First time user of Epoxy..........

[David_Jersey]

I have used fibreglass resin and cloth (?!) before to repair stuff, but for nothing major or that gave a tidy result (no MOT's here /forums/images/graemlins/shocked.gif /forums/images/graemlins/smirk.gif).

I have read the articles in the mags and it seems to me that Epoxy is pretty much the same idea, except it is "better" and also that you can add stuff to the Epoxy resin so that it can act as more of a Filler than Fibreglass Resin can and then sand it down more easily than FG Resin.

What I was thinking of doing is using it in a non structural way to coat bare fibreglass for cosmetic reasons only. (the forepeak on my boat is the Head and loads of storage, but does not have any Gelcoat on the inside of the hull - at present it has been painted and to be honest looks absolutely fine............but I think it would look better with a smooth finish.

My initial plan is:

a) Clean off any flaky paint / abrade the existing fibreglass (wire brush / a wire brush on an electric drill), but this will not remove every last flake of paint - in fact because of the nature of bare Fibreglass I suspect that there is no way to remove 100% - any views on whether the Epoxy will stick enough to this sort of surface?

b) Remove as many fittings as possible and mask up any that are left.

c) mix up some Epoxy Resin to a formula that means that when cured it can be sanded smooth by electric sander and by hand, but thick enough to cover up the raw fibreglass and no doubt a few imperfections / dings - would I need to add cloth? or would it be thick enough on it's own, even if it takes a couple of coats?. (I can't remember what you add to the Epoxy? and is the result that "user freindly" in practice to sand down?)

d) paint it by hand, however many coats it takes to get a coat that looks right!

I would like the end result to look like it was moulded / the original Gelcoat.......indeed like the outside of the hull would be nice. Of course I have a tendency towards aiming high (wishful thinking??!).

I appreciate that this would be a lot of hard work for very little result (in technical terms called "a pig of a job" /forums/images/graemlins/grin.gif), but it is an excuse to "dissapear from the world" and it is the sort of project that suits me as someone with more OCD than skill - I.e. I will keep plugging away until I get the right result!

BTW I do have something to practice on at home and that if it turned out to be a disaster / I am more useless than I think - it would not end up being on view (the wash basin "cabinet" unbolts from the bulkhead and the inside could do with a repaint - no reason why I can't use it as a test piece).

Any thoughts?

 

[polwart]

by no means an expert - but would "Flocoat" be better? it should give you a gel coat like finish - in essentially one step - although that depends how rough the current finish is.

 

[srp]

You can't use ordinary chopped strand mat with epoxy resin (it's held together with a styrene binder that dissolves with ordinary polyester resin, but won't with epoxy resin). In any case, you shouldn't need any mat for what you want to do. If you want to use epoxy, you need a filler powder of some sort, such as colloidal silica or microballons. Don't use microfibres as the mix will be very hard to rub down. Microballoons are best in this respect.
You'll have to get as much paint off as possible - use an angle grinder with a flap wheel (from Screwfix.co.uk), and it will help to wipe over with acetone just before you start.
Don't forget to buy a full complement of protective gear - decent face masks, gloves, disposable overalls with a hood, etc etc. GRP dust and epoxy resins are not nice. If you're working in the depths of the bilge you could really do with some sort of extractor to pull the dusty air and fumes out through, say, the forehatch.
Of course, you could always just slap on a thick coat of bilge paint........

 

[tazzle]

I love epoxy - incredibly strong and very forgiving. But what you are describing sounds like plastering and polishing a skim coat - in my experience horribly hard to do with epoxy because of its stickiness; using micro balloons (the filler that gives easiest sanding) means mixing up to a peanut butter consistency. And making it stick to the substrate more than to the applicator.

I can see pots of epoxy curing before you get the finish, and epoxy smeared everywhere and coating everything except the surfaces you want to cover ...

Thick builder's poly (damp proof membrane) is the cheapest material to use to get a gel-coat like finish to things made by laying-up epoxy but I can't see how this can be used on the surface of a large 'plastered' area, especially if curved and in confined spaces.

 

[yogi]

How large is the area that needs to be done. Would it be possible to lay up a smooth area of fiberglass with gelcoat cut it to size and glue it to ceiling. This could be done if the curvature is in one direction.

 

[oldsaltoz]

G'day David,

Your project will not only take a lot a time and effort but also cost plenty do it properly and create a lot of mess; but if you must......

First of all make sure you are protected, a good mask, not the silly paper things, you need one that will filter fumes and dust, some throw away or disposable clothing with long sleeves, ear plugs, goggles, masking tape for wrists, waist, neck and trouser legs, this "may reduce itching after grinding / sanding". also a good strong fan set up in the companionway and leave the forward hatch wide open, this will reduce the amount of dust in the saloon.

Now for the project: Remove anything you can, if it's held by bolts/screws or glue, rip it out, now wash the whole area then wipe with acetone. make sure the fan is on.

If just go in and start sanding without first cleaning you will just spread any contaminants and may have problems later getting the finish you want.

As you plan to plaster the walls it would be faster to remove and smooth the walls with a grinder, if you must use sandpaper or flap wheels use a 40 grit. Make sure the fan is on.

When you complete the sanding wash the area in fresh water and let it dry for at least 24 hours, more if you can.

Ok ready to apply the first coat: Start by wiping down with Acetone, this will remove any surface moisture and all the finger marks. mix a small batch of resin (about a cup full for the first run, you can mix larger batches as you gain confidence). Mixing should be done in large containers that will give a large surface area to dissipate heat; apply a thin coat of resin over an area about one square metre and mix some Micro Balloons or 'Q' cells with the remaining resin to about a toothpaste consistency.

Application Tools:
You need to keep the layer nice and thin to reduce cost and weight but at the same time match the curve of the hull so the finish looks moulded. The best tool for this is an old / second hand Straight Backed Saw, just grind the teeth off to avoid damaging yourself, you need the back edge only to be in reasonable condition. You will also need a wide scraper to load up the saw from your container.

Application method:
Load up the back edge of the saw and place on the area you just coated with resin and lay over to about 12 degrees then drag it across the area, keeping the blade bent to conform to the hull shape, it's better to press too hard than not enough. The wet resin you applied will stop the mix getting dryer as you progress. Don't get too hung up on a perfect finish as you go, it's very easy to sand and easy to fill any low spots later.

When you coated the whole area it's time to start sanding, this means using by favorite tool "The Torture Board."
As your curves will be concave you need a flexible board, I would use a strip of 3 ply about 2 and half to 3 feet long; to hold the grit (225 grit paper) just drill 2 holes close to the end countersink them on the paper side, add small countersink threaded bolts and run them thru' small blocks (handles) on the non paper side. Now for the torture bit...
For a smooth finish you need to use a figure eight motion, holding the boar horizontal, push along and down then up and around and pull back and down then up and around, forward and down and so on, each cycle is a figure eight, move about the width of the board after each cycle completes. After about and hour of this you will know how it got it's name. Mark any imperfections with a pencil (Not a marker pen) as you go or you may not find them again.

Fill any imperfections and sand them down using the board. was the area with fresh water to remove all dust and do a final check for any marks.

Your next step will be to coat the area but you have not nominated what you plan to use. After all that effort I would use a polyurethane with long chain polymers, very durable and supper smooth so easy to keep clean and looks fantastic (provided the area is well finished). Just apply a suitable primer coat, sand it and apply he next coat after cleaning up again. the Polyurethane is best if sprayed, but can be hand painted but this best done by 2 people, one to roll on the paint and the other to tip it off with a suitable foam brush.

Let's know what you decide.

Note: I'm not at all sure I would be using an epoxy resin for this project, Epoxy will stick better than standard resins but you should have a good enough key if you grind the walls.

Also Note: you can reduce the itch by taking a very hot bath / shower before you start and smother you extremities with talcum powder as soon as you have padded yourself dry. another hot bath / shower after grinding will wash off the talc and glass dust.

Andavagoodweekend......

 

[Guest]

After you have sanded it to the requirements of epoxy so you won't trap dirt and moisture, you might as well just paint it.

Use a 2 pack and use undercoat first. I might be a complete fan of Epoxy and Gelcoat resins for construction, but paint companies have worked very hard to produce products that can coat and level a surface.

Trying to plaster toothpaste on to a large area and then sand it smooth is cruelty. Putting a nice runny mixture on with a paintbrush etc. is easier but unless you get the thixotropic bit right you will spend hours trying to keep it on the walls.

It is inside, and as long as you keep away from it for a week or two to cure fully, it will be a very clean surface. We used International paint on the inside.

 

[David_Jersey]

Thanks folks, given me more than a bit to chew over. Bit more preparation than I had hoped for, but in principle nothing that scares me off. Although I suspect that once completed this will be a job that will fall into the category of "never again" - but one of the benefits of pig ignorance /forums/images/graemlins/grin.gif

And "Microballoons" is the stuff I could not remember!

As I said, will start on the Test Piece and see how I get on.

 

[Strathglass]

There are much better things than microbaloloons which are easier to sand. Look at the various epoxy web sites,
Most things have been covered in the answers.
Main thing is to protect your health and wrap well up.
Certainly possible but very hard work. Finish with two part polyurethene paint.

iain

Iain

 

[clyst]

The easiest and quickest way to achieve the finish you require IF THE THICKNESS OF THE FILLER IS MINIMAL AND I MEAN MINIMAL is to coat and smooth the area with interior "pollyfilla"after preping . When dry sand and "paint" the whole area with thinned epoxy (50/50 meths) building up to undiluted mix . The thinned epoxy will soak into the pollyfilla and bond to the original FG .

 

[yoda]

I think you would be better off using a polyester gelcoat mixed with microballons as a filler / skim, sand smooth and then apply gelcoat by roller for a final finish. PM me and I'll get some more details together, it could be a lot cheaper than epoxy and give you a pigmented finish.

Yoda

 

[Avocet]

I'm currently doing something very similar on Avocet (but on the outside of the hull)! OldSaltOz has been advising me as I've gone along and everything he's told me to do has worked just fine!

On this particular project though, how rough is the inside of your hull? Are you sure it hasn't been flowcoated? Plenty of boats are. Avocet looked like she was fibreglass on the inside but with a pigment in the last few laminations. In fact, when I grind it, there are no fibres for the first few millimetres. I was wondering whether it might be easier to abrade your inside surface with the coarsest grit you can find using OldSalt's "torture board" method and then spraying (if you have the right safety equipment) or brushing a high-build epoxy surface primer on it. That might save some time and a vast amount of dust! You could then just locally fill the low spots and it will use much less resin (plus your boat will be bigger on the inside)! Alternatively, try applying some "flowcoat" resin - already pigmented white so if you scratch it, it still looks white udnerneath. I believe you can spray flowcoat with a gravity-feed gun but the styrene fumes will be pretty nasty.

If you want to go down the filled epoxy route, I got my epoxy and microballoons from "Marineware" in Southampton. They sell SP stuff and it seems to work fine. The microballoons are hollow phenolic resin spheres and the resulting mixture is dark brown.

The only other thought that crossed my mind is that if you coat the inside with epoxy, you might limit your options for bonding anything to is in the future (can't think of what you might want to bond but you never know)! Epoxy sticks very well to polyester. Even on the outside of Avocet where I've spilled the odd bit on an area of hull that hasn't been cleaned or abraded, it still sticks so well that it pulls the gel off the laminate when I try to remove it! The trouble is that nothing much sticks to epoxy so you'll have to use that forever thereafter! Also, if you're doing it this winter, remember to ask for "fast" hardener. It lowers the strength of the cured epoxy very slightly but this isn't a strength-critical application and the slow stuff will take forever to go off below about 15 degrees centigrade.

 

[William_H]

Forgive my expletives but your ideas are madness. You will be up for a lot of work for little beneficial outcome. I suggest paint the inside again wityh the kind of paint originally used. A water mix exterior house paint would go well. More coats wioll improve the texture but you will never get it like the outside.

One other comment. Polyester rssin goes nicely with the various fillers from talc powder to microballoons no problem just like epoxy. good luck olewill

 

[David_Jersey]

I will have another close look at hull to see if she is flow coated, although now I think about it I beleive she is, if you mean by this that the fibreglass is not raw and has at least a covering of FG Resin (the problem with not knowing the technical descriptions!).

OldSaltOz post was very informative, I suspect he has worked with Epoxy / FG once or twice before!

Also appreciated were the comments "You are mad" - never any harm in making someone think twice (or thrice!) /forums/images/graemlins/cool.gif

 

[DeeGee]

I too think you are daft. You say that there is no structural need for the work, it is just a question of cosmetic. So I would suggest you look at some new-ish boats and you will see the normal standard of finish on the inside of fibreglass, inside a cockpit locker for example. That finish will always be flo(w?)coat, which is gelcoat and wax. It makes a perfectly good finish.

Now, with the time you have saved, you can make a new tender, rewire the electrics, lie back on a berth and read all the back numbers of PBO for ideas to fill this time you have on your hands.............. /forums/images/graemlins/wink.gif

 

[Avocet]

Have you considered carpet? There's that nice rot-proof polypropylene stuff that often gets used on boats. Keeps condensation down too!

 

[David_Jersey]

[ QUOTE ]
you can make a new tender

[/ QUOTE ]

This has hit "technical difficulties" - the tubes filled up with water (missing one valve) /forums/images/graemlins/blush.gif, trying to pour water out of a deflated dinghy is like trying to wrestle with a greased pig /forums/images/graemlins/shocked.gif /forums/images/graemlins/laugh.gif

[ QUOTE ]
I too think you are daft

[/ QUOTE ] /forums/images/graemlins/shocked.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif /forums/images/graemlins/laugh.gif

On a previous boat I used cheap carpet tiles (fixed with carpet tape) worked really well and easy to put up cos any mistakes only ruined 1 tile. They even stayed up! But not what I am after here.