DIY equipment feet - Page 1
Forum section: electronics / projects

author: ElectronicSupersonic
author_rank: Regular Contributor
timestamp: June 23, 2022, 09:11:41 pm
content: Hi,If you need a set of new/replacement rubber/silicone feet for your equipment, you can buy these in hardware stores and/or online. But if you have some spare RTV (or other type of mould making related silicone), you can make your own feet in various shapes and sizes. Reed on to know how.Basically the hardest part of making you own feet is the mould to form the feet (apart of finding the silicone in reasonably small quantities of course). One of the most easy to find and readily available options are medications/drugs blisters. Such blisters come in various sizes and somewhat different shapes. Say there are blisters with dome shape bottom/top (depending on how you look at it) or flat bottom, there are also blisters for capsules (i.e. oblong in shape).Depending on your project requirements one can surely find suitable version of a blister. Here I'll show how I did my first set of feet using blister from round pills with dome shaped bottom.You will need several things:1. a flat rigid base surface (a piece of PCB in this case)2. a double-sided self-adhesive tape3. a medications blister4. yet another piece of a flat rigid base surface (a piece of PCB yet again)5. a set of weights (metal attachment plates for glass tables in this case)And a silicone of courseHere are some pics to illustrate...The end result...Basic explanation of the process.Take an empty medications blister (3) and using double-sided self-adhesive tape (2) attach it to a flat rigid base surface (1). Obviously blister is to be attached dome/flat surface facing the tape. Do not forget to remove any foil leftovers to interfere with the mould cavities. If you are using a two part silicone (as I did in my case; two part RTV platinum cure translucent silicone), mix a small amount (I've use two identical plastic bottle caps which was exactly enough for 10psc of 12x5mm feet) and pour it in the mould. Take another piece of flat rigid base surface and place (4) it on top of the blister (to squeeze out any excess silicone and ensure a flat attachment surface) then press it down with the weights. Leave the the whole thing to cure (it was 24h in my case, but the actual time would obviously depend on the silicone used). When cured, remove weights and the top plate, then remove the feet from the mould (if it hadn't done so already together with the top plate). Cut each feet out with exacto knife or nail scissors. Now you have your own feet, congrats!Caveats (yes there are some).Blister mould cam be deformed from normal pill extraction, so it is best to use an unopened blister and remove the pills by cutting them out. Silicone (the version I've used) is prone to air bubble formation, hence these bubble can damage the end product (silicone can be degassed, but this requires appropriate equipment). Some types of silicone are difficult to attach since it doesn't stick to anything (this is exactly the trouble I have).Other considerations.There are many types of silicone, so many options are available (including hardness, colour, resistance to chemicals, etc.) to experiment with. There are great many of different pill out where with different blister sizes to suite many different needs. I've used Sh13 (Shore A) hardness silicone which is far to soft, but that's all I had available, Sh30 - Sh40 (Shore A) would probably be more appropriate.Hope it's of any use to anybody...

author: Benta
author_rank: Super Contributor
timestamp: June 23, 2022, 09:15:45 pm
content: I think I'll just buy them. No offense.

author: ElectronicSupersonic
author_rank: Regular Contributor
timestamp: June 23, 2022, 09:18:16 pm
content: Quote from: Benta on June 23, 2022, 09:15:45 pmNot judging you

author: james_s
author_rank: Super Contributor
timestamp: June 23, 2022, 09:58:38 pm
content: I guess this could be useful if you have the materials on hand and can't find quite the right style of feet to buy, but otherwise it seems a bit like machining your own screws, a lot of work for something you can usually just buy ready made for a modest price.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 23, 2022, 10:45:05 pm
content: The main disadvantage of the "bought versions" is that quite often they don't stay glued in their place for very long.I've made similar equipment feed by just putting a few dabs of hot glue on the bottom ob equipment. When they're brand new they tend to stick (it's glue all right) but quite quickly a bit of dirt gets embedded in the surface.Also, if you first put a (wood) screw in the place you want your equipment feet, let it stick out a bit and then melt the glue around it they are quite strong and won't fall off anymore.The feet can be leveled by for example making the outside of the glue wet so it cools fast (but the inside is still pliable) and then laying a sheet of glass or some other flat surface on it that depresses the glue dots a bit.

author: tooki
author_rank: Super Contributor
timestamp: June 24, 2022, 11:26:52 am
content: Quote from: Doctorandus_P on June 23, 2022, 10:45:05 pmWhich is likely due to the usual culprits with adhesive failure: insufficient surface preparation, and incorrect adhesive selection. 3M makes their rubber feet with three different types of adhesives for that reason. (And presumably other adhesives available when having them custom made in quantity.)

author: inse
author_rank: Super Contributor
timestamp: June 25, 2022, 07:08:59 am
content: Another issue may be that it is going to be difficult to glue silicone.I'd expect that most double sided tape will not stick very well to the silicone.Maybe that's the reason why most feet are made of soft PVC or rubber.

author: tooki
author_rank: Super Contributor
timestamp: June 25, 2022, 02:35:12 pm
content: Quote from: inse on June 25, 2022, 07:08:59 amYou should probably have read the original post fully.Quote from: ElectronicSupersonic on June 23, 2022, 09:11:41 pm

author: inse
author_rank: Super Contributor
timestamp: June 25, 2022, 03:32:59 pm
content: You mean, with all the details? - I gotta stretch my attention span!If he already knows, my question is: why??

author: ElectronicSupersonic
author_rank: Regular Contributor
timestamp: June 29, 2022, 12:40:57 pm
content: Quote from: inse on June 25, 2022, 03:32:59 pmThe answer is simple. I know it now, after trying (different methods) and failing.Some things are not known beforehand and are only apparent after the fact.Fortunately I was able to solve the issue by using additional mounting posts/bosses (see attached image). Bosses are made out off disposable electronic cigarette endcaps. I've simply removed the endcap, cut/sanded it down to an appropriate height then inserted the already made feet inside (it's exactly the right inside diameter to hold the feet snugly). Then the whole thing can be either glued with any adhesive, or mounted with a screw. Now it holds properly.

author: Haenk
author_rank: Super Contributor
timestamp: June 29, 2022, 01:58:58 pm
content: Still I can get a mix of differently sized feet for AFAIR 2 EUR at my local ALDI/LIDL (seasonal offer though).Interesting your the DIY part itself, but still pointless, at least for my needs

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: June 29, 2022, 02:08:54 pm
content: Oh hello, if you focus on vintage computers, there are some feet I have never found replacements for, like the 128D keyboard...

author: tautech
author_rank: Super Contributor
timestamp: July 02, 2022, 05:48:16 am
content: Lots of alternative options here:https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/