Making a Shape out of Fiberglass?

[Ron Earp]

I want to make a smooth shape for the front of my trailer to increase the aero, something like what is shown on these pages:

NoseCone Pull Trailers

What would be the best way to make it? Create a solid surface out of wood and then cover that shape with fiberglass? If I did that what sort of fiberglass would I use, oz/thickness/etc, and how much resin would I need?

Or, are there better ways to make something like this?

Any insight you shape makers can provide would be welcome.

Thanks,
Ron

 

[Terry Oxandale]

Ron, I'd just make this shape out of foam. Not sure, but I believe the pink foam sheets at Home Depot are resistant to resin whereas the blue is not (just hear-say). Personally, I've always used floral foam to make my unusual shapes, and if I used other foams that were not resistant to resin's effects, then I'd simply cover the foam with masking tape. What I liked about the floral (crispy) foam is that it can be sanded really easy (won't load up the paper) to the desired shape. If the sides are pretty flat, I use aluminum as the mold or buck, but then, why not just make it out of aluminum in the first place if that were the case?

I would think you're planning on a lot of driving to make this project financially worthwhile

Here is a 100% all fiberglass body (sans the C-pillar and roof) I home-built using this glass-on-foam technique.

 

[Dalton Veitch]

That's damn impressive, Terry

 

[Rick Muck- Mark IV]

Ron,

If this is for your open trailer, look into a truck tractor roof deflector! Ross Henry found one in a trash pile and mounted it on his open trailer. Aero and stone protection in one fell swoop! Close the bottom in with plywood and you have extra storage as well as the aero benefits.

 

[Ron Earp]

Hey Terry. I remember the pictures of the Z when you first put them up but didn't remember you'd made them. Nice work!!!!!

I'm not sure this project will be financially logical, but, I'm going to try it anyway.

So blocks of floral foam? I do have an aunt who is a florist.....

I do have to go to Lowe's this AM and I'll see what they have. I remember the blue insulation they have as I used it to insulate the trailer. Don't remember pink but I'll check it out.

If I do make the shape and wish to cover it what sort of glass and resin do I need to consider?

 

[Ron Earp]

HEy Rick,

I'm trying to make this more aerodynamic:



Thought I'd put a rounded shape up there. Move the solar panel to the top and remove the ladder.

A truck piece might could work, but, it'd likely be too large. I need that window for sleeping in the box, else it'd feel like a coffin in there even with the door open.

Terry - what kind of floral foam? Wet or Dry? Found a place that sells it and cuts to size.

 

[Gregg]

Ron for something that size I wouldn't use floral foam. I would go to Lowes and buy 1/8 sheet of white melamine board and make a small pyramid. It wouldn't have rounded edges but would accomplish what you are trying to do. Two coats of wax and mold release and just glass over.

 

Ron Take a look using Bendable plywood for the form. Look up u tube. (Rowleycompany1)
a short bit of info on what bendable plywood can do. It is also made in a MDF version.

 

[Wally]

HI Ron We made a frame out of electrical conduit and angle Iron and covered it with this material. White PolyMax HDPE Rolls - FarmTek

We made the mistake of using the Black ( to match the trailer color ) In the sun the black expanded so much it would work the rivets loose. Switched to the white no problems for 5-6 years ( wish I had some picture of that trailer ) This stuff will contour with a heat lamp and some patience. And you can use Clear if you wish.

 

[Gary]

I have used the following product for building round cabinets and pedestals. It makes nice consistent bends. Works great and about $35 for a 4x8 sheet.

Bendable Plywood

BENDABLE PLYWOOD Description: Plywood with a single face veneer and core plies with all grain running perpendicular to face to allow cross-grain bending. Uses: Used mostly as a substrate for building cabinets, etc., with rounded corners. Sheets with clear face veneers are suitable for furniture. Available Sizes: 1/8" and 3/8" are common, though thicker sheets are produced. Sold in 4x8' sheets. Common Grades: Able to conform to tight radii without splitting or cracking with no need for kerf-bending or steaming. Pros: Flexibility allows radiused corners, decorative shapes. Cons: Not designed for structural use, quality of face veneer varies greatly. Where to find it: Building-supply stores and hardwood retailers.

 

[DARREN]

Hi Ron,

Fibreglass materials. If you are going to make a shape, then take a mould off it and then make the actual part then you'll need:-

Mould release wax. 4 or 5 coats onto your prepared surface.
Gel Coat.
Catalyst.
Matt - I always start my layups with a 450g/m layer then 600 for every other layer, i guess you'll want 5 or 6 layers for the mould and maybe 3 or 4 for the part.
Resin - 3 or 4 times the weight of resin to matt. So if you use 10 kg of matt you'll be wetting it out with 30 or 40 kgs of resin.

Mix your resin with 1-2% of catalyst, 2-4% in the gel coat.
I always apply 2 coats of gel first as it gives you a thickness of gel to use to tidy up and bad patches, or stone chips at a later date.

So if you make a mould, preapre the surface of the pattern with 5-6 waxes, gel coat on then wait to dry, 2nd gel, wait to dry. Wet the area with resin, lay on the matt and wet it out use a roller to consolidate it and get it into all the corners and free of any air bubbles. If its a big thing then consider only laying up a couple of layers then let it dry before doing a few more. Leave it to cure over night at the very least.

When you have released the mould from the pattern, then wax it 3 or 4 more times. Then 2 x gel coat, and then your choosen layup (1 x 450 + 2 or 3 600), let it cure over night again. Once released from the mould trim off the excess using a 1mm slitting disc in an angle grinder.

Hope that helps.
D.

 

[Ron Earp]

Thanks fellows.

Can anyone think of anything that is already produced, like a small fish pond for example, that might have a shape like in the picture?

Maybe I could adapt something that already exists.

 

[Al Snow]

Truly I would think a modern plastic bath tub. There are lots of shape around, some symmetrical end to end (for side filling) and are pretty strong/light. Just grind off the plug-hole and avoid an avocado one please. cheer al

 

[Scott Calabro]

Perhaps a used fairing (read junkyard) off the roof of a Peterbilt etc, could be modified to suit and give soft storage space as well.

Air Fairings and Shields by Airodyne Industries LLC

 

[Ian K]

Thanks fellows.

Can anyone think of anything that is already produced, like a small fish pond for example, that might have a shape like in the picture?

Maybe I could adapt something that already exists.

A skylight:

Buy Skylights

Ian

 

[Ian K]

That skylight link has a link for replacement domes, where you can specify some dimensions. Not sure how expensive, but I suppose you could buy one, and then use it as a mold.

Ian

 

[Ron Earp]

Awesome Ian, drawing faxed. I'll post back here on progress.

The company that makes these trailer caps wants $495 for one that is 82"x20" with a appropriate sized bubble in the middle.

 

[Ron Earp]

About $450 for single done - so essentially the same as the company that makes trailer caps.

 

[Jac Mac]

Got an EAA sport aviation chapter in your neck of the woods?, might still be a couple of older dudes around who could show you how to free form one out of a sheet of Lexan, or has the whole of the USA lost touch with DIY & adopted check book building...:sad:

Actually, check out U-tube, bound to be someone who has put a video up of vac forming or free blowing one for a kitplane somewhere..

 

[Graham]

Ron, I'd just make this shape out of foam. Not sure, but I believe the pink foam sheets at Home Depot are resistant to resin whereas the blue is not (just hear-say). Personally, I've always used floral foam to make my unusual shapes, and if I used other foams that were not resistant to resin's effects, then I'd simply cover the foam with masking tape. What I liked about the floral (crispy) foam is that it can be sanded really easy (won't load up the paper) to the desired shape. If the sides are pretty flat, I use aluminum as the mold or buck, but then, why not just make it out of aluminum in the first place if that were the case?

I would think you're planning on a lot of driving to make this project financially worthwhile

Here is a 100% all fiberglass body (sans the C-pillar and roof) I home-built using this glass-on-foam technique.

Terry,

That HAS to be just about ther best looking Z out there. Major kudos to you for that bodywork.

Ron, sorry for the thread drift.

Graham.