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Jim...question... do you use a shop vac or a vacuum-pump???

 
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TK 109
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Joined: 11 May 2007
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Location: Galena, Ohio

PostPosted: Mon May 28, 2007 5:41 pm    Post subject: Jim...question... do you use a shop vac or a vacuum-pump??? Reply with quote

I get decent results with my 5.0 HP w/d vac, but i can only put like 3-4 molds on the surface, or one REALLY big mold. I get good results, but i'm wondering if i can get a tighter pull if i boost the vac up to a pump. my oven works great (my corners actually get hotter faster than the center does now!), i'm just wondering if i can load more molds on the surface if i have a stronger vacuum.... WHAT DO YOU USE?
My dad and i demolished and tore out our spa on our porch, leaving behind a curious-lloking water pump behind. It appears to have a vacuum-port and an exhast-port. the pump is 1 HP, and is can be set for HI or LOW settings. could i just hook this up directly to the floor flange at the bottom (the vac-port, that is) using some pipe and just forget about the tanks and such, or do i need to go all out and buy all of that stuff?
Many, questions and info, i know, but.... I just want to know... Very Happy
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jegner
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PostPosted: Mon May 28, 2007 7:53 pm    Post subject: Reply with quote

Hello!

I have a shop vac. 6.5hp if I recall, and it does what I need done. I do have a Robinsair pump, and a 28 gallon tank, but have to replumb for the switch over to hi-vac.

Honestly, as long as I'm pulling HIPS its hard to upgrade to vac system, but when I need to do some ABS or PETG, I'll switch then.

I get good results with a shop vac too. As far as the number of parts, or the size of the mold, I have not noticed much differnece.

Jim
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TK 109
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Location: Galena, Ohio

PostPosted: Tue May 29, 2007 5:11 pm    Post subject: Reply with quote

if i wanted to go "hi-vac", would i have to buy a tank and fittings and such, or can i just hook the spa water pump up to my forming platen? Confused
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jegner
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PostPosted: Tue May 29, 2007 6:35 pm    Post subject: Reply with quote

That gets into CFMs, and unless your hi-vac pump is really fast, mostlikley, you will need a tank to hold a resivor of vacuum. The pump evacuates the tank, the tank is the vac you use.

Hi CFM is 10-20!
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drcrash
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PostPosted: Tue May 29, 2007 7:53 pm    Post subject: Reply with quote

TK 109 wrote:
if i wanted to go "hi-vac", would i have to buy a tank and fittings and such, or can i just hook the spa water pump up to my forming platen? Confused


I don't know if the water pump would work at all. Its design may depend on the physics of water in one way or another. (To maintain its seals, to run at roughly the right RPMs, and/or for cooling.) If you pump air with it, it might not have the right torque, might over-rev, and might burn out. Or it might just not suck very hard. (It's probably a centrifugal pump, and water weighs a whole lot more than air, so it might not throw the air around very hard.)

If you have nothing better to do with it, you could try it. You will presumably need a tank.
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TK 109
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PostPosted: Sun Jun 03, 2007 2:51 pm    Post subject: Reply with quote

how much would this beastly tank system cost? Cheapest? How do i plumb it? do i even need a tank? Confused Question
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drcrash
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PostPosted: Sun Jun 03, 2007 5:35 pm    Post subject: Reply with quote

TK 109 wrote:
how much would this beastly tank system cost? Cheapest? How do i plumb it? do i even need a tank? Confused Question


Unless you have a very high volume high-vacuum pump (and those tend to be really expensive) you need a tank. But that is usually the cheapest part, i.e., free. (An old hot water heater tank from a broken or upgraded hot water heater that somebody will give you if you're willing to haul it away.)

Or for a small former, you can use a $20 air carry tank from Wal-Mart.

The plumbing isn't very expensive. For a one-stage high-vacuum system, you need a ball valve ($6-12 depending on size and whether you find it on sale at Harbor freight. You can often get 1/2" fully ported quarter-turn ball valves for $5 there, and 1" valves for $10. For a 2 x 2-foot former, go with 3/4")

You also need a few feet of PVC pipe (a few dollars) or large-diameter hose (also a few dollars, by the foot at Lowe's), and a few fittings that cost a dollar or two each. (PVC or galvanized, whichever is cheaper.)

For a two-stage system with a vacuum cleaner plus a vacuum pump & tank, you also need a big check valve (like a sump pump check valve a la Doug Walsh, around $7 at Lowe's).

It's nice to have a vacuum gauge (a NoShok costs $3.50 plus a few bucks shipping from the online store on eBay), and a few cheap fittings to connect it. With fittings (a $2 tee, a $1 adapter, and $1 worth of PVC hose), that'll probably set you back about $12.

So, very roughly, $25 or so for the most basic plumbing, not including the pump or the tank. Add $20 for a small tank, or $40 for two, if you just want to run out and buy something, but really, look for a free one if you have the space for a water heater tank. Add $12 for a vacuum gauge. Add another $10 for two-stage operation. (But if you have a big free tank and a fast enough pump, you don't really need two-stage.)

But before you spend money & time on the actual plumbing, you might want to ge t a vacuum gauge and see if your spa pump will pump air well enough to bother with it.
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Tired of buying cheap plastic crap? Now you can make your own! www.VacuumFormerPlans.com
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TK 109
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PostPosted: Mon Jun 04, 2007 2:49 pm    Post subject: still many questions! Reply with quote

could i just buy all that stuff cheaply from lowes or home depot (forget home depot, they suck at everything Laughing )?
what size plumbing fittings do i need? do i need a certain ype of hot water heater (30 gal, 20 gal, etc.)? many questions still left unanswered...
It might just be easier is you just told me everything you know about vacuum-pump systems for vacuum-forming... Embarassed
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drcrash
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PostPosted: Mon Jun 04, 2007 3:27 pm    Post subject: Re: still many questions! Reply with quote

TK 109 wrote:
could i just buy all that stuff cheaply from lowes or home depot (forget home depot, they suck at everything Laughing )?
what size plumbing fittings do i need? do i need a certain ype of hot water heater (30 gal, 20 gal, etc.)? many questions still left unanswered...
It might just be easier is you just told me everything you know about vacuum-pump systems for vacuum-forming... Embarassed


It's all here on tk560.com somewhere or other. (Hence my suggestion that we have some topic index threads.)

Almost all the stuff is easy to find at Lowe's, but you can find better deals on some of them if you shop around (Home Depot & Harbor Freight have cheaper prices on some things, like ball valves at Harbor Freight).

The ball valves are just regular plumbing valves you can find in any plumbing department. (Make sure they're fully ported quarter-turn valves. "Fully Ported" means that the ball in the valve has a hole through it that's about the same diameter as the pipe size inside diameter. "Standard Ported" valves don't, and will restrict flow somewhat.) Bronze ones aren't very expensive, especially at Harbor Freight, and plastic will do fine, too. I use bronze ones because you can get them with threaded connections, and hardware stores generally sell the plastic ones with socket-weld connections only. (You can get them with threaded connections online.)

What sizes you need depends on how big a vacuum former you're making. For a 2 x 2 foot single-stage high-vacuum system, I'd go with 3/4" pipe size, maybe 1" for a low-vacuum-only system. (A low vacuum system will suck somewhat less air per unit time through the same size pipe, but not a whole lot less, surprisingly enough.)

For a small former (up to 16 x 20 or thereabouts) 1/2" pipes & valves, and 5/8" high-pressure washer hose (on 3/4 hose ends with 1/2" NPT fittings) will do fine. There's not much point in going smaller than 1/2" for the main path between the platen and the tank, even for a much smaller platen, because the stuff just isn't very expensive, and smaller ball valves are actually more expensive. (Because they're not common plumbing fittings.)

For a two-stage system using a vacuum cleaner (a la Doug Walsh), up to 2 ft x 2 ft. or so, you can probably use the same 1/2" stuff on the high-vacuum side, because most of the air never goes through the high vacuum system.
(You'll use a 1 1/4" sump pump check valve for the path to the vacuum cleaner.)

For a two-stage, two-tank system with no vacuum cleaner (a la me), you'll want the same size valves & pipes as for a one-stage system. (Because most of the air does go through both of the ball valves.) The valves are pretty cheap at Harbor Freight, though, even for fairly large ones. (Like 1", which is big enough for a 2 x 4 foot platen.)

For gauges, 1/4" inside diameter PVC tubing is fine, and cheap at Lowe's; you can get the gauge with a 1/4" hose barb on it that plugs right in. (Actually, 1/8" is fine, too, but 1/8" fittings aren't as common and cheap.)

Lowe's (my local one anyway) has a pretty good selection of brass and nylon hose barb fittings. Brass is nice, but nylon is fine too (and cheaper).

The only parts of the plumbing you're likely not to find at Lowe's are:

1. the vacuum pump and
2. a good check valve to put ahead of your pump (the McMaster-Carr catalog is probably a better place to look)

Everything else is just plumbing stuff, in the plumbing department, or in the case of hose barbs with NPT (regular pipe thread) fittings on the other end, you may need to look in the air tool accessories rack.
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Tired of buying cheap plastic crap? Now you can make your own! www.VacuumFormerPlans.com
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TK 109
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Location: Galena, Ohio

PostPosted: Tue Jun 05, 2007 1:30 pm    Post subject: Reply with quote

shweet (yes, shweet Smile ) good information, thanks man! Very Happy
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