| Author |
Message |
Randall Hays (Bulldogie)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 29, 2004 - 10:17 am: | |
After raising the roof, I got to wondering if I could not make my own bus caps by framing in with 1 1/2 inch steel tubing and then skining with 19 ga. paint lock steel. Would seem like that if I kept the same roof line all the way back and all the way forward, I would have just about the same look as a fiberglass roof and save a lot of money. Any Ideas or suggestions would be appreciated, |
TWODOGS (Twodogs)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 29, 2004 - 10:31 am: | |
I thought about this...listen to this...you can get the air dams off big trucks for almost nothing or free...try body shops,wrecking yards,the fiberglass thingy on top of the cab that deflects air off the trailer,do alot of measureing & draw what you want & cut it out of the air dam........... |
David & Lorna Schinske (Davidschinske)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 29, 2004 - 10:49 am: | |
I think the fiberglass caps are really just a "shortcut". I think (based on what our caps look like) that if you are good at shaping and forming metal then you could do your own. Kinda like the difference between fiberglass fenders and someone building their own fenders. Our caps seem to be on the thin side (maybe they are all like that although our front cap is capable of "standing" on it's own) and need support under the fiberglass. The biggest problem that I can see (based on our Eagle) would be those curved corners (where two radiused edges meet). |
George Myers
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 29, 2004 - 11:13 am: | |
I made the front cap for my Phantom using the fiberglass on plywood technique. The plywood simply holds the fiberglass in place while the polyester cures. It has been there for several years now and is still in good shape. The step-by-step process is shown in "Making a New Front Cap" that is described in the "Video" section at http://www.busnut.com/seecs.html. |
Ed Jewett (Kristinsgrandpa)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 29, 2004 - 11:38 am: | |
Styrofoam, or the blue insulation foam sheets glued together, shaped with a belt sander (about 80 grit belt or coarser) to the desired radius, cover with any suitable plastic film to keep the fiberglass resin from eating the foam up, and you have a good mold for the corners. Check the plastic film first to see if the resin will dissolve it.
Ed |
Marc Bourget
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 29, 2004 - 1:00 pm: | |
I'd use a combination of the techniques mentioned.
Depending on the design, the curvature changes from the front cap to the roof line.
Use plywood for forming ribs at relevant points between the styrofoam and you can use a straight edge interspersed with the sander to fair one curvature to another. It doesn't have to be straight lines giving a faceted appearance, just for guidance purposes. I've used a strip of plastic 2" wide and 3' long like a "French Curve" to transition two different curves.
The choice of plastic film is important if you want to employ compound curves. It will need to stretch if you want to avoid "joint lines" which will have to be smoothed out of the mold before you lay your cap. This 'finishing' of the mold is real tedious work, btw.
Best aerodynamics would be as close to a 12" radius as possible. Asthetically matching the large radius to the existing 'box' is problematical at best.
The layup will shrink, (FF, help here?) depending on the process used, I've heard up to 1/8" per foot (but I forget if regular fiberglass or an epoxy system), so you have to make allowances in the mold if any dimensions are critical
Bob Belter made his front cap out of Aluminum and a planishing hammer. An english wheel is less punishing to the ears. You'd use the plywood as forming guides with alu as well, but wouldn't have to fill the spaces with stryofoam.
Onward and Upward
Marc Bourget |
Philris
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 29, 2004 - 2:34 pm: | |
If you use epoxy instead of polyester resin it will not attack the foam used for the form. |
Barrett F.
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 29, 2004 - 8:48 pm: | |
There is a special foam that most suppliers can get to moldmaking. Resin won't attack it, and it shapes easily with knives, rasps, cheese cutters and wire wheels. The you just buff it to the desired smoothnessa nd coat with mold release. Depending on the mold, plywood stiffeners help maintain shape and squareness. In a female mold, you'd use mold release, then 2-3 coats of gel-coat and then lay up alternating layers of woven and matt glass applying as little resin as possible, just enough to wet-it-out, then roll it with a special roller to remove voids, airbubbles and excess resin. The fiberglass gives the strength, the resin bonds it. Too much resin will make it prone to cracks, esp in the gel coat. I'm STONGLY considering making my own, as most of the ones I have seen look a bit generic (or maybe lack character). If I'm gonna do this, I want mine to look GOOD as well as functional (insetting lights, maybe air scoops, etc. Building the mold is usually surprisingly easy. Cardboard or other such materials, covered in waterbased polyurethane and then coated with several layers of mold release works well in many instances. Be warned that resin, hardener and glass isn't cheap, but buy bulk quantities helps a lot in that area also.
-Barrett |
Sojourner (Jjimage)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 29, 2004 - 8:59 pm: | |
Hi Barrett,
What is "special foam" your talking about?
Thanks
Sojourn for Christ, Jerry |
Bob Oakman (Bobsbus)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, November 02, 2004 - 3:24 am: | |
IMHO, the work involved in fabricating your own caps outweighs the cost of purchasing manufactured ones. I actually started to tinker with making my own caps and just got lazy I guess. If you are real handy and have the time to kill it may not be so difficult.
Let us know what you decide. |
J.B.Phillips (Jbp)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 04, 2004 - 11:17 am: | |
Hi, I am new to this site although I have been listening and looking for the better part of a year. DOES ANY ONE MAKE A FRONT CAP FOR A CROWN? I am in the process of converting a 78 Crown with a mid entry door.
J.B.P. |