Due to cost considerations with our student car I won’t be able to make a female mold this year and will have to mold straight off a plug. I was wondering if there was a good method to cheaply remove most of the peel ply texture. I’ve read about using clearcoat or brushing resin on but I’m curious to know if there are any other methods too.
Thanks in advance!
If you’re bagging this. Instead of using peel ply you can use release film either perforated or not right on the finish surface but this will still leave a stippled surface. Wooden boat guys came up with other technique using plastic film to reduce the amount of finish work required.
See: http://forum.woodenboat.com/showthread.php?79616-quot-Toner-quot-topcoat-to-hide-blushed-epoxy
But this only works for relatively flat surfaces.
If you’re just using the peel ply to consolidate a wet layup without a bag I think Duratec VE clear top coat sprayed would work great. Adds some weight though.
are you painting it afterwards? if so the peel ply texture is good for spraying on and regardless youll have to sand the primer before painting.
I have to use peel ply since I’m infusing this part. Infusing with release film didn’t work out well the one time I tried. We are painting this.
I’ve never really painted parts either so I’m guessing you spray a primer on first, sand and then spray the actual paint? I know you have to do this for houses and cars but I thought you could paint directly onto epoxy without primer.
I wasn’t thinking infusion. Sorry.
You can paint directly on epoxy but filling the peel ply texture usually requires some sort of building primer or other finishing.
thats correct, you need to primer first, sand down then paint. I wouldnt worry about the peel ply texture if I was you. You should have no problem peeling the peel ply off and spraying with a duratec primer.
Cool, thanks guys! I’ll do that then. Wish I could build a female mold and do this right but I can only do so much with limited funds.
How many parts are you going to make off it? If you’re only going to pop 1-3 parts off, you might want to look into a plastic faced plaster tool. The majority of your cost will be in your surface coat, which isn’t TOO bad. The rest, you can bulk up with plaster. Its cheap. 
As for the peel ply, I’ve heard mention of peel plies that are very fine, but I’m not sure about their use in infusion, nor how ‘fine’ the surface finish really is. I need to do the same thing and will need a fine peel ply for parts that require looking ‘pretty’ on both sides and I also want to try to pull off a male plug while still retaining a good surface finish. My supplier for materials is in Riverside and I’ll ask him about it. If it works out for me, i’ll let you know and give you some.
I’m only going to make one part and if I make another it’ll be because I messed up the first one. How would I make a plaster faced one off tool and what materials are required? A cheap ok mold is pretty much the best I could go for at this point.
Right now the peel ply I use is that light green teflon coated one from Airtech. Finer weaves would reduce the texture a bunch. I’m glad your supplier is in Riverside since that’s local for me. At this point I don’t have much time to wait for shipping!
Thanks
Get Airtech release film with MP22 perforation. (WL3900 film will do). This will work perfectly for infusion.
For one-off female moulds you could CNC the mould from PS foam (heavyweight, some 80 kg/m3) then pull a flexible film into the cavity with vacuum (Stretchlon 200 film or PVA film). This will usually give satisfactory results, and this is how TU Delft University does it for their Formula car.
You just need some surface coat (epoxy), some torn up chopped strand, and some ultracal 30 by US Gypsum. I think the closest place that sells it is a place called Laguna Clay in Industry, CA and from what I remember, its $30 for a 100lb bag. Drive to Redondo Beach, and I’ll give you my bag. To make the PFP tooling, just apply a layer of surface coat to a prepped plug. Once its tack-free apply a second layer and throw all the torn up chopped strand matt onto/into it, mix your plaster and back up the whole piece with it as quickly as you can. The heat of the curing plaster should aid the curing of epoxy surface coat
So you can place the MP22 perf-release film directly on the part prior to the peel ply and it’ll infuse just fine? You still probably get SOME pattern transfer from the peel ply I’m sure, but that sounds like a good option if you want a part to look nice on both sides.
You are missing something. Peelply is only used directly against the laminate, to provide a course surface.
Although peelply can be peeled off, it is never ment as a separating layer between laminate and consumables. That is what perforated film (release film) is for. This lifts off without any problem or effort.
For infusion, you do need a very open perforated film, such as MP22, P1, P16 or P perforation.
For wet bagging you can do with P3 or P31 perforation, depending on your needs.
The great thing about laminate-peelply-releasefilm-infusionmesh schedule is that you can easily lift off the infusion mesh (together with the release film) and keep the peelply on as long as possible. Any contamination that might occur will not harm the product.
Also it is so much easier to pull the peelply off, as you do not need the infusion mesh to come with it.
I see. So its main advantage is in aiding the removal of consumables from the part. That sounds like something realllllly worth trying, considering how much effort it took me to remove the peel ply from my last part along with the flow media. I thought you were suggesting it as a means of reducing the peel ply texture from the part.
I went to DOD composites training and have some pretty extensive composites fabrication experience…so take that for what its worth.
Id like to chime in and say that peel ply is a barrier for consumable materials… technically speaking.
It can sometimes be used as a separating medium so that a better resin matrix is achieved when using pre preg laminates as well as wet lay up process.
Here is just a sample stack up process for a better understanding. Generaly for graphite scarf repair 2 layers of peel ply with a layer or two of glass, then perforated film. Woven breather is then layered and then the stack up is bagged.
The first layer of peel ply will leave a slight pattern on the surface depending on how its tailored. But… the second layer seemed to help keep the surface slightly finer in texture.
The glass is used as an absorbant layer and the woven breather works well to increase vacuum on tight corners or buckets and keep the bag from leaving any pattern.
I would reccomend using a thin layer of glass on top of the composite then using peel ply over that… you could easily sand the glass smooth and not distort carbon weave pattern. This is kind of a not widely used method in the commercial diy sector but is used quite often for corrosion preventative methods in aerospace composites fabrication.
FYI thin glass is generally transparant when wet and cured and is very easy to sand. Trust me once you break in to the carbon you will know it right away… when wet sanding.
In lamens terms it would be like using a “clear” high build sanding primer when doing body work on cars… you can block sand the glass layer for a super super slick straight part.
And if there are any over lay guys reading this consider this a method to greatly reduce the time it takes to do roof cap overlays and such… you could instead of wet laying actually lay the carbon dry with 77 spray. get the perfect pattern desired. Then lay a very thin layer of glass. Bag it… infuse it … sand then clear… But… ive never done it.
Thinking about it makes sense but… generally things are not so easy at first and technique would majorly be a significant factor here.
Later.
Ever tried to peel a peelply off a post cured laminate, with about 1,5 millimeter (1/16") of resin filled infusion medium on top? Last time I did that, I used an overhead crane for that. Not nice if you have to do 50 sqm (500 sq ft).
Perforated film is so much easier.
Here is a link to a pdf where Airtech shows recommended stacks:
Never that large…but yup. I have had to throw panels away because there is NO WAY to remove the distro and peel ply.
Our other facility uses perf. release often in infusion. Leaves the surface shiney, but you still have print through from the distro media. But bag side will always be contoured to the fibers.
generally we use thin glass over the peel ply… then perforated then woven breather… i re read my post and understand it as such… but a miss understanding could definately make things worse.
the stacks i was talking about earlier are kinda more geared to pre preg laminates… not so much infusion. infusion leaves alot of extra resin so yeah… i could see too much being a major problem.
fyi perf over peel ply then breather is always used during a co cure or de bulk on parts needing numerous plies… like 20+.
sometimes its hard to get it all right with the english language… lol
Thanks for all the help guys.
We’re doing fiberglass body parts this year and we might get sponsored by Airtech. If so I’ll ask for the infusion release film but if not I’ll just have to run the infusion with peel ply then spray clearcoat on and sand that.
The one off mold though is very intriguing and I’m going to test it on my own time. For the car though I can’t ask for more funds for a non critical system. It’s more important that our money goes into the drivetrain and welding than body panels. I do wish I could do this the right way though 
Canyon, How short of budget is the project? have you tried approaching any composites companies to see if they can help you or the project?
The car as a whole is about 600 short, but were working hard to fix that gap by selling carne asada tacos and asking family of members.
I’ve approached Airtech International and Mr. Jerry Jackson said they would be happy to give us materials like tacky tape and vacuum film. He just needs a letter on school letterhead so one of our professors should be doing that now.
At first I was worried about the cost of the mold, we know a guy that makes fiberglass boats but since times are tough he needed to charge us 200 to make a mold with his chopper gun which was too much.
But I think bicanek’s technique will work great and as luck would have it Laguna Clay is right next to the school. For a one off part I think it’ll work great! I’ll post results as soon as I get them.