Diffuser project

General Composites Discussions Composites Talk
#1

Hey everybody,

My name is Noel and I’ve been reading some threads and this is my first post. I’ll post up pictures after the explanation. I’m currently working on a diffuser for my toyota mr-s and I made it out of 2 layers fiberglass cloth, 2 layers csm, and way too much resin. So the final product is very heavy and not very stiff. I wanted to ask for some suggestions as to how I might be able to make the diffuser as light and as stiff as possible. I was thinking maybe 2 layers of CF at 90 degrees and some type of coremat. Ideally, I’d like to vacuum bag the “real thing” at some point too.

The current diffuser I have needs A LOT of work and the plan is to smooth it out as much as possible to make a mold off of it for the final diffuser. This one has bubbles and waves and just did not come out very well. Basically, I was using cheap polyester resin that was curing really quickly and really cut down on my working time.

Okay pictures (please go easy on me)…

Here’s a rough sketch of what I was trying to make…

First I built a mold to make the plug for another mold, haha.

Here is is all taped up and waxed before the lay up

more pictures to follow…

#2

Sorry I hope it makes more sense after I post more pictures…
the gf helping me out


here it is “roughly” trimmed to make sure it fits…

I’ll add the strakes once it’s been smoothed out. I’m still debating whether to make the strakes from 3/4" laminated foam core, or just make about 1/8" strakes out of FG or CF. The foam core would look cool but vacuum bagging it would be pretty hard I think.

#3

cool project… i made one but 1/2" for a school project…
http://muibubbles-design.com/index.php?/bubble-tech/mazda-rx-7-rear-diffuser/

i highly recommend getting a fiberglass roller… it will help the wet out process without adding MORE resin. this will help shed some of that extra resin weight…

as for rigidity, remember, youre making a huge flat panel essentially. so try “flanging” the sides like I did on my diffuser. its only about 1/2’-3/4" of an inch high and adds rigidity to the structure (the outside lip on my diffuser)

#4

Thank you very much for the advice and the pictures were also helpful. I really regret not getting a resin roller, but I’ll work with what I have. I’m wondering if once I add the strakes if that will help with stiffness. The flanging might be the way to go, thanks again!

#5

the fg roller is a million dollar tool. it makes life SO much easier… although this isnt ideal, you may also want to try a squeege- i uses one that is used for apply window decals. i tried it and it helps get all the excess resin out and helps wet out but not as great as the FG roller…

#6

yeah I wish I had picked one up, I ended up using so much resin it’s ridiculous, I’m planning on making a mold off of this once it’s cleaned up, then using carbon and 1/8" divinycell core for the final diffuser.