Can't say I've ever seen any for sale, tho why not make your own from -

small piece of folded cooking foil
silvered cardboard (tin tray lids)
self-adhesive alu tape

You could even add a couple of M3 screws for an authentic removable blanking look

Yes ! they are thin sheet metal and use screws but found silver Mylar duct tape (not the same as the regular grey duct tape) applied to the outside is a better alternative.
added: PC Hoarder Patrol mentioned AL tape but the Silver ALU tape would work without any need for anything else. Just cut a small oval and cover it !
https://www.amazon.com/3M-3311-Silver-Aluminu … /dp/B007Y7EOT0/

I did just glue a piece of similar color plastic to cover one of those holes recently.

Never seen any for sale but I have some from old cases... The nicer cases came with real covers and not the dumb punchouts.

I've even seen some plastic covers and might even have a couple.

cyclone3d wrote on 2020-10-14, 04:55:

Never seen any for sale but I have some from old cases... The nicer cases came with real covers and not the dumb punchouts.

I've even seen some plastic covers and might even have a couple.

would you be able part with few for db9 and db25 holes and plastic covers, never came across any and is there pics to see what they look like

PC Hoarder Patrol wrote on 2020-10-14, 02:09:

Can't say I've ever seen any for sale, tho why not make your own from - […]
Show full quote

Can't say I've ever seen any for sale, tho why not make your own from -

small piece of folded cooking foil
silvered cardboard (tin tray lids)
self-adhesive alu tape

You could even add a couple of M3 screws for an authentic removable blanking look

never thought of that - as i know it a cosmetic thing but would like to any dust out or minimize if possible

Horun wrote on 2020-10-14, 02:13:

Yes ! they are thin sheet metal and use screws but found silver Mylar duct tape (not the same as the regular grey duct tape) applied to the outside is a better alternative.
added: PC Hoarder Patrol mentioned AL tape but the Silver ALU tape would work without any need for anything else. Just cut a small oval and cover it !
https://www.amazon.com/3M-3311-Silver-Aluminu … /dp/B007Y7EOT0/

as i know it a cosmetic thing but would like to any dust out or minimize if possible and will keep in mind as i never heard of alu tape here in uk

Baoran wrote on 2020-10-14, 04:16:

I did just glue a piece of similar color plastic to cover one of those holes recently.

excellent and i know it a cosmetic thing but would like to any dust out or minimize if possible

Robhalfordfan wrote on 2020-10-14, 12:28:

Baoran wrote on 2020-10-14, 04:16:

I did just glue a piece of similar color plastic to cover one of those holes recently.

excellent and i know it a cosmetic thing but would like to any dust out or minimize if possible

If it bothered me I'd just stick in another DB25/DE9 connector, even if I didn't have anything to hook it up to internally.

Robhalfordfan wrote on 2020-10-14, 12:28:

Baoran wrote on 2020-10-14, 04:16:

I did just glue a piece of similar color plastic to cover one of those holes recently.

excellent and i know it a cosmetic thing but would like to any dust out or minimize if possible

Do keep in mind that you can reduce airflow to try and get less dust into your case, but this will also reduce cooling. Especially in older cases (roughly AT up to perhaps very early ATX era) airflow is already pretty bad.
Reducing dust is better accomplished by not putting the PC case on the ground and keeping the immediate surroundings of the PC as clean as possible. Dust filters can get clogged up and might impede airflow (especially when forgotten).
I ended up preferring relatively larger cases (even for µATX) so the dust would at least stay on the bottom of the case more instead of clogging up fans and sitting on top of horizontal areas (like PCBs or drives or drive slots or even cables and vertically mounted fans) where it is easier to clean, with less dust clogging up HSFs. Another thing I ended up doing was to increase airflow (even using a hacksaw to improve the back fan exhaust holes so I had grill-covered openings instead of the lots of tiny openings that don't really cool as well) and to use larger HSFs as I reckon that faster airflow will also help prevent dust settling somewhere inside the case.

All of these help prevent the buildup of dust and also will help prolong the life span of my parts and increase stability.

Robhalfordfan wrote on 2020-10-14, 12:25:

cyclone3d wrote on 2020-10-14, 04:55:

Never seen any for sale but I have some from old cases... The nicer cases came with real covers and not the dumb punchouts.

I've even seen some plastic covers and might even have a couple.

would you be able part with few for db9 and db25 holes and plastic covers, never came across any and is there pics to see what they look like

Here is a pic of my whole collection of them. Seem to be pretty simple to make.

The DB-9 plastic covers for the populated ports would be the same as come on the HD-15 vga cables. Never seen a cover for DB-25 size.

Some Dell computers that had onboard video and came with a video card came with pretty nice covers for the onboard vga. I might have a few somewhere but not sure.

Tetrium wrote on 2020-10-14, 12:52:

Do keep in mind that you can reduce airflow to try and get less dust into your case, but this will also reduce cooling. Especial […]
Show full quote

Robhalfordfan wrote on 2020-10-14, 12:28:

Baoran wrote on 2020-10-14, 04:16:

I did just glue a piece of similar color plastic to cover one of those holes recently.

excellent and i know it a cosmetic thing but would like to any dust out or minimize if possible

Do keep in mind that you can reduce airflow to try and get less dust into your case, but this will also reduce cooling. Especially in older cases (roughly AT up to perhaps very early ATX era) airflow is already pretty bad.
Reducing dust is better accomplished by not putting the PC case on the ground and keeping the immediate surroundings of the PC as clean as possible. Dust filters can get clogged up and might impede airflow (especially when forgotten).
I ended up preferring relatively larger cases (even for µATX) so the dust would at least stay on the bottom of the case more instead of clogging up fans and sitting on top of horizontal areas (like PCBs or drives or drive slots or even cables and vertically mounted fans) where it is easier to clean, with less dust clogging up HSFs. Another thing I ended up doing was to increase airflow (even using a hacksaw to improve the back fan exhaust holes so I had grill-covered openings instead of the lots of tiny openings that don't really cool as well) and to use larger HSFs as I reckon that faster airflow will also help prevent dust settling somewhere inside the case.

All of these help prevent the buildup of dust and also will help prolong the life span of my parts and increase stability.

If we are looking at old 386 or 486 PCs though the cpus don't use much power so if you put a heatsink and small fan on them I don't think case not having very good airflow is going to cause any problems. Also during pentium 2 and pentium 3 time period the airflow got much better and you can actually install case fans in those.

cyclone3d wrote on 2020-10-15, 01:41:

Here is a pic of my whole collection of them. Seem to be pretty simple to make.
DB-9_and_25_covers.jpg

I have some of those similar to the bottom left and the top right, most are in AT cases but also have a couples spares. Yes they are very hard to find now but decades ago you would see them often at local computer stores in bins with other hardware...

Another DIY suggestion would be to cut an IO blanking plate to length and then either tap for screws or drill for nuts / bolts

PC Hoarder Patrol wrote on 2020-10-15, 04:34:

Another DIY suggestion would be to cut an IO blanking plate to length and then either tap for screws or drill for nuts / bolts

Or aluminum sheathing.. or literally any other thin-ish metal. You could even make some out of soup or soda cans.

Just need a tin snips to cut them out.

cyclone3d wrote on 2020-10-15, 01:41:

Here is a pic of my whole collection of them. Seem to be pretty simple to make. DB-9_and_25_covers.jpg […]
Show full quote

Robhalfordfan wrote on 2020-10-14, 12:25:

cyclone3d wrote on 2020-10-14, 04:55:

Never seen any for sale but I have some from old cases... The nicer cases came with real covers and not the dumb punchouts.

I've even seen some plastic covers and might even have a couple.

would you be able part with few for db9 and db25 holes and plastic covers, never came across any and is there pics to see what they look like

Here is a pic of my whole collection of them. Seem to be pretty simple to make.
DB-9_and_25_covers.jpg

The DB-9 plastic covers for the populated ports would be the same as come on the HD-15 vga cables. Never seen a cover for DB-25 size.

Some Dell computers that had onboard video and came with a video card came with pretty nice covers for the onboard vga. I might have a few somewhere but not sure.

would be to part with at least one of each size

cyclone3d wrote on 2020-10-15, 04:37:

PC Hoarder Patrol wrote on 2020-10-15, 04:34:

Another DIY suggestion would be to cut an IO blanking plate to length and then either tap for screws or drill for nuts / bolts

Or aluminum sheathing.. or literally any other thin-ish metal. You could even make some out of soup or soda cans.

Just need a tin snips to cut them out.

i would have go at one but i actually do not own any tools that could do the job or even know what tool would do to or how to do it the job 🤣

Baoran wrote on 2020-10-15, 02:25:

Tetrium wrote on 2020-10-14, 12:52:

Do keep in mind that you can reduce airflow to try and get less dust into your case, but this will also reduce cooling. Especial […]
Show full quote

Robhalfordfan wrote on 2020-10-14, 12:28:

excellent and i know it a cosmetic thing but would like to any dust out or minimize if possible

Do keep in mind that you can reduce airflow to try and get less dust into your case, but this will also reduce cooling. Especially in older cases (roughly AT up to perhaps very early ATX era) airflow is already pretty bad.
Reducing dust is better accomplished by not putting the PC case on the ground and keeping the immediate surroundings of the PC as clean as possible. Dust filters can get clogged up and might impede airflow (especially when forgotten).
I ended up preferring relatively larger cases (even for µATX) so the dust would at least stay on the bottom of the case more instead of clogging up fans and sitting on top of horizontal areas (like PCBs or drives or drive slots or even cables and vertically mounted fans) where it is easier to clean, with less dust clogging up HSFs. Another thing I ended up doing was to increase airflow (even using a hacksaw to improve the back fan exhaust holes so I had grill-covered openings instead of the lots of tiny openings that don't really cool as well) and to use larger HSFs as I reckon that faster airflow will also help prevent dust settling somewhere inside the case.

All of these help prevent the buildup of dust and also will help prolong the life span of my parts and increase stability.

If we are looking at old 386 or 486 PCs though the cpus don't use much power so if you put a heatsink and small fan on them I don't think case not having very good airflow is going to cause any problems.

This is absolutely true. But I would recommend to mount at the very least a fan onto a DX2-66 or faster because the (large passive) heatsink I installed on my DX4-100 at first did end up getting uncomfortably hot after prolonged use even with the u-shaped cap off. It will start to matter more once people start moving into 3D territory (think Voodoo 2 + VGA card + several sound cards etc).

My guess is that this is also a reason why AT PSU fans tended to run at full speed all of the time. Might even have been a prerequisite of the AT standard but I don't know from top of my head. But I wouldn't be surprised if there was (for the AT standard) some very basic provisions for air circulation prerequisited.

Also during pentium 2 and pentium 3 time period the airflow got much better and you can actually install case fans in those.

Well, do have to mention that it isn't very hard to improve AT case airflow with a basic ATX case as airflow inside AT cases was often pretty much abysmal. Best AT cooling I saw most AT cases have, was provisions for a case fan at the front (with barely any intake openings for air to come in).

With the earliest ATX cases, it was easy to see the main difference in system cooling when looking at case models that have both an AT and an ATX version, but with the increase in GPU and CPU TDP this new boost in system cooling which the new ATX standard provided, quickly became insufficient (particularly around when Intel started pushing its hyperthreading CPUs, though Thunderbird was also not one of the coolest running CPUs).

This is when we started to see cases appear like the AOpen H600A, Chieftec Dragon, etc and larger copper stock HSFs and increasing diameters of case fans (along with added provisions to be able to add more of those fans).

dionb wrote on 2020-10-14, 12:39:

If it bothered me I'd just stick in another DB25/DE9 connector, even if I didn't have anything to hook it up to internally.

That's what I did, thanks to a big bag of assorted I/O plates I have.