Restoring checked fiberglass Deck on 1967 Boat

What would you recommend? I have thought about sanding to somewhat smooth, but leaving the cracks, then filling the cracks with fiberglass resin or autobody filler/glazing of some sort, then sanding to smooth, then spraying gelcoat with glitter like paint? I plan on changing the deck color to light blue or turquoise.

I need allot of help with the basics. What prep? What product? What gun? What tip? What else don't I know?

Here are guns I have considered:



https://www.amazon.com/Fibre-Glast-...lcoat cup gun&qid=1560860859&s=gateway&sr=8-2



https://www.amazon.com/Accuspray-16...m gelcoat gun&qid=1560860910&s=gateway&sr=8-2

 

Welcome to the forum.

I wish I didn't have to start this way. But bad news. Those cracks extend all the way down into the fiberglass structure. Your proposed cosmetic fix will craze in short order. It will require the removal and replacement of the damaged fiberglass to effectively prevent the return of the alligator.

My suggestion;
Carefully grind away all crazed gelcoat. As eventually as possible grind off 1/8 inch of the CSM glass. Lay down 4oz twill fiberglass cloth. Lay down 5 oz of CSM fiberglass. Fair and paint/gelcoat.

It is more tedious than difficult job. Fortunately there's many glass work shop's near the Delta.

Good luck

 

Blueknarr: Thank you for your reply. Wayne at Fiberglass Hawaii, (Ventura, CA) where I buy my fiberglass said the same thing. So, unless someone else here has further prep suggestions, we've got most of the prep covered.

Except for the rubber/aluminum deck/hull rail. Should I remove it when I prep?

So, on to what product? What gun? What tip? What else don't I know?

 

Absolutely remove the rubrail. It will get torn up pretty badly if left in place. And you will want to repair the crazing under it.

 

He could probably "Rhinoline" it with some kind of rubberized plastic.

 

Blueknarr why do you recommend laying up Chopped Strand Mat ("CSM") as a top layer?

In my experience, it is hard to hand layup/squeegee without rolling up fibers and making a lumpy mess.

Blueknarr and others, I have worked with the Knytex X-Mat cloth/mat sandwich before and found it to be great for hand layups over existing properly prepared old polyester fiberglass. What do you think about using X-Mat instead?


Blueknarr why do you recommend sanding past the offending gel coat and 1/8" into the existing fiberglass? What benefit is to be obtained by sanding below the offending gel coat? Hopefully the gel coat is a different color than the glass structure layup which will provide a great sanding guide. So, why sand into the glass structure?

What fairing glaze do you recommend?

 

What is the blue at the margin of that crazed area ? It isn't crazed. I wouldn't be tearing into it with sanders, you have to have a firm idea of what you are trying to achieve, if you are intent on restoring it to original condition, it will then show up all the other sins of the thing, in sharp relief. Rub it down with some sandpaper to the point it is reasonably smooth to run your hand over, and hit it with an epoxy high-build primer, you can use a squeegee to work it into the cracks, sand smooth, perhaps another coat of primer, then a couple of coats of gloss finish, an alkyd or PU one-pack good enough. Otherwise, lots of work put into something that is worth not much. Tearing through the old gelcoat, you will find it next to impossible to get a nice smooth finish, particularly around the perimeter, and that "rolled" edge. No way baby !

 

Thank you for your reply Mr Efficiency! What does this mean?

 

I mean is that light blue gelcoat, at the margin of the deck moulding ? It appears in good condition. If you want to be a perfectionist, that could turn into a lot of work, I would not be looking at getting down through that gelcoat, unless it is somehow lifting at the edge of the cracks, which seems unlikely.

 

There are two approaches to restoring the deck discussed in this thread. I appreciate both and would like to explore each of them deeper.

True to his username, Mr Efficiency suggests the second approach:

I am concerned about epoxy because I want to spray gel coat with glitter rather than paint/clear coat with glitter for the surface. So, what do you think of using this polyester based product vs epoxy?

What say you Blueknarr?

My 82 year-old father-in-law gave me the boat. When I realized it involved so much work (I can now take the Mercruiser I Type Model 120 stern drive apart in my sleep. Let's see if I can put it back together with my eyes open...), I told my wife, I will give it to a charity. When the charities refused to take it, I told my wife, I can sawzall it up and put in the trash, but the 120 HP GM in-line 4 is a little heavy for that. At the last Thanksgiving family get together I told everyone that "I can't even find someone to give this boat to!" My father-in-law replied, "I did."

So, the challenge is on. And I have a little experience working with fiberglass already and have many things fiberglass in my life, so spraying gel coat as a paint is something I have always wanted to learn.

I love the Ozzies, because they are direct. You don't have to be as proper or gentle or cutsy clever with them as with their Kiwi counterparts. Ok, then, Mr Efficiency do you want me to learn this craft working on a more expensive craft? If so, please send me your three most hated friends with more expensive boats.

From a design perspective, the hull also interests me. It is narrow up front, with a short front deck so as to put the body weight on the bow, it is wider at the stern to bouy the heavy weight of the engine and its stern drive, but it has a stern hull with multiple sharp chines like a 2-cycle stand-up jet ski from the 1990's. Maybe the design works. Maybe it doesn't. I will put it in the water prior to restoring the deck.

1967 REBEL - MERCRUISER 120 HP

Manufacturer: Webell Marine
Serial No.: 289
Model Name: Rebel
Year Built: 1967
MerCruiser Stern Drive: MerCruiser I Type Model 120
MerCruiser Stern Drive Unit Serial No.: 2263798
MerCruiser Marine Engine: 120 HP GM in-line 4 cylinder
MerCruiser Marine Engine Serial No.: 2231097

I appreciate you guys.

 

Sorry I've been away for a few days.

There will be a definite color difference between the gelcoat and glass mat.

The cracks extend into the structural fiberglass mat. If the structural cracks are not fixed, they will re-crack any gelcoat or paint cosmetic fix within a few years. Two way to prevent crazing from returning quickly. One grind away 100% of damaged fiberglass mat and replace with new mat. Or add a layer of woven fiberglass. It took a few decades for the crazing to develop, they will return eventually. Trying to extend it to a few more decades. The thicker the layer of new glass, the longer it will take.

A thin layer of mat (veil) is used between woven fiberglass and gelcoat/paint to prevent the weave pattern from telegraphing (print thru) the gelcoat/paint.

 

Crazing like that is typically from a gel coat job done poorly, normally incorrect catalyst ratio or excessive thinning with solvent. If it’s too thick it’s even worse.

Covering it with glazing compound is a waste of time, some epoxy products claim to work, and they might if it’s not too bad.

If you don’t go through the hassle of removing all the crazed gel coat the cracks will return the first time the boat is flexed or stressed.

Coating it with a very flexible truck bed product would the easiest method that has a good chance of holding up for more than a very short period of time.

 

ondarvr and others: Thank you for pointing out the likely cause in addition to its remedy. My guess is that the gel coat is quite thick. And the Summers in the Sacramento Valley area of California usually hover between 80 to 100 and can get up to ~110 occasionally. So, my guess is that thermal expansion and contraction added to the causes you listed. What gel coat mfr. and product which will perform better under such conditions?

Blueknarr and others: I am glad you got away for a few days! One thing about the rub rail. Clearly the deck was produced in a different mold from the hull and then the two were mated together.

In everything I have worked on before, there is no rub rail, and glass seam on the interior joins the deck and hull.

This is likely a crazy newbie question, but what is the likelihood that the deck is held onto the hull solely by the rub rail and if I remove it the deck will separate from the hull?

 

I would suggest not spraying gel coat, it will be a major project to remove the crazed junk and then getting the surface looking even half decent again.

Either do nothing, or use truck bed liner, and not the cheap stuff from the auto parts store.

The deck should just be held in place with the screws through the rub rail. Not many manufacturers went to much more effort than that

 

I doubt the cracks extend into the glass, it would be madness to start tearing into it, anyway. You'll never get it looking any good, removing the gelcoat, with the radiuses you have there, gouging is inevitable.