Deck core repair - Do I have everything I need?

[redpointist]

I'll be attempting to recore a section of my deck in a week and need to go ahead and get the order placed so that I can get started on it next weekend. I've never done any fiberglass work so I'm not entirely sure I've got everything I need lined up.

The "softspot" is about the size of a dinner plate, but i sounded out the area around it that I'm not getting a sharp sound from the hammer, and the area is about 4 feet by 1.5 feet. I think I'm going to try to reuse the top skin of fiberglass, but I know theres a chance that I'll ruin it when I try to remove it. I'm planning on ordering 1.5 gallons of resin/hardener. I'm assuming that will be enough if I reuse the top skin, but will it be enough if I end up having to reglass the entire surface?

Also, I'm not sure what kind/ how much of the actual fiberglass to order. I'm ordering through Jamestown, and this link contains my options: Fiberglass Supplies

In my shopping cart right now, I have 1 gallon system 3 silvertip resin, 1/2 gallon silvertip slow hardener (should I switch to fast? weather is predicting mid 60s temps), dispensers for the bottles, mixing sticks, 3/8 x 3 inch aluminum laminating roller (should i get a bigger one?), silica thickener, and micro ballon fairing compound. I still need to decide what kind and how much glass to order, and I'll get the balsa wood locally. I also have a circular saw, full fasked respirator, and gloves at the house. Am I missing anything? You can see my wishlist is here if the link works: https://www.jamestowndistributors.co...ck%2Fsy1ZfA%3D

Thanks so much for the help, I'm a bit nervous about tackling this project!

[JPA Cate]

Given your urgency, why don't you PM minaret or mainesail and put the question to them; they are possibly the most knowledgeable posters on the subject that we have on CF, as far as I am aware.

Ann

[Dale Hedtke]

You haven't mentioned what material you plan to recore with. Plywood, foam, balsa? The core material will fill up most of the volume.
WEST Epoxy has a lot of reference material that I am pretty sure you can reference on line. Check it out. Also look on YouTube. I'll bet you'll find instructions there.
The project you have in mind is not a beginner's project, but definitely within the range of DIYers.
The FAST hardener is probably not a good idea. If I were you once I got everything in place (resin, etc.) add some local heat by tenting the area with a tarp and sticking a lightbulb inside. Be careful not to set anything alight.
Also, you will need to refinish the deck around the repair. You can use a one or two part polyurethane, or perhaps gel coat. The 1 part PU is the easiest, but least durable. Another big question.
Try to find someone locally that can help. If you have a local source for epoxy & supplies, they might be able to provide help.
Good luck.

[SVTatia]

I assume you have done the research and have the technique, right?
If not, here it is:
WEST SYSTEM | Projects | Fiberglass Boat Repair and Restoration - Fiberglass deck repair-Part 1, Replacing damaged balsa core - download the pdf.

You will also need: A gallon of acetone if the dimensions are as you said, disposable brushes and plastic spatulas to spread epoxy and a grinder as you will need to grind the bottom glass (be careful not to grind thru the cabin) after you remove the gunk and to bevel the surrounding area and the top that you will be re-using when you cover it off. If you mess up and cannot reuse the top, you still need a bevel on the good glass around the area. 60 or 80 grit disks will do the job quickly.
You may also need some weights to press down when you cover it, specially if reusing the top, such as concrete block(s), etc on a plastic sheet.

[Dale Hedtke]

Be careful with acetone. It is not recommended by some as acetone is sometimes a recycled product and can have contaminats that could interfere with adhesion. I got this information from MAS Epoxies BTW. Lacquer thinner, alcohol, or MAS's solvent are better choices.
Also, wear plastic gloves of some kind (latex, etc.) ALL THE TIME. Do NOT get epoxy on your skin. Try not to remove epoxy with laquer thinner from your skin (it will just drive the mix into your skin.)
Epoxy is easy to work with; take your time.

[SVTatia]

Originally Posted by Dale Hedtke

Be careful with acetone. It is not recommended by some as acetone is sometimes a recycled product and can have contaminats that could interfere with adhesion. I got this information from MAS Epoxies BTW. Lacquer thinner, alcohol, or MAS's solvent are better choices.
Also, wear plastic gloves of some kind (latex, etc.) ALL THE TIME. Do NOT get epoxy on your skin. Try not to remove epoxy with laquer thinner from your skin (it will just drive the mix into your skin.)
Epoxy is easy to work with; take your time.

Personally I would not use lacquer thinner or alcohol to cleanup a surface before epoxy. Acetone dries immediately and leaves nothing behind.
I guess the sales rep had some vested interest as he mentioned one of his products as a substitute?

[Delancey]

Where is the rotten core located? A diner plate is a relatively small area. Is that the absolute limit of the rot? Might be bigger when you get into it. How did the rot occur? Water infiltration from fasteners or hardware installation or something else? Do you have access to the underside of the deck?

Small areas can sometimes be addressed by drilling closely spaced holes (maybe one inch grid) and injecting thickened epoxy which can be a lot less work than cutting one of the skins and having to deal with glassing and refinishing. But really we need more details to advise properly.

[Sailorman Ed]

Great timing - this is also on my list but want to do it from the inside to preserve the deck finish. I have 2 spots about 12" dia. and think I have complete access from below. Any suggestions as to the best way NOT to make a mess? And replace balsa only with balsa?
Ed

[Cheechako]

Where is it? are you sure you cant do from the inside? no painting or color matching etc. Yes it's a little tedious but for that small an area (i did a whole V berth from the inside) you'll save a lot of time and trouble, albeit you might get resin in your hair! haha. BTW, you can even replace core between a bulkhead and the deck skin. (if the bulkhead is tabbed on the cored inner skin)

[boatpoker]

Slow down a little.... You say you are using System 3 which is an epoxy. Neither one part paint nor gelcoat will stick to it afterwards without special preparation.

I strongly recommend you use polyester resin instead. It is much less expensive, much less finicky, easier to sand and much less sensitive to environmental conditions for setting. I usually recommend epoxy for the below the waterline work but on deck it is simply not necessary.

[Noreastern]

I knew you cannot gel coat over epoxy but never heard that one part paint such as "Brightside" would not stick. I re-cored a large section of my deck with epoxy and painted with brightside over six years ago and besides it being faded as brightside will in that time it never pealed.

[a64pilot]

I posted this once but it never showed up

You said you have never worked glass before? I would strongly suggest you hire someone and be their helper, or at least get a friend who has done this kind of thing before, or start with some smaller, less visible projects first.

[boatpoker]

Originally Posted by Noreastern

I knew you cannot gel coat over epoxy but never heard that one part paint such as "Brightside" would not stick. I re-cored a large section of my deck with epoxy and painted with brightside over six years ago and besides it being faded as brightside will in that time it never pealed.

I believe it's always good to follow a manufacturers recommendations. Interlux is quite specific about epoxy substrates requiring two part primers for all of their one part paints.

[ssanzone]

1st. ann is right... minaret is the guy in the know.

a few basics...

poly resin sticks to poly resin but will not stick to epoxy.

i would recommend you buy 3 gallons which is prob 30% more than you need but balsa is pretty thirsty AND you dont know how much cloth you will need (at least 3 layers) / how much 410 (407). I assure u that there isnt much worse than coming up half a gallon short when you are in the middle of laying up fiberglass.

my last bit of advice is around trying to reuse the top coat. while it is a smart idea aesthetically, the chances that you get the piece you cut out back in clean / level is pretty slim given this is your 1st time. while it increases the complexity (a lot) if you can do the repair from the bottom up it will keep the deck looking good.

if you want to practice... buy a gallon of joint compound from your local hardware store and practice applying thin layers to build up to a specific point. it is a lot thicker than resin but about the same consistency as the resin will be after mixing in the 407 or 410 (which never goes as far as you think it will).

go slow and clean as you go instead of at the end.

gl.

-s

[redpointist]

Thank you all for the feedback! I'm taking the week of the 17th off for vacation time to work on the boat so I figure if I order by monday it should be here in time to get a good start.

I do have a friend that works at a powerboat manufacturer who has some experience with fiberglass and would be willing to help out. I don't think he's done a core repair specifically but hes at least somewhat familiar with using fiberglass.

The soft area is on the cabin top, aft of the mast (a few feet from the mast) and on the port side. It came from a leaking handrail installed there. I'll be putting epoxy plugs where the screws pass through to prevent this from happening again.

I'm actually still torn about whether to go from above or below. If I had a removable headliner I would definitely try from below, but my boat has a nice molded in cabin ceiling liner with a pattern that I'd have to cut through. And honestly I think I'd end up looking at a cut in the ceiling liner more often than a section of non-skid on the deck that doesnt quite match. I'll have to ponder this a bit more.

Any other comments on whether I should use epoxy or polyester? I hadnt really considered using polyester previously but am not opposed to doing so if its a good idea.