Patching plastic so it is watertight

[bullethead123]

Hi all,
I have had to drill some holes in the heat exchanger of my dishwasher in order to clean out some accumulated grease. See link:


https://www.diynot.com/diy/threads/siemens-dishwasher-e23-error.597315/post-5310232


My problem is now to seal the holes. I'm thinking to cut some squares of plastic and affix them with Araldite or some other epoxy adhesive. Can anyone advise me on the best way to go about this or suggest a better solution?

All solutions considered.
Thanks, Chris.

 

[freddiemercurystwin]

Fibreglass rather than Araldite?

 

[Alec_t]

What is the maximum temperature the heat exchanger has to tolerate?

 

[bullethead123]

Thanks FM's twin. I was thinking to use a square flat bit of plastic cut from the lid of a washing tabs box fixing it to the HE with araldite. Do you think I should source a sheet of fibreglass instead? What should I use to fix it then if not araldite?

Thanks Alec. Not sure what max temp would be. Is there some high temp stuff I could use?

How about JB weld?

 

[bullethead123]

J-B Weld 8297 HighHeat Temperature Resistant Epoxy Putty Stick, Machine Gray, 2oz https://amzn.eu/d/967OVE8

This stuff maybe?

 

[bullethead123]

JB Weld Original Cold Weld Formula https://amzn.eu/d/dKkdtFH


Or maybe this stuff?

 

[bullethead123]

Ive got this stuff in the shed. Says OK up to 180 degrees, warerproof and good for plastics.

 

[Nozzle]

Drill and tap then screw in a nylon/ABS fitting?

Nozzle

 

[bullethead123]

Mmm, l like your lateral thinking Nozzle.

Trouble is I don't want to obscure the water/air/fat pathway. If I could get some threaded plugs with a thread 5mm wide and no more than 2 or 3 mm deep that may work

 

[bullethead123]

Any suggestions?

 

[Harry Bloomfield]

Any suggestions?

You need an adhesive, which will partially dissolve the plastic, plus an extra piece of the same plastic to use as the patch. There a couple of types of such adhesives, used for plumbing and electrical conduits.

 

[Nozzle]

Mmm, l like your lateral thinking Nozzle.

Trouble is I don't want to obscure the water/air/fat pathway. If I could get some threaded plugs with a thread 5mm wide and no more than 2 or 3 mm deep that may work

You just cut down the fitting so it's the correct length (depth)

Nozzle

 

[bullethead123]

Mmm. My feeling is, that with only a couple mill to play with, I won't get a very effective seal.

FreddieMercury'stwin, is this the stuff you are suggesting?

Is it waterproof?

https://www.toolstation.com/big-boy...ja8jy_tU8aAkBOEALw_wcB&gclsrc=aw.ds#full-desc


HB, can you suggest a suitable adhesive?
I'm not sure what the original plastic is. How would I find out?

 

[freddiemercurystwin]

Yes that's the fella, pretty easy to use. It's 100% waterproof and should bond well with plastic. Just cut out a bit of the sheet just bigger than the holes and paint over it with the resin, repeat until there's a few layers.

 

[Harry Bloomfield]

HB, can you suggest a suitable adhesive?
I'm not sure what the original plastic is. How would I find out?

Any plastic welding adhesive, which is designed for the particular type of plastic, will at first dissolve the surface of the plastic, until it has evaporated. Best way to test it, is on a corner of the plastic where it will do no harm.