First Time Fiberglass and Confusion! Wide Tray with No Template?

Sep 9, 2018
Asheville, NC
I've been trying to understand the differences between the Aramid and Fiberglass/ 1708 1208, glass balloons, cabosil and from all the stuff I am reading it doesn't really explain what all that means. From what I have gathered, 1708 and 1208 are thicknesses of material, what kind I'm not sure. Ive seen reinforcement with Aramid and fiberglass but i don't understand which is used where and why. Also Im confused if glass balloons or micro balloons are used with, or in place of cabosil, and again why? I think I understand the process of what I need to do, but i need some help understanding the materials im working with.

Im trying to get it together before Daytona this year and Im about to reinforce and paint my ski. I would like to remove my existing footholds and replace them with some sort of wide tray but it seems like I can't find a wide tray template anymore. Hurricane Industries no longer sells their set, nor does BOB. Unless I just can't find them. So how would I go about widening my tray without using a template? Ive never been anywhere close to fiberglass and as some of you may know, it seems intimidating at first. Any help would be greatly appreciated! I have found a few helpful links and I will include them below:

Reinforcing a PWC/Superjet Engine Bay

Thanks to Req for posting this also

Thanks to smoofers for this


Sionis Industries
May 11, 2009
West System Product manual

Start cruising the front of this manual. Although west system brands or trademarks their products by a certain numerical name (403,404,105,205 etc) . you still can read up on the intended purpose and uses for any given product. For instance what adhesive filler is easier to sand or which has a higher strength, Which cloth to use based on load and structural needs. Read it over. is also a good resource to look into.

Layup materials such as "Aramid or Kevlar " are made of different synthetic materials as opposed to traditional fiberglass. which are typically stronger and lighter based on what layup method used. If you are not vacuum bagging and this is your first time experimenting with laminates. Don't over think it and buy things you do not need. most of what you're trying to achieve can be had with the 1208 or 1708 "Biaxial" ( this is the stitching on the back of the cloth that staggers the glass sandwich construction) Take your time and surface preparation is key.

Before you "wide tray" your hull. you need to assess the floatation foam and see if it is saturated and heavy with water. If so , your first step may be cutting the tray open to do this and removing the wet foam. Also, resealing cooling lines or adding additional tubes for such. if you choose to cut your tray sides and foot holds out. I suggest making as minimal cuts as you can. Reassembly will be easier and glassing in fewer pieces will be much cleaner. you can refoam with the 2 part expanding system much like the oem style. or cut your on EPS foam insulation board like the blue or pink stuff from the hardware store.
Sep 9, 2018
Asheville, NC
If you are not vacuum bagging and this is your first time experimenting with laminates. Don't over think it and buy things you do not need.

Before you "wide tray" your hull. you need to assess the floatation foam and see if it is saturated and heavy with water. If so , your first step may be cutting the tray open to do this and removing the wet foam. Also, resealing cooling lines or adding additional tubes for such. if you choose to cut your tray sides and foot holds out. I suggest making as minimal cuts as you can. Reassembly will be easier and glassing in fewer pieces will be much cleaner. you can refoam with the 2 part expanding system much like the oem style. or cut your on EPS foam insulation board like the blue or pink stuff from the hardware store.

Yeah I’m defiantly not trying to over complicate this haha. It’s easy to geek out on projects like this but I’m trying to keep it simple and effective.

I cannot confirm that my foam is waterlogged, but I can say that the back of my ski feels much heavier than I would expect and I did notice by the end of this season, my ski was taking on water beyond what I would consider to be normal. It is a 1995 Yamaha Superjet that looks well used. So that being said, I was planning on cutting out the whole tray and refoaming the rear of the ski. I would be shocked if it wasn’t saturated with water. I rode this ski all season and absolutely love it except for the footholds and the way it looks. So before it gets too cold I’m ready to cut it up and glass it! I have found some videos on installing a “wide tray kit” but I don’t think those exist anymore... so that’s where I’m kinda stumped as to how I can cut all that away and just reshape it?


havin fun
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May 10, 2006
clearwater FL
ill try to keep this short, the basics the way I think of it is this.
chop strand or mat looks like spaghetti, the glass is like long threads and can be in continuos or chopped variety. since its non directional its a good print blocker and if weight is not an issue you can lay this up really thick and it makes the cheapest strongest but not lightest glass. Like a 19 foot searay boat is prob between 3/4 to over an inch thick, its heavy and strong as steel. this I use for print blocking and filling uneven areas or tight places to sort of smooth them out so you can lay a woven over it easier. since the strands are not straight its strength non-directional. its strength will come from building it thick. but for us its better as a first layer to smooth out irregular surfaces and block print. tear this into small pieces to build up tight areas or go over corners. 3/4 oz is pretty thin, I like 1 1/2oz but comes in other weights/thickness. the glass is labeled by how much it weighs per square yard.

next you have cloth. comes in all sorts of weaves. usually a 0-90. but can be made in many configurations. some weaves are more pliable due to how they are configured. meaning they will conform to more curvy surfaces easier than a stiff straighter weave. for thinner parts or something you might want to flex or if you have a surface with curves these will lay easier with thinner oz than a heavy reinforcement. surfboards get a thin cloth like 4oz and since all the strands run 0-90 that means half go north and south and the other goes east west. this gives you tension and load spreads in those directions. so now you can see how a nondirectional like chop vs cloth that has glass strands that go from one end of a part to the other absorb impacts or hold weight and disperse that strain by the way its designed. I use 4, 6 and 10oz. glass is strongest when it is straight as can be so by weaving over and under you bunch up the material and lessen its strength in this way. the benefit is its ability to conform to curvy shapes. also you can lessen this bunching by weaving where is skips over top 2 to 6 strands before going under. these can also be woven in any number of directions like +-45.

next you have a combination of these which is like the 1208 or 1708 where you bond a chop with a woven. this gives you the benefit of both types and is usually used to build up laminate. for example you could use several layers of 6 oz cloth or one layer of 1208. so hopefully you can start to see based on what your needs are that you have materials with specific properties that allow you to choose a layup schedule to fit those needs.

then you have the carbon and kevlar. which are stronger strands per oz. this brings us to the resin.

polyester resin is the cheapest , vinylester is the other end price and strength wise. and there are several others like gp and iso and in the same way that different glass types are used for specific things so are the resins. some have low shrink, some are high strength, some are better for below waterline, etc.

the thing about the esters is that they only bond to the same type. this is why you usually have a hard time bonding to metton like is used on the bottoms of some of our skis, its a different resin. its not going to stick to epoxy resin either. and before anyone jumps in and says they did it and it works, yes I know cause my cheapazz did it too. but its not gonna last. so if you lay up poly or the repair is made with poly you can bond to that with poly resin. also the ester resins will disolve the binders that hold the chop glass where the epoxy wont. you also should not use it for carbon or kevlar as its not as strong as epoxy. the resin is the binder that holds the glass or carbon together so it makes no sense to use a weak binder on the strong material. so for example if you want to make a mold you can use chop and poly since its not going to be subjected to any forces but just needs to be thick to withstand curing and not flex and also does not matter how heavy it is. but if you want to make a competition freestyle ski you want the least weight which means use the strongest materials so you can use the least amount of layers. you will also orient the glass to make the best use of its strength in a given direction.

epoxy resin will bond to ester resins and just about everything else.

one last thing, with kevlar and other aramids, they dont absorb the epoxy resin like other materials do so you essentially are just encapsulating them in resin. this can lead to issues with delamination which is why its usually best to not mix them with other materials. since regular glass has different strength vs kevlar is kinda like how different metals expand at different rates, so while your fiberglass may bend or stretch and has some give the kevlar might not have the same amount of give and this can cause them to break away from each other.

so to put this all into perspective this is how I use what ive just described.

if Im making a mold I would use chopped glass 1 or 2 layers. starting out I would lay resin down and break small pieces ( torn not cut ) and place in any funky areas first. if you have holes or scrapes you need a filler usually to fill that stuff. im saying if I have a small dip or step, put that down first so the next layer can lay flat over the area. then switch to a heavier material like 1708 or 1700(no chop) and put 3 layers down. you have to be careful not to do too many layers at once. so stop there and if needed when that kicks lay up your next layers. poly resin or something cheap. if its gonna be a mold ill use long term use iso resin.

if I wanted to build a light thin flexible part like say an rc car body, I might go with several layers of 4 oz of 6 oz. w no chop this time. this will hold its shape but bend without breaking a really good amount. id prob use a gp or vinylester resin

if you wanted to build something really strong and light use carbon and epoxy. the best way is vacuum bagged so you can get the proper resin to fiber ratio. thats a whole other topic though.

if I needed to fix a hole like in the top deck where a bilge fitting was, I would use several pieces of 10oz cloth to build it up inside and out and could use an ester resin since thats what its made from. or say something bigger like you shorten the hull I would use epoxy and some thicker material. obviously if you had tight areas you would start with the chop and then switch to the bulky material.

for a tray you can do a lot of ways. lay a single layer of 1208 or 1708 in a big piece like the size of a full sheet of turf, cut out the parts. maybe mock up in carboard first and transfer to the glass, and then use 3 or 4 more layers to bond it all together and into the hull. you can pour foam into the gutted tray and sand it all to the shape you want and then glass over. you can make a wooden mold or whatever material you want and lay a tray up off that and install. ive taken a squarenose that had a cracked tray, cut out the insides of the gunwhales, refoamed and re-layed the tray flat, side to side and then reinstalled the sides which I also thinned down to make it a wide tray and bonded all that back in. that thing will never break again. the owner was a big guy and wanted to make sure of it.

last thing about glass is its awesome! you can mess up- grind it back down and re-glass. Trust me, if I can do this, anyone can do this. Dont be afraid to make mistakes. sometimes they are the best way to learn. I like to call it failing upwards. I might not be able to tell you how to do it right but I can tell you a hundred ways not to do it! and that is equally valuable. oh and be safe, protect yourself, gloves, mask etc all that stuff is cheap when compared to a hospital visit.

Hope my very limited and very basic info helps somebody. Im sure volumes of books could be written on this stuff but I just tried to cover what I use and how I use it. if you have questions post em or shoot me a pm. Im not around like I used to be but im still around.

And please feel free to correct, or add to anything ive posted. you never stop learning, I know Ive learned a lot from others on the site.
May 22, 2017
SW Tenn
Great write up! You dont give yourself enough credit on your glassing. I have a set of your tubbies and they are solid!


Super Hero, with a cape!
Jun 21, 2007
St. Pete, FL
Tom21 did a great job explaining everything but he did not cover the fillers.

Cab-o-sil, milled fibers, cotton flock, microspheres and talc are all fillers. These are not used with glass. Think of them like bondo. They are going down before or after you have laid glass.

Say you do a layup and you have a wave in your glass affecting your appearance? Fix it with a coat of filler.

Have to lay down glass in a tight spot or you have a radius too tight to bend the glass over? Put down filler first so you don't get air under your layup.

I'll give you an example. I am making a part for my camper and the layup is ugly side out. When not bagging you get slight unevenness in the layup and a woven finish, and if you don't have butted seams (you shouldn't) you get high spots. I mix a filler of talc to smooth the surface before gel-coat / paint.

That camper example is what you will experience with you tray. You wont get a smooth finish with your layup (ripples and weave finish), but once its cured you can smooth it out with a layer of filler.

Each filler has its advantages and disadvantages. The denser the filler the stronger it is, but the harder it is to get it smooth and the harder it is to sand it.

Density highest (strongest, hardest to sand)
Milled fibers
Cotton Flock
Lowest density (weakest, easier to sand)


Milled fibers - Larger repairs. Like a 1/2 crack (you'd grind out the crack, put glass on one side, pack it with milled fiber filler, glass on the other side)
Cotton floc - Same as above.
Cab-o-sil - Great for bonding two less than perfect surfaces, like a sponson or foot hold install. Very hard to sand, but very easy to make a nice thick paste. Wipe off the excess and body work with a lighter filler.
Talc - Come back to this
Microspheres - Lighter than talc, easier to sand, but leaves pin holes in the sanding surface because they literally are hallow spheres. This is what you want to use to smooth your tray for turf.
Talc - The replacement for microspheres on surfaces that need to be sanded for a finish. Removing that fuel fill and want a clean finish? Microspheres will leave visable pin holes. Mix up some talc based filler.

To make a filler, just stir it into your resin until you have a peanut butter consistency. You can also mix fillers. Throwing in a bit of cab-o-sil into the millde fibers will help prevent runny spots. Which resin? The same resin you are using with your glass.

For your tray...

Simplified use 3:1 laminating epoxy with 1208 biaxial cloth. Prep and finish with talc, cab-o-sil and/or microsphere based filler.s
Jul 30, 2015
Sacramento Delta
Just a couple of tidbits I have learned.

First, don't use polyester resin on SMC hulls. Most oem stand up production skis like Kawasaki and Yamaha are made out of SMC. Read this:

"Next, you need to select the correct resin. While SMC is a polyester—based material, it cannot be repaired with polyester resin. This is due to there being a mold release agent present throughout the entire SMC part. Unlike conventionally molded parts, where release agents are applied to the mold surface, SMC is compounded with a release agent dispersed within the resin mix for faster processing. This means that as the damage is sanded to prepare a good bonding surface, fresh release agent is exposed. Polyester resin products do not offer a strong enough physical bond to adhere to this surface. Because of this, SMC should only be repaired using epoxy—based resins, fillers, and adhesives.

How do I finish an SMC repair? Most SMC repairs will be painted, and only catalyzed type paint systems should be used."


Second, don't gelcoat SMC hulls or decks. Why? Because gelcoat is polyester resin. There is no epoxy gelcoat. (Gelcoat provides great U.V. protection.)

Third, don't use chopped strand mat cloth with epoxy resin. Why? Because chopped strand mat fibers are bound together to create a cloth by Styrene Monomer. Styrene is a thinner for polyester resins. So polyester resin dissolves the styrene on the chopped strand fibers and creates a great bond with the chopped strands of fiber. Styrene is not a thinner for epoxy resins. So the styrene in the chopped strand mat cloth will inhibit the epoxy from binding properly with the chopped strand fibers in the chopped strand mat cloth.

Fourth, use Knytex X-Mat DBM 1708 or other similar material with epoxy resins. X-Mat consists of chopped strand fibers which are sandwiched between two layers of fiberglass cloth. The sandwich is actually stitched by a sewing machine with thread to form a chopped strand cloth without the use of styrene. The two layers of fiberglass cloth are stitched together to keep the inner layer of chopped strand fibers together -- without the need for Styrene Monomer. Basically X-Mat is the replacement for chopped strand mat cloth when using epoxy resins.

Fifth, there is no epoxy paint top coat (at least that I am aware of) because epoxy has little to no U.V. resistance. That means that your epoxy repair or rework is not U.V. resistant. So paint your ski. I like Valspar Tractor and Implement paint and adding Valspar Enamel Hardener. But I would like to experiment with Epifanes two-part polyurethane paint sometime in the future. The Harbor Freight 120 cc HVLP Touch Up Air Spray gun with the 0.8 tip rocks for painting jet skis because it is small which is great for getting into engine compartments and in my experience with the Valspar product the 1.8mm tip on the H.F. full size H.F HVLP gun is too big and makes orange peel unless the weather is cool and you use enough hardener to make it flow on the surface. Use a respirator with chemical cartridges not just pink dust cartridges.

If anyone knows this guy:

invite him over here to share his knowledge and experience in this thread.
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