Yay! I got a dremel! A couple of questions (cutting and airflow considerations)

Z

Zinn

Guest
I love new tools! There's nothing quite like ripping open the box to awesome new power tool and sniffing all the wonderful new plastic smell. It's Christmas all over again! I feel giddy like a schoolgirl! Yay!

Er, anyway. I've gotta say I'm impressed by the construction quality of the Dremel Multipro 2855-01. It feels very solid and there is a lot of attention to detail. I've never used a rotary tool before, so maybe they're all super awesome like this, but yeah, it's definitely a great piece of engineering. I can't wait to fire it up!

A couple of questions:

1) Will the non-reinforced cutting discs that came with the kit be sufficient to put an 80mm fan hole in aluminum? Or should I get some better discs?

2) Should I use this thing to cut plexi? I've heard that plexi can melt at the higher speeds, so is lower speed okay to cut it with, or should I look into another method of putting a hole in my side window? (Not even sure I need to do this yet, we'll see how the extra 80mm hole does)

3) Can you guys give me some tips on what I can do to improve airflow in this thing? At stock volts and 3.15 ghz my E6300 w/ Zalman 9700 is loading at 60C (I've mounted and remounted and remounted). Running with the side panel off drops both ambient and load temperatures by 10c. I think the wind from the chipset fan is interfering with the 9700 to some degree, but that one low-CFM 80mm fan in the back isn't helping.

I'm dead set on another 80mm fan in the back, (not sure why Lian Li didn't at least cut this in the first place). Wind from the 2 80mm fans in the front bottom is effectively blocked by the 8800 card, so there's a pretty sizeable deadzone in the front.

I was thinking about putting one of these bay-intake HDD coolers in to bring more air through the front and pointed at the CPU area. Or would that extra 80mm hole be sufficient? Or am I way off base?

A pic of my crappy airflow setup:
system.jpg


Help me out here! I'm pretty new at this airflow stuff. Thanks :)
 
Anwser to question #3 i'd say just take a 120 mm fan and put it in between 3 front bays blowing in should help with the airflow. Also if your into ghetto mods i'd try to separate the heat coming from the 8800 and the chipset away form the cpu by like putting some plexiglass in between. Hell you got the dremel so experiment. GL
 
Zinn said:
1) Will the non-reinforced cutting discs that came with the kit be sufficient to put an 80mm fan hole in aluminum? Or should I get some better discs?

2) Should I use this thing to cut plexi? I've heard that plexi can melt at the higher speeds, so is lower speed okay to cut it with, or should I look into another method of putting a hole in my side window?
Click to expand...

1) NO! those things are pretty weak and should only be used on plastics or not-too-hard woods. There are a couple of reinforced cutting discs available - regular and extra strong. I'd recommend the latter.

2)Slow on a Dremel is 5000 prm. That's too fast for plastic cutting without melting in my experience. You can use it and make sure you leave enough room between the cut and the finished edge to allow the messy edge to be removed after cutting. That makes for a lot of work.

Better to use a plexiglass cutter.

If you want something stronger than plexiglass, use polycarbonate.
 
Holy crap. This looks like crap. Yeah I put a hole in my case today. It was the first time I'd ever used a dremel so I wasn't expecting it to be perfect, but, this is pretty ugly.

owch.jpg


Oh well, the hole isn't even but at least it's not jagged. I sanded it down to a non-lethal sharpness and slapped a fan on there.

Now my load temps are like 4C cooler! It may be ugly, but it's working (somewhat). I still don't see how people do such precise cuts with the dremel. I'll bet I need some more practice.
 
rofl, I could have chiseled a cleaner cut with my dick. :D

yea, just stick some black molding on it and hope it looks round. haha.
 
Dam dude I don't know what to say. If you have any spare PC cases practice on those, but then again its to late ? At least it is in the back and not that viewable!
 
why use a dremel, when you could have just went out and bought a hole saw for a drill? It makes cleaner cuts and only cost like $30.

edit: Nice system by the way ;) Is that the new Zalman 110mm h/s?
 
itschop said:
Dam dude I don't know what to say. If you have any spare PC cases practice on those, but then again its to late ? At least it is in the back and not that viewable!
Click to expand...
I wish I had practiced a little first. I did use a template but I kept going off course. I'm not too worried about it since the fan is mounted straight and the system is cooler. It looks fine from the other side with a fan mounted, and it works fine. This is my first cut ever and I know next time I will do better.
AMD RULES said:
why use a dremel, when you could have just went out and bought a hole saw for a drill? It makes cleaner cuts and only cost like $30.

edit: Nice system by the way ;) Is that the new Zalman 110mm h/s?
Click to expand...
Hole saw would have cost me $35 and the Dremel was $60. I just wanted the added flexibility because I would eventually like to do a serious case mod (on a different case :p)

Yeah it's the Zalman 9700.
 
Ok you seem kinda spastic so im going to go over some safety issues with you first. :D

Wear eye protection, gloves, and a mask (it's not cool to inhale aluminum particulates.)

Ok now that thats over... lol

Tell us that you masked the cutting area off (even steady handed peopel should do it) see the picture below, I cut a 120mm blow hole in the top of my praetorian 730. I looked up the lian li you have and I really think a 120mm blow hole is in order. 120mm is much quieter and will move the air you want out. Make it an exhaust blow hole, the low pressure it creates inside the case will suck alot of cooler air into the case. Measure everything out on the inside and cut away! top it off with an A.C. Ryan Grill (it'll match brushed lian li aluminum >>> http://www.frozencpu.com/cat/l3/g36/c221/s543/list/p1/Fans-Fan_Grills-120mm_Fan_Grills-Page1.html

PC190021.jpg
 
dremels take a LOT of practice to use neatly. Go find an old case or if you don't have one, some scrap steel / aluminum and just practice cutting. As you've discovered they cut through metal like it's butter, so it's very easy to get wavy and jagged lines with one. and as has been mentioned, wear a mask. metal dust will get into your lungs and stay there for years. Aluminum dust especially is extremely toxic (crack open a can of coke and you'll see they deposit a thin layer of plastic on the aluminum to keep the coke from dissolving it and poisoning you). It should never be breathed in or swallowed.
 
Yeah I will definitely practice before I try doing that again :eek:

Next order of business is to put two 120mm fans on top of the case, and that has to look nice, so I will definitely spend some time doing test cuts on junk cases
 
A couple suggestions from an experienced metal worker ...

1] - If you need a round fan hole, my suggestion would be to cut an octagon (8 sides) or a decagon (10 sides) first. Then you can round it from there.

A common mistake many make when to try & use cut off disks around curves. NOT a good idea. The wheels are made for lateral operation only. Twisting and putting sideways (lateral) force on the wheels is using them in a way which they were not designed for. Will cause premature disk falilure - either breaking or excessive wear.

2] - do not cut all the way through at 1st. Better to follow your line with the disk making a shallow channel. Then work your way through the metal panel gradually lengthwise. Much MUCH easier to stay on track that way.

To help illustrate - - http://img73.imageshack.us/img73/2434/spin37sq.jpg

w1retap said:
rofl, I could have chiseled a cleaner cut with my dick. :D

yea, just stick some black molding on it and hope it looks round. haha.
Click to expand...
LMAO! :D
Funny! But hey, everyone has to start somewhere.
 
How common are tinsnips to cut fanholes? I didn't want to pay $60 for a two-time-use holesaw, didn't want to go through a dozen dremel disks, and didn't want to clamp down for the jigsaw, so I punched a two centimeter hole with a punch die thing and cut the hole with tinsnips in a cheap steel case.

It gave me a very nice, clean cut. Could've been tidier (I didn't get a perfect circle, but I chalk that up to me and not the snips.)
 
Snips are very common - I use them all the time.

Thing is .... snips are one of those tools often used, but very seldom used properly. All it takes is once
and the snips will never cut right again.
 
Sus- Have you ever used the electric snips? Or "nibblers" as I've heard them referred to as.
Some of them claim to be able to go through 14g aluminum, especially if you're using an air compressor. They also claim to only bend one side of the metal and leave the other side clean and unmolested, which would be nice for cutting holes in aluminum cases. I currently use a 4.5" hole saw for 120mm fan holes, but these seem kinda nice and I'd like a professional machinist's opinion.

I have a nice, powerful air compressor setup so I can use an air or electric powered one.
Here's a couple examples of both electric and compressed air models:
http://www.northerntool.com/webapp/wcs/stores/servlet/product2_6970_200305419_200305419
http://www.amazon.com/exec/obidos/ASIN/B0002T5U4U/dealtime-tools-20/ref=nosim
http://www.amazon.com/4-Amp-Electri...=pd_bbs_sr_1/002-3296329-3919217?ie=UTF8&s=hi
 
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I can attest that you really do need good eye protection, I had a cutoff wheel break on my and put a good mark into my eye glasses, if I would have had nothing on then it would have been my eye with the gash in it and not my glasses.

I don't like the reinforced cutting wheels for more intrecite work, just remember to go slow, dont force it, Let the RPMs do the work, dremels have very little torque and when you try and go to fast it just wears everything out and causes jams and slips.
I had a cheapo case I was useing for a while and did not like the built in fan grills, they were ungodly restrictive, the case had 6 80mm fan holes I had to cut out. I used a dremel with stock 1" cut off wheels and I was really amazed at the results I got, who ever said you can't cut round holes with a dremel does not know what there talking about, the key is to go slow and to use as little disk penetration as possible (maybe not the best words to use, but I don't really know how to describe what I mean). also remember you can always go back and cut a little more out, but if you cut to much your screwed. I really wish I had pics so I could show the results, but the case is long gone.
quick Paint image showing what i mean by penetration.
dremelqv4.jpg
 
I tend to use a jigsaw for most of my large area cuts, then use a dremel for sanding, edge smoothing, trimming, etc. Much faster then a dremel and if you use a fine cut metal blade they're great for acrylic/plexi. Although you may want to put just a dab of liquid soap on the blade if cutting a piece thicker then .25 inches. That and you could find a cheap one around 30 bucks.....
 
Take it slow and easy, and you don't have to cut completely through in one pass. You'll get cleaner, more precise results by making multiple passes.;)

Edit: Susquehannock already said it..Heh.
 
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