Steam press repair

[GoSeigen]

We have an old steam press which I am hoping to repair. The problem is the element is shorting to the case. The element is sandwiched between two layers of a kind of thermal interface sheeting but at one particular point the metal conductor has worn through the sheeting to make contact with the metal body. The hole in the sheeting is very small and I'm casting around for a good way to repair it durably. Obviously a similar material would be best -- it needs to be mechanically tough (to prevent getting worn out again), withstand the high temperatures of the element and be electrically insulating without being excessively thick (the current sheeting seems to be less than 1mm thick).

I've considered insulating tape but I think the heat would get it in no time and it would wear through quickly. I suspect a superglue repair would also not withstand the heat. I could try to buy a similar material but am far from suitable shops, so was casting about for something I could cannibalise from somewhere else. e.g. would I find suitable material in an old laptop power adaptor or similar?

Any clever ideas gratefully accepted.

GS

EDIT: how about a piece of old sanding disc? That should be tough and withstand plenty heat...

[NearlyThere]

Mica sheet?

Something like this : https://www.amazon.co.uk/Microwave-Resi ... 0C623PRW9/

[Itsallaguess]

I've considered insulating tape but I think the heat would get it in no time and it would wear through quickly. I suspect a superglue repair would also not withstand the heat.

A flexible soldering mat might offer a good solution in terms of thickness and pliability, with Amazon offering the fairly cheap one below if postal delivery might suit you -

Rothenberger 67022 Plumbers Soldering Mat up to 1000 Degrees C -

https://www.amazon.co.uk/Rothenberger-67022-Plumbers-Soldering-Degrees/dp/B005GOP22Q

Cheers,

Itsallaguess

[Itsallaguess]

The hole in the sheeting is very small and I'm casting around for a good way to repair it durably.

Another option with a very small hole might be to butcher some high-temperature cable-sleeving, if it can be placed securely over the hole.

Some of the Ebay options below are really thin and cheap, and offer protection up to 600 degrees centigrade -

https://www.ebay.co.uk/sch/i.html?&_nkw=high+temperature+cable+sleeve

Cheers,

Itsallaguess

[BullDog]

Trim a fire blanket and use it as the insulation layer?

Mica sounds a great idea but is very brittle and I think it would deteriorate rather quickly.

[bungeejumper]

Predictable boring comment. There's always an Eeyore somewhere. Are you sure this repair is a good idea? Does your insurance company have views on DIY-mended stuff that involves mains heating elements?

Okay, okay, I'll shut up now. Good luck, whatever you decide.

BJ

[BullDog]

Predictable boring comment. There's always an Eeyore somewhere. Are you sure this repair is a good idea? Does your insurance company have views on DIY-mended stuff that involves mains heating elements?

Okay, okay, I'll shut up now. Good luck, whatever you decide.

BJ

Certainly something to consider for sure, I'd say.

[pompeygazza]

what about heavy duty kapton tape.

[servodude]

Apparently sugru (being in a big part silicone) is good at high temp.
Or can you pinch a bit of ceramic blanket from a boiler?

[88V8]

Obviously a similar material would be best -- it needs to be mechanically tough (to prevent getting worn out again), withstand the high temperatures of the element and be electrically insulating without being excessively thick (the current sheeting seems to be less than 1mm thick).

EDIT: how about a piece of old sanding disc? That should be tough and withstand plenty heat...

Sanding disc or belt sounds like a good idea.

I was thinking of thin silicone sheet, but it seems to top out at 230C or so, and dunno how one would glue it.

V8

[GoSeigen]

Wow, plenty of great ideas there.

Predictable boring comment. There's always an Eeyore somewhere. Are you sure this repair is a good idea? Does your insurance company have views on DIY-mended stuff that involves mains heating elements?

I think the original design is slightly flawed with the current problem almost inevitable. Of course I'll try to find a replacement part but need a decent repair for the time being. I'm a qualified electrical engineer so will try to use my expertise appropriately. That's why I came here in the first place and didn't just put duck tape over it! Definitely will not be introducing any novel flammable material so if the repair fails we're back to where we are now (a tripping RCD). It's not uncommon for various heating devices to fail with a short to ground so absolutely vital that earth wires are properly connected appropriate safety devices in place.

what about heavy duty kapton tape.

I wondered about that. Have never used it myself so will have to look up its properties.

Apparently sugru (being in a big part silicone) is good at high temp.
Or can you pinch a bit of ceramic blanket from a boiler?

Another product I've never used. I wonder if it would get too brittle at the interface with the present material?

No boiler around here unfortunately. But now you mention it I remember something similar I once used to line the door of a wood burner...

Trim a fire blanket and use it as the insulation layer?

I'll have a look at ours, see if it's suitable. How do they stay non-flammable though? Don't know anything about these things. One problem with patching with this sort of material is securing it in place as I'm not sure an ordinary glue would last.

Another option with a very small hole might be to butcher some high-temperature cable-sleeving, if it can be placed securely over the hole.

Again, securing it in place is the problem. I thought heat shrink might also work, but with the same challenge.

Mica sheet?

Hmm, I wondered if the current material is a kind of mica. Though it seems to be a laminate of some sort, is flexible enough to form creases if bent.


Thanks again for the ideas, for now I actually decided not to introduce any new material. I cut off a corner of the upper layer (less important) of the sheeting, and inserted that in between the top and bottom layers where the damage is, securing it with super glue for the time being. It's also held in place to an extent by a metal plate bolted over the sandwiched element. The repair will probably fail in the same way as the original, but hopefully not anytime soon, and hopefully I can find a new replacement part or replace the steam press in the meantime.

Now off to google, see if any of the above will do a better job...

GS

[BullDog]

Trim a fire blanket and use it as the insulation layer?

I'll have a look at ours, see if it's suitable. How do they stay non-flammable though?

AFAIK, fire blankets are woven glass fibre. So inherently non flammable. But I'm sure you'll DYOR and not just take my word for it.

[jfgw]

My immediate thought too was mica. Two other uses for it are for the waveguide cover in a microwave oven (open the door and look right) and to support the elements in a toaster. This is usually quite brittle and will snap if bent, and is not hard-wearing.

Nomex is used for slot papers in electric motors and can be had in small quantities from Brocott: https://brocott.co.uk/nomex-motor-transformer-insulation-0-36x900x200mm/. It is available in different thicknesses and is like a thin card and can be creased without damage. It is quite tough and hard-wearing but is rated for only 155°C which may not be sufficient for your needs, however.

I would avoid silicone near electrical switches or commutators.


Julian F. G. W.

[jfgw]

How hot does the element get?
What does the insulation material look like?

Another thought is fish paper but this is lower temperature than Nomex. You can get it off eBay, and self-adhesive versions are available. https://www.lemonfool.co.uk/viewtopic.php?f=73&t=34020


Julian F. G. W.

[GoSeigen]

My immediate thought too was mica. Two other uses for it are for the waveguide cover in a microwave oven (open the door and look right) and to support the elements in a toaster. This is usually quite brittle and will snap if bent, and is not hard-wearing.

Yes, that is very much what the steam press element looks like, with the addition of the two extra layers of the same material (I think) sandwiching the element layer. There seemed to be some thermal paste applied too, which I renewed.

If I can find an old broken toaster I'll see if the material is very similar.


GS

[csearle]

I applaud all this DIY stuff. We live in a throw-away society. If someone is aware of the safety issues and takes appropriate care then it is a good and satisfying thing to effect one's own repair. C.