seanreit

My Feedback: (60)

As it applies to layups in a mold if any?
THE BIG SUCKER BOTTOM OF THE PAGE:

http://winshiprc.tripod.com/carbon_fiber_composites.htm

cactusflyer

My Feedback: (4)

Sean,

I guess I don't understand the question. The verbiage on the web page pretty much spells it out. I have cone quite a bit of bagging with the Aerospace Composite set up and it works nice. The only drawback it the small volume that the pump delivers. For a large bag such as a fuselage layup, I piggyback another tank onto the system to store some vacuum so that the initial pull down goes rapidly. I guess the larger volume slows down the cycle time of the pump as well.

It looks to me like the "big Sucker" just handles more volume and I'll bet that the pump will last forever in a hobby application.

I hope that this helps,

John

Robrow

I use similar types of pumps with all kinds of composite layup's both wet and pre-preg most every day, what exactly is it you need to know Sean? Is it the fuction of a vac pump in layup's or why this particular pump?

Rob.

patf

My Feedback: (4)

Sean

I think the last few sentances sums it up. This is for larger applications, a small aquariums style pump on a large layup can take an hour to get things going. this large one will get it under pressure quickly

seanreit

My Feedback: (60)

I have the high end vac pump, I just could not wrap my head around the need for the pvc pipe tied into it. I guess you pull the vac in the pvc, and then open a valve inside the vac bag and whamo?

Seems to me you would want a slower pull down of the vac bag, at least in my experience. Thanks for the help.

Hustler58

My Feedback: (1)

Sean, I have my vacuum hooked up to 60 gallon compressor tank. And the line that goes to the part I am bagging has a valve so I can regulate the vacuum at the part. I open the valve to vacuum fast and then when it gets close to the final pull I slow it down so I can adjust the bag as necessary. Once the bag is pulled tight I open the valve all the way to get all the vacuum I can. The picture is of a spinner I make for Hawker Sea Fury's. The spinner is larger than normal. They use them to race at Reno. It adds 15 knots to the plane.
Butch

mr_matt

My Feedback: (10)

The PVC tank provides a buffer, a storage tank of vacuum.

The vacuum switch has hysterisis, so the large tank means a longer time between switching on of the pump.

mr_matt

My Feedback: (10)

Butch what is that breather material? And have you ever tried a flexible bag material (almost like a sheet of rubber)?

seanreit

My Feedback: (60)

Matt, so refreshing to see there are some who understand the value of that concept!

Thanks for the additional info Butch. Guess I'll get one of those portable 20 gallon compressor steel tanks and make one up for myself. What adjustable valve do you use? Can I just use one of those air compressor valves with the knob on the side, and get a vacuum gage for it instead of a pressure gave? And hook it to a T to static air like I do currently? I'm using a pvc valve right now to regulate vauum, but my gage jumps around a bit and I think it's because I'm using such a cheap valve (like two bucks at home depot).

Also, where do you get your switch Butch? And do you use the relay? Or just a pressure switch.

Robrow

The pumps we use have multiple individual ports which are isolated from each other and have independently variable vacuum pressure. They also have moisture traps as quite often when pressure is pulled down we get condensation.

Usually we have to use more than one port on multiple jobs on multiple vac posts. One will be used to pull down the inner bag to the cast/positive, then the layup is applied, followed by the outer bag. All the air is then pulled out before any resin introduced on a wet layup.

The bag material is either pva or pvc or even latex. The pva bags are used wet, this makes then very flexible and allows them to conform to any compound shape. PVC bags are heated to give them the flexibility to conform.

Main resin we use is acrylic on wet jobs, 1 hour from mixing to fully cured, it's usually 80% rigid/20% flexible just to take the edge off the rigidity.

PVC pipe is used because of it's wall thickness and resistance to collapse.

Hope that helps, Rob.

Robrow

By the way materials we use include carbon woven 12k and 6k, carbon/glass, carbon/kevlar, uni and woven, also nylglass mix. Also forgot polyyurethane resin as well as dozens of thermoplastics PE,PP Northplex (mouldable type of perspex , etc.

We have a lot of offcuts so anyone that would like to try something just let me know.

Rob.

Hustler58

My Feedback: (1)

I use a polyester felt. I buy it from De-Comp Composites. I have never used the flexible bag material. Would like to!

ChuckC

My Feedback: (24)

Sean,

I have the exact pump and am using an old 25# Freon can - the size of a gas grill bottle - as a reserve tank. It's nice and fast and allows the pump to cylce just like an air compressor.

You can also get all the parts from Airtrol - I got the vacuum gauges, vacuum regulater and vacuum switch from them. VERY easy hookup, just exactly like an air compressor. Ended up using thinker walled, semi-rigid poly tubing and Festo fittings. The jump up to this quality pump and set-up is really nice; the pump will still cylce even with a leaky bag.

seanreit

My Feedback: (60)

I have the nice vac pump, is there a link to the cycle switch off pressure?

ChuckC

My Feedback: (24)

This is what I am using:

Homepage - http://www.airtrolinc.com/

Specific switch I'm using - http://www.airtrolinc.com/components/f4200x.htm

I think I got the 10 amp switch and I have a bigger vacuum pump....huh. :-)

It's worked great for me so far; you just have to get a myriad of fittings and teflon tape. I think I got most, if not all my threaded fittings at Hoe Despot. I got mine from Grace Technologies - there's links to vendors on their page. They'll mail them.

454

My Feedback: (9)

hustler58 can you make those for a merlin III B I would love to tell the Boss that two new spiners would give us 15 knots

( not really kidding)

sirrom

My Feedback: (4)

Sean,
Even though you are a JR man I will post this information which will show you how to make the pump from your initial link. Go and read the following. I actually made one of these and it works extremely well. You could probably use a bigger pump or bigger PVC pipe, but for wings and stuff it works well as they describe it.

Patrick

seanreit

My Feedback: (60)

Huh?? "Go and read the following" did you forget a link?

sirrom

My Feedback: (4)

sorry Sean. I thought I posted it.

http://www.joewoodworker.com/veneering/welcome.htm

dragonpilot

My Feedback: (38)

You could buy or build one of these. They hook up to your air compressor or your pump/drum configuration. Set it and walk away.
These aren't cheap but I'm sure you can build one. FWIW...
maybe some info from their website is useful to you www.qualityvak.com