VOGONS


First post, by x0zm_

User metadata
Rank Member
Rank
Member

Yeah, another project to take up my time when I haven't even finished the last one. Sue me! This is nothing more than a project of circumstance, with the right parts being around at the right time.

USJHIia.gif

Project Outline

Every PC component used in this build is hardware I had laying around, or recently obtained for free. For the water cooling section, I spent no more than $50 total. It's done on a budget, and done with a heavy focus on DIY and learning new skills. No retrofitting modern blocks. No retrofitting old blocks. I made them (and will make the rest) with nothing more than a hand saw and a corded hand drill.

I didn't have specific purpose for the build. I just wanted to make some water blocks by hand. I decided on Slot 1 since I have a lot of Pentium IIs without coolers and it's something a bit different. The fact it ended up being retro hardware was just a matter of circumstance.

The case was something I found in a council rubbish collection not too long ago and it had an 80mm fan port at the front in a horizontal desktop form factor. That pretty much settled the deal.

I only decided to use NT 4.0 because I already have a 98SE machine and am building my latest DOS/95 machine, which will likely also have NT4.0. So this will probably just be a build, enjoy for a bit and disassemble project. Either way, I'm finding it interesting to work on so I thought I'd share the ride with you fine folks. I'm a decent way through it already so I'll keep the first post as the introduction and the second post to share my progress so far.

Project Hardware & Specs
PC:
Case: Unbranded desktop ATX case. [Found it, cleaned it up]
CPU: Intel Pentium II 350MHz [On-hand]
Motherboard: AOpen AX64 Pro [On-hand]
Video Card: Matrox Mystique 220 4MB [On-hand]
Sound Card: Guillemot Maxi Studio ISIS [On-hand]
RAM: 768MB of ECC SDRAM [On-hand]
HDD: Maxtor DiamondMax Plus 8 40GB [On-hand]
FDD: Panasonic JU-257A896P [Was inside the case when found]
ODD: TBD [Will pick one out of my collection. I like the whiteness of the one in this case so I think I'll keep it for something else... 😜]
PSU: Corsair CX450 [On-hand]

Cooling:
CPU Block: Custom Block
Pump: SC-600 [Bought]
Reservoir: No-brand acrylic 60mm / 100mm res [Bought]
Fittings: Mix of POM barbs & various fittings I had around [Bought/On-hand]
Radiator: Unbranded 80mm Rad [Bought]
Temp Display: Unbranded but lightly modded [Bought]

Now onto the meat of the post...

WIP:
[Dimension95 - Building] 233MMX|64MB|Canopus Trio64V+ w/ Scenic/MX2|SB16|All the MIDI & More!
[BlackLight: NT4.0 Multimedia Workstation] - PII 350 | Matrox VGA | 768MB RAM | Hand Made Water Blocks!

Finished:
[TOXIC - P3 on Water]

Reply 1 of 19, by x0zm_

User metadata
Rank Member
Rank
Member

A Closer Look At The Hardware

Motherboard: AOpen AX64 Pro
This motherboard is from the old family business. It was in service from the early 2000s until 2018. As such, it's a bit dirty but works a treat! I'd love to give it a clean but I don't have enough isopropyl left at the moment.

Aside from having it on hand, I picked this board for its known stability and the fact it will happily accept up to 2GB of ECC memory. The Rubycon capacitors are a nice addition.

6i1CbANl.jpg
6EepyYJl.jpgA8BFFGel.jpgS6JKyy8l.jpg

CPU: Intel Pentium II 350MHz SL2U3

You all know it, some of you may love it. It's a stock standard Pentium II. With a whopping 512KB of L2 cache, it was certainly a beast for its time. That said, a 450MHz would have been nice. 😈

2PRclgyl.jpghYS5QK0l.jpgVPgpmFxl.jpg

RAM: Memory Card Technology - 3x 256MB SDRAM ECC DIMMs

I'm not sure where these came from. Somewhere, obviously. They've been in my RAM collection for a long time. There was actually four of them but the board only takes three DIMMs, so that's that.

Using Hyundai memory with the assembly of the DIMMs made in Denmark of all places, it's certainly a bit of an oddity.

w7xkThcl.jpg06SEP4rl.jpg
NPPNdX3l.jpgtoD31sal.jpg

Video Card: Matrox Mystique 220

I had it laying around. It may be replaced later. It may not. 4MB of memory. Meh.

qRAjJjal.jpgv9elnKml.jpg
oGqWHxyl.jpgMTK0gjdl.jpg

Sound Card: Guillemot Maxi Studio ISIS

A breakout box. 36MB of sample memory. Record up to 8 tracks at once. Everything you need for a home recording studio. Why do I have this? It looks cool!

AtBGimsl.jpgPVLqYZcl.jpg
BVhsIc4l.jpg7siOvQTl.jpg
ORR4SuMl.jpgIptoB54l.jpg

Case with Bits and Pieces

As stated, I found this case on the side of the road. It had an optical drive, a PSU which was promptly discarded and a floppy drive. Here it is, with the radiator, PSU and my little temperature display mod installed.

Vi4CZtFl.jpg2fcQ3K6l.jpg
AqYK7U0l.jpgW7fvm2El.jpg
ZC2yJetl.jpgc6JStMUl.jpg

Fittings

They're made of acetal. They're G1/4 BSPP threaded. They have o-rings. They cost 20 cents each. Mission accomplished as far as I'm concerned.

ZUPQdcel.jpgXbqcwBal.jpg

Pump and Reservoir

The SC-600 is a staple of Chinese water cooling pumps. I wasn't going to spend real money on a DDC or D5, nor did I really want to use one of my spare DDCs. Reservoir is well, a reservoir.

6pXiMMYl.jpgRPFNZ8kl.jpg

Materials

Aluminium and acetal are my materials of choice for this project. I was going to go with copper, but aluminium was much cheaper so it allowed me more freedom to experiment at a much lower cost. I am using 3mm thick aluminium plates as the cold plates and 8mm thick acetal plates as my block tops. I've made all my gaskets out of 1mm EPDM rubber sheets.

UTOLFiVl.jpgaB5Yn5bl.jpg
eHCUTrul.jpgNFPWUNll.jpg

CPU Water Block Concepts, CAD & Creation

I set out from the get-go to design a block that was simple to make with nothing other than some basic hand tools and materials. I avoided using the laser cutter, drill press and access to an acquaintances CNC router just for the sake of that oldschool style. With measurements taken with a pair of callipers and more precise information from Intel datasheets, I set out to design something simple in Fusion360. It went through a few revisions, mainly due to case spacing. What I ended up with is as follows.

rFeMPvZl.jpgsUbXimOl.jpg
0Nm2lYLl.jpgQPHlNGWl.jpg

I tried my best to design it in such a way that the tolerances will be enough so that it'll still work using hand tools without any real jigs for accurate drilling. Holes are drilled approximately 1.5mm in the center over Intel's specified heat zone to give some additional surface area.

Mounting is achieved with #6-32 hex head screws, since that's how the thermal plate on the CPU is threaded. The gasket is attached to the cold plate with some (yet undecided) rubber to metal bonding adhesive. The acetal top is attached to the cold plate with M4 screws. Though my renders show countersinking, I'm not sure whether I'll go with countersinking or hex head as well. I don't have experience countersinking into plastics by hand so if it goes well on scrap, I'll go ahead with it. If not, it'll be plain ol' bolts.

I didn't take many pics of my progress up until this point because I was never planning to make a build log or even post it in the first place, so I'll throw in what I do have that was shared on the Watercooling discord.

bruc9kTl.jpg5kCjfJZl.jpg
bQWze65l.jpgoCeZC20l.jpg
Acetal & Aluminium cut to size.

ZoYyt4Kl.jpgsuwDNzol.jpg
nwejQtsl.jpguhfknUtl.jpg
Lapping the bottom to get it nice and smooth. Not yet polished. Guest appearance from my Level 60 mage on WoW Classic.

v33HtEpl.jpgfT7pR1Kl.jpg
Cutting the gasket. Extra left on the edges to allow for trimming for it to be flush after adhesion. May try recut it with a sharper blade.

pBkLorOl.jpgYHjBGoql.jpg
RS3WFThl.jpg0fRMEaul.jpg
Drilling the holes into the top of the cold plate. Not too bad since I wasn't using any jig, nor did I center punch anything first. 🤣

So that's basically where I'm up to. Need to research and purchase the right adhesive for the gasket since I do not trust the pressure alone to compress it enough given the odd shape.

Misc. Pictures, Thoughts & What's Next

D7VXXMil.jpgMrzRVhPl.jpg

First attempt at the display using a spare 5.25" bay. Cut too far out, but it shows the nice yellow/green colour the display has. Same as on all the old MHz displays. I like it!

Powered by molex & temperature from a 10k thermistor that's inside a G1/4" BSPP fitting. Not a great temperature indicator but still a fun little display.

So what's next? I need to pick an adhesive. I'll likely make a block for the video card (not pictured since it's currently pulling duty in another machine that I use regularly until that machine's replacement arrives). I may make one for parts of the motherboard. A northbridge & southbridge is the dream, but unlikely due to component placement. Maybe get them close and joined by some tubing.

Aside from that, there's not really much to do. Build it all and install the OS and some software I suppose. All straight forward.

Hope you enjoyed a look into this oddball project and hope to post some updates sometime soon.

WIP:
[Dimension95 - Building] 233MMX|64MB|Canopus Trio64V+ w/ Scenic/MX2|SB16|All the MIDI & More!
[BlackLight: NT4.0 Multimedia Workstation] - PII 350 | Matrox VGA | 768MB RAM | Hand Made Water Blocks!

Finished:
[TOXIC - P3 on Water]

Reply 2 of 19, by x0zm_

User metadata
Rank Member
Rank
Member

I purchased my adhesive and I'm currently testing it out on some scrap rubber and aluminium. I've also installed the pump & reservoir into the case.

As you can see, I used the high tech, very practical solution of a spare sock to be the buffer between the case and my hard wood flooring. It worked.

bqWpr1wl.jpg ITk2Soul.jpg ZEsb6A8l.jpg

I've also thought about using 1.5GB of RAM. I do have a 1GB SDRAM ECC DIMM, and it plays nicely with two of the other 256MB ECC DIMMs.

PiBRIgWl.jpg

It's a bit skewed. It looks wrong. But hey, the build isn't meant to be any specific thing or time period. It's just a fun parts build!

Speaking of parts, I dug this part out of the parts box.

dLJvEIll.jpg

A build can't be called BlackLight without a blacklight, can it? Underglow perhaps.

Pending how the seal holds up, I'll hopefully finish the block this weekend. If it fails miserably, I'll go look for another solution.

PS: I found out today when going to test my custom cables for my Pentium MMX build, that the PSU has decided to die. That's before I plugged in my cables for reference. Three year warranty, died around 45 days out of warranty. Makes you think huh? Might give warranty a go anyway via consumer law protections.

WIP:
[Dimension95 - Building] 233MMX|64MB|Canopus Trio64V+ w/ Scenic/MX2|SB16|All the MIDI & More!
[BlackLight: NT4.0 Multimedia Workstation] - PII 350 | Matrox VGA | 768MB RAM | Hand Made Water Blocks!

Finished:
[TOXIC - P3 on Water]

Reply 3 of 19, by chinny22

User metadata
Rank l33t
Rank
l33t

Love your bizarre projects rest of us skip as it seems to much work and the mix of old and new especially water cooling old hardware.
Although I can finally say I do work up to your standard, Also used a sock to stop and old server scratching the floor, figured it's missing its feet, socks are meant for feet, so basically the same thing anyway right?

Reply 7 of 19, by D3FEKT

User metadata
Rank Newbie
Rank
Newbie

Brilliant, Love your fabrication work.
AX64 pro is a solid board, had one for years running no problems. Don't understand why the VIA chipset had such a bad wrap over the years.

Reply 8 of 19, by x0zm_

User metadata
Rank Member
Rank
Member
chinny22 wrote:

Although I can finally say I do work up to your standard, Also used a sock to stop and old server scratching the floor, figured it's missing its feet, socks are meant for feet, so basically the same thing anyway right?

Absolutely. Nothing better to protect the floor from anything else above. 😉

Badscrew wrote:

What kind of kit do you use for the temp sensor and display?

It's some cheap Chinese thing. It cost me something like $6.00 AUD. Took it out of it's acrylic stand, used the stand cutout to trace the size of hole I needed to cut, then cut the hole in a 5.25" bay.

O1OLM37l.jpg

Though the end is a G1/4" bit, it really is just a thermistor. I am considering picking up a second one and adding a film thermistor instead so I could have a second display for CPU temperature and not water loop temperature. I'll pick up a few and experiment.

D3FEKT wrote:

AX64 pro is a solid board, had one for years running no problems. Don't understand why the VIA chipset had such a bad wrap over the years.

For sure. I could likely count the amount of times the PC with this board had to be shut down from the 15 or so years of service it had on one hand.

I've got some updates!

First matter - the CPU block. Testing seems to hold up well. Water has not spilled, so I've set up a second test with acetal clamped on top as I haven't yet done screw holes, placed it on its side and will leave it and check for leaks in the morning.

Second matter - case mods. I don't remember if I said this in the original post or even the post where I found this case, but there were actually two of them. I originally only took one but upon finding out the case was so cheaply made that they used three metal standoff screws and the rest were plastic clips, I went back to grab the second case. It was in much worse shape, but I did want those metal standoffs. I ended up keeping the top panel and the front panel as well.

Because of that I do have quite a bit of freedom. The good condition top and front panel are being kept safe and as is, and the two worse condition ones are going to be painted and modded. The actual case body from the second one was rusted and not worth keeping at all.

That puts this build into some very unusual territory. It can have the stock beige look, or swap two panels and it looks completely different.

Since it was raining today I sat under the back verandah and did some basic prep work.

O0nbVtnl.jpg

Here's the bad front panel. No buttons, no little plastic bits, a bit scuffed, dirty.

QQuxpA0l.jpg

Bad cover. Dirty, minor rusting, paint scratching. Hard to show without taking 20 different photos to show it, but I'm sure you all know what I'm talking about.

jYNz3rPl.jpg

Sand that paint down with 160 & 240 grit to prep for a new layer of primer and paint.

X16128ol.jpg cKYut62l.jpg

Now we see some nicer sanded panel and cover. Removed most of the issues.

z3Zlqqyl.jpg

Now we've got the cover back on the case. Much cleaner now.

R88BC5fl.jpg BqnIZOhl.jpg

I only had thin masking tape. It'll have to do.

R5JOJLhl.jpg

Some measurement time later and we've got a window cutout plan. It'll show most of the motherboard, the pump, the reservoir and the tubing. I may take it in another 10mm on each side.

As for case colours... I'm feeling like going for an SGI theme with purple and grey. Purple for the front panel, grey for the top cover. 😁

I'm a bit excited for this...

WIP:
[Dimension95 - Building] 233MMX|64MB|Canopus Trio64V+ w/ Scenic/MX2|SB16|All the MIDI & More!
[BlackLight: NT4.0 Multimedia Workstation] - PII 350 | Matrox VGA | 768MB RAM | Hand Made Water Blocks!

Finished:
[TOXIC - P3 on Water]

Reply 9 of 19, by x0zm_

User metadata
Rank Member
Rank
Member

So in the end I decided against the window. If I decide to keep the build, it'll make putting a monitor on top of it quite difficult.

With that out of the way... today I did some painting. The grey is too glossy, but that's nothing that can't be fixed with some sanding once painting is completed and a more matte clear coat. I had a neighbour's cat walk over it at some point as well, so that will be some fun sanding and repainting once it's fully dried.

Picture dump incoming!

Surfaces were sanded with 160, 240, 400 and 600 grit sandpaper in preparation for painting.

JSd0wdel.jpg GeSc0CTl.jpg
ukLhFrvl.jpgnmZI9uul.jpg

fnouKugl.jpgZFbT0kHl.jpg

Poor colour rendition in this room (even if I prefer that colour, but only a limited paint selection to keep under budget), though I am happy with the grey bottom. Once it's fully dried I'll remove the bits that stuck up from the masking tape, sand it out and apply some satin clear coat to the grey. I'll also have to do some additional minor sanding for a couple of bits that dripped due to the curve of the bottom.

FK5bKEdl.jpg

I still need to do one more side of the top panel as well, as well as fix up where the cat walked.

In addition to that, tonight I'll be testing functionality for some of my spare (black) optical drives that I never use as painting candidates. They will likely be in grey too, to balance out the purple.

I am also making some changes to the CPU block that will allow for greater flexibility in making blocks for other components. This includes changing the G1/4 threading on the blocks to M5, and using M5 fittings instead with 6mm/9mm tubing. In addition to the benefit of 6/9mm being a bit more era appropriate, the use of smaller fittings will allow better placement of inlet and outlet for things like the video card and possibly north bridge/south bridge on the motherboard.

On top of that, I made some changes to the gasket design on the CPU block. Though it sealed fine in my testing, I am adding more leeway that doesn't encroach on the keep out zone specified for SECC1 cartridges that will really do nothing other than give me more peace of mind.

bKnw3tsl.pngaPIwSQGl.png

Thankfully those barbs are under $1 each. I'll have to wait for shipping from across the country, but I have plenty of other things to work on in the meantime!

Painting should be finished tomorrow. After that I'll get back to work on blocks. 😎

WIP:
[Dimension95 - Building] 233MMX|64MB|Canopus Trio64V+ w/ Scenic/MX2|SB16|All the MIDI & More!
[BlackLight: NT4.0 Multimedia Workstation] - PII 350 | Matrox VGA | 768MB RAM | Hand Made Water Blocks!

Finished:
[TOXIC - P3 on Water]

Reply 12 of 19, by x0zm_

User metadata
Rank Member
Rank
Member

It is quite an interesting colour. In my PC room with cool LED lighting, it has the colour of an SGI O2+. In another room that still has quite warm, near incandescent coloured lighting, it looks a lot like the Indigo 2.

Here's some updates!

Everything is now fully painted. The top cover is still drying, I don't want to touch it for a couple of days just in case it's not fully dry to avoid fingerprint marks on it. I've painted a DVD drive that was in pretty rough physical shape so I didn't care too much about "ruining" it.

I've also done the design for the Northbridge and Southbridge blocks. The Southbridge may change slightly, but I'm happy with the Northbridge. At least as much as I could be, since it is about 1mm away from the CPU block. 😵

JLwXaZOl.jpg

After cutting the aluminium and acetal to size, there it is.

XSKJwkMl.jpg H54BHajl.jpg

Carefully removed the heatsink which was adhered with thermal tape, and then cleaned it off.

rp3jpzfl.jpg

And of course the compulsory "check I didn't ruin the board" test while holding a fan up against the NB & CPU.

So with that, I'll present the very simple Northbridge and Southbridge block designs!

EB8kLbll.png U4XVQlxl.png

They're very simple. Nothing drilled it into it other than the screws to hold it together, unlike the CPU block due to the much lower heat output.

GEqtgUrl.png

As I said before I'll likely make some changes to the SB block since I realised that there's one component that slightly taller than the SB itself.

In terms of the fittings I'll be using for the blocks, I'm using some SMC M-series - more specifically the M-5AU-6 and M-5ALU-6.

yQIm3tzl.png RBribmJl.png

So that's where we're at as of today. 😀

WIP:
[Dimension95 - Building] 233MMX|64MB|Canopus Trio64V+ w/ Scenic/MX2|SB16|All the MIDI & More!
[BlackLight: NT4.0 Multimedia Workstation] - PII 350 | Matrox VGA | 768MB RAM | Hand Made Water Blocks!

Finished:
[TOXIC - P3 on Water]

Reply 13 of 19, by x0zm_

User metadata
Rank Member
Rank
Member

Sorry it's been awhile. Life and all that.

Here's what I've worked on on and off over the last month in spare time.

nui0ykVl.jpg

Baby fittings! G1/4 10/13mm compression for comparison.

SyZNuz9l.jpg fbQE6Ztl.jpg

Everything cut out for the North Bridge block.

Nrhlq5Ul.jpgQdBrXutl.jpg

Applying silicone.

43auvtbl.jpg

Trimming off spillage.

vPuAuyMl.jpgfi4hwejl.jpg

Sanding and heating the acetal top to give it a shine. First time doing this, my heat was too high but I'll keep that in mind for the other two blocks.

uWsTLTSl.jpg8akUu21l.jpg

Drilling holes.

hZ5qM1Gl.jpg

What it'll look like with screws (don't have the right depth on hand, they're on their way).

mBCvBHPl.jpg ph8qafkl.jpg

Chamfered edges. I only had some 12" monstrosity so it didn't come out nicely. I'll have to get finer and smaller files if I want to do this again.

f9F41hkl.jpg154rCe4l.jpg

Tapping the M5 holes for fittings. G1/4 barb for size comparison when installed.

yBfKgh0l.jpgWSOFIYAl.jpg

Was bored one day so I drilled random holes in the NB block while eating lunch with no real pattern at all. Just extra surface area.

hElp1Yll.jpg
Pgmyhkzl.jpgR0vS0Vhl.jpg

Gasket for CPU block cut out and adhered. That's currently setting. I'll be adding more adhesive on the inside between the gasket edge and the aluminium for added security.

WIP:
[Dimension95 - Building] 233MMX|64MB|Canopus Trio64V+ w/ Scenic/MX2|SB16|All the MIDI & More!
[BlackLight: NT4.0 Multimedia Workstation] - PII 350 | Matrox VGA | 768MB RAM | Hand Made Water Blocks!

Finished:
[TOXIC - P3 on Water]

Reply 15 of 19, by x0zm_

User metadata
Rank Member
Rank
Member
dan86 wrote:

That gasket scares me. Hopefully it doesn't leak. if you use it with a sealant Id opt for stuff Toyota makes, its called something like.FIPG Black Silicon Sealant.

Already leak tested, don't worry! 😁 It didn't leak even without the silicone after facing & lapping both the aluminium and acetal parts. It's just there for added peace of mind, really. Will keep that silicone in mind though, cheers!

WIP:
[Dimension95 - Building] 233MMX|64MB|Canopus Trio64V+ w/ Scenic/MX2|SB16|All the MIDI & More!
[BlackLight: NT4.0 Multimedia Workstation] - PII 350 | Matrox VGA | 768MB RAM | Hand Made Water Blocks!

Finished:
[TOXIC - P3 on Water]

Reply 16 of 19, by dan86

User metadata
Rank Member
Rank
Member
x0zm_ wrote:
dan86 wrote:

That gasket scares me. Hopefully it doesn't leak. if you use it with a sealant Id opt for stuff Toyota makes, its called something like.FIPG Black Silicon Sealant.

Already leak tested, don't worry! 😁 It didn't leak even without the silicone after facing & lapping both the aluminium and acetal parts. It's just there for added peace of mind, really. Will keep that silicone in mind though, cheers!

That is very good. Hopefully is dose not leak latter down the road.
But I have to ask? Why not a cross drilled block? They're very simple to make and were very popular back in the day. Not that your block is bad or anything. Just curious to why you went that way you did with the block.

Reply 17 of 19, by x0zm_

User metadata
Rank Member
Rank
Member
dan86 wrote:

That is very good. Hopefully is dose not leak latter down the road.
But I have to ask? Why not a cross drilled block? They're very simple to make and were very popular back in the day. Not that your block is bad or anything. Just curious to why you went that way you did with the block.

Had made them before. Wanted to try something new without using my drill press. A lot of it is just experimentation for later projects and providing a challenge by setting some limitations.

Of course, if I was using the drill press I'd either be doing double sided metal material drilling and filing a pin design and brazing/soldering it together, or a cross drilled block.

Don't really plan on keeping this system long anyway. I honestly just wanted an excuse to get into the garage and mess around. 🤣

WIP:
[Dimension95 - Building] 233MMX|64MB|Canopus Trio64V+ w/ Scenic/MX2|SB16|All the MIDI & More!
[BlackLight: NT4.0 Multimedia Workstation] - PII 350 | Matrox VGA | 768MB RAM | Hand Made Water Blocks!

Finished:
[TOXIC - P3 on Water]

Reply 18 of 19, by dan86

User metadata
Rank Member
Rank
Member
x0zm_ wrote:
Had made them before. Wanted to try something new without using my drill press. A lot of it is just experimentation for later pr […]
Show full quote
dan86 wrote:

That is very good. Hopefully is dose not leak latter down the road.
But I have to ask? Why not a cross drilled block? They're very simple to make and were very popular back in the day. Not that your block is bad or anything. Just curious to why you went that way you did with the block.

Had made them before. Wanted to try something new without using my drill press. A lot of it is just experimentation for later projects and providing a challenge by setting some limitations.

Of course, if I was using the drill press I'd either be doing double sided metal material drilling and filing a pin design and brazing/soldering it together, or a cross drilled block.

Don't really plan on keeping this system long anyway. I honestly just wanted an excuse to get into the garage and mess around. 🤣

Experimentation is always a fun thing to do. I'm really interested in seeing how well the block cools.