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I bought a 6 year old house, and the Previous Owners did basically zero maintenance.

The oven is a Bosch underbench electric unit, and it looks like the glass cap/protector for the interior light has broken off at some point, so they kept using the oven with the lamp exposed. The lamp does turn on when in use. I expect this has been left like this for at least 2 years, maybe up to 6 based on the condition of the rest of the oven.

This leads to a threadded glass ring welded into the fitting by dried/hardened food/oils, and looks like this:

enter image description here enter image description here

I've got the replacement cover already, and its essentially a very short glass jar with one thread around the top so I know this ring should unscrew conventionally.

I've tried blasting it with conventional oven cleaner to dissolve the shite, but its not getting into the threads.

I've tried some other solvents like "Contact 60" an electrical contact cleaner, and some other household liquid cleaners hoping they'd wick up the threads, but that's made no difference.

There's around 4mm of "neck" exposed so I can grip it with one hand and rotate, but the whole light fitting is loose, and I don't want to overstress whatever mountpoints are there. The glass is sharp too, so can't put too much pressure on it, even with a teatowel to hold it.

  • Do I have to open the oven and remove the whole light assembly, then work it on the bench?
  • Should I try to break the remaining glass with a hammer, or alternating heat and cold like cutting the neck off a beer bottle? Feels risky.
  • Or do I give up and get a service wallah out to do it?

Edit : Here's the new fitting, to show what the old one will be like:

New fitting

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    An old trick to remove a broken light bulb was to wedge a raw potato into the base of the bulb and rotate. But that doesn't solve your loose fitting issue.
    – bib
    Nov 27, 2018 at 12:30
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    Be sure the light is off before sticking the potato in. :) If you go the route of breaking the glass, a hammer and a nail punch would work. Glasses and gloves first though. Nov 27, 2018 at 13:09
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    There could be a silicone ring intended to keep cooking vapours away from the lamp. It will now be serving to make it difficult to turn the remaining glass. I think (and it's only my opinion) that it would be best to try gaining access to the back of the light fitting by disassembling the oven. Can you find any sort of service manual for it? Nov 27, 2018 at 19:47
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    @AndrewMorton yes the manual is a user manual and simply says "unscrew and replace lamp" The brand new cover has no silicon gasket, so its unlikely to have one in there now (but not impossible) I think its just food grime baked in there.
    – Criggie
    Nov 27, 2018 at 19:56
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    @Criggie Have you tried undoing it while the oven interior is still hot, so that the congealed grease is a little less viscous? Expect to accidentally burn yourself. If the lamp fitting is on the rear face of the oven, it might only need the removal of four or five screws to gain access (once you have got the oven out). Nov 27, 2018 at 20:03

12 Answers 12

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I have had some luck with a hot oven and needle nose pliers getting stuck fixtures apart, make sure to unplug prior to doing this, also I have found that sometimes turning clockwise (tighting) then back counter clockwise can help break loose whatever is causing the glass to stick. After tightening if it backs out a little then start going back and forth and usually they will come out. Worst case is a small punch to fracture the glass but this is my last resort.

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  • I might try a cold oven (easier to work in) and heating with propane torch on the glass ring with needle nose as suggested. Keep in mind tho that heat expands, so this method could make it tighter, but you might be able to burn up some of the greasy gunk too.
    – Tyson
    Nov 27, 2018 at 21:46
  • Good thinking - I'll start with a hot air gun. The oven should be rated for temperatures even when its coming from something else.
    – Criggie
    Nov 28, 2018 at 0:52
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Good news - it came off!

A Hot air gun was useless as was a butane torch - I suspect the heat was not softening anything and the adhesives were well and truely burned on. Perhaps spraying cold water on the hot glass might have helped crack it, but read on.

In the end I used a teatowel in one hand to cup the entire fitting and then pushed an "automatic punch" against the lip, and one piece cracked out on the first try. Against the other side, it took a dozen hits before breaking the same way, with a vertical crack and a chunk out.

enter image description here

I left the lamp in place to protect the socket from any damage. Its already got oil burned on the glass.

So then I could simply unscrew the remainder and it fell out in two pieces after one rotation, which I caught in the teatowel.

Not sure if it was the increased grip, or if it was the shock which broke the hold but it turned freely after that.

enter image description here

Despite using a damp catching cloth, there were heaps of tiny glass shards in the bottom of the oven. Had I attempted to use heat and cold to crack the glass, it could have made a bigger mess.

enter image description here

Careful cleanup is required here - glass fragments are no fun near food.

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  • It would be nice to give credit to the answers and comments that suggested punches and heat by up voting those.
    – Ed Beal
    Nov 28, 2018 at 3:53
  • @EdBeal fair point - done.
    – Criggie
    Nov 28, 2018 at 5:56
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First of all, i apologize for my english. I am fromm Greece. The solution in this problem found with an unexpected way as i was searching for something usefull to unscrew the broken glass cover. I read all your solutions and i was ready to use the hammer, until i saw inside a cabinet the tool which i use to pick up the hairs of my dog from the sofa. I put some more packing tape around it, but from the opposite side so the glue side is from the outside. Then i stuck it in the cover hole and i begun to turn it. I had to hit it a little with the hammer and as i was disapointed that i will break it anyway, i tried one more and the cover turned around. I send you the photos . Thank you!

enter image description here enter image description here

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  • In America we call that a "lint roller", and that's a great, creative use for it! Don't worry about your English - that was perfectly readable.
    – FreeMan
    Dec 19, 2020 at 13:55
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enter image description here

I used a pair of 10" pipe grips used in reverse i.e opened outwards into the broken glass ring, I managed to turn the glass a little before it broke into 2 pieces. this took about 10 seconds to do. Power was turned off and goggles worn.

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I just had the same problem. My successful method was to warm the remaining glass and metal housing with a hairdryer, it took several goes to soften the grease etc. Then I had a small plastic tub of my granddaughters play-doh in a drawer which is around 2” diameter at the base and tapers towards the lid.

By inserting that inside the broken cover, pushing up and unscrewing it I was able to unscrew the threaded glass portion of the cover, hooray! Engineer call out had been quoted as £99 inc. vat plus any parts!

Hope this helps others.

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  • Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably take our tour so you'll know how best to contribute here. Jan 24, 2020 at 11:50
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I had the same problem, with the light protector broken a few millimetres from the thread so there wasn't much to grip to remove it. After trying a number of the suggestions here and elsewhere I ended up doing what I was hoping to avoid. I attacked it directly with a hammer. (Initially, I tried using a screwdriver between the hammer and glass but the glass was too smooth so the screwdriver kept skidding.)

The hammer method worked easily and with much more control than I expected. At no point did I feel in danger of damaging the oven. This is the method I would recommend/use again.

As others have said, there were a lot of glass shards. The oven liner caught most of them but then I vacuumed inside the oven and light housing; I didn't want to damage the inside surface of the oven by wiping glass across it. I wiped it gently with a damp cloth afterwards and am confident there is no more shards in the oven.

I hope this helps someone.

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    Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, props for taking our tour before posting; few newbies do. Jan 26, 2020 at 13:10
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Looked at some of the suggestions regarding this. Looks like the heavy handed ‘bash it with a hammer’ approach is easiest. I’m going to cover the glass threaded part that is still in place with clear sellotape to try and cut down on the shards flying off. Let you know how it goes.

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  • Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably take our tour so you'll know the details of contributing here. Apr 4, 2020 at 13:37
  • IME cleanup is most important. I was lucky in that the oven had been cleaned, so every surface was hard and smooth. If the oven was even slightly dirty, there is the potential for glass fragments to stick, and be hard to sweep out. Upshot - clean the oven first.
    – Criggie
    Apr 4, 2020 at 21:36
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I tried hammering but the broken glass ring would not break!

But I got it out by jamming the top of this plastic tub of salt, covered in 2-3 layers of newspaper, into the ring. The rough glass gripped the newspaper/tub nicely as I twisted. I did preheat to 200c then cool to hand-warm, then turned power off.

Good luck! Wear gloves/goggles for the tiny glass shards!

Photo of my salt container

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  • Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably take our tour so you'll know the details of contributing here. Jun 27, 2020 at 22:54
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I had exactly the same problem due to A long term tenant in our flat not telling us they'd broken the lamp cover. I took the hammer and nail punch approach., but with the punch angled so the glass would be pushed anti clockwise. This started it to turn, then I finished the unscrewing with pliars. NOTE : YOU MUST EEAR SAFETY GOGGLES BECAUSE TINY GLASS SHARDS WENT EVERYWHERE

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Tried a few of the ingenious suggestions here but in the end I had success using two inch piece of kindling and a hammer. There was enough of a jagged edge on what was left of the glass for me to put one end of the wood against it and tap the other end in an anti clockwise direction. It’s nice when it starts to turn! The wood is soft enough not to cause glass shards but hard enough to move the glass. The bulb was similarly broken with no glass left, just the metal screw part. That came out with some thin nosed pliers and a bit of twisting. Sorted!

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A 2" / 5cm spray can with duct tape wrapped around the bottom end - sticky side out - until it almost fits inside the glass cover, and then press into the glass cover and turn while keeping upward pressure into the glass cover. Worked well, but glass cover wasn't 'welded in' with old fat/oil etc.

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My glass was broken but would not run past a certain point. It may have been threaded. Anyway, I noticed there was a gap above the glass ring where I could get one side of some mole grips on and get some purchase on the broken, sharp side with the other. This caused a chunk of glass to break off. I repeated this until I had broken right through the glass ring and then it was simple to repeat this ok the other side and it came out in 3 chunks. Wear goggles, and clean the oven thoroughly.

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  • Welcome to the site - congratulations on your success!
    – Criggie
    Aug 7 at 21:58

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