£20 RVK Cheapness

[F-E_Man]

It was some time ago I did this, so it's just drawings.

 

A cooker hood contains some sort of reversed blade centrifugal fan. If you go with brands like smeg, a look at the manufacturers specs will show a 250 meter fan is fitted, as found in a 4" RVK style. It's just packaged differently.

 

Ebay sells these for £20 all day long.

 

Now this packaging problem isn't as bad as you might think. For a start you get a speed control. The mouth of the fan can have a duct glued straight to it, or you could add a top hat flange but that's not cheap enough for this thread.

 

Cardboard boxes. They're cheap enough for this thread. The following image shows how a cardboard box around the fan can be used to create a vacuum within the box that will draw air in from the grey duct. Shown as a purple line.

 

That could be a fair inlet fan, using the hood filters for dust reduction. How about the carbon often in these though. Well.. It's about 20mm thick. It's good for hollowing out and using as a free hose spigot, rather than buying a top hat flange. The second image shows how to make it a carbon filter though. Simply build a wall round the hood, and fill it with loose carbon. Using the hood filter to hold the dust back. This bed depth should be ~50mm. The cheap ones we buy are 30mm deep, but industry choose 50mm beds and the latest filters are now punting 60mm deep beds. Fill it to 70? 

 

 

 

 

 

 

Glad I did a copy. Inserting the image lost my write-up

[Guest]

I'm on downtime at the moment because of the hotter weather but also my growing space, which is an old airing cupboard, is having a refit. I've been thinking of a few ideas for passive intake using a light baffle but I might just fix one of these into a frame with lattice/louvre door.

 

Wouldn't have thought of that if you hadn't put this up, cheers!  

[Saddam]

Cooker hood fans aren't designed to run 24/7 for months at a time, that's why they're 20 quid and not 60, shit parts and bearings. Regarding the carbon, I don't think it'll stay put for long with just a cooker filter, not with a 250m3 fan blowing through it. Packing the carbon is correctly is quite important if you want the filter to scrub the air properly. There is a thread here somewhere about repacking old filters with new carbon, doesn't look like fun tbh.

[Greenfinger53]

I'd sooner take my chances with a fan off Gumtree if my budget was £20 in am emergency. But it's not a part of kit you should be saving money on, get a good quiet reliable one to start with

[Guest]

@Greenfinger53 it's not really about the budget or an emergency though, the application is a nifty idea if you're looking for a low profile intake.

 

Food for thought and all that.

[F-E_Man]

@Saddam and @Greenfinger53 It's the same fan. Perhaps better. Perhaps worse. You have to look at the manufacturers specs to see what is in it. The best reverse bladed, external rotor induction motor, centrifugal fan I ever had was from a Neff. It came used, ran for years and was then given away. Where it was in use for years till they outgrew it.

 

A good one is better balanced than anything you find in the grow shop, because people pay hundreds for them, mounted in metal boxes, to go in the house. It's also wired to go different speeds. It is the superior fan if you get the right one.

 

Why do you think I posted it?

I swear people just like to shit on peoples parades more than learn anything here. Saddam even got 3 likes for making some stuff up, while I get just 1 for sharing, not an idea, but something proven over a decade or so. The carbon won't blow away, it's being sucked through ffs.

 

I have probably added more to the repacking thread than anyone here, and have more to add.

 

Seriously, your the choir preaching to the vicar.

Edited July 22, 2017 by F-E_Man

[Guest]

I think Saddam got the likes for trying to prove a point about quality, keeping it unbiased you do tend to get what you pay for we are all aware of that.

 

I have been looking at an East Midlands company that offer a unit for £50 with 5 year part and 2 year labour gaurantee.

 

Either way if I have a baffle on my cupboard fronting or one of these I still have to have some sort of box built on the fronting!

[Saddam]

I wasn't trying to piss on your fireworks IronMan, it's a good idea, someone should make flat, stealthy CFs instead of the standard round ones.   They're a pita to hang and aren't too stealthy either. 

Cheap fans are rarely a wise investment, might get you out of a fix if you're broke though.

 

[botanics]

Fucking crack on I say, if it fails then it fails, if it don't saved yourself some pennies and besides you don't learn really until a go has been had

[ineedofusername]

Like this post has given me an idea for a drying box I have a new extractor with twist in carbon filters that came with a hob oven set might build a box under it for drying and then the pipe into main tent for extra smell control