Aluminium Grades

[michael]

Does anyone know which grade of aluminium is best suited to high speed cutting with router, I have a few bits some clearly cut easier than others?

Also as i'm undergoing a redesign of my coolant system, is it best to mist the coolant or flood with Aluminium routing.

Any advice?

[John S]

T6 is about the easiest to obtain that cuts nice, it's the architectural sheeting that cuts like wet butter.

Best coolant for aluminium is WD40, in fact that's all its good for :heehee:

Because it's expensive make your own 75% paraffin [ the UK stuff ] and 25% any hydraulic oil, or ATF, that red automatic transmission fluid.
You don't need much, those kitchen type spray bottles work well but you have to be there.

I had often thought, but never done anything about it, of using one of those Peristaltic pumps

http://en.wikipedia.org/wiki/Peristaltic_pump

Positive displacement, no waiting 10 minutes then the alloy builds up on the cutter and just as you go to stop the machine a great big snot of muddy water hits you bang on.

With a spray head you get get a fine mist which is all you need except decent ventilation

..

[michael]

T6 is about the easiest to obtain that cuts nice, it's the architectural sheeting that cuts like wet butter.

Best coolant for aluminium is WD40, in fact that's all its good for :heehee:

Because it's expensive make your own 75% paraffin [ the UK stuff ] and 25% any hydraulic oil, or ATF, that red automatic transmission fluid.
You don't need much, those kitchen type spray bottles work well but you have to be there.

I had often thought, but never done anything about it, of using one of those Peristaltic pumps

http://en.wikipedia.org/wiki/Peristaltic_pump

Positive displacement, no waiting 10 minutes then the alloy builds up on the cutter and just as you go to stop the machine a great big snot of muddy water hits you bang on.

With a spray head you get get a fine mist which is all you need except decent ventilation

..

Cheers John, I did wonder about raiding a bottle and washer pump of an old car from Albert Looms! Then modding it to include a return to recirculate coolant with some filtering of course, even thought of using a cheap car oil filter for this?

for misting does it require an air feed? Or does the nozzle it self create the mist?

Michael.

[John S]

Cheers John, I did wonder about raiding a bottle and washer pump of an old car from Albert Looms! Then modding it to include a return to recirculate coolant with some filtering of course, even thought of using a cheap car oil filter for this?

for misting does it require an air feed? Or does the nozzle it self create the mist?

Michael.


Can't honestly answer the misting question as I have never done it, if the pump has enough pressure then it should mist given the right nozzle, think hosepipe but if it's low pressure then it may need a bit of a hand.
Then again a simple air spray system will mist, like a cheap spray gun.

Not sure about a car oil filter as a return system because on a car it's pumped. Someone would need to work out how long it takes to flow thru by gravity and is it backs up too much.

Sorry not been more helpful but as I say no experience.

[edit]
The professional misting systems work total loss but use very little liquid.

[michael]

Still very helpful John,

Just dont care much for standing over the machine for a couple of hours to spray bloody WD (usually gets blasted straight back at me by the routers exhaust!)

I could use a pump no problems and maybe some crude form of filtering, maybe just go total loss and use a water based coolant I can mix large quantities of my self.

Michael.

[Tom]

Somewhere on CNCZone I saw someone had used a cheap airbrush (http://cgi.ebay.co.uk/Air-Brush-Airbrush-Sprayer-Spray-Gun-Painting-Tool-Kit_W0QQitemZ140318086710QQcmdZViewItemQQptZUK_Cra fts_DrawingSupplies_EH?hash=item20ab9c1636&_trksid=p3286.c0.m14&_trkparms=66:2|65:15|39:1|240:1318|301:1|293:9|294 :50). You'd need compressed air, but they don't use much....

[John S]

You can always use a fridge compressor with an airbrush, cheap and quiet.
there was an article in MEW in the last couple of issues on doing just that.
.

[michael]

Some great idea's coming out here from the Derby/Notts Group!

Cheers John S & Tom.

[John S]

Not only that I did a search on Ebay for airbrushes out of interest although I don't have any interest or want one ? :question:
Found a link to someone selling small coiley 1/8" gas air lines so bought two for blow guns on the machines.

All the coilies I have are massive and it's like going 5 rounds with Mick McManus getting then to go where you want.

Next thing lacking are small blow guns?

KIP where are you ???

Plenty of blow guns but all massive for small machines or got 6 foot levers.

.

[michael]

That is a bloody good mister Kip, wonder how well a fuel injector would work with a fuel pump, They create a good mist. Easy to control coolant quantity etc.

Michael

[HiltonSteve]

For flood coolant what about using a pond fountain pump like this one -

http://www.diy.com/diy/jsp/bq/nav.jsp?action=detail&fh_secondid=9218515&fh_view_size=10&fh_location=%2f%2fcatalog01%2fen_GB&fh_search=fountain&fh_eds=%C3%9F&fh_refview=search&ts=1243785422549&isSearch=true

I bought one for leak testing a job we did for the m.o.d., just threw it in a bucket of water and left it pumping water onto a bearing for 2 days. Worked a treat! Plugged a hose pipe onto the top were the fountain attachment usually goes.

They have a flow adjustment built in as well.

Michael - I have one in my garage if you want to give it a go.

[Ross77]

That is a bloody good mister Kip, wonder how well a fuel injector would work with a fuel pump, They create a good mist. Easy to control coolant quantity etc.

Michael

Hi Michael
The fuel pump idea should work, A friend uses them on most of his machines. not used as misting though, just constant flow which is recirculated.

[John S]

Diesel injection pump isn't really suitable, the clearances inside required to get up to 115 bar to 280 bar - 1700 psi to 4,000 psi means the slightest lack of lubrication or grit and it's toast.

Going slightly off topic but whilst looking up these pressures which I had forgotten [ past life ] I found out that the latest diesel with high pressure common rail systems use pressures up to 2,000 Bar or 29,400 psi.

Home made water jet anyone ?

[John S]

They are even more fragile....Some reduce engine power and even cut the engine to "not" run out of fuel....kills the pumps.

Right, Didn't know that not had the pleasure of owning / running one of these our two vehicles are on the last of the mechanically injected engines with no brain etc.

Hate to loose this independence.

On topic I did tell Michael T6 machined OK :whistle:

.

[michael]

Right, Didn't know that not had the pleasure of owning / running one of these our two vehicles are on the last of the mechanically injected engines with no brain etc.

Hate to loose this independence.

On topic I did tell Michael T6 machined OK :whistle:

.

Yes you did mate!

Michael
:clap:

[rinderpest]

Im told that the Al from pistons is nice to work, melts nicely for casting into ingots and machines cleanly. Another reason to visit Looms?
Havent used pistons myself but I have used hard disc chassis; nice light alloy that melts easily (dont know temps - got no thermocouple).
Used the melt to cast a replacement key cos the buggers* wanted £8.50 for what seems to be a bog-standard mortice key.
Theres someone with a website about casting etc who uses HDD Al regularly with good results, I'll try and dig out his URL.

Does anyone in the Derby/Notts area know a good source of fire bricks?
I only need a dozen or less for a small electric Al melting project, I dont need a pallet full! Preferably the ones you can cut with a wood saw.

Jim

*I tried 3 different keycutters, one had a nice engraver that looked PC driven. He wouldnt let me play after Id sniffed at his prices.:heehee:

[Ross77]

How easy is it to cast alui. did it years ago at college but always ended up looking like an aero lol bubbles bubbles......

Do you need main gas? definatly interested in getting in to it.

Sorry to be off topic again

[Ross77]

I'd suspect your aero would have been caused by too wet a sand/clay mix (clay bonded brown sand?) if using petrobond you get none of that.


I'll be building 2 new furnaces this year, one for cast iron and another tilting furnace for Al.

I'll take some pictures and might break a habit and write about it :)

As for off topic....it's about Al so it's on topic :beer:[/quote]
:clap:Yeah it was a brown sand and i seem to remember it had to be preety wet to retain the shape, Cheers! the poor finish has always put my off doing it again, but like you said the posibilites and time saved in milling from billet would be well worth the effort.

Look forward to the pics and demo. :yahoo:

Are alloy wheels a good supply for melting down?

[HiltonSteve]

I feel a need to share some of my experiences with cast aluminium, this will be only personal views, not aimed at anyone or trying to spoil anyones fun in trying to make your own as I am all for having a go at something and f@&king it up and trying again as sometimes this is the best way to learn!

Cast aluminium will always be full of aero holes, I once tried to water cool a vacuum forming tool that was made out of 20 chocolate box female aluminium castings which were cast by a foundry that specialized in aluminium. After 40 hours of drilling 1mm holes and then linking all the holes by back drilling the castings then free hand milling all the tracks to link the holes and then mounting them on a nice solid 1" aly plate found out that after I had water tested it that I had made myslef a very expensive and very large water sprinkler!

Threw it straight in the scrap bin and started again, tried it a couple of times again with different grades and methods of cast aly with same results. In the end I gave up and watercooled the 1" extruded aly back plate by drilling and plugging, never bothered with water cooling the castings again.

Personally I don't think you can cast ally without aero bubbles, I may be wrong but would take a lot of convincing!

By the way just bought some T6 aly plate today - £39.70 for a piece of 550x300x20mm. I have not had the fun of making it but can have more fun machining it and for £40 I know what I would rather be doing.....

Still interested to see your results though.

[HiltonSteve]

Aw crap....my cylinder head on my car is Al.....And the casting for the Xcalibre hydraulic drill handle I did last year is doomed...@ 120Bar too :eek: ....Hand held :eek:

Nice cheap piece of plate!

Heat treatment and temperature control all play a part in casting Al....What was the structure (crystalline) of the Al like?

I see "Ali" and "ally" but the periodic table has it as Al.....shorter too :)

Like I said, inetrested to see what people results people get, not saying I'm right or wrong as nobody ever is!

Ali, ally, al who gives a f$ck, what do you expect after drinking a bottle and a half of wine.

Good point about the cylinder head though, never thought of that one before....

[John S]

I think is down to method.
Just sticking a few lumps of alloy in an old pot, melting it and pouring into another old pot will get you anything, good bad or indifferent.
For a start iron is soluble in molten aluminium and the gasses cause bubbles.

You also need ge gassing tablets to throw in that cause all the dross, shit , crap and German routers to come to the top so it can be scooped off and thrown at next doors cat.

Material also plays a part just because you stuff one grade in it doesn't meant you get that grade out as it changes in the melt.
professional smelters melt a charge, run a test to see what's in it or more important what's missing and then lob in ear of bat, tongue of newt to make up.

Things like pistons when melted contain most of the original metal plus carbon from the burnt oil and deposits which doesn't help, clean alloy is hard to get in quantities.

One of the best grades is LM25 which is available in ingot form but rare to find as scrap items, when heat treated this is closed grained, machines nice and can even be bent slightly proving how ductile a casting can be.

Unfortunately to make good casting it then becomes another hobby at the expense of others.

.

[HiltonSteve]

Found a possible answer -

Quote

I would bet that what you are looking at is a shrinkage cavity or the location of a trapped air bubble. The melting and pouring of metal isn't really a very scientific field. The solidification of that molten metal is. If the solidification isn't done at a very controlled rate, you will have cavities where the solidification left a void. Likewhise, especially with aluminum, if molten metal isn't properly degassed, you can leave pockets of air. If the product was then cut, it would appear as a pin hole on the surface of the piece.

End quote

Not my words but sounds plausible...

[HiltonSteve]

SO what your saying is. .. You Fubar`d:heehee:

errr.... looks like it!

Won't be using that foundry again for 2 reasons,

1 - They are (were) sh1t

2 - They went bust about 10 years ago.

Live and learn....

[John S]

Manor Foundry in Ilkeston, upper Granby Street, bottom of Bath Street, side of Tesco's, look for the big green sand silo.

Goes runs and one off's, guy called John runs it, knows what he's about as well, never had a bad casting

[Ross77]

So is Al casting best left alone then for small quantities?

Kip/John
fancy doing a crash course in Al casting for idiots? :beer:

[HiltonSteve]

The one i was talking about was a foundry in Ashbourne!

Used to get castings from John at Manor foundry occasionally, is he still there! Bloody hell! Got to agree though, quality castings.

[Ross77]

It's a long round trip but bring your pattern and have a pour! :beer:
Very tempting, got some friends that live in yorkshire so maybe arrange a holiday/ playtime, if I can convince my better half that there are plenty of shops to look at........:whistle:

I was thinking of a forum based do's and don'ts but i suppose the best way is it see it done.

[Ross77]

Cool, Pm me your address if you want so i can work out the trip. After all this studying thing I deserve a break.

Cast some Ali, few beers and then scarper quick...(Think I can fit that mill in my boot) :naughty:

[Ross77]

Only £1100 for a brand new one....I'd get the sq column version.


Thats £1099 more than I want to spend, (dam that yorkshire blood)

Only joking about the mill, my agricultrally engineered pillar drill will be much better :joker: