Hi guys
To guarantee a perfect wetting out of the cloth and a high fiber fraction what do you think about infusing the diy prepreg?
After the cloth is infused can I stop the process and lay the bag with mesh and peel ply into the fridge?
I am specially interested in diy prepreg because that way I could use standard nomex in my pieces.
I guess the vacuum cycle when curing will take care of most of the air voids.
Also normal prepreg resin is quite sluggish, so hard to infuse.
And the resin loss when infusing 1 layer of carbon is dramatic. (a lot goes in the infusion mesh).
I dont care much the resin loss as I will wet out 3 layered multiaxial cloth 0/+45/-45 in one step.
I dont understand very well your first point. Do you mean that as I stop the infusion air will get into the wetted cloth but that this air will be correctly removed in the final vacuum curing cycle?
On your second point:
I have heard of people using standard resin for diy prepregs and interrupting the curing with -18ºC.
Is the use of special resin a requisite?
i use a regular epoxy system for pre preg. I use a medium hardener. Its good for about a week in the freezer. I also had a really slow hardener that would be good for over a month. I didn’t like that stuff though. I really like making my own. This way i can use a resin system i like and the curing temps are much lower. I use painters plastic to to pre preg the carbon on. I still haven’t been able to get that embossed sheet yet. I haven’t seen it in less that a 2000 ft roll.
No, just that a perfect impregnation at first might not be needed, as during the final cure cycle air voids will be taken care off.
On your second point:
I have heard of people using standard resin for diy prepregs and interrupting the curing with -18ºC.
Is the use of special resin a requisite?
No, but to obtain best results…
Anyone ever find a source for small quantities of the embossed plastic? Any epoxy recommendations?
i have given up on the embossed sheet. a friend of mine tried a smaller supplier. It took 30 days to get a response. in the end. They were not interested in dealing with small amounts.
If the Airtech embossed film is any good, I can see what I can do re. smaller rolls (100 meter or so). I usually can get Airtech in the spot where I want it to be (but sometimes not…)
After some searching I MAY have a possible solution. I found polyethylene embossed film available on EBay as “plastic mulch”, which is embossed with a taffeta pattern. It is available by the roll for about $100 for about 800yrds plus shipping. That makes cost pretty cheap and you aren’t stuck with a palate of plastic. It looks like everything else is the similar. Thoughts?
I looked on EBay but couldn’t find the particular pattern that you mentioned. I’ve long thought there must be something out there that will work as well; spent some time looking into films used by other industries. Found some stuff used by the tire industry but nothing I could get a sample of.
Here is the link:
http://cgi.ebay.com/Plastic-Mulch-Film-4-Black-2400-1-25-mil-Row-Cover-/220465599810?pt=LH_DefaultDomain_0&hash=item3354c61542
I search embossed plastic film, or in this case embossed plastic mulch.
this is the embossing and it is just plain polyethylene and it is available in up to 8 foot widths. I did contact the seller to get this info, it isn’t listed in the auction.
Thanks for the lead Rob. Interesting.
I have been very pleased with misting spray adhesive on dry fabric to produce prepreg-like handling/fitting characteristics
Hi,
I’ve been interested in this thread for a while but the difficulty of finding the embossed plastic seems to be a problem.
I’ve found that pro-set sells an embossed vacuum bag material (see link)
http://www.marineindustrial.co.uk/index.php/vacuum-bagging/embossed-vacuum-bagging-material.html
Do you guys think this would work?
If I am laying three layers below the core and three above the core would you prepreg three layers in one step and the other three layers in another step? The mold has little curvature and no corners (wing mold).
I received a sample of the Micro Embossed film above and I think the embossing is too fine to do a good job releasing. The pro-set stuff that jordi mentioned looks like it could work.
Jordi - would it be possible to request a sample and let us know how it works? I wonder if there are any sources for that stuff in the US.
Borridos - for even saturation I think you would do one at a time.
I thought about preimpregnating three layers altogether using vacuum infusion that way I would get an even wet out.
Humm, I hadn’t thought about that. Interesting idea. Lots of process involved though.
Well two infusions are less work than wetting out 7 layers of 7 sq metre each.
And flat infusions shouldnt be troublesome and the process should have an ideal resin content.
Another solution would be to use compoflex against the mold to be able to infuse eurocomposites closed nomex honeycomb. The dealer told me it works, however i would distort the wing mold by 0,6mm. The finish is ok according to him but not glossy.