Softening epoxy

[old martParticipant @oldmart]

Acetone does attack epoxy to some extent, we had tanks of acetone to rinse off Skydrol hydraulic fluid used in civil airliners because it is non flammable. The rinsing had to be fast as the eoxy paint finishes would suffer if exposed to the acetone for more than a few seconds. We had to test various hydraulic sub assemblies including shimmy dampers and they were always contaminated externally with the Skydrol (phosphate ester) which would not be safe to handle without being rinsed off before final inspection and packaging. You wouldn’t want to get any in your eyes, it hurts.

[michael howarth 1Participant @michaelhowarth1]

I had a tube of epoxy that went hard, took it back to the shop, he exchanged it quite happily but told me to microwave the dodgy tube – it worked a treat.

Mick

[John HaineParticipant @johnhaine32865]

Hmm – in my case the tubes are metal so microwave wouldn’t work!  Anyway this is a brass block with epoxy (Araldite?) that has cured over 30+ years.

It has sat in a jam-jar of acetone since last Wednesday with no sign of softening, so I think I will be making a new block.  I have a brass bar end which has one hiding inside…

[old martParticipant @oldmart]

Bad luck with the acetone, MEK is hard to get now as it is harmful to the ozone layer. It’s amazing what lurks inside a block of metal when you have the machinery dig it out. What about simply running a milling cutter straight through the leds and glue to remove them?

[KEITH BEAUMONTParticipant @keithbeaumont45476]

O;d Mart,

Your saying you had tanks of acetone,as a rinse,”because it is non flammable” does not sound right to me,  Acetone is very flammable.

Keith.

[John HaineParticipant @johnhaine32865]

<p style=”text-align: left;”>OM, as this is a sort of conservation job I want to preserve the original block, given it’s shape I wouldn’t want to risk drilling or milling out the components.</p>

[Michael GilliganParticipant @michaelgilligan61133]

This one-pager comes from a respected source, John … but it doesn’t get you much further:

https://www.tedpella.com/technote_html/Reworking_Cured_Epoxy.pdf

MichaelG.

[Dave HalfordParticipant @davehalford22513]

Epoxy gives up when exposed to soldering iron temperatures.

[John HaineParticipant @johnhaine32865]

Not this stuff!

[KEITH BEAUMONT]

On KEITH BEAUMONT Said:

O;d Mart,

Your saying you had tanks of acetone,as a rinse,”because it is non flammable” does not sound right to me,  Acetone is very flammable.

Keith.

Read my post again, Keith.

[KEITH BEAUMONTParticipant @keithbeaumont45476]

Read again and again and it still sounds as though you are saying Acetone is non flammable. Where am I going wrong?

Keith.

[duncan webster 1Participant @duncanwebster1]

He’s saying the hydraulic oil is non inflammable, but it’s ambiguous. The oil is based on poly phosphate ester, which is quite good at removing skin. We wouldn’t have anything to with it. Another non flammable oil is water glycol mix, but you have  to work at lower pressure, heavier cylinders and pumps. If yoh want thd best of both worlds then use Fomblin, but it’s expensive. Per fluoro poly ether if I remember correctly

[Robert Atkinson 2Participant @robertatkinson2]

If you think Skydrol doesn’t burn read this (or look at the pictures)
https://asn.flightsafety.org/reports/2012/20120221_C130_130342.pdf

If it hadn’t been on take off with a prompt decision to abort they would have crashed. I’ve seen the aircraft in person and the images don’t do justice to the level of damage.

Robert.

[Cyril BonnettParticipant @cyrilbonnett24790]

This might give you some ideas

https://shop.machinemfg.com/comprehensive-guide-to-removing-araldite-from-stainless-steel/

As for MEK, Methyl Ethyl Ketone is available on ebay, it’s not for use in small places, we used it to repair fairings, it does soften Araldite.

[Dick HParticipant @dickh]

At risk of pointing out the blindingly obvious. An epoxy is a  3D cross-linked polymer. Solvents will swell  the matrix but not break the bonds cross-linking the matrix.

Indeed you can estimate the degree of cross-linking from how much a sample swells when exposed to a particular solvent.

Heating an epoxy will under certain circumstances increase the degree of cross-linking before the heating degrades the matrix (chasing the Tg).

The pineapple juice reference was not a joke but aimed at the enzymatic degradation of the cross-linking in the polymer.

Sorry , ex polymer chemist.

Else you could try conc. Sulphuric

[Wade BeattyParticipant @wadebeatty78296]

Have you tried nitro thinner from an auto paint shop? Often used to clean spray guns used with 2 part paints. Most materials it affects, some not at all.

I’d give the pineapple juice a go, if it does not work you can use the left over and mix up a Mai Tai or rum punch!

Wade

[John HaineParticipant @johnhaine32865]

Thanks again for all the suggestions. As I noted above I am going to make a new component so I no longer have the requirement.  If a mod would kindly lock this topic now it would save you kind people’s time.

[Author]

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