MG Chemicals - 832HT-375ML 832HT High Temperature Black Epoxy Encapsulating and Potting Compound, 11.5 fl. oz 2-Part kit

Very useful epoxy. Easily mixed by volume or weight and be cured at RT or 65C. Cures hard and has excellent chemical and heat resistance properties. This is my "go to" epoxy for most of my product development needs...

The mix ratio is 1.6:1Are you kidding me??? Wtf? And all they include in the “kit” is these tiny 30ml cups. What kind of nonsense is 1.6:1? How am i supposed to measure that accurately? Every other epoxy company has somehow managed either 1:1 or 2:1. I regret buying this.

I’ve ordered this epoxy twice (Dec 2018 and March 2020). I’m using it as a potting epoxy where the thickness is around 6 to 10mm (diameter ~8mm).Cure time: My application is thick. I need to extend cure times. I’ve noticed that it’s best if I let it sit for at least 72 hours followed by an oven cure at around 140 to 160F for 2 hours. I typically turn the oven off after 2hrs and let everything cool to room temp with the oven door closed. Lately I’ve even allowed it to sit for a week prior to the oven cure. If allowed to sit for an extended time, followed by oven cure, it seems to maintain a very shiny, perfect, black finish. Testing the surface by touch too early will dull the finish. The oven cure seems to ensure a hard smooth finish. Oven curing too early seems to result in a lesser surface which is difficult to explain.Leveling: It self-levels well and even after popping a bubble from air entrapment hours after mixing with the depth of pour I’m using. The assembly I am using it on has a tendency to trap and release air over an extended time but if you pop the bubble it will tend to self-heal. That extended cure time gives you a lot of working time.Adheres well to a prior pour: If you pot something and need to add additional epoxy later it seems to adhere to itself very well. I tried an experiment where I poured a level surface, about 3-4cm in diameter and 5mm thick. I allowed it to cure in ambient, 65-70F, for 2 weeks. I then mixed a fresh batch and placed a 1cm spot of new epoxy on the cured surface. I tried to remove the 1 cm spot 2 weeks later and it will not release. It acts as if it is a permanent part of the original pour.Electrical resistance: Someone mentioned the epoxy is electrically conductive. I just tried to measure resistance on a fully cured section with the meter set to mega Ohms and my meter measures infinite resistance (flashes out-of-scale). The sample I tested ambient-cured without oven cure for about 6 weeks. I’ve never tried it prior to cure. The comment by the other reviewer was alarming but I could not repeat what the other reviewer experienced.Bottle type: The hardener in my most recent purchase came in a bottle with a “child-safe” pill-bottle type top. The hardener was skinned over (evidence of air exchange). My prior order came in a nicely fitting normal screw top lid like the resin bottle had each time. The older screw top hardener never had a skinning issue even more than 1 year after the initial purchase with a partially filled bottle. Thankfully I saved the older bottle. I immediately I transferred the contents of the pill-bottle to the older bottle and I’ve had no issues since.Mix: I mix by weight so I make certain I have the proper ratio. I’ve had a couple of samples which seemed to essentially never fully cure. I assume that it was due to a small portion of resin which may have been in an area where it was difficult to mix with the hardener. I mix in a Dixie cup and normally 20 grams of resin plus 10 grams of hardener so it is certainly a manageable amount to thoroughly mix. The issue has not occurred again but I now discard the wooden stirring stick and apply with a new stick (I use wooden coffee stir sticks and pop bubbles with a round wooden toothpick).Temperature resistance: I’ve only exposed it to about 325F and never to the claimed upper limit.Extras in the kit/measuring: Most of the small plastic measuring cups came cracked. These were one-time use at best. They are garbage and I wish they would eliminate them from the kit. I use a Dixie cup, wooden coffee stir sticks, and a gram scale; of course using a separate stir stick for resin and hardener. The resin pour can be stopped by sliding the stir stick across the pouring surface and the hardener is lower viscosity and can be incremented easily by allowing it to drip from the stir stick into your cup.

Fairly viscous, about like cold honey - mix very well to avoid pockets of uncured resin. Very long working time. I used this for a high temp fiberglass application (heat shielding). It wets out the fiberglass better than I expected given the viscosity.This epoxy cured fairly soft/tacky until I baked it for an hour @150F per the directions, which hardened it and eliminated the tacky feel.Note to the manufacturer: 1.7:1 ratio by volume is a difficult ratio to mix in the cups provided for small amounts. Mixing ratio by weight in the instructions would be helpful so the user can measure small amounts with a scale.

I was hoping this would work as a short run epoxy mold for my injection molding machine. I'm injecting ABS at 430ºF which is under the rated temperature for this product. I tried both 100% epoxy and a mixture of this epoxy and aluminum powder and neither was able to withstand the short duration temperatures of the molten ABS. Small features became brittle after 2 castings the mold failed. Overall, this "high temperature" epoxy isn't worth the added cost over standard epoxy in my opinion.

Finding this product to be pretty versatile. one usage I can think of right off hand is the coating of windings and laminations on the blower of a refrigerator. Fantastic!!

I used this epoxy for a 3d printer build to ensure my hot end heated evenly and my thermistors reported temperature accurately, for that it was very effective.

This potting compound failed on a very important project I had. The issue is that it indeed is electrically conductive ... which is not what MG Chemicals claims. Worse ... when I contacted MG Chemicals ... they did not respond to emails or inquiry. I will never use MG Chemicals again ... and if you use this product having read this ... you deserve the problems you bring down on yourself. I documented and tested these observations thoroughly .... and had my associate review and confirm them.