We took some time to help a friend do an infusion part from his open layup mold. The part is a “hood” for a custom freestyle jet ski. Fun excercise.
It weighs a tick under 2lbs untrimmed and just out of the mold.
Here’s some pics of the layup and just out of the mold.
Cool. I would like to see it installed 
Nice part! How are you planning on trimming it?
I’m not sure… I was in a hurry the day we demolded and had to leave the office. I need to follow up and see how the part finished out after clearcoat. Normally on something like this I would use a reciprocating saw to rough cut and then trim in and detail with air sanders and sanding blocks. I’ll see how it’s going this coming week.
We just did another. Here it is fresh out of the mold this afternoon.
PVA, Clear coat then Kevlar Carbon Hybrid backed with several carbon fiber layers. I think these hybrids are a bit more difficult to get a good presentation in a mold like this with many contours due to the contrast showing every little detail but it certainly smacks one’s eye…!
What kind of clear coat in the mold? Man thats nice!
The clear coat is duratech.
I wantto get back to using the duratec clear… The VE works very well. How many mills do you spray? With a marine clear gel coat resin we spray about 25 - 28 mills. With the Duratec because its so thin, I’d usually spray 10 - 12 ills of that.
Hey John, I couldn’t tell you the exact mils. I spray looking for the point of wet or “flow.” I don’t thin it out when spraying up in a mold. Put in a low temp oven after spray up at about 90 - 100 * F and the clear levels out really well. This part will get a PU clear over top. The duratech was for working against the PVA and also having something to sand/prep for the PU clear coat. Strictly utilitarian in this case.
Very nice work! especially the hybrid one!
What I dont quite understand is, how are you keeping the fiber in the mould like that? Especially the top layer, the rest can be spray glued, but the top layer wants to be nice. Do you clear coat the mould and then let it harden fully? Or are you using a gel coat and letting it tack, to stick the fabric prior to infusion.
It is really pretty much the only problem I have at the moment, getting the fabric to conform to my complex mould without bridging.
cheers
Thank you. While you’ll find different thoughts on this process, I have my own. The carbon fiber version was done with PVA, no clear coat and epoxy resin. I’ve been using the 3M 77 spray adhesive although there are probably better choices for epoxy(I forget what it’s called) I actually used the 3M 77 on the PVA even though it’s delicate. It was fine and aside from the mold capturing the part a little, the part was removed without hassle. You can see the PVA still on the part in the picture with some areas roughed up from us handling it.
As far as placing the “surface” piece of fabric. All I can say is, keep the spray tip on the 3M 77 very clean, use a very fine quick shot for mist and at a distance to keep any “spitting” from reaching the mold. It’s tedious but it works. I’ve never had a “goo” on the surface issue like I’ve read about. Also I spray only as I go.
If it helps - on that first layer, I find the “y” axis so to speak of the mold, drape or fold the fabric and lower it into place along that axis. From there I lightly tamp the fabric into place from the center of the axis, front and rear. Once I have that middle section in place, I’ll allow one side of the “x” axis to relax over the mold and begin working the other side from the center outward using a light mist as I go. At this point I’m usually misting the fabric and not the mold. once I’ve established the one side of the x axis line, I’ll work from that line forward and rear until the fabric is down out to the edges. Repeat on the other side. This jet ski part has a “return” or reveal on the edges so I seated that detail after the fabric was placed out to the edges all of the way around. I trimmed from there and just followed the same process for the other layers. As far as bridging, you have to work from the center of your x and y axis outward. You can’t get ahead of the seated fabric. When you do, you create the bridging. Relief cuts in the tight or inversion areas is the other side of dealing with it. You’ll just have to figure that one out through trial and error.
I used the same process on the kevlar version even though I put a clear coat in the mold. I did the kevlar part at the house as homework. I was sippin coffee and blabbing with my Mom who stopped in to see my little boy all while placing that first layer. Patience gets it.
The guy who owns the mold has been working on building his own parts from the mold with infusion and has been very successful most recently using the same process. He just built one with a plain weave that looks great. I was in a hurry when I saw and didn’t think to take a picture.
Hope this answers your question. Been a long day…!
Thank you very much for the detailed reply! I understood fully and will be giving it a go shortly! Good thinking on the 3M 77, I actually picked some up in the meantime. Seems many are using it.
Will post my results soon.
cheers
Nice Parts , very good job, what Resin did you use
Love to see some photos mate !
Very nice.
It definitely doesn’t leave you with much rim area for bagging tape and all the infusion goodies.