LocostUSA.com

Here is the next video, Episode #29: Building the Body Mold – Front Cowl Flange -> https://youtu.be/h6rWEDG7eGE

Doors, Hatches, etc
In most projects you will need to build doors, hatches, etc. The best way I found to do this is to build your buck as if there are no openings. For example, on the driver’s side of the vehicle, sculpt that side so it flows from front to back with no marking the edges of the driver’s door.
1. Then carve a groove into the side of the plug that outlines the door. The groove should just deep enough so it can be seen in the mold.
2. Make a mold of the door that extends 3’ beyond the groove for the mold flange.
3. Now you can no make the door threshold, door jam, hinge mount, weatherstripping flange, etc. Within the groove that outlines the door, cut into the plug to form those inner panels.

Step 1

Step 3


Front Cowl Flange
The front cowl on the Tiger 700 is basically just a simple hatch. It opens and detaches. Now that the mold of the front cowl panel is complete, I can cut into the plug to form its mounting flange. The cowl mounting flange will be cut in ¾” horizontally and then ¾” vertically. This flange will hold the cowl in position and keep the rain out when driving.

Here is the next video, Episode #30: Building the Body Mold – Complete the Mold -> https://youtu.be/d599tWokjco

The Tiger’s body shape is somewhat complex. There are places where it contours outward, there are inward concave panels, and at the bottom is curved inward as well. With all these shapes, it will require a mold with many interlocking adjacent sections.

The first step is to layout the dividing lines between the mold sections. It is imperative that each section of the mold can be pulled away from the plug without some negative contour hooking or locking it in place. In addition, each section should be as large as possible to minimize the seams that require sanding on the final body panels.

Add flanges for each mold section
A 3” (75mm) flange needs to added around the edges of each mold section. The flange is typically oriented at the 90 degree angle to the surface of the plug. The flange adds strength to the mold, allows a way to screw adjacent mold sections together, and aligns adjacent mold sections.

The mold for the flange can be fabricated using clay, sheet metal, wood, foam core board, etc. I chose foam board because its inexpensive, easy to find, and it cuts easily. This is a very fast way to layout the flange molds.

Hot Glue Gun
A hot glue gun is a great tool to temporarily attach the foam core board to the plug. Hobby level hot glue guns range from 20A – 100A models. There are more powerful guns, but the price rises steeply after 100A. I used a 100A glue gun and it had plenty of heat to get the job done.


Precise Alignment of Adjacent Mold Sections
It is imperative that adjacent mold section align to each other. Any misalignment will result in a ridge in the final body panels. Ridges require significant bodywork to correct.

Some molds simply drill holes in the flange to align and attach adjacent mold sections together. There is often some looseness of the screws within their holes that allow a small amount of misalignment. A better method is to add alignment keys to the flange to ensure precise alignment.

Plasteline clay or molding wax are a quick and easy way of making alignment keys. Simply push a small ball of clay/wax on to the foam core board until it adheres. Then use a razer blade to make clean cuts into a pyramid shape. A shallow pyramid (left) will save you time when you clean it out of the mold flange.


Make the Mold
Follow the same process used on the cowl mold.
1. Apply a release film. I used unpolished wax followed by PVA. Don’t forget to apply it to the flanges as well.
2. Apply 1 thick coat of gelcoat.
3. Add fillets to smooth out any contours are too sharp for the fiberglass fabric to conform to.
4. Apply 1 layer of a lighter fiberglass fabric and resin. For example, a 4oz to 6oz woven fabric with polystyrene resin.
5. Apply multiple layers of fiberglass and resin to build strength through thickness. A common choice for molds is 6oz cut strand mat with polystyrene resin.

Prepare the Flange for Adjacent Molds
Start by removing the foam core board flanges and clean the clay/wax out of the alignment keys.

Here is a molded flange with the foam core board removed.


Here is an alignment key molded into the flange.


Inspect the surface of the molded flange and repair any rough or negative contours. Body filler can repair most defects. Here is an example of an area where the fillet material left an air void that needs to be repaired.


Use a chisel clean up any gelcoat that leaked between the foam core board and the plug surface.


Drill Screw holes in Adjacent Mold Flanges
Once the adjacent mold has cured, drill screw holes through the flange sandwich before releasing the mold. The screws will hold the mold sections together when you make the final body panels. The screw holes should be 8-14” apart.

Molding small Trim Pieces
Small pieces can be glued to foam core board and then follow the same steps to build the mold. There was one additional mold for the small eye brow trim pieces that go over the front suspension.


Many Adjacent Mold Sections that fit together
The Tiger 700 body has a complex 3-dimensional shape, so it required 15 molds.

Here are all the mold sections on the floor.


Here are all the mold sections screwed together.

It's been awhile rumbles.. nice to see you posting again on this unique project

Please keep the updates coming- I'm learning a lot from your stuff as I'm still on the fiberglass learning curve

--ccrunner

_________________
Dean

1972 Honda N600 Restomod "ccrunner's N600 VFR800 repower"

1963 Volvo P1800 Restomod
http://locostusa.com/forums/viewtopic.php?f=36&t=16309

1959 Berkeley SE492 Restomod...
viewtopic.php?f=36&t=19397

"ccrunner's 1960 MGA coupe Restomod" found on MGExp.com

Here is the next video, Episode #31: Mold Repair and Final Plug Tasks -> https://youtu.be/EcyzEhh7Hdw

Mold Repairs
No matter how careful you are when building the mold, there will likely be imperfections that require repair. The most common problems are:

The mold does not release from the plug
This is the worst possible scenario. One likely cause is a negative contour that is locking the mold to the plug. The other likely cause is that the plug surface was not fully covered with a release film such as wax, Poly Vinyl Alcohol (PVA), or chemical release agent.

To resolve this issue, you will probably do significant damage to the plug to release the mold.

Voids in the mold
There may be areas where the mold did not fully conform to the surface of the plug. For example, the fillet material or fiberglass fabric may not have filled into the tight corners. These voids can be repaired using body filler.


Wrinkles in the Gelcoat
There may be areas where the Gelcoat lifts away from the plug. These areas look like wrinkles in a face. Resin shrinks as it cures, especially Polystyrene resin. So when the fiberglass/resin is laid on top of the gelcoat, it adheres to the gelcoat and causes wrinkles as it shrinks with the mold cures.

To prevent this, let the gelcoat cure completely. Then apply a thin fiberglass fabric (6oz or less) to protect the gelcoat. Once the thin layer of fiberglass has fully cured, you can apply multiple layers of thick fiberglass fabric/chop strand to build the mold’s strength.
To correct gelcoat wrinkles, fill the voids with body filler and sand smooth.


Fabricate Body Mounts
The plug starts with the chassis and then builds up in layers of plywood, foam, plaster, etc into a solid shape that is securely anchored to the chassis. All those layers of the plug will be removed, so there will be nothing to support the final body panels. This makes it difficult to align and mount the “floating” body panels.
An easier way is to fabricate some of the body mounts while the plug is still in place. These mounts will align and hold the final body panels in place while you fabricate the rest of the body mounts.

Mounting the Rear Engine Cover
The rear engine cover is a single large body panel that is about 1/3 of the entire body. While the plug is inplace, I decided to secure the rear engine cover with 3 of its 5 mounting points. The rear cover needs to be removable, so the engine may be serviced. Therefore, the mounts must latch / unlatch easily.

Rear Most Mount
The rear most mount is difficult to fabricate from metal mount because the tail is a complex compound shape. So, I decided to use composites.

Step 1: Cut an access hole in the plug. Now that the mold is complete, I can cut holes into the plug to get this work done.


Step 2: Use 2-part pour foam to take up the shape between the panel and the underlaying chassis. The 2-part pour foam is mixed in a Zip-lock bag and then placed between the panel and the underlaying chassis. The foam expands as it cures in the bag and fills in the space to make a perfect mold of the mount. The expansion of the pour foam exerts a significant amount of pressure, so place some reinforcement tape (Gorilla tape) on the panel to keep it from blowing out.



Step 3: Once the 2-part pour foam is fully cured (30 minutes) it becomes quite stiff. The excess foam is trimmed off and sanded to a final shape for the mount.


Step 4: The finished foam is covered with fiberglass to form a hard shell.

Step 5: The fiberglass covered foam mount is glued to the final body panel.

Front Mounts for Engine Cover
The 2 front mounts on the engine cover will be a hook and bar latch that is difficult to fabricate while the plug is in place, so I temporarily welded a plate at each front corner to locate the panel. The plates are attached with small spot welds so they can be easily removed once the final mounts are fabricated.


Main Body Mounts
The main body is a single panel that will be permanently mounted (not removable). I decided to establish 4 of the 14 body mounts while the plug is still in place.

The 2 rear corners of the main body rest on the metal chassis, so that locates the rear of the body with no mounts needed at this time.


Two mounts were added to the front of the body.


Destroy the Body Plug!
I have completed my molds and fabricated enough body mounts to suspend the final body panels. The plug has served me well, but now it’s time to go.

I have been working with the plug for so long that it feels like and old fiend. I closed my eyes as I plunged the knife into the body. To my amazement, the plug actually bleeds pink!

The plug was built up in many layers. First the plastic wrap to keep the chassis clean, then a solid plywood armature, then XPS foam sheets, spray foam, and finally plaster to smooth the surface. I live in North Carolina where the humidity is high, so the plaster layer absorbed a significant amount of moisture. It was so moist that much of the plaster reverted back to a liquid and it literally bleeds on to the floor.

Here is the next video, Episode #32: Body Panel Samples -> https://youtu.be/hLIB1BC-HAE

Select the Materials for the Final Body Panels
The molds are now complete and ready to build the final body panels. Its time to select the reinforcement fabrics, resins, and core materials that will go into the body panels. There is a wide variety of materials that can be combined in limitless ways.

Reinforcement Fabric Choices

Chop Strand Fiberglass Mat
As the name implies, chop strand is made up of small pieces of cut fiberglass fibers that are glued together with a polystyrene glue. Then polyester resin is applied to the chop strand mat, the polystyrene in the polyester resin breaks down the polystyrene glue and release the chop strands. Chop strand mat is not compatible with epoxy resin.
Chop strand mat is a good choice for molds that have many compound curves. It is easy to apply and builds thickness quickly. The downside of chop strand mat is that it absorbs a lot of resin, so the finished part tends to be heavy. For example, I used chop strand mat to build the mold and it weighs about 100lbs.

Fiberglass Fabric
Fiberglass fabric is a single layer of long fiberglass threads woven together. There are many different weaves to choose from.
• 1 over 1 means that 1 horizontal thread is woven over/under 1 vertical thread. 1 over 1 weave is less expensive, but the weave restricts the fabric’s drapability over curved surfaces.
• 2 over 2, 4 over 4, etc. means that the weave skips over threads. For example, a 2 over 2 weaves the horizontal thread under vertical 2 threads and then over 2 threads. Likewise, it weaves the vertical thread under horizontal 2 threads and then over 2 threads. This looser weave allows the fiberglass threads more room to move, so they drape better over curved surfaces. The downside is that the fabric threads tend to unravel as you work with it.

S-Glass Fiberglass Fabric
S-Glass is specifically made for structural applications. The fiber is about 20% stronger than normal fiberglass. S-Glass is woven similar to normal fiberglass fabric. The downside is that it is 2x the cost of normal fiberglass fabric.
Biaxial Fabric
Biaxial fabric consists of two layers of fabric stitched together, with their fiber strands lying at +/- 45 degrees to the edges (instead of along the roll and across at 90 degrees). Biaxial builds strength and thickness quickly. The downside is that does not drape as well as single layer fabric. Biaxial is sometimes called “1708” fabric.

Carbon Fiber fabric
As the name implies, the fabric is made from long carbon threads that are woven together. Carbon fiber is much stronger than fiberglass and yields much stiffer parts. Carbon fiber fabric comes in a variety of different weaves, similar to fiberglass fiber.

Aramid Fabric (Kevlar)
Aramid Fabrics are engineered to be impact and abrasion resistant. Aramid fabrics are used in bullet proof vests, front splitters, race car floors, etc. Aramid fabric comes in a variety of different weaves, similar to fiberglass fiber. Kevlar is a brand name for aramid fabric.

All of the above reinforming fabrics come is a variety of weights. The lighter weight fabrics drape better, but are not as strong as the heavier fabrics.

Resin Choices
There are three main types of resins: polyester, vinyl ester, and epoxy.

Polyester Resin
Polyester resin is the most widely used type of resin. Polyester resin is UV resistant and least expensive. Polyester is not as strong/stiff as epoxy resin. Polyester resin has a shelf life of 6-12 months

Epoxy Resin
Epoxy resin offers the highest strength, but is the most expensive resin. Epoxy resin will yellow with UV exposure if not coated with a UV resistant topcoat. If polyester gel coat is applied to epoxy, it will not bond. However, if epoxy is applied to polyester gelcoat, it will bond. Epoxy resin also has an exceptionally long shelf life of 24-36 months.

Vinyl Ester Resins
Vinyl Ester Resin is often considered a cross between polyester and epoxy resin. The cost of Vinyl ester falls between polyester and epoxy. Vinyl ester resin is becoming more commonly used in high performance composites like racing, marine, and aerospace. Vinyl ester resin has a very short shelf life of only 3 months.

Core Material Choices
A core material is a structural layer that is embedded between laminate layers. Core materials are optional, but they add significant strength to a laminate. The most common core materials are foam, wood, and honeycomb.

Foam
Closed Cell foam is a light weight core material that is easy to cut, trim, and shape. It is used extensively in aircraft and performance automotive structures. Vinyl foam is commonly used and can be thermoformed with a heat gun. Polyisocyanurate is another common foam core material.

Honeycomb
Honeycomb is a panel of beehive like cells nested together. The honeycomb structure is naturally strong and leaves 90-99% open space in the panel. Nomex, aluminum, and paper are common honeycomb materials. Nomex honeycomb is used primarily for structural aerospace applications. Special layup techniques are needed to ensure the open space in the honeycomb doesn’t fill with resin.


Wood
End-grain balsa is a widely used core material. It is light and less expensive than foam or honeycomb. It is easy to cut and trim. Plywood is also commonly used, but is significantly heavier. The downside is that wood may absorb water and rot over time.


What is the Best Combination of Fabric, Resin, and Core?
With all these choices, what is the best combination of fabric, core, and resin for your project? That all depends on the priorities of your project. The selection for this project is based upon the following priorities:
1. Strength - The first priority is to build sufficient strength into the panels. The panels need to be strong enough to withstand minor impacts, wind resistance at highway speeds, and reduce the chance of any cracking.
2. Weight - The overall weight goal for this vehicle is just 600lbs, so the second priority is to minimize the weight of the body panels as well.
3. Cost - This is a home project, so I need to keep my expenses in line. However, I’m willing to spend a little extra money to achieve priorities #1 and #2.
4. Time – I’m a workforce of 1, and my time is limited. I need to streamline the lay-up process where I can. I would like to mold the final body panels within just a few weeks.

Find your own Solution
Now it’s time to discover the layup schedule that will achieve your priorities. Its good to start by educating yourself by reading books and viewing YouTube videos on composite layups. Some good resources are:
• FiberGlast.com website has an excellent Learning Center with practical guidance
• Composite Material Fabrication Handbook #1 by John Wanberg, ISBN: ‎978-1929133765
• Composite Material Fabrication Handbook #2 by John Wanberg, ISBN: ‎978-1929133932
• Composite Material Fabrication Handbook #3 by John Wanberg, ISBN: ‎978-1935828662
• How to Fabricate Automotive Fiberglass & Carbon Fiber Parts Paperback by Dan Burrill & Jeffrey Zurschmeide, ISBN: ‎978-1613253663

These resources will provide a general sense of available materials and how to combine them into a quality composite layup. However, they won’t give you a sense of judgement about how strong these materials are in real life. For that, you need to build some samples and test them.

Choose Challenging areas of the Mold for the Samples
The first step is to choose the most challenging contours of your mold for your samples. For example:
• Areas of the panel that will be weakest. These are area that are essentially flat panels with no compound curves. If your sample is strong enough in in these areas, it will be plenty strong in the compound curved areas. You may need to add core materials to strengthen weak areas.
• Areas with sharp curves or complex shapes. It can be a challenge for the fabric to lay down tight into sharp curves or complex shapes. The fabrics weave pattern and weight effect its drapability. You may have to use a different more flexible fabric in the areas that have sharp curves or complex shapes.

Choose Sample Fabrics
Choose the reinforcement fabrics based upon the project’s priorities. If light weight is important, choose stronger materials like carbon fiber. If weight is not important, fiberglass chop strand mat or biaxial may be a good choice.

Choose Sample Resin
If light weight is important, try epoxy resin. If low cost is important, polyester resin may be a good choice.

Build the Sample in Several Steps

• Mask around the sections you want to build samples of. Then apply wax, PVA, or release agent to ensure the sample doesn’t stick to the mold.
• Start with samples that will probably be to light to satisfy the strength you need. Release the samples from the mold and test their strength to gain a sense of judgement. Then add layers in several steps until you achieve your strength goals.
• In some cases, you may need to try several combinations of fabric, resin, or core material to meet your strength goals.

Samples for the Tiger 700 Project
The main body side panel offers both the weakest area and the sharpest contours. I masked around the sample area and applied wax and PVA.


Sample #1:
The first sample used 2 layers of 6oz carbon fiber on the flat weak area and 3 layers of 6oz S-Glass on the sharp contour. The S-Glass was laid at a 45-degree angle to improve its drapability. The laminate was bonded with polyester resin.
Once cured, the sharp curve seemed to drape OK and had sufficient strength (Success!). However, the flat area with carbon fiber was too flexible.


Sample #2:
Since the flat areas in Sample #1 was far to weak, Sample #2 focused on adding strength to that area. In this sample, I used the same 2 layers of 6oz carbon fiber, but added a large panel of 1/8” vinyl foam core material. A heat gun was used to bend the core material to match the shape of the mold.


The edges of the vinyl core were sanded down, so the top layer of carbon fiber would follow the contour of the bevel and reduce any air gap in the laminate.


Although the shape of the vinyl core sheet was bent quite accurately to the shape of the mold, it still lifted during when the polyester resin was applied. This caused several defects in the final lamination. Even with these defects, the panel was significantly stronger.


Sample #1b:
I then added 2 thick layers of gelcoat to the outside surface of Sample #1. This added a small amount of strength, but not nearly enough.

Using the lessons learned from Sample #2, I decided to add 2 ribs of vinyl foam core to Sample #1. The ribs were made of the same 1/8” vinyl foam core, but were only about 2” wide. I also cut scores into the ribs about every 1” along its length. The scores allowed the foam rib to naturally follow the curve of the mold.

I then encapsulated the ribs with 2 layers of 6oz S-Glass and polyester resin. This added significant strength, but not enough.


Sample #3:
I now have a good sense of how strong 2 layers of 6oz (12oz total) of carbon fiber is, so let’s compare it to other fabrics.
I made a sample of 12oz of S-Glass and another sample of 12oz normal fiberglass on the same contour of the mold. Both samples were far more flexible than carbon fiber. The S-Glass is supposed to be 20% stronger than normal fiberglass, but I saw almost no difference in strength.


Sample #4:
All my samples up to this point have been laminated with polyester resin. Epoxy resin is stronger but more expensive.
Sample 1b has been the strongest experiment so far, so I decided to replicate it, but with epoxy resin.
Success! Sample 4 was significantly stronger than Sample 1b.
The following photos show the difference in strength. A 30lb weight was placed on both panels. The polyester panel on the right fully collapsed, while the epoxy panel on the left barely deflected.

Lessons Learned

Sample #4 will be the layup schedule used in the final body panels. However, Sample #4 would produce a body that weighs 40-45lbs. The goal is 30lbs. I will modify the layup as follows to reduce weight:
• I will reduce the gelcoat from 2 thick layers to 1 layer.
• I will reduce the inner layers from 2 layers of 6oz fiberglass to 2 layers of 4oz fiberglass.
Other general lessons learned:
• Stiffness and drapability conclusion
o The carbon fiber is much stronger than S-Glass or normal fiberglass.
o The S-Glass is supposed to be 20% stronger that normal fiberglass, but I experienced almost no difference in strength.
o The vinyl foam core ribs added significant stiffness. Scoring the ribs is an easier and more consistent way of ensuring a tight laminate.
o Using a 6oz fiberglass fabric on a 45 degree angle will drape along the sharp curves of the mold.
• Cost conclusions
o I decided not to use S-Glass since it is 2x the cost of normal fiberglass.
o I decided to use Second Quality carbon fiber fabric. Second Quality carbon fiber has cosmetic defects that don’t impact its strength. First quality Carbon fiber is 6x the cost of normal fiberglass. Second Quality carbon fiber is just 3x the cost of normal fiberglass.

I would highly recommend you add the following mat'ls to your experimentation:

Kevlar/Aramid: Stiff, light, and extremely damage tolerant. Even the popular carbon/kevlar hybrid fabrics will save you some weight and balance stiffness/toughness.
Lantor Coremat/Soric: You won't find a simpler way to stiffen a laminate.

For your application I'd recommend epoxy resin with one layer of 5-7oz kevlar for the outer ply, one ply of 2-3mm coremat, and one layer of 2-3oz kevlar for the inner ply. For the few places on your body that you have a lack of moldline (larger flat section) a small 0.25-0.50" tall foam stiffener placed between the coremat and inner ply would be cheap and efficient.

If you go the kevlar route invest in the application specific scissors. Also, trimming the finished laminate can be difficult since the kevlar fibers are so tough. Sanding with good quality paper (220grit) works well. If you have some stubborn dry fibers that won't cut apply some superglue and then resand.

One last word of advice. If you go the epoxy route most all of your fiber/fabric weave choices will have the correct sizing applied so that the epoxy will adhere. If you want to use poly/vinyl-ester resin you might want to look at getting a fiber that has sizing that is taylored for those resin systems.

_________________
My build http://www.locostusa.com/forums/viewtopic.php?f=35&t=7370

Jaf,

Thanks for the recommendation.

I'll try Lantor Coremat/Soric core and Aramid fabric on my next project.

I have actually finished the body, but I'm way behind on posting my progress. I have a few more posts to bring you all up to date with where I am on the Tiger 700.

I'm officially tuned in now and will be anxiously awaiting the video of the body layup. 2nd Quality carbon is the best thing going, another good one is end of rolls, and experimental weaves. I think I'm still on my original roll of 1st quality carbon since I only use it for the visual layer.

Don't spill the beans yet but if you can provide any detailed weight data during that portion of the build......gel coat, resin, fabric, core, and then finished weight that would be great.

_________________
My build http://www.locostusa.com/forums/viewtopic.php?f=35&t=7370

Here is the next video, Episode #33: Body Panel Samples -> https://youtu.be/_EtwdqEoUmI

In this chapter we will finally build the carbon fiber body panels.

Using what we learned in the sample panels, the body panel layup will consist of the following:
1. Apply PVA and wax to the mold to ensure the body panels will release.
2. Apply polyester gelcoat
3. Smooth out the sharp corners of the mold with fillet material
4. Apply carbon fiber interwoven with fiberglass cloth.
5. Wash the cured laminate
6. Apply vinyl foam ribs
7. Encapsulate the ribs

Steps 1, 2 & 3 are the same as performed earlier
Step 1: Apply PVA and wav to the mold to ensure the body panels will release.
Step 2: Apply polyester gelcoat.
Step 3: Smooth out the sharp corners of the mold with fillet material.

Step 4: Apply carbon fiber interwoven with fiberglass cloth.
There are numerous methods to layup a composite. The most common methods are:

Wet layup: A wet layup is when you wet the mold surface with resin -> apply a layer of reinforcement fabric -> apply more resin -> apply a layer of reinforcement fabric -> etc.. This is the simplest layup method, but the reinforcement fabric layers may shift during the lamination.

Dry layup: A dry layup is when you apply 1-3 layers of reinforcement fabric in the mold and tack it down so it doesn’t move -> then add resin. This method ensures more precise application of the reinforcement fabric, but special care is need to ensure the resin completely saturates all layers of the fabric.

Vacuum Infusion: Like a dry layup, you apply the layers of reinforcement fabric in the mold and tack it down so it doesn’t move -> apply a release ply material -> apply a porous material that the resin can flow through -> then apply a plastic sheet that is sealed to the mold. A vacuum is then applied to one end of the layup and resin is sucked in from the other end of the layup to wet the reinforcement fabric. Vacuum Infusion is more expensive and difficult, but it produces parts that are lighter and stronger.

Pre-Preg: This starts with a reinforcement fabric that comes coated with thick resin already applied. When heated, the resin liquifies and saturates the fabric. The first steps are like Vacuum Infusion. Apply the layers of reinforcement fabric in the mold and tack it down so it doesn’t move -> apply a release ply material -> apply a porous material that the resin can flow through -> apply a plastic sheet that is sealed to the mold -> A vacuum is then applied to layup. The mold and laminate are then placed in an enclave where high air pressure compacts the layers even tighter while raising the temperature so the thick resin will liquify. Pre-Preg is most expensive method, but it produces the lightest and strongest parts.

For the Tiger 700 project I chose the Dry Layup method to give me more precise control over the carbon fiber fabric. I applied 2 layers of 6oz carbon fiber interwoven with 3 layers of 4oz fiberglass fabric. The carbon fiber and fiberglass are interwoven to increase strength.


I also used 1” wide fiberglass tape around the edges to reduce any chance of cracking.


The fabric was tacked down using a very light spray of 3M Super 77 adhesive.

These layers were then saturated with epoxy resin. The excess resin was removed with a squeegee and then compacted using a ribbed roller.


Step 5: Wash cured laminate
When the epoxy cures, it generates a rouge layer on its surface. The layer of rouge inhibits the next layers of laminate for adhering, so it must be removed. This rouge is water soluble, so it is easily washed off with a hose.

Step 6: Apply vinyl foam ribs
Ribs add strength to the body panels, just like the ribs in your chest. I made my ribs from 1/8” vinyl foam that had a 3lb density. I wanted ¼” thick ribs, so glued a double thickness of the foam on top of each other. I then sanded the edges to create a gentle beveled slope that the fabric could follow.


I then cut scores in the rib about 1” apart to allow the rib to conform to the shape of the body. Each score was cut about half way through the foam.


The ribs are then tacked in place with the very light spray of 3m Super 77 adhesive.


Step 7: Encapsulate the ribs
The ribs must now be encapsulated to add structural strength. The first laminate of carbon fiber created a hard shell. To reduce cost and save weight, I chose to encapsilate the ribs with 2 layers of 4oz fiberglass cloth. The same dry layup method was used, but special attention was paid to ensuring the cloth adhered tightly to the ribs.


Joining Body Panels
You may have body panels that are too large or awkward to laminate in a single step. If so, you will need to:
Step 1: Locate the mold section joints to accommodate joining panels
Step 2: Hold back the lamination from the joint edges
Step 3: Gelcoat the joint
Step 4: Patch the panels together

Step 1: Locate the mold section joints to accommodate joining panels
The front body is all one piece. It wraps 270 degrees around from the right side to the left side, so it would be very difficult to laminate it all at the same time. So, I decided to split the mold down the front and laminate the right half and left half separatly. See photo above.

Step 2: Hold back the lamination from the joint edges
When laminating each half, you need to keep the joint clean where the two molds meet. The process of applying fabric and resin is always messy, so leave ¾” margin at the joint edges. Then clean the joint with acetone to make double sure it’s clean.


Step 3: Gelcoat the joint
Apply a strip of Gelcoat in the margin where you held back the laminate. This will help the joint disappear in the final panel. Let the gelcoat cure completely.

Step 4: Patch the panels together
Fill the margin with fillet material made of resin, Cabosil, and short strand fiberglass. This will fill in any gap or roughness in the margin.
While the fillet material is still soft, push the first layer of carbon fiber into it to ensure a good bond. Then laminate additional layers of carbon fiber with resin (as normal). To ensure a good strength, the patch should use 1.5x – 2.0x the number of the fabric layers used in the rest of the body panel.


Release the Body Panels from the Mold
Its finally time for the body panels to emerge from the mold. Like before, remove the screws holding the mold sections together, give the mold some percussive love (bang it with a rubber hammer), and use plastic wedges to separate each mold section.


The result was a body that weighs a total of just 35 lbs!

I just posted episode #34 Body Mounts and Trim on Youtube -> https://youtu.be/uos3apx6DYI

This video shows how I mounted the fixed main body, as well as the removable engine cover and front cowl.

I posted the next video on Youtube, Episode #35: Building the Interior Panels -> https://youtu.be/ylBn7OtGtcw

In this episode I fabricate molds for the interior panels and lay up them up in light weight carbon fiber.

Really coming together, great to see. Brilliantly documented build, thanks for taking the time to share your experiences.

Have you run the engine since taking the plug off? Surely a blast down the driveway is in the near future? 90% there, only 90% to go!

Thanks,

The car is finished! Its registered, licensed and insured. Its a good driver on the backroads and the freeway. I've been showing it off at local cruise-ins.

I'll post some videos soon...

Woohoo! Congratulations!Oh yes please do! That's been quite a project, and I learned a lot about practical fiberglassing from you.

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Locost builder and adventurer, and founder (but no longer owner) of Kinetic Vehicles

Here is episode 36 video. Its a 17 minute summary of the entire project from start to finish-> https://youtu.be/-_cDFjCVGZM