Fiberglassing - will Kevlar help in front like a rock guard?

[Esteban]

I'm building a teardrop with a fiberglass over plywood outer skin and planning to use epoxy boat paint for the outer finish. I'd like to protect the front from stone pitting. Some teardrops have aluminum rock guards on the front. It's not a look that appeals to me for a painted teardrop. I'm considering using Kevlar cloth on the front to make it stronger. Thinking of doing a first layer of epoxy and Kevlar just in the front. Then a layer of fiberglass cloth and epoxy over the entire roof and hatch. The front would then have two layers of cloth with one of them being Kevlar. From what I've gathered from Kayak building sites fiberglass is the better outer layer with Kevlar underneath.

Does using Kevlar cloth in front too seem like a good idea for a less visible rock guard?

My teardrop is not intended for much off road use. Sometimes it'll be towed on dirt roads to campgrounds. It's about time for me to order epoxy and cloth from Raka.

Thanks in advance for your ideas.

[HossHoffer]

Steve,

Kevlar is not as easy to work with as fiberglass. Great stuff but in your application I am not sure that it is worth the extra bother or cost. A layer of 180 fiberglass would be just as strong and very little weight difference. As far as using it as a rock guard it should work fine. If you really want it to look good then vacumn bag it like we do in aviation. If you do use the Kevlar then yes it works better as an inner ply. In fact I would sandwich it in between fiberglass. How about some carbon fiber?

[doug hodder]

Steve...the kevlar although costly will prevent rock penetration, I personally don't think that is going to be an issue based on how you plan on using it. It won't do anything for the chipping that is going to occur. That is happening on the paint surface and the top coat of resin. Kevlar is under all that. I think the kevlar is overkill. I don't do cloth on mine at all...but do install a nose bra. Just my opinion, others may vary. Doug

[Esteban]

Hoss and Doug, thanks for your ideas. I was loaned a teardrop to camp in for the SLO Gathering. It had plywood with an epoxy paint as the outer skin. Over time it cracked and checked so Robert, the owner, is going to sand it down and fiberglass it. I know it's not the same thing I'm planning but it made me very aware that plywood needs to be well protected to weather well over time. My tendency is to overbuild. A couple yards of Kevlar would cost $40 - 50. A modest cost if it helped to protect the front of the teardrop. It seemed worth asking about.

I'll be doing hand layup of the fiberglass, with no prior experience. Vacuum bagging is beyond my capabilities. I've done of carpentry, drywalling, and painting. At my house I've had to go back to tape and mud some areas of drywall again where it stress cracked. I want the outside of the teardrop to look good, be water and weather tight, durable and pretty low maintenance. Without a big do over down the road.

Hoss, I googled "180 fiberglass" and and have no idea what it is. Can you give me more info. please?

[Juneaudave]

In the simplest terms...think of fiberglass as the strength to the build...and the paint/varnish/bra as the protection to the fiberglass. The fiberglass will give you the strength (kevlar is not necessary for strength), the extra layers of protection (such as varnish/paintor a bra) will keep a rock ding (for instance) from penetrating the coating and damaging the fiberglass.

[schaney]

Esteban, from the stand point of gravel nicks I didn't believe the cloth type is going to come into play. The nick will be in the paint or surface layer of resin/epoxy surface layer. For nicks, it's about how flexible the top coating is verses the inner layers. I have found Durabak to be a great coating in the rock chip zone.

The Kevlar would come into play for improved resistance to impact damage if you kick-up something like a chunk of rethread.

[Nitetimes]

I think something like this would be much more useful for protecting your finish. Clear Guard

[angib]

I second most of the above - Kevlar is really great for abrasion resistance which is why it's so good for canoes/kayaks, but that's not at all the same as the 'stone ding' problem. For protection against stone 'punctures' (ie, dents or actual holes), it's just thickness of almost any reinforcement that will help, but that's quite different from stone chips.

I would be tempted to have removable stone chip panels so that (a) they can be removed periodically for repainting and (b) they allow you to repaint a small area (ie, not having to repaint the whole body to avoid the join line where you stopped the repaint).

Andrew

[Esteban]

Using Kevlar cloth for glassing the front was an idea I threw out wondering if it would help much to protect the front from small rock dings. Looks like the better idea is to use an extra layer or two of fiberglass cloth and epoxy on the front. I'm planning to paint the teardrop with rolled on white epoxy boat paint so should the time come to need to fill or patch some dings a little touch up paint shouldn't be hard to blend in.

A clear bra might be nice for extra protection if they don't cost an arm and a leg. Or I win the lottery.

Thanks for the ideas. You saved me time, aggravation, and money.

[let's went]

I have no personal experience sheathing with Kevlar and can only say that the price, difficulty cutting and dealing with the sanding "fuzz" has kept me from trying it. I do have experience dealing with a Kevlar/Carbon fiber mix that is available from Jamestown Distributors. The gold and black weave is very appealing but probably not appropriate for your project. Most small home-built boats use 6 oz. fiberglass. Raka sells glass in weights from .75 oz. to 10 oz. I find the weaves below 6 oz. to be more difficult to wet out. There are a couple of polyester fabrics available: Xynole and Dynel. These fabrics are often used on boat decks or other high abrasion areas. Neither of these fabrics will wet out clear, but they do wet out easily. They drape very nicely and will conform more easily to shapes than glass (none of that cutting darts to get the cloth to lay flat on a curve). I use 4 oz. Xynole. It absorbs epoxy like no tomorrow and will ultimately have a weight similar to 8 oz. glass. That extra epoxy weight can be reduced by adding significant amounts of micro-balloons to the fill coats. That fill will give a nice white substrate for your white primer and paint and it makes fairing a breeze.

[Stevebaz]

The resin will just chip try Rino liner the ureathane base will just bounce the rocks off.

[HossHoffer]

Hoss, I googled "180 fiberglass" and and have no idea what it is. Can you give me more info. please?

Sorry, 180 would refer to the weight of the cloth. It is a thicker weave, very strong. For your application I would pre-impregnate your cloth and then apply it to the wood. Have fun with it and keep us updated.

Hoss

[elderjay]

The show Smash Lab sprayed Rhino liner over buildings to see if they were blast proof. They put a half inch layer over plywood and couldn't get through it with a shotgun. It actually prevented the wall from buckling during a car bombing.