 


Myth 4: GoSun is worried about our vacuum tubes breaking.

With thousands of stoves in circulation and a large community of supportive and enthusiastic users behind us, we are confident in this technology and its ability to power people's lives around the world. 

The possibility of breaking a tube, however unlikely, is a small price to pay for reaping the benefits of the tube's heat capturing and retention properties. We understand that accidents happen and we stand by our Two-Year No-Questions-Asked-Warranty covering tube breakage on all GoSun Products.  

7 Responses

Giuliana Fornaciari
Giuliana Fornaciari

August 23, 2019

unfortunately I broke my gosun sport, during the too vigorous cleaning operation. the bottom of the inner tube has broken.
I extracted some pieces of glass. I lost the vacuum pack.
Is it dangerous to continue using the solar oven even if it is broken?

purtroppo ho rotto il mio gosun sport, durante l’operazione di pulizia troppo energica. si è rotto il fondo del tubo interno.
ho estratto alcuni pezzetti di vetro. ho perso il sottovuoto.
è pericoloso continuare ad usare il forno solare anche se è rotto?


February 22, 2018

@JAMES THOMPSON Don’t worry about cooling the tube down unless it’s particularly hot or you’re inserting cold or freezing food. If uncertain, just insert the tray slowly to make the temperature change more gradual. Hope that helps!

Matt Gillespie
Matt Gillespie

February 22, 2018

@UNKNOWN69 Tubes from the 60s, if used for solar hot water heating may still be usable, but given the reality of glass degrading over decades (it’s technically a liquid after all) we would not suggest it.


December 17, 2017

How about vintage tubes from 60s? are these fragile to drops? I don’t mean direct drops but if the device is dropped with tubes inside of it, will tubes break from stress even if they are secured properly?


August 27, 2017

I want to use this tube to cook sausages, ground meat and white potatoes. Do I have to cut everything up before I put it in the tube? Is the tube as big as a gallon of milk? And how easy is it to place and remove food from the tube?


October 12, 2016

Hi, if your food isn’t frozen or very cold then it should be OK. Remember that thermal shock needs over 180c difference. So a food tray at 4-5c out of the fridge into an empty, already vented tube shouldn’t easily meet glass at 190c. Gently and slowly insert the metal tube so any heat difference is spread over the glass base evenly.

James Thompson
James Thompson

June 28, 2016

if you cook a full tray, then have another tray to put in with cold food on it, how long do you have to wait before starting to cook again, ? does it have to be covered up any amount of time away from the sun to cool, before staring another tray?

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