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/diy/ - Do It Yourself

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File: 55 KB, 800x800, vacuum-pump-dst-25-800x800.jpg [View same] [iqdb] [saucenao] [google]
1330520 No.1330520 [Reply] [Original]

So I am in the process of building a vacuum veneer press for my shop.

I am currently planning on using a 25m3/h pump, that is capable of producing a 95% vacuum. The type of tubing i initially planned on using has an internal diameter of 12mm. However, after talking to one of the guys at a shop, that sells pumps, he told me, that 12mm is too small of a diameter. That seems strange to me though, since 25m3/h only equals like 400l/min. Compare that to a vacuum cleaner, which has 4x the volume per min, but only twice the hose diameter at 25mm.

Am I being bullshitted? What hose diameter should I choose?

>> No.1330524

The diameter shouldn't matter much. If the guy couldn't tell you why it's too small then he's just an idiot talking crap. What should matter is the wall thickness so it doesn't get crushed under the pressure.

>> No.1330525

>>1330520
>Compare that to a vacuum cleaner, which has 4x the volume per min, but only twice the hose diameter at 25mm.


doubling the diameter means the area goes up by 4x, so it's equivalent in that sense.

>> No.1330531

>>1330524

Of course the diameter matters. You cannot suck 400l/min through a 2mm*2mm hole, just like you can't vacuum your floor with a garden hose, since there is just too much flow resistance.

>>1330525

I am going for a 3/4" inch tube, reinforced with a steel wire, now just to be on the safe side. Additionally, this should allow me to evacute the press really quickly in the beginning using a 200l vacuum tank.

>> No.1330533

>>1330531
>You cannot suck 400l/min through a 2mm*2mm hole, just like you can't vacuum your floor with a garden hose, since there is just too much flow resistance.
But you can you faggot. You just get lower l/min you fucking faggot.
Why are you even asking if you are so smart you fucking faggot?

>> No.1330537
File: 212 KB, 1218x1015, 1513088135323.jpg [View same] [iqdb] [saucenao] [google]
1330537

>>1330533

>You can suck 400l/min through a 2mm*2mm hole, you just get lower l/min.

I don't even....

>> No.1330538

>>1330537

I think the angry one was saying that he can vacuum with a garden hose.

>> No.1330542
File: 152 KB, 750x626, 1518265637283.jpg [View same] [iqdb] [saucenao] [google]
1330542

>>1330538
>I think the angry one was saying that he can suck a golf ball through a garden hose.

>> No.1333030

>>1330520
It doesn't matter at all.

Vac pumps are so slow that you can use 1/4 tubing like for an ice maker and it'd be fine.

>> No.1333035
File: 68 KB, 1000x1000, sioux-chief-hydroponic-irrigation-tubing-900-02206c00101-64_1000[1].jpg [View same] [iqdb] [saucenao] [google]
1333035

>>1330520

The problem is that, at very low pressures, the pressure drop through a tube becomes a significant portion of the pressure available in whatever you're trying to evacuate. This is why high-vacuum chambers (like those for electron microscopes) have relatively large hoses.

That being said, 95% vacuum (~1in/Hg) isn't a terribly hard vacuum. For vacuum degassing epoxies and general fuckery, I just use the thick, nylon-reinforced braided vinyl hose from the hardware store, which has the same 12mm ID you're looking at. Pic related. Cheap, available, and it works great. For vacuum lamination, I don't imagine you'd need anything fancier.

>> No.1333035,2 [INTERNAL] 

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