Fiberglass Spyder Cracks

[455maveric]

Ok its time to start working on my boat to get it ready for paint and it has like a said spider cracks whats the best repair on them and what is the best paint has any one used endura paint

[Mikes402Jetboat]

If I were you, I would go to a place like Tap Plastics...or a good fiberglass product supply store in your local area. Get some literature on making fiberglass repairs...and buy a gelcoat repair kit. (get some mold release wax otherwise known as PVA). There are also some excellent video's on fiberglass repairs that you can buy, that is how I learned to make gelcoat repairs. Read the information or watch the video's completely...several times...before starting to do any of this type of work.

Usually fiberglass stress cracks like you described are actually caused when the boat is first pulled out from the fiberglass mold (new) and usually don't surface for many years afterwards.

I would not want to give you any bad advice here...but from what I have read in the past about these "stress cracks" is, you have to grind them all the way out to ensure they don't grow, or come back again later...then make you repairs to the fiberglass and gelcoat. Please ask an expert on fiberglass repairs before doing anything to your boat you might regret. You can always run the boat over to an expert for a quote to fix it, and ask lots of questions about the proper way they would fix your problems.

I have made several gelcoat repairs on my boats, and on some friend's boats too. It is not hard to do, and if you make a mistake it can always be ground out and done again. It's basically only liquid plastic repairs.

By the way...if you plan to make any gelcoat repairs yourself. Always mix your gelcoat up with the pigment color, but leave out the MEKP (hardener) until you get a good color match tested on the side of your boat.

I usually do my gelcoat repairs out of the direct sunlight... and not at noon time. Something about the sun at noon always makes it hard to get a good color match. Smear the gelocoat without hardener on a section close to the repair to test the color match. To remove the unhardened gelcoat you just smeared on the boat, use acetone to clean it all off. This will not harm anything, and will remove all traces of the mess.

To properly prepare a spot for a gelcoat repair, always wash the area first to ensure to get off any waxes, or oils or dirt from the repair area.

If there is a scratch you want to fix, wash the area first, then use 80 grit sand paper folded on an edge to rough up the inside of the groove of the scratch, followed by acetone on a clean rag to clean out the roughed out scratch area. Tape off the repair area (I use black electrician tape) so you will not be putting extra gelcoat on the boat where it is not needed. Mix your gelcoat with pigment and get your color match, smear a sample on boat (without hardener) wipe off with acetone. When you get a good color match, add the proper amount of MEKP (hardener) and mix it up well. Use popsicle type sticks for mixing...cheap and disposable. Apply gelcoat to the scratch until the gelcoat is slightly mounded over the top of the repair area. I use acid brushes to apply gelcoat, cheap and disposable. Once the gelcoat is applied, use mold release wax (PVA) in a pump spray bottle to spray over the top of the gelcoat repair...go have a beer...or take a break and come back in about 15 to 30 minutes and test a small area with a fingernail to see if the repair is hard yet. If not, pump more mold release wax on it and go away again. Failure to cover a gelcoat repair with mold release wax, can actually prolong the drying time of the gelcoat. Mold release wax is available at most plastic gelcoat supply shops. Most gelcoat repair kits have a clear plastic sheet you can put over the repair too. The idea here is to seal off the oxygen from the gelcoat to get it to harden up. I don't use those clear plastic covers for repairs, because I would have to use a sqeegy to flaten the repair....homey don't do that. I like the mold release wax, because it does the same thing and just washes off with soap and water. I just don't like the idea of messing up my gelcoat repair by trying to flaten or squeegy it out, just so that plastic sheet for the gelcoat repair kit will have full contact with the gelcoat. I throw those clear plastic sheets away for the repair kits.

PVA (mold release wax) I believe that is also called Poly Vinyl Alcohol
Once the repair is hard take off the black tape and wash the area with soap and water. Use wet dry sand paper (i use 320 grit first to knock down just the extra gelcoat added followed with 600 grit) with water to sand down the hump of your repair. It is going to look like hell until it is buffed out with fiberglass polishing compound...so don't freak out.

Try a small repair first if you have one, then move up to bigger repairs when you get the hang of it.

Good luck to you, and if you think you can't do it...you are wrong...go for it!

Mike in Missouri - I pronounce that Misery!

[455maveric]

well the whole boat deck needs a refinish so lots of work ahead

[Jacob]

Usually fiberglass stress cracks like you described are actually caused when the boat is first pulled out from the fiberglass mold (new) and usually don't surface for many years afterwards.

That is one of the best, most in detailed responses I've seen on S&F in a while.

I did not know that about stress cracks. I thought they were created by the severe flexing of a hull?????

[Mikes402Jetboat]

Wishing you the best of luck with all your repairs, if you have any other questions...feel free to just ask me. Yup...I am an extreme detail freak...I just can't help it!

I was an aviation mechanic in the US Navy from Sept 78 to Sept 82 just out of High School, and I have always enjoyed working on my own projects. My squadron was based out of Whidbey Island Washington. VAQ 137 - The Rooks.
My aircraft was the Grumman EA-6B. Tactical Electronic Warfare Jammers. Probably the most ugly plane on the planet, but they work well...zapping just about anything that makes an electronic signal. I heard they were going to retire the planes in the eighties, but I still still them being used on aircraft carriers even today.
My Rate (Job description) in the Navy was AMS3. (Aviation Mechanic Structural Petty Officer 3rd class). I actually considered starting a business in gelcoat repairs over the last few years, but I am probably too far off the beaten path from the local lake to make a decent living at it. Glad to be of assistance to you in the future, if you have any other questions.

Just remember...it's only plastic...you can fix each spot yourself as you have time to and save a ton of money! You might not even have to repaint the boat if you can color match all the repairs well. Try a small spot first to get used to it... then get a little more aggressive. You can always grind it out and do it over if you are not satisfied with the first try.

Mike in Missouri

[455maveric]

THanks for the help i wish i needed only to do spots but some one painted the boat once and looks like they sanded through the gell coat. I will have to sand it to get all the old paint off due to it is pealing off in places

[Mikes402Jetboat]

Check with Jamestowndistrubutors.com for top coat paints.