In the next two months I’m going to start building a nose cone for the FHSAE team on campus and I was wondering if anyone had tips or suggestions. I’ve never built a unique shape before so I’m quite anxious to see how the process and plug turn out. I’m planning on emulating other teams who have used foam, and sealed it with bondo and high gloss primer but I’m curious to see if there are better techniques or processes out there.
Thanks in advance!
I like MDF, it shapes very easy in to any shape you want using planes and chisels, and its nice and flat plus much more durable than most foams. Foam works very good too.
I wouldn’t spend to much money on it, if your team is anything like my old team it will only get used for one year then thrown out.
MDF or UDF (like MDF but without the hard crust) is real nice as it can be CNC’ed and can handle 80deg without distorting.
There are two different ways that i usually build plugs.
One is with sheets of mdf (thin mdf can be curved gently) be sure you use plenty of stiffening ribs inside tho to stop it flexing and build it on a good solid base. Body filler edges and corners. Will need painting to get a good smooth surface. 2K primer works well and can be flat and polished good snough for most items.
The other way to make plugs is to cut ribs to shape at say 4 inch spacings, fill the gaps with foam. Sand to shape (using the ribs as a guild to the shape). Once happy with the shape cover with grp (if polyester resin is used make sure is compatable with the foam and wont melt it). Sand the high areas. Cover in filler. Once happy with the shape it will again need painting. 2K primer will work again.
The second method is usually better if you require a 3d shape that is quite complex.
Remember the better the finish on your plug the better your parts will be. Make sure you are happy with your shapping and get someone else to come and be critical about your shaping and surface finish! You will be thankfull later
2k primer can be buffed out easy without a lot of sanding (rubbing compound & a buffer)
I built this about 10 years ago for a FF project
I really did not know what I was doing but a lot of bondo over wood & foam. Primer & block sanding was the drill.
The spaceframe of the car lived inside the plug while I built it.
(damn,I was skinny back then)
wow! thats awesome.
for plugs i will use fibreglass/mdf as a general base but i like the green shaping foam, so very easy to shape with the speedfile, but fifty times worse with the dust and itchyness, green shaping foam dust is nasty!!
then just covered with a layer of glass and then the smoothing process starts - then painted with 2k to start moulding!
I’d probably use a combination of mdf and urethane foam. Wrap it all with a layer of 4oz or 6oz fiberglass cloth, then bondo etc.
I think I’m going to use the rib method that Matvd suggested, spacing the out cross sections every half foot or so and then filling it in with expanding pour foam. I just have to figure out how I’m going to get the slight undercurve at the tip of the cone.
Other Formula teams
Attached are some pictures of a practice cone I’ve been modeling. It’s not the actual one but the general shape will be somewhat similar.