Author Topic: Fan (Read 19560 times)

John Rudd · « **on:** June 18, 2016, 05:51:52 AM »

So,
I've attempted several times now to make a replacement cooling fan for my drill that I'm refurbishing....(in fact I have somewhat of a collection now amounting to around 18 of them...different models of course...)
The last effort resulted in me missing an index point on the rt and resulting yet another failure...

So I'm thinking, a metal mold machined frim aluminium, with slots cut and a recess bored for a boss to cast a fan using some form of plastic or fibreglass/resin compound...

I need the process to be repeatable as I need six of these fans.....

Any thoughts on a suitable casting material?

RobWilson · « **Reply #1 on:** June 18, 2016, 08:19:16 AM »

Hi John

What about sticking the broken motor fan back together and taking a silicon mould from that , then make resin castings from that .

Just a thought mate .

Rob

PS I went for option two ,,,,,,,,,,,,,,,, curry and bear

Bluechip · « **Reply #2 on:** June 18, 2016, 08:54:08 AM »

Err ... you can buy the damn things. Had them from here, generic, fairly easy to modify.
Shipping took about a week or so IIRC.

http://www.ebay.co.uk/itm/Plastic-Impeller-Motor-Fan-Blade-10mm-x-84mm-x-23mm-Gray/291633922728?_trksid=p2047675.c100008.m2219&_trkparms=aid%3D444000%26algo%3DSOI.DEFAULT%26ao%3D1%26asc%3D37255%26meid%3D44d1157dfd9e4d5bae4166ad9cd1f191%26pid%3D100008%26rk%3D2%26rkt%3D6%26sd%3D291601424207

Have a shufti, see if you can find one near enough to modify.

Dave

PS What flavour was the bear ??? Starter or Pudding course ??? We need to know !!!

John Rudd · « **Reply #3 on:** June 18, 2016, 09:57:54 AM »

Thanks Dave, had a look but the larger diameter ones are difficult to mod becausecthe blade tips are unsupported...I think they will just rip if I try to machine it...

Bluechip · « **Reply #4 on:** June 18, 2016, 10:32:38 AM »

Machine ??? Mine were polypropylene I think.

Machined the blades with 'state of the art' multi-axis Gilbow tinsnips ..

A bit primitive down here you know. Almost qualify to be Geordies ..

Dave

John Rudd · « **Reply #5 on:** June 18, 2016, 11:48:44 AM »

'K had another go on the mill with one more of me blank disc....
Got all the blades cut nicely, just had to clear out 'bits' in between.....swapped to a smaller cutter (3mm) going nicely when'crack' another one broken....So more scrap perspex...,
I've realised what I'm doing wrong here I think.....

As I approach the edge of the disk, the cutter seems to be forcing the disc down...Now its only supported in the centre on the mandrel I made for it...so I think it needs a disc of the same diameter at least to offer support to the edges....

Is my theory flawed in some way or should I just go back to the nursing home?

Anyway here's a foto of what I need to make.....

appletree · « **Reply #6 on:** June 18, 2016, 01:35:40 PM »

Try putting vacuum cleaner fan in google, in the good old days they were aluminium. Not sure what you are after or how efficient it needs to be but a simple disc with blades rivetted on would make quite a draft. It never ceases to amaze me what industry can produce when needed often very simple (cheap and nasty on the face of it) but reliable and cost effective.

efrench · « **Reply #7 on:** June 18, 2016, 02:34:38 PM »

Make a cut, put in a backer piece. Continue until all blades are cut.

or

Get a 3d printer

John Rudd · « **Reply #8 on:** June 18, 2016, 03:04:00 PM »

Quote from: efrench on June 18, 2016, 02:34:38 PM

Make a cut, put in a backer piece. Continue until all blades are cut.

Care to elabborate please? Pictures are good

efrench · « **Reply #9 on:** June 18, 2016, 05:15:06 PM »

John Rudd · « **Reply #10 on:** June 20, 2016, 11:02:58 AM »

Got a bit more done today....one new fan machined from solid....a lot of hard work....

Sadly I'm inclined to discard this one, making them out of metal is just too heavy....
Anyone seen any fibreglass filled resin that I can mix with hardner and mold into a fan?

seadog · « **Reply #11 on:** June 20, 2016, 12:27:24 PM »

This is quite informative John - https://davidneat.wordpress.com/materials/casting/fillers-for-resin/common-fillers-for-resin-casting/

RobWilson · « **Reply #12 on:** June 20, 2016, 12:31:52 PM »

Good going John

Machine up a mould and purchase Joules fine plastic injection moulding machine ,sorted

Rob

awemawson · « **Reply #13 on:** June 20, 2016, 12:34:36 PM »

In the absence of a 3D printer my approach would be to glue up the original, or your best copy, fettle it to a good finish with car bodywork filler, and take an impression in Vynamold :

http://www.mbfg.co.uk/vinamold.html

Release from Vynamold and pour in resin of your choice, no doubt with a filler added.

If you form a decently thick edge to your Vynamold it will hold it's form yet be flexible enough to release the pattern. I still have a few vynamold forms I made over ten years ago and they would be fine for resin casting even now.

(I was lost wax casting iron in sodium silicate bonded sand)

Joules · « **Reply #14 on:** June 20, 2016, 02:34:26 PM »

LOL, 3D printed fan's.......

Another Vynamold user here, usually taking impressions off plaster of paris than machining up a part to take an impression.... I have a wee bit of experience with fans, but mine usually ran very hot except this one where I slipped with a Dremel cutoff wheel. Twice !!! at 90 degrees...

DMIOM · « **Reply #15 on:** June 22, 2016, 03:56:34 AM »

Dave

RotarySMP · « **Reply #16 on:** June 22, 2016, 09:17:03 AM »

Wow Joules. Do you have a thread somewhere with more info and photos of making that turboprop?
Mark

Joules · « **Reply #17 on:** June 22, 2016, 10:05:26 AM »

Sorry Mark, it was a commercial unit. I was fortunate enough to have the opportunity to work for the UK outfit that builds miniature gas turbines. My favourite engines where the gas generators used in the turboprop and helicopter variants.

John Rudd · « **Reply #18 on:** June 22, 2016, 11:46:50 AM »

Joules,
Would that have been Wren Turbines ?

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Author Topic: Fan (Read 19560 times)

RobWilson

RobWilson