Applying Fiberglass to dinghy

[John Stevens]

When I lay the fiberglass sheet over the bottom of the hull do I put down a layer of wet epoxy first or put the cloth down then epoxy over it?

TIA,

John

[Reno]

Hey John:

I'd suggest a thin layer of epoxy first to assure the wood has good coverage and that the epoxy has soaked in. Just before the epoxy is dry, ( by that I mean "Tacky" but not too sticky to mess up your cloth) you can lay the cloth over it and apply more epoxy. If, on the other hand, you haven't had the time and the wood coating layer of epoxy has dried, (no longer "tacky") then I'd suggest a light sanding with around 150-200 sand paper prior to laying on the cloth and then the adhering epoxy.

[Barry Pyeatt]

I personally would not recommend going higher than 80-100 grit before applying epoxy. 80-100 on plywood leaves enought "tooth" to achieve a good mechanical grip to the plywood. Going to finer grits should be saved for finish work after you have the epoxy and glass applied and are getting ready for paint. Even then going higher than about 120 grit will leave you with problems with primer and paint bonding to the epoxy.

The 150-200 should ideally be left for the final coat of paint prep.

Depending upon the brand and hardner choice, you can wait on applying the cloth until it hardens, it doesn't have to be applied while tacky as long as the glass and epoxy coat is applied before the time period suggested by the hardner mfg. Most hardners have a blush that develops after hardning/curing. When that happens, a scotchbrite pad and warm soapy water will remove it and make it ready for glass and a second coat of epoxy.

Applying an initial coat of epoxy before glassing generally assures you of not having any "dry" spots on the glass because the plywood has soaked it up.

[Kudzu]

When I built my Kayak we placed the cloth on the boat and then poured on epoxy and worked it in with plastic squeegee's. Came out perfect.

[Charlie Jones]

Hi John- welcome to the board.

I always roll on a coat of epoxy before glassing. I usually let it cure past the sticky stage, then either scrape off any lumps and bumps, and or very quickly run over the hull with 100 grit to take them off. Just enough sanding to make sure nothing will snag the glass fibers.

Then I lay out the cloth, smoothing it into place and do whatever it takes to make sure it stays put. Tape, lead weights, what ever. I then pour on resin and squeegee it out into the cloth, moving excess resin into the dry areas as I go. I generally start close to one end, wet out three or four feet, then go back and catch the end. Then I finish from where I stopped.

The plastic bondo spreaders that come in a three pack work well as squeegees as do the credit cards apps you get tons of every month I save those to use as epoxy and glue spreaders.

Get some throwaway gloves and use them. An apron isn't a bad idea either

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[John Stevens]

After I apply the first layer of epoxy, then the fiberglass, then the epoxy again is that it for epoxy? Or... do I give it another coat?

Do I use a regular paint brush to put on the first layer of epoxy before the glass?

I'm making an 8 foot pram approximately 4 feet wide. I will be coating the entire boat with epoxy. How much will I need? Also how much fiberglass will I need?

TIA,

John

[Barry Pyeatt]

You can use the throw away "chip" brushes or very short nap roller covers, but the plastic bondo spreaders work very well to move and smooth the epoxy around and don't soak up or hold the epoxy and end up throwing it out. They also clean up easily where you wil go thru a lot of roller covers and chip brushes doing the same job.

I wouldn't think that you would need more than about a gallon to do the job. But having never done an eight foot dingy, I'm just guesstimating.

Yes, epoxy, glass, epoxy, sand, sand, sand, prime, paint and use.

[capt jake]

DEFINITELY use the bondo spreaders! THey (IMHO) can't be beat in this application.

My 2 cents and there ain't no change left!

[tdrown]

When I was glassing the Weekender last year I was told, by a fiberglassing expert to put down a thinned coat before the glass (I used polyester resin, not epoxy). According to him, not doing so would severly highten the risk of delamination.

[John Stevens]

Another few questions on the glassing. Do I need to glass the seems before I glass the entire hull?

Also, when glassing over the outside what is the normal overlay amount where the pieces of fiberglass meet?

TIA,

John

[Charlie Jones]

nope - you don't need to glass the seams first, unless it's an extremely high stress joint- none of the joints on your boat are gonna be that high stress.

I usually overlap about 2 to three inches. See the picture above- The glass is laying about 2 inches over the chine out onto the bottom. The bottom in that pic is already glassed . It lapped down the side about the same amount. Then I did a rough fairing of the edge and then laid on the sides.

[John Stevens]

That is what I thought from the picture above, just wanted to make sure my eyes weren't playing tricks on me.

When you say you lapped it over the side are you talking about the inside of the boat? Which leads me to my next question: is it best to epoxy the inside of the hull first or after I glass the outside or does it even matter?

Thanks,

John

[Charlie Jones]

on the outside.

John- what I do when building is cut out the parts, then the exterior (or whatever will get glassed) gets one coat of epoxy and a quick sanding. The parts that AREN'T getting glassed, or those parts that might be difficult to reach later get at least two coats, then a good sanding. Then if it needs it I roll on another thin coat, sand that and go on.

So I'd epoxy the inside, and at least lightly sand it before putting the boat together- yes. Also- having the inside coated keeps the ply from stealing epoxy from your fillets as you apply them. If the wood is uncoated, part of the epoxy soaks into the plywood and tends to make the filleting material dry out as you use it. I much prefer filleting over precoated and sanded wood.

For others reading this thread- I should tell you that John is a professional singer / entertainer and has a really nice CD out full of sailing type songs- ask him about it. I have a copy and really have enjoyed it.

[Greg Luckett]

Charlie,

Thanks for the tip about John's CD.

John, would you tell me more about it, cost, and the means to obtain one of yours?

Thanks,

Greg.

[John Stevens]

Thanks for all the replies concerning my glassing, this site is a great resource. And... thanks for the kind words about my music Charlie. I am currently out of CD's but will be making more in the future. Anyone interested can listen to some clips at this site: http://www.mindspring.com/~johnstevens/Beach.htm

Thanks again,

John

[Greg Luckett]

Thanks for all the replies concerning my glassing' date=' this site is a great resource. And... thanks for the kind words about my music Charlie. I am currently out of CD's but will be making more in the future. Anyone interested can listen to some clips at this site: http://www.mindspring.com/~johnstevens/Beach.htm

Thanks again,

John[/quote']

John, any new CD's yet?

[Charlie Jones]

John lives right where hurricane Charley visited. We still haven't heard anything from him. Hoping that it's from power outages.

[Greg Luckett]

:cry:

Hope he is okay.

We have not yet heard from our family and friends living in the Tampa Bay area either.

[John Stevens]

Yes we made it through the hurricane! The house had some damage and we were without power for a few days but we are ok. Thanks for asking. It's amazing what FL summer days are like without air conditioning;-)

Greg, concerning the CD, please send me an email with your mailing address.

John Stevens

johnstevens@mindspring.com

[JeffM]

John,

Thanks for asking about glassing so I won't have to.

A question for whoever: I've read that I shouldn't used excess epoxy in the glass -- that I should squeegee until the weave shows through. (I didn't do this with my first butt joins -- they're thick with epoxy!) Should the glass then be filled in and smoothed with a second coat before it cures? I expect it's a bad idea to sand semi-exposed glass.

Jeff