[smoknrv4]

I'm looking to build a vacuum bagging set-up, for my foam wing scratch building projects, anybody have some ideas, or websites to visit on this subject. Some pictures of your set-ups would be cool also, for anybody that has one.
Thanks

[helibuff]

have a look at this site he as interesting stuff

http://www.nextcraft.com/vacuum_bagging_01.html

[Guest]

I had the same idea as I was about to start glassing my Mirage2000 2 weeks ago. I spoke with John Dutkoski of http://modelsbyjohn.com/. He has a ton of knowlege in the glassing area. He suggested NOT to vacuum bag a foam wing as it would simply collapse the foam.
Makes sense if you think about it.

I ended up laying 3/4 oz cloth and I bought the WestSystem for about $100 This was over the top I believe. You can get the same results with Finishing reson from HK for 5 bucks. The WestSystem may be the way to go for larger scale aircraft, but for an EDF or simlar, save your money.

[k.fluney]

Originally Posted by smoknrv4

I'm looking to build a vacuum bagging set-up, for my foam wing scratch building projects, anybody have some ideas, or websites to visit on this subject. Some pictures of your set-ups would be cool also, for anybody that has one.
Thanks

If you are going to sheet the Toni wings with vacum bagging, they don't need it. I just go the old way, thin foam cores can twist. Flat surface, with 3/4" plywood on top and two cement blocks for 24 hours. Wings come out perfect with no twists. Also not to much epoxy as well, just spread the epoxy on the balsa sheeting and take most if it off with an old CC. Also brush along the LE,TE,centre and tip, all you need is about 1/2" wide.
All of my pylon racers have been done this way.

Ken

[smoknrv4]

Yeah I was just going to do the toni the ole fashion way, that's how I've done all my foam wings up until now, this project of building a vacuum is for fun and experimenting, all your using is low pressure so foam cores don't disintegrate.

[Mike Emilio]

Originally Posted by vettster

, , ,
He suggested NOT to vacuum bag a foam wing as it would simply collapse the foam.
Makes sense if you think about it.

I certainly don't agree with that.
I've done alot of wing bagging, and never once had a core collapse. You only need maybe 3-4 psi, and that ain't enough to colapse nothing. If you crank it up around the 15-20 psi range then thats a different story, but who would foolishly do that with foam?

When I vacuum bagged the big Avro Arrow, I was running about 15-20 psi.
In this case, you need the extra pressure to extract more resin into the bleeder material.
In this picture, you can see that the gage is already about 1/2 way up the scale.

[smoknrv4]

Originally Posted by Mike Emilio

I certainly don't agree with that.
I've done alot of wing bagging, and never once had a core collapse. You only need maybe 3-4 psi, and that ain't enough to colapse nothing. If you crank it up around the 15-20 psi range then thats a different story, but who would foolishly do that with foam?

When I vacuum bagged the big Avro Arrow, I was running about 15-20 psi.
In this case, you need the extra pressure to extract more resin into the bleeder material.
In this picture, you can see that the gage is already about 1/2 way up the scale.

Absolutely agree, you got to use common sense. Just enough pressure to suck all the air out, and a little more to compress. I think its the only way to go personally.

[moo]

Originally Posted by Mike Emilio

When I vacuum bagged the big Avro Arrow, I was running about 15-20 psi.

Mike, if you have equipment that can draw more than standard atmospheric pressure (15 psi or 760 torr) let me know and I will make you very rich, as you have just rewritten basic physics. (or you are way below sea level)

at work we had a $5k vacuum pump and glass chamber that could draw down to 2 torr at work for plasma etching, even the pump oil was horrendously expensive


anyway: psi x square inches of wing = simulated weight on foam

[Guest]

Originally Posted by Mike Emilio

If you crank it up around the 15-20 psi range then thats a different story, but who would foolishly do that with foam?

Someone thats never vacuum bagged before I presume.

I think John was looking out for my better interest. Saved me a ton of extra work just to glass an EDF.

[Mike Emilio]

Originally Posted by moo

Mike, if you have equipment that can draw more than standard atmospheric pressure (15 psi or 760 torr) let me know and I will make you very rich, as you have just rewritten basic physics. (or you are way below sea level)

at work we had a $5k vacuum pump and glass chamber that could draw down to 2 torr at work for plasma etching, even the pump oil was horrendously expensive


anyway: psi x square inches of wing = simulated weight on foam

(15 psi is closer to 775.72 torr )


My pump is rated for a full 29" hg.
Oil filled, rotary vane, , , the oil was $60.00 per quart.

I don't use a vacuum gage simply because I need to know the pressure being applied.
When bagging, inches/hg means little, but the psi is very important to monitor.
I have an oil filled psi gage on it (bourdon tube design).

When I degass a mix of silicone, I go to maybe 22" hg .

My chamber is about 4 gallon in size with a heavy Lexan lid.
I can degass about 1 gallon of silicone in about 7-8 minutes.
I could put the vacuum gage on for this, but I don't bother.
Since I have a full diameter Lexan lid, I can see what's going on inside the chamber.
When the rising and bubbling stops, it's done, , , , so you don't really need any type of gage at all.