Hi,
I am new in this forum and of course new in CF, to tell you the through I surprised in this forum about the knowledge of the members. Second I must inform you that my English is not quite well so I am apologies if I don¢t understanding your meaning.
So my question is:
• Why we are using Vacuum bags?
• Can you show me with pics how to create bags!
• What Material is that bags?
• Is the vacuum any special machine?
Maybe the upper questions is silly, sorry.
Thank you in advice!!!
Vacuum bagging removes any air voids which is the weak link in any composite part. It also compacts the laminate so you get a stronger part. It is nearly impossible to vacuum bag a wet PER (polyester Resin binder) lay up as it “B” stages too fast but with VIP (Vacuum Infused Process), you can use PER. Wet lays, use Epoxy with a long “B” stage timing.
Special PE, PP or Nylon plastic sheeting for a higher temps and quality (you don’t want holes in the bag at all). and it is sealed with many things but sticky tape (looks like strip caulking) is the norm. There are also silicone track and lock strips for high production set ups too.
Vacuum pumps can be little ones to monster pumps, just depends on your needs: over lays lees pump, Pre-preg oven curing or autoclave…monster pumps to 30 in mercury of vacuum.
And welcome to our nightmare…
Why? it compacts the layers down, and if wetlayup, gets rid of the exess resin matrix which is weaker than the CF part. If prepreg, it compacts the layers down to avoid air spaces.
Check out Airtech (http://www.airtechonline.com/) and see if you can get a product catalog, they ahve some good info for beginers on why and how. Many pics. I am working on a set of pictures for my work, but isn’t complete yet.
Bagging can be most any kind of plastic. However, I don’t know what it is. There are economy ones, REALLY stretchy ones, and high-temp ones.
The vaccum pump is any kind really, as long as it can pull up to 25-27in of Hg. We have 2 continuous duty ones, one is large, vac only, and the other is a vac/pressure one, which means as it sucks one side, it blows on the other, so you can use it as a compressor, or a vac pump. Most run from 200$ up to 1000$ or more, depending on what kind, and how good.
do NOT use HVAC ones, since they are overly complicated, and are NOT rated to be run for a few hours.
Vac bagging is only one of many kinds of ways to make composites of course. But is the one way to make it perfect.
Riff42,
Can you give me some examples (make, model) of an inexpensive vacuum pump? I have no idea what to look for.
Thanks,
Chris
Try www.joewoodworker.com theres several pumps/manufacturers listed.
He sells a rebuilt Thomas pump for $159 that pulls over 20" with no problem. I bought mine from him a few years ago for $250. Its a cool little pump. All the plans for making your own system, and, all the parts are on joewoodworker.com
Gast is another company you my want to look at. They sell a cheap pump for $215. They also sell some full blown industrial pumps.
If you want cheap. This is cheap, and you will grow out of these systems quick. It wont pull much more than 11" with out straining: http://www.acp-composites.com/acp-vbs.htm
If you want expensive stuff here you go: http://www.torrtech.com/Pages/Pumps.htm
yeah, and do NOT get a HVAC vac. pump. They are not rated for continous duty, are expensive, and I still don’t understand what the 5 different ports are for.
I need to sell that and get a real vac. pump.
Also take a look at the Robinair 5600. I have been running 3 for 3 years all day and one finally went out 2 weeks ago. Plus they are pretty cheap. You can get them on Ebay for like $230
If you want cheap, try modifying a modern Fridge compressor (non CFC version)
I use one for making kiteboards and have not had a failure yet although I have imployed a built a homemade vac switch so the pump is not on all the time.
Works gret for me and has done for 3 years and over 10 boards.
where can you get fridge compressor? how much can they pull?
Since you are in Anaheim, there plenty of applinates repair shops or dead ones (leaking feon) laying around.