Basic Vacuum Bagging Set-Up

Basics of Vacuum Bagging


Vacuuming bagging is a technique used to create mechanical pressure on a laminate during its curing cycle. During vacuum bagging, layers of reinforcement and resin are laid-up by hand before being sealed in an air-tight environment. It is then attached to a vacuum source, which pulls the air from the bag and creates the desired pressure. Why would you want to use this technique? Well, vacuum serves several functions.

•Vacuum bagging removes trapped air between layers.

•Vacuum bagging compacts fiber layers, making for more efficient remission of force between fiber bundles.

•The force created during the process prevents shifting of fiber orientation during your cure.

•Vacuum bagging will reduce humidity within the product

•Ultimately, it will optimize the fiber to resin ratio in the composite part.

Vacuum Bagging Setup


The Following diagram highlights the basic vacuum bagging setup.

Setting up vacuum bagging

Films, Peel Ply, and Tapes


The first materials you must consider are the films, peel ply and tapes. When choosing these for your vacuum bagging project, it’s important to consider the following:

•What is the size and shape of your part?

•Does it have a deep cavity or sharp corner?

•What temperature range is your lay-up?

These will all factor into the decision making process for your film.

For individual product information, check out the Fibre Glast Films, Peel Ply and Tapes Store Page.

Fittings and Tools


Next, you will want to look at your vacuum fittings. These are used to create air-tight connections between your part and your vacuum source. Without connections that are leak-proof, your vacuum bagging projects will be dead in the water.

During this time, you may also wish to look though vacuum bagging Tools. These tools are important for setting up and monitoring your vacuum bagging system. From air detection to basic cutting implements, each of these ads a degree of convenience and efficiency to your project that will save you both time and money.

You can view our items at the Fibre Glast Vacuum Fittings Store Page as well as the Fibre Glast Vacuum Tools Store Page.

Vacuum Pump


Finally, you will need a vacuum pump for your vacuum bagging system (we imagine it would be hard to get your project started without one of these.) Fabricators have two options when it comes to this; a vacuum pump or a vacuum generator that is used in combination with an air source. In order to determine which is correct for your project, consider the following

•Basic size of pump and part

•Rate of air displacement in cubic feet per minute (or CFM)

•Ultimate pressure, measured in inches of mercury (or Hg)

For information on individual pumps, check our listings via the Fibre Glast Vacuum Pump Store Page.

Further Information


For betting understanding of these factors and the vacuum bagging process, we offer a white paper on Vacuum Bagging Equipment and Techniques. To get a better picture of the process of vacuum bagging, check out our YouTube video tutorial below.

Interested in starting up a vacuum bagging project? Let us know your opinions in the comments below. Be sure to check out our Facebook and reach out to us on Twitter @FibreGlast for more news in the world of composites.

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1 scott campbell { 02.25.13 at 1:48 am }

i enjoy your videos, and i ask you to get either some people there of find online to get people to visit and use this valuable resource you have. it seems vastly underused for these “black arts”.
each one teach one!

2 TJ Wheeler { 09.24.13 at 11:17 pm }

trying to find low cost vacuum bag for EVA laminate processing at 150C or about 300F that is affordable, and either disposable or reusable. These are the Normal processing temperatures, not the max needed for the bag, which would be higher.

3 { 09.25.13 at 1:54 pm }

Thanks for the question TJ.

Unfortunately, we aren’t familiar with EVA laminate processing. Sorry we can’t offer a product recommendation for you.

Good luck with your search.

4 Johnk416 { 05.20.14 at 5:30 pm }

I truly appreciate this article.Really thank you! Fantastic.

5 Adam Marosi { 11.25.15 at 12:35 pm }

Thanks for the explanation on Vacuum Bagging Setup.

6 Bill { 11.30.15 at 8:44 pm }

I will be repairing the underside of a hull (upside down repair). Would vacuum bagging work with a wetted out multi-layered reinforcement or would vacuum infusion (Resin Transfer Molding [RTM] ?) be a better choice due to the weight of a large wet laminate placement upside down

7 Bill { 11.30.15 at 8:48 pm }

With regard to my previous message today, are there wetting agents readily available for epoxies to decrease the surface tension of the fibers for better wet out in resin infusion (RTM) or is this not necessary?

8 Bill { 11.30.15 at 8:51 pm }

What kind of vacuum power would be required to pull resin up both sides of a hull on a repair 36″ wide X 60″ long – the resin traveling through the reinforcement equally on both sides of the hull for approx. 18″ each side?

9 Baleegh Zaman { 01.03.16 at 1:34 pm }

dear it is nice to have such a blog

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