Fiberglass help

[jdiaz78]

My tower is finally coming in tomorrow. I have purchased the marine grade plywood backing plates to help with the thickness of my contact points inside the hull. It comes with some kind of resin that attaches the plywood to the inside of the boat to help fill the voids since the hull has a curve. I plan on using fiberglass sheets on the other side of the plywood to also secure it to the rest of the fiberglass. I have never done any fiberglass work, but it doesn't look very hard on youtube. My question is about a resin I found at Lowes. The link is below. I have read that you want an epoxy resin to attach new fiberglass to existing fiberglass. This resin doesn't say if it is an epoxy resin, but states it can be used on fiberglass. Also, how many layers of fiber would you put on to make sure it is secure? Thanks in advance.

http://www.lowes.com/pd_331528-98-2...berglass+resin&facetInfo=&state=R#reviews_tab

This is the cloth I'm looking at.
http://www.lowes.com/pd_331525-98-2...s+cloth&productId=3228210&rpp=32#BVRRWidgetID

I'm open to suggestions.

 

[JC6275]

This sounds like something @Glassman could help you with, maybe he will chime in...

 

[Glassman]

That stuff will work. Perhaps not the best, but it's available to you and fairly inexpensive compared to other alternatives I would suggest.

This an easy job so don't stress over it. Also, I'm describing one way to skin this cat. You could probably do it one of several variations of this method.

Be sure to prep the area properly. Mark off where you intend to place the plywood and sand an area at least 2" beyond that. Sand very well using very coarse sandpaper. 60 - 80 grit. You want to make the surface rough so that the resin will get good adhesion.

Be very careful mixing the catalyst into the resin. Many people add too much catalyst either because they don't measure properly or they are trying to speed up the cure rate. Don't do that.
Patience is a virtue in this instance. Over catalyzing can actually start a fire!
I'd suggest that you play with a small amount first so that you can become familiar with the cure rate. If it starts smokin', you added way too much catalyst!

Also sand the face of the plywood that will meet the hull. Chances are there will be a void where the two parts come together. You want to minimize that void as much as possible.
Once both parts are sanded, you want to figure out how you'll keep the wood in place while the resin cures.

Do this in advance so you won't be scrambling while trying to hold wet parts.
Either cut a length of scrap wood that you can use to wedge under the wood between the floor and the inside of the rail to press it up against the hull or depending on location and access you may be able to use very deep clamps if you have them.

Now that you've pre-fit your parts and are ready to dive in, clean both surfaces well with acetone. Don't soak the wood, a wipe will do since it's new.

Before mixing the resin/catalyst take about a 10" square of that cloth and a pair of scissors and use the scissors to cut up the cloth into tiny bits about 1/2" to an inch. Just make a small pile of shredded glass. That shredded glass will be mixed in with some of the resin mixture to create a filler that you will use to fill the void between the wood and the hull. You shouldn't need too much.

Go ahead and mix up the resin, brush it on both the hull (the entire area you sanded) and on the face of the wood. Set the wood aside. Mix up the chopped glass with a fair amount of resin. It will form a big glob. Using a putty knife, smear the glob on the side of the wood you coated and press it firmly in the spot on the boat you coated with resin. Press hard to squeeze out any excess. Catch any excess with the putty knife and use it to smooth over the edges of the wood. Put your brace in place to hold the wood while it cures. Place something underneath to catch any dripping material. Use this time while the material is still workable to smooth over the edges and make it pretty. Let it set. Go do something else. Like cut a sheet of that glass to fit over and 2" beyond the wood you just put in place - if you haven't already.

Before the resin on the part has fully cured, while it is still tacky, mix up another small batch over resin. Remove your brace. Brush the resin over the wood and 2" beyond. Let that soak in, it will take at least two coats. Don't let it start to cure - get the glass on it.

If you somehow miss your window of opportunity and the resin has started to cure and is no longer tacky, then let it cure. Once dry, sand it well and proceed as below. Don't just brush resin over newly applied resin without sanding first - you won't get good adhesion.

This is a small area, you can apply the glass dry and wet it out in place or you can pre-wet it so you aren't hanging upside down getting arm cramps while you try to brush it on in place - your call depending on where it is and how accessible it is.
Using your fingertips and the tip of the brush, lay the glass over the area. It should stick. Load up your brush slightly and brush the resin through the glass until it is saturated. Use the tip of the brush to work the resin and make it nice and smooth, feathering out the inevitable stragglers of glass strands. If any are left hanging, don't worry. Let it cure and you can clip off any hanging threads.
If you want to put another layer of glass on there you can, probably not necessary. Between the resin and the compression of the hardware that holds the tower in place, that wood isn't going anywhere.

Did they supply the proper hardware? Hopefully you have either a stainless backing plate or very large stainless washers. Backing plate be better. Have fun. PM if you have any questions. I'll give you my # if you want to go over anything.

 

[jdiaz78]

Thanks for the information. I'll probably get to start this next week. I'll p.m. for your number when it gets closer.

 

[Glassman]

Thanks for the information. I'll probably get to start this next week. I'll p.m. for your number when it gets closer.

OK, I'll be around Mon - Thurs next week, after that I'm gone to the river, then to the desert through Memorial Day. Best of both worlds!

 

[biglar155]

Great Post @Glassman !

Definitely a "keeper."

 

[Glassman]

Oh, I found this shot. I'm pretty sure that this is the rear leg of my tower shot from inside. You can see that they used a backing plate and a washer.

 

[jcyamaharider]

That post needs to be in the member tips section!

 

[Gym]

Oh, I found this shot. I'm pretty sure that this is the rear leg of my tower shot from inside. You can see that they used a backing plate and a washer.

View attachment 5525

In the picture it also appears there is some other reinforcement imbedded into the fiberglass.

 

[Glassman]

In the picture it also appears there is some other reinforcement imbedded into the fiberglass.

That would be the wood.