Using cheap clear epoxy resin as a poor man's conformal coating? - Page 1
Forum section: electronics / general

author: Shay
author_rank: Regular Contributor
timestamp: February 26, 2025, 11:52:05 am
content: Conformal coatings can be quite expensive; the least costly quality option I found is Plastik 70, although its shipping costs are very high for me. Moreover, the common inexpensive spray coatings are inadequate for repairing boards in high-humidity, high-temperature environments. Therefore, I am considering using a low-cost epoxy resin from AliExpress, given epoxy’s reputed resistance to humidity and elevated temperatures. However, I am uncertain about the quality of these economical alternatives. Has anyone tested them, and does this seem like a viable option? I understand that this solution will not meet IPC standards or any standard at all, as it is intended primarily for repairs on general Class I consumer electronics. What are your thoughts?Example of clear epoxy resin for cheap:https://www.aliexpress.com/item/1005007273414752.html?spm=a2g0o.productlist.main.9.411a4bab1iatVt&algo_pvid=6496059f-1b01-48d7-bd48-92c05b9562e0&algo_exp_id=6496059f-1b01-48d7-bd48-92c05b9562e0-8&pdp_ext_f=%7B%22order%22%3A%22363%22%2C%22eval%22%3A%221%22%7D&pdp_npi=4%40dis%21ILS%2198.94%2134.63%21%21%21195.92%2168.58%21%40%2112000040027622974%21sea%21IL%21165171836%21X&curPageLogUid=HgXz4DdsDFSf&utparam-url=scene%3Asearch%7Cquery_from%3A#nav-reviewhttps://www.aliexpress.com/item/1005006546452596.html?spm=a2g0o.productlist.main.2.411a4bab1iatVt&algo_pvid=6496059f-1b01-48d7-bd48-92c05b9562e0&algo_exp_id=6496059f-1b01-48d7-bd48-92c05b9562e0-1&pdp_ext_f=%7B%22order%22%3A%223%22%2C%22eval%22%3A%221%22%7D&pdp_npi=4%40dis%21ILS%21134.15%21100.61%21%21%21265.64%21199.23%21%40%2112000037623740522%21sea%21IL%21165171836%21X&curPageLogUid=TcZBDmjye3a3&utparam-url=scene%3Asearch%7Cquery_from%3Ahttps://www.aliexpress.com/item/1005007846895831.html?spm=a2g0o.productlist.main.6.411a4bab1iatVt&algo_pvid=6496059f-1b01-48d7-bd48-92c05b9562e0&algo_exp_id=6496059f-1b01-48d7-bd48-92c05b9562e0-5&pdp_ext_f=%7B%22order%22%3A%22242%22%2C%22eval%22%3A%221%22%7D&pdp_npi=4%40dis%21ILS%21115.32%2142.67%21%21%21228.36%2184.49%21%40%2112000042512239027%21sea%21IL%21165171836%21X&curPageLogUid=7p7I5sSCgkSK&utparam-url=scene%3Asearch%7Cquery_from%3A

author: tom66
author_rank: Super Contributor
timestamp: February 26, 2025, 11:59:51 am
content: One of the challenges with conformal coating is thermal cycling, how will your epoxy hold up after years of components heating up and cooling down? In my experience epoxy is often brittle and tends to crack. Conformal coatings tend to be flexible and allow for this expansion and contraction. They are also breatheable.Ultimately you apply conformal coating to a PCB to improve its reliability, and cutting costs in an attempt to improve reliability is rarely appropriate.

author: Refrigerator
author_rank: Super Contributor
timestamp: February 26, 2025, 01:26:53 pm
content: What about silicone coatings? There are many automotive applications where the electronics are gunked over with potting silicone.Would casting silicone work the same? AFAIK casting silicone should be fairly inert unlike RTV, which can be acidic or neutral. There are thinners for silicone, so you can make it quite runny or thick.Another thermal cycling concern is that some epoxies can expand significantly with thermal cycling, so there might be issues with SMD components being jacked off the board by expanding epoxy under them.

author: m98
author_rank: Frequent Contributor
timestamp: February 28, 2025, 12:40:27 am
content: This stuff should do the trick:https://aliexpress.com/item/1005006447944510.html