jester_s1

I'm sure it's been done, right? The idea is to make a PVC vacuum tank and use a ball valve (or something else that's better?) to seal it once the vacuum cleaner has done its thing. Does it work? Or is leakage too big an issue?

speedracerntrixie

My Feedback: (29)

Paul, I have yet to make a 100% leak free bag. For this to work you would have to be continually run the vacuum cleaner. The problem with that is the motor needs the airflow to stay cool. It would end up burning out the motor fairly fast.

jester_s1

Point taken.

rgburrill

Has anyone used the clothes storage vacuum bags? I've used them for clothes for years and the hold vacuum quite well. And I use a vacuum cleaner with them.

speedracerntrixie

My Feedback: (29)

I thought about those after making my reply. If I am correct I think the bag material is pretty thick? May still work for bagging wings though provided it will hold vacuum at a constant rate.

jester_s1

That's what got me thinking about it. Yes, the plastic is pretty substantial. They hold vacuum for a year or longer. I don't know if it's enough vacuum though.

speedracerntrixie

My Feedback: (29)

Or if it's too much. I bag wings cut with 1lb density foam at 5" vacuum. I think at around 10" the foam will crush. I had a vacuum switch failure once and discovered a 1/4" thick wing in the morning. For the cost of a set of cores and sheeting you can build a vacuum system.

rgburrill

Yea. they crush my shirts but the do hold for a long time. I guess just using the eyeball method for watching vacuum pull could be a problem using a vacuum cleaner anythime.

jester_s1

Speed, do you have a link to plans for a vacuum system? I' know about the EZ vac. If I build more, it would make sense. But I'm a one plane a year guy at best.

invertmast

My Feedback: (23)

veneersupplies.com

speedracerntrixie

My Feedback: (29)

Jester, all you need to do is buy the vacuum switch on the link that Invert provided, find just about any vacuum pump at a surplus store. Make a tank out of 3" PVC pipe and caps. Install the vacuum switch to the tank and wire the switch to the pump. Plumb a line from the pump to the tank with an automotive check valve. Total cost shouldn't exceed $75.

jester_s1

Pardon my stupidity, but there are a lot of vacuum pumps to choose from, and most are considerably more expensive than you're talking about. What kind of surplus store do you mean? I assume I'd be looking for a diaphram or piston type pump? For this application, CFM probably isn't a big concern?

sensei

***

speedracerntrixie

My Feedback: (29)

Jester, many guys are using refrigerator compressors.

Pylonracr

Jester, I splurged and bought a new vacuum pump from amazon for about $75 ish, the switch from Veneersupplies, and built a fairly large vacuum storage tank out of 15' of 4"ABS pipe, 2 T fittings and 4 caps in an H shape. Probably $125 or so in the whole thing and it has worked flawlessly for many years. I can turn it down to 5 inches for wings and up to 24 inches for carbon fiber components. Well worth the investment.

Scott

jester_s1

I scored a free mini fridge today. It's leaking coolant, but the compressor still turns on. So I'm going to get started building my system. Thanks to all of you who chimed in to help me. I've been flying for a while, but am pretty new to real building.

jester_s1

Looking at the veneersupplies website, I found the plans they have for the system which I've linked to below. They include the MAC valve and a few other items. The guide says that the pump won't restart if it's under vacuum already, which creates the need for the MAC valve. But it sounds like you guys are making it work without one? Their kit puts me at $171 without the pump.

ProjectEVS.pdf
Or I see this setup that's an air bleed/continuous run system that is a lot simpler.
https://www.joewoodworker.com/veneer...acuumpress.htm

Pylonracr

Jester, all you need is the vacuum switch. Build a vacuum storage tank out of some ABS pipe, the bigger the better, but what space you have will dictate the size. The switch will operate up to a 10 Amp start up current, and I don't see a mini fridge pump exceeding that. No on the MAC valve, not necessary for our systems. Pick up a 2" vacuum gauge and screw it into your tank: kind of hard to adjust the switch when you do not know how much vacuum is in the tank. I bought mine from Grainger for about 20 bucks or so. My old version of the switch is good from 2" to 25", the new ones are a high and low. I would get the low switch, and wire in a DPDT toggle switch so you can have off in the center, switch regulated one way and continuous run the other. For carbon you will run the pump to 20" or so and shut it off, turning it on as necessary throughout the day to maintain vacuum. If you lay up early, by the end of the day the resin should gel off and the 10" of vacuum regulated by the switch will be fine until the resin fully cures.

Scott

countilaw

It seems to me it would be easier just to buy the EZ vac systems and get everything you need to start bagging. By the time you scavenge all the parts and buy a pump you would have spent a lot more than the cost of the EZ vac system. https://store.acpcomposites.com/ez-vac-systems It's a lot easier to just take it out of the box and plug it in and use it, than trying to put one together just to save a couple of bucks, (which probably wouldn't happen anyway)

Pylonracr

The problem is the EZ Vac system has a pump rated for Up to 8" of vacuum. Pretty much useless for composite work, but if it could be accurately controlled it would bag wings. You are still back to needing a vacuum switch to control the pump.

Scott

countilaw

The pump takes care of its self. Bags wings perfectly. Don't knock something if you've never used it. Seems like we've heard from another "self proclaimed expert".

Pylonracr

One more TROLL to add to my ignore list

speedracerntrixie

My Feedback: (29)

The EZ vac system works for bagging/sheeting wings but that is about all its good for. Mine never gets used for a couple reasons. 1. It takes much longer to pull down a wing size bag then my pump/tank system. 2. One very small leak in the bag will reduce the bag's compression by half. The bag needs to be leak free, sounds easy in theory but sometimes you just have that tiny leak that you just can't find.

Pylonracr

Shawn, when was the last time you had a perfectly leak free bag? If you can do it every time I want to know how.....

Scott

speedracerntrixie

My Feedback: (29)

I manage one maybe 50% of the time while doing wings and flat panels. When bagging fuselage molds I hook up both pumps and aim for 20". Of course the home jobs are much easier then bagging the aft end of an Atlas SRB. Since we only had 90 minutes working time it took a team of 5 to get the bag in place and reach 24" of vacuum without running out of time.