cascade style

[lolito_fr]

Been thinking about this. I see your point BigBen2k, about the equivalent hydraulic diameter being too small. Makes sense actually, seeing as the (predominant?) friction losses arise from contact between the fluid and the pipe walls. (hydraulic diameter is defined as four times the ratio of cross section to wetted surface)

However, the equivalent hydraulic diameter is only used to determine the pipe losses. In this case, the "pipe" is the length of insertion of the needle in the cup. At roughly 1.5mm, this constitutes a very short pipe, IMO. (even if the hydraulic diameter is only 1.8-1.25=0.55mm)
I haven't worked out the theoretical losses (any volunteers?), but I should imagine that they would be considerably lower than the head loss due to the nozzles themselves.
Therefore I don’t believe that the head loss due to this "restriction" would impact the overall flow rate a great deal and I can't see how this is suddenly going to stop the jet from impacting the base of the cup

So yes, in theory maybe the cups are too narrow. In practice though, I wouldn’t like to use smaller diameter jets (my fingers are too big!?).
The other option would be to increase the cup diameter. (dumb technical considerations include drill size here…) This would reduce the density of the nozzle array, and the velocity of the water rising out of the cups would suffer, reducing the secondary cooling effects.

Edit: Impact of extra losses due to cups, and other obstructions on the water return path was determined (approximately) here :
http://forums.procooling.com/vbb/sho...4&postcount=20

[grassi3000]

How did you fix the needles in the block? did you glue them in or did you use silicone? How did you manage not to close the inside of the needles while fixing them?

[superart]

Originally Posted by MMZ_TimeLord

The rant is based on fact... however... the applicator I got for my liquid arcrylic glue has a hypodermic needle tip that is flat (read not usable for injecting into people)... I'm sure these could be procured in other sizes as well... just look around a bit.

Like this and this and even this.

So don't say you can't get them legally... just say you have to look.

Yea, except that a box of 100 hypodermic needles, enough for about 4 blocks, costs like $6. Where as ONE of those needles costs $7. So you can go the hypodermic route and pay 7 bucks for 4 blocks, or "look harder" and pay $175 just for the needles for each block.

[Groth]

For the U.S. people at least, the easiest source is McMaster-Carr. Is there anything they don't sell?

[lolito_fr]

Nice link. 1ft might be enough for a block, and the prices are reasonable. Excellent selection of sizes as well

for Grassi: I made the holes for the needles a little small, that way there was no need for glue or silicone. Just a nice push fit. Anything that does get in the needles can be cleared out with a small drill bit.

The hardest bit is making the holes in the base plate and the polycarb so that everything lines up. If I had to do it again, I'd space the holes out a bit more. 0.4mm between cups is a bit too close for comfort when you're making this by hand

[grvydude18]

yeah, i was wondering if someone would point out the price or not, i had saw that myself when i looked at those sites, and 7 dollars for one needle, no thanks, at that price it would be cheaper to straight out get the cascade... anyways, groth, thanks for the link, that is very helpful

[MMZ_TimeLord]

Those prices are PER FOOT... not too expensive really...

One foot ... for one block... $7-12 ... I'd pay that.

[grvydude18]

i was referring to when people were saying use the refiller needles, sorry for any confusion, no the tubing idea is great, ill probably us it actually, thanks again.

[grassi3000]

Originally Posted by lolito_fr

for Grassi: I made the holes for the needles a little small, that way there was no need for glue or silicone. Just a nice push fit. Anything that does get in the needles can be cleared out with a small drill bit.

My problem is, that the block was plannes without the needles, and as for that I have to glue them into the holes. My dad said, that I should try some sort of Loctite (I don't know if it is available in the US too). Its some sort of superadhesive (translated by google . Should I try this, or some sort of silicone?
So you say, if something gets into the needles, I should use a drill....

[superart]

Am I correct in assumeing that stainless steel and copper wont produce a battery effect?

If so, would you be able to use those McMaster tubes for both the cups and the needles?

For example, you could use the 8988K78(0.013"od/0.007"ID) for the pins, and then solder or ASepoxy 5560K69(0.020"od/o.016"ID) tubes to a 2mm cpper plate, and that would give you the cups. That way if you dont have tiny drill bits, you can still try this.


Would such an idea work?

[grassi3000]

It shouldn't have battery effekt, but i think, if you use such needles as cups to the heat wouldn't be brought away from the DIE as efficientely as if the cups were drilled, because there you have two materials connected together.

[superart]

but the "floor" of the cups,where the water jets hit, would still be the 2mm piece of copper.

also, this would only be an alternative if someone didnt have tiny drillbits, and wanted to try this.

[WAJ_UK]

quite an interesting idea. It would also give you an idea of how much heat is transferred to the water from the walls of the holes in the cascade. I wonder how thin you could make the baseplate though and still keep it stiff enough.

[Butcher]

Originally Posted by superart

but the "floor" of the cups,where the water jets hit, would still be the 2mm piece of copper.

also, this would only be an alternative if someone didnt have tiny drillbits, and wanted to try this.

Probably cheaper and easier just to buy a suitable drill bit. They aren't all that expensive.
For instance a 5/64" (1.98mm) drill bit costs less than $1, probably much less than a load of extra stainless steel tube.

[lolito_fr]

Grassi, to stick your needles in place I'd suggest epoxy resin (eg Araldite, if that exists over there). Put it on the needle rather than in the hole if you don’t want to have to clear them out afterwards…
Silicone isn’t that much of an adhesive - especially if it's applied thinly - so it probably wouldn’t be a good idea.
You could also try superglue (cyanoacrylate ?), but it does dry rather quickly

As for using more tube for the cups, I'm not sure that it's a good idea because:
- I don’t know if you can solder stainless steel?
- You'd have to make the holes further apart
- As said above, stainless steel is more of an insulator than a conductor of heat.
- Drilling 1.8 to 2mm diameter holes in copper is not a problem anyway

[bigben2k]

Nickel (Stainless Steel plating) will still have a battery effect. The question is to which extent it will. (Or is the plating Chrome?!?)

Here's one:
http://www.mcnallyinstitute.com/CDweb/g-html/g001.htm

Here are a few more interesting bits of info:
http://www.engineersedge.com/galvanic_capatability.htm

http://rds.yahoo.com/S=2766679/K=gal...alv_series.htm


You can take the baseplate thickness well under 1mm, with the right jet tube configuration.

Drill bits will leave an angle at the bottom of the "dimple", which is undesirable. A square cutting endmill would be much preferable.

[superart]

Originally Posted by bigben2k

You can take the baseplate thickness well under 1mm, with the right jet tube configuration.

Drill bits will leave an angle at the bottom of the "dimple", which is undesirable. A square cutting endmill would be much preferable.

You can still use the endmill in a standard drill-press for cutting purposes, right?

Also, how much would an endmill like that cost. I remember my high school shop teacher bitching and moaning at me (and rightfully so) about how expensive those things are when I broke one of the endmills we had. :shrug:

[snowwie]

maybe you said it already and I missed it, but how much, if at all, do the tubes intrude into the cups? or are they level at the top of the cups?

Looks very nice

[Butcher]

According to that link Stainless steel is 0.50 and copper 0.35 meaning they aren't that bad for battery effect. It's actually less different from copper than solder (0.65). Besides, I've run Al and Cu mixed without issues, just use some anti-corrosive additive in your water.

[bigben2k]

Check out the link I posted in my block design thread ("Radius", in sig) for a cheap source of endmills. Yeah, the big ones can be expensive. Yes, they'll fit a drill press.

The ones I found are "solid micrograin carbide". A really really cheap one would be made of HSS (High Speed Steel) but it won't last long at all.

[Butcher]

How good is a normal drill press at actually milling stuff? What does it not do that a real mill does?

[Incoherent]

Originally Posted by Butcher

How good is a normal drill press at actually milling stuff? What does it not do that a real mill does?

The bearings in a drill press are not designed for side to side loading, they will not cope with a large end mill for very long. The headstock of a mill is designed to deal with these kind of loads and is typically far more accurate.
That said, a small endmill in a drillpress and an XY cross-slide would probably work for small jobs although I'd say you'd be breaking bits frequently because of the vibration which will occur when the bearing starts to wear. Also a drill chuck is not suitable for endmills.
So answer is, not very good.

Cheers

Incoherent

[Gooserider]

Butcher:
How good is a normal drill press at actually milling stuff? What does it not do that a real mill does?

Incoherent's answer to this actually made a great deal of sense I would add that in many (most?) drill presses, the chuck is press fit onto the spindle, typically with a JT33 taper, and no retaining hardware. This works fine when it's used as a drill, but side loading will often cause the chuck to fall off. At best this damages the workpeice, and / or the tooling, at worst it can cause user injury... :oops:

Gooserider

[killernoodle]

Originally Posted by Gooserider

Incoherent's answer to this actually made a great deal of sense I would add that in many (most?) drill presses, the chuck is press fit onto the spindle, typically with a JT33 taper, and no retaining hardware. This works fine when it's used as a drill, but side loading will often cause the chuck to fall off. At best this damages the workpeice, and / or the tooling, at worst it can cause user injury... :oops:

Gooserider

Put the chuck in the freezer for a while, then put it in and hit it with a hammer and it will never come out... Guarenteed

What about changing the bearings on a drill press to something that deals with side loads a little better?

Another question... I am planning to use woodworking router bits to mill out the cavity in the plastic on my GPU and NB waterblocks... will this work ok?

[lolito_fr]

Put the chuck in the freezer for a while, then put it in and hit it with a hammer and it will never come out... Guarenteed

good idea except that on my drill, the chuck is the "female", therefore I think it would be the other way round, ie put the drill in the freezer.

lol