I Love Gel Coat

[SlumpGumpy]

Lots of opinions on how to lay it down. What to thin it with etc etc
I just jumped into it with the help of Richard from Tiny's Fiberglass.
Sprayed some small areas with a Preval Sprayer
i heard use acetone, don't use acetone, MEK Solvent, styrene on and on.
All I could find locally was MEK and acetone locally. Went with MEK
i think styrene brings out more shine and color in the gel coat, but since I was spraying down on the hull I didn't care too much
went on beautifully hardened in under 24 hours and sanded great. Lots of orange peel (because of the MEK) but it all sanded out
was very intimidated for the past couple weeks before starting the project
its not rocket science
follow directions. I even went a little light on the MEK P(hardener) and it still turned out fine!
Weve heard it a million times that prep work is key. This holds true in gel coat.
If you're on the fence, jump over and get it done.
Im not a very bright fella and my work turned out great.
Ill be redoing my whole boat in the next few years with a whole new color scheme. Thanks to Tiny's fiberglass and the great threads here on BBC
i will use styrene when I decide to re do the whole boat. It may make the gel coat "pop" and hhopefully there won't be so much orange peel to deal with.

[DaleHollar1]

Congrats on your success. Best pointer I could give you if you spray entire boat is go get you a good 2.0-2.5 tip spray gun and use disposable cups. You will see though an entire boat is very time consuming.

[BASSCAT7]

The orange peel was not from the MEK, it is inherent in gelcoat spraying outside of the mold. Thinning gel is a necessary evil when spraying, but thinning also reduces the UV resistance of the gelcoat.
99 % of gelcoat spraying problems outside of a mold are Operator error, either with the gel mix, or the spraying gun technique.



You can use a lot of various solvents to thin the viscosity of the gel to try and lower the Orange Peel/Alligatoring on the cured finish, but all of them in one way or another will reduce the physical properties of the gelcoat as far as weathering, so the least amount you use the better the final gelcoat will hold up.

Very small amounts of solvent used as thinner will have little affect, but adding more to get the gel to level and lay smoother will have adverse affects on the weathering characteristics of the final gelcoat finish.

A little bit of finish sanding for Orange peel is a trade off for better weathering and UV resistance.

Gelcoat gets its UV ( weather resistance ) from the amount of pigment in the finish, so if you add a thinner that does not evaporate as the gel is laid down, the result is the thinner that is left reduces the amount of pigment in the finish.

The pigment issue comes into play when using styrene, MEK, toluene, and other solvents that don’t evaporate fast and cross link with the gelcoat itself when curing.

Acetone is used by a lot of places to thin, it evaporates very fast, 50 % evaporates in the air as the gel is sprayed, but it also does not help much with the leveling of the gel if it evaporates too quick.
Styrene Monomer is used a lot as a thinner, it is probably the best all around to use, but it will not have too much of an affect on the finish as compared to the MEK as both are slower evaporating solvents.



Like you say, spraying gel is not rocket science ( though the mixing is a science LOL ) that the finished product result can have 5 different people come out with 5 different results because of all the different variables in the gel mix / spray environment / operator awareness.

[ShawnD]

Sorry for thread jacking, But I have a question :
How much sanding do I need to do to prep for new Gel coat if I have 2 layers of automotive paint, 1 layer of primer and the original layer of Gel coat?
Keeping in mind that I have done fiber glass repairs to the top cap with Epoxy resin.
From what I understand because of the epoxy repairs I would need a special primer?
Thanks.

[BASSCAT7]

Sorry for thread jacking, But I have a question :
How much sanding do I need to do to prep for new Gel coat if I have 2 layers of automotive paint, 1 layer of primer and the original layer of Gel coat?
Keeping in mind that I have done fiber glass repairs to the top cap with Epoxy resin.
From what I understand because of the epoxy repairs I would need a special primer?
Thanks.

What is the top surface ? The auto paint ? How large of an area is the epoxy repair ?

[ShawnD]

What is the top surface ? The auto paint ? How large of an area is the epoxy repair ?

The repairs:
edge of the entire lip of the topcap where the rivets are and the splash well I had to fix the transom so I removed the rear of the topcap.

The top of the surface is 2 layers of auto paint followed by a primer and the the gelcoat underneath. I don't know what type of paint it is but its cheap and thin.
I've started sanding a small area where the Trolling motor is.

[javelin90]

Can you post some pictures oe email them to me at summajet.mojo@verizon.net
Thanks, Garland

[Scott S.]

Gel coat is nothing more than colored resin, and resin has styrene in it. The use of acetone will make the gel softer, and will scratch very easy. You will have to spend a little bit of time finding a good gun, most have a tip that is no good, to small. 2.0-2.5, I don't go any smaller than 2.5, I also use a 2.5 gallon presure pot. I save empty water and or gallon mik jugs, cut the top off and leave the handle. I will mix the gel and catylist in the jug and set it inside the pot, and I do the same thing with the acetone, clean up is super simple, the pot never gets dirty and only takes about 1/2 gallon of tone to clean the lines out.

[ShawnD]

Here's a few pictures that I have on my photo bucket.