Vacuum bagging and Vinylester

Hi guys, is it possible to Vacuum bag vynilester resin ?
I'm talking of a full 10 mm laminate...or will the resin cure too fast?

 

How big of a panel are you talking about?
What kind of vinylester?
What is the temperature of the shop?
What type of material are you going to use to build that kind of thickness?
Have you done any vacuum bagging before?
What is the shape of your panel (i.e. how intricate is it, how much extra time is going to take you to apply your wet-pregs)

Would need to know these things before trying to develop an answer.

Vinylesters have longer open working times than polyesters or DCPD's, and you have enough of a thickness there to promote a good cure and barcol, its a thin skin that none of the resins listed above like to cure at when being bagged.

Because of the thickness your talking about, if you wet-preg and bag it your going to have alot of extra resin that you really dont need, have you thought about infusing the panels? or looked into infusion at all?

 

Hi Adam.
Thanks for your answer.
Attached the mould for the hull I'm talking about,it's a total of 15 m2,it still has to be faired and sanded,lamination will start in 5 days (hope so!)
I will not do the thing by myself, the yard will take care of that, I'm the designer.
I'm not shure about kind of resin,what kind should I use? and what kind of catalyst?

The yard and me are not big fans of infusion, here in my country many manufacts done that way are having problems of delamination,since this is a racing rib I would prefer to avoid that,also the yard has never done that.

Material used is mainly 0/90 825 gr (300 300 and 225 mat)
and some +- 45 825 gr (300 300 and 225 Mat)

Sorry for using metric units,if it's a problem i'll convert the numbers.

The reason I would like to go bagged is that I'm hopping that could help to eliminate somehow the resin in excess,and give better "numbers" in terms of structural properties...just leyt me know if I'm thinking wrong and wasting time.

 

My understanding of the dimensions is about 30 feet long and maybe 6-7 feet wide? is that correct?

I think if you were to wet-preg that and drop a bag on it, you'd throw alot of resin away in the bleeder.

You have a very good platform for infusion there in my opinion. Especially considering your wanted to eliminate excess resin. Infusion's these days are routinely running 70/30 glass to resin content.

Your already going to be buying and using the vacuum bag supplies (tape, final bag, peel ply, bleeder, etc) so to be able to put your materials in dry, pull vacuum on it and have time to get a perfect (or as close to perfect as you can get) bag in terms of inches of Hg, all you would have to do then is introduce your resin.

I don't have a ton of experience in infusing, but from what I do know nothing on that piece sticks out as being a problem in terms of flow rate.

I would check into the infusion if it were me, figure out the materials and run some test panels and then decide from there.

hope this helps

 

Yes, most any type of resin can be used for infusion and bagging, you just need to pick a resin with the correct specifications for each type of use. If you let the resin supplier know what you want to do, they can set you up with the correct product.

 

Thanks guys!
And sorry forgot the dimensions...25 by 7 ft

 

While it is entirely possible to vacuum bag a vinylester laminate,you ought to ask the resin supplier about problems with exotherm if,as it appears,you wish to bag the whole laminate at once.The other consideration is whether there will be time to apply the bag before the cure begins.Other people may have applied bigger vacuum bags but you need to understand the likely behaviour of the materials you will be using.

 

there are a lot of kind of vinyl ester resins on market specifically developed for the vacuum bagging and infusion, with long gel time and a low exotherm.
Off course more specifical is the resin, more is costly.
A low viscosity (at least 200 cps) and low styrene content is required too for infusion (and sometime for vacuum bagging too)
Be careful of compatibilty of 225 mat with infusion and vacuum bagging resins (binder), this is mostly the reason of delaminations, not only in Italy.
Continuous strand mat is commonly used together with uni/by/multy axial fibers because without any kind of binder and because work better as a flow media for the resin.
See:
www.reichhold.com
www.aoc-resins.com
www.derakane.com

 

hi,
me i'm using the vacuum bagging everyday for my job. I make 2 pieces by 8 hours and each piece have 36 meters long. This is some pieces for wind turbine blades. I also make a mold for a small boat in my garage and I will use the vacuum bagging process also. If you have some question about the process maybe I can help you.

just scuse my english....i'm french and not totaly bilingual....

PLS
from Gaspé, Qc

 

The extra effort to set up an infusion rig could be worth it on a hull like that. Bagging a wet layup will pull a lot of resin out into the breather, you'd need a really heavy breather and you'd waste a lot of resin. It would work, though.
If you decide to go wet-lay, instead of infusion, I'd suggest using a high-elongation bag like Airtech Stretchlon. These bag films are much quicker and easier to work with than conventional films, allowing you to get full vacuum much earlier in the cure. If the bag takes too long to apply, your resins are already starting to cure by the time vacuum is applied and so you end up with lumps and poor inter-layer bonding.

 

We used VE 9300-400 from Reichold but end up in Pre Relaease. Any suggestions