Other Vaccum Bagging

[swapmeet]

I've read some info on the X pertaining to this. I know Waternut used vacuum bagging to lay up his hull.

Since we have the Composites section now, I thought this would be a good place to consolidate info for this technique.
If anyone has experience with this, please post up your suggestions here.
What you've learned,

• What did work
• What did not work
• Where you recommend buying supplies?
• What other products can be used to save money? (I.E. I read where a guy used the intake on a small air compressor for a vaccum pump.

 

[txsuperjetfreak96]

X2

 

[XJCrawler]

What are guys using for cheap pumps and vacuums?

 

[BrightE's]

Bump for some expert opinions

 

[tokarzl]

http://209.20.76.247/ss/assets/HowTo-Publications/Vacuum-Bagging-Techniques.pdf

A venturi vacuum generator with a bronze muffler is a cheap way, the venturi generator develops 10 psi at 1 SCFM and is designed to run off shop air with at least 60 psi at 2 SCFM. This uses air from a compressor to create a vacuum and does not require a pump. Once your bag has reached a vacuum (14.7 psi) and you pass your drop test (Turning the pump off and watching the pressure if no change in pressure is found over about a half hour there are no leaks) the pump can be eliminated this can take anywhere from a couple minutes to 10-15 minsvfollowing the drop test, depending on the size of the application.

It is probably the easiest way, not the most consistant and if you do not have a compressor large enough to run constant 60 psi could be a problem.

not ideal but will work : http://www.harborfreight.com/25-cfm-vacuum-pump-98076.html

Make sure to use a good quality bagging material that will stretch a decent amount makes it much easier. Also learning on a flat part allows you to get a feel for the technique before taking on contours and complicated shapes.

 

[kevbo]

What are guys using for cheap pumps and vacuums?

An airbrush compressor is perfect for composite bagging, you can find used Thomas compressors for around $50. Venturi transducers are great if you have free compressed air otherwise your home compressor will be running all the time. Most dedicated bagging material is expensive because it is made for high temperature cures so it pays to be creative. I have substituted common Home Depot material for room temp cures. Practice before making an expensive part, everyone gets wrinkles at first.

 

[Kawastyler]

Here the greatest fairY tale off vacuum bagging:

You can work Inaccurate-the vacuum press the layers and you have good parts.

But it is complete other way round. Airbubbles were bigger in vacuum and PRESS RESIN OUT!!!!

You can dryout your layers with this!
Bigger vacuum the bigger is this effect.


Andy

 

[SirMrManGuy]

Here the greatest fairY tale off vacuum bagging:

You can work Inaccurate-the vacuum press the layers and you have good parts.

But it is complete other way round. Airbubbles were bigger in vacuum and PRESS RESIN OUT!!!!

You can dryout your layers with this!
Bigger vacuum the bigger is this effect.


Andy

Agreed. Get a big table, lay down plastic sheeting on top of it (fresh plastic for each layup session, I used Home Depot drop cloths or even cut up garbage bags a few times to cover the tables...area needs to be clean). Pre cut your sheets to fit your mold, mix your resin, then wet the sheets out, squeegee as much resin out as you can then do the layup. A second set of hands is really nice for moving larger sheets into the mold.

For a vacuum pump we had a Welch 1400 series pump (about $150 used on ebay) that was mounted to a 5gal air tank. The air tank had a valve manifold on it so you could evacuate the tank then use the tank to evacuate the mold quickly which is very useful for larger layups with tight curves (jet skis, vehicle bodies etc). This tank setup is also good if you have a smaller pump. Vac pumps are rated in terms of "hogging" and "holding." Hogging is a measure of how quick a pump can evacuate the air from a mold and holding is a measure of what pressure the pump can sustain. A smaller pump may have trouble getting all the air out of a mold in a decent amount of time, so the tank makes up for it. I've found cheap pumps to be a pain in the ass and venturi's were annoying, the Welch was great, spend the money and get one if you plan on getting even somewhat serious about this.

Other than that, just buy good supplies (quality tacky tape, peel ply, cotton and plastic). Its worse to loose a few hundred in carbon because you tried to cheap out on supplies that weren't meant for it. Also, I like using mold release wax and PVA for complicated shapes, makes the release easier. Also we had a few plastic wedges that were attached to an air gun for blowing compressed air between the part and the mold to get it to release (I think they were harbor freight felling wedges for chain saws with a hole run through them and tapped 1/4npt and air guns).

That said I haven't done much jetski carbon or anything other than room temp cures, but I've done a few vehicle bodies and racing seats back in the day.

 

[Kawastyler]

The best way to make compositeparts is vacuuminfusion. Use this since 2 years with best results. But you need a 100% sealed vacuum. Suck vacuum in the evening and stop pump. Next day must be the same vacuum, then start pump and infusion can start.

Hull is out off mold with no work on it after remoulding.

 

[SirMrManGuy]

The best way to make compositeparts is vacuuminfusion. Use this since 2 years with best results. But you need a 100% sealed vacuum. Suck vacuum in the evening and stop pump. Next day must be the same vacuum, then start pump and infusion can start.

Hull is out off mold with no work on it after remoulding.

You do great work!

Can you show us some more of the infusion setup (resin trap, hoses, pump, tanks etc)? I've done it once on a small part but never anything ski sized. Do you let the resin come flow in at multiple places or just one?

 

[Kawastyler]

Can make some pics tomorow......

 

[DarkWater]

Styler, you definitely make some sick looking composites.!

 

[txsuperjetfreak96]

^
^
Word

 

[WFO Speedracer]

If you are doing parts with lots of curves don't even think of using cheap vacuum bagging materials,you need stretchalon vacuum bagging plastic, vacuum pumps need to be sized to the job you intend to be doing, if you are doing a complete hull you need a kickass pump, for smaller parts a much smaller pump will suffice, putty tape which can be found at RV dealers makes a good substitute for vacuum bagging tape, again use common sense, if its a carbon part get the best materials you can afford.

I have pulled small parts with a compressor made from a nebulizer, small pumps are a PITFA, I upgraded to a Skylar lab equipment pump I got off Ebay for $75.00 shipped, it was worth every penny !

 

[Cannibal]

I plan on building one of THESE. They are fully automatic with a vacuum reservoir.

I've bought some epoxy from THIS PLACE and I'd like to give their Stretchlon bagging material a go.

 

[Stblaz08]

We use a vacmobiles. Pump and catch all in one for infusion as well as just vac baggin they work great and well with the money ....

 

[Kawastyler]

Beginning


20min later

 

[Kawastyler]

Hood

 

[sportfish258]

Take a look at www.smooth-on.com . They have an increadable vacuum and infusion technique . It's a little $

 

[swapmeet]

I have a airbrush pump I'm not using (I use shop air) so if that will work, that would be cool. Buddy of mine has a vacuum pump for AC work that he's not using. Said its pretty beefy.


My personal goals are related to reinforcement. I want to bag the layers of carbon and Kevlar onto the sides of my hull. Also I think I want to bag my tray. Ultimately I want to build parts, but the reinforcement will come first.

To the kawistyler guy, having a hard time picking up what your putting down, but I don't think I want to mess with infusion. Seems more difficult.

But you do make some great looking parts!

Where do ya'll reccomend buying the parts? I like where kevbo was headed, since I'm using low temp epoxy, I can probably save on some of the parts. Since he's local maybe I'll hit him up and share what I find. I may do a how to, or just incorporate it into my build thread... But I'll post a link here.