Thread: Bottom Gelcoat repair
12-19-2011, 12:37 PM #1
Bottom Gelcoat repair
The bottom of my black RXT's hull took a beating on our Exuma trip. Here's a photo...I'm not sure if the white that I'm seeing is actually fiberglass or not. There are very small divots, but I can't tell if it's just the color of scratched gelcoat, or if they're actually all the way through to the fiberglass. In anycase, they've been there for about 35 hours now with no additional gelcoat peeling.
What's the best course of action? Should I buy a cheap spray gun and just do a quick gelcoat spray over all the scraped area? Or should I use a fine tip paint brush and just do small spot treatments to all the affected areas?
12-19-2011, 04:48 PM #2
exact problem i am having although way less, (less scratches)
ive been trying this and that method here and there...
results = paint brush.... wont recomend.. looks ugly+ leaves lines and isnt very smooth that might slow down the ski (i think) i guess you could sand it down and polish it but thats work...
roller (like the one to paint ceiling) even worse result... avoid it....
applying it with a stick and covering it with film... like on the upper body work... imho best way... but way TOO MUCH work... and you will need ALOT of that film...
i have not tried it on a ski yet. but useing a paint gun (to a compressor) i gelcoated a piece of plywood (to make it waterproof ( long story short, needed to cover a hole in the ground for afew days and that cover had to resist people walking on it... plus water proof so it wouldnt break after getting wet))
it came out to be NOT BAD.... id say... for scratches like these... might as well be the best method but... cheap paintgun ....thin gelcoat... and still some sanding/polishing to do...
so really... make a test sheet of melamine (like the kitchen shelves ( compressed saw dust or so )) its pretty cheap and test out all the methods....
the roller might perform better if its somekind of special roller i did not get my hands on... paintbrush should be the same results... the aply/spread/cover with plastic should be the same as my results... and spray gun...( had tons of these cheap guns i got for free... but trial and error...... most got messed up...
so really... for best results WHILE being time efficient... paint gun...
imho the BEST results is with the plastic ( but not much better than paintgun)
the next results are paintbrush... ( i guess it could be OK.... with alot of work and such...)
worst results ive found... paint roller.... id just avoid it unless they make some kind of special roller for gelcoat
hope i helped.
12-19-2011, 05:03 PM #3
12-19-2011, 06:56 PM #4
- Join Date
- Sep 2009
For best results, you should do a fill operation with paste gel coat, leveled off, then an overall spray of gel coat, followed by wet sanding and buffing. Your hull will look like brand new.
To start, you should use acetone to thoroughly clean the bottom, and ideally use a red scuffy Scotchbrite pad with acetone to clean and give the over coats a good mechanical bite. You need to buy a quart of gel coat, a tube of hardener, and a small container of Cabosil. (a thickening agent for making gel coat paste) Please keep in mind that the first thing to know about gel coat is that it needs to be protected from air while it cures or it will not harden properly. The "old" way of doing this was to put a membrane (like saran wrap) over it, or spray it with PVA after applying it. Both of these methods suck. The "modern" way is to use a added wax to the gel coat, which rises to the surface after you apply the gel coat and protects the surface from air. You just need to remember to remove the wax with thinner before applying the next coat or it won't stick.
If you buy your quart of gel coat from GelCote in Sea Doo black, it will already have the wax mixed in it. That is why I recommend using their stuff; it is the right color and is ready to use.
You start by filling all of the scratches on the bottom so that they are all level with the surrounding area. You do this with a paste of gel coat. You basically mix up a batch of gel coat, and mix in Cabosil to form a paste. Then you simply squeegee it into the scratches with a body filler squeegee. Very light scratches need either little cabosil, or none at all. Deeper scratches need more body to the paste, and are best filled in 2-3 stages, being sure to remove the wax after each stage. Do not (!!) try to build up around the scratch in one pass thinking you will save time! Sanding always sucks, and the less you need to do, the better off you are. I use a relatively coarse wet sanding paper (180 for bad cases, 220 for most applications) to get a very even sanded look on the entire area.
Once you have it level, then you can spray on the gel coat. For this you can use a cheap throw away sprayer (Preval works good). Don't use a good gun, or you will regret it. (once it sets up, which it will if you are a beginner, it cannot be removed from the gun) Use a large tip, and only reduce (ideally with styrene) enough to spray a smooth coat. (don't over-reduce or you will get less shine)
After spraying, usually 2-3 coats, you can use stages of wet sanding, 400, 600, 800 1200 then buff it out with rubbing, then polishing compound.
12-19-2011, 07:43 PM #5
12-19-2011, 07:45 PM #6
Its the bottom of the hull, paint some gelcoat over it so you dont end up with delaminating fibreglass and ride it.
First time you pull it up on to some sand etc your going to have new marks...
12-19-2011, 08:37 PM #7
erm... Sea dood.... that method IS the way to go... but only that MOST sratches there are so LIGHT you cant even fill them.....
its less than 1 MM thick... and is imposible to do it your way as it takes too much time.....
for nost of the scratches id use a paintgun , THEN see/look at the deeper scratches and FILL THEM your way.... once done, you could respray and you have 1 BIG even coat with WAY less work then your method.
12-19-2011, 09:32 PM #8
- Join Date
- Sep 2009
12-19-2011, 10:44 PM #9
ive sprayed it on a ski... just not a huge area really, it was the front nose part, above and under (roller was scratching it) and the bunk scratches aswell..
i clearly said ROLLING gelcoat was a HORRIBLE idea.......
im not an expert @ gelcoat in any way. but i was sharing my personal experience + results from experiments i tried.....
and as for the results, why is SPRAYING it on, then i repeat THEN FILLING the areas that need to be filled and then RE SPRAYING....
what im doing is saveing up time because some marks wont be a problem any more,
just being logical. is it better to fill the whole ski with gelcoat (big area)
or spray some gelcoat on, SEE that 1/2 the scratches are gone and only CHIPS need to be filled in...
and another thing. if your NOT going for prof. looks. its better to SPRAY some gelcoat on then have NO gelcoat and leave the fiberglass in contact with water...
just makeing my point. no need to get mad, you may have 30 years of EXP. in gelcoat, your way MAY be the best.
but this is an opinion. and i find that spraying gelcoat on, he might say "ohh it doesnt look so bad" and keep on riding with chips and pock marks on it.
so its saveing time by ALOT . sure the chips will be there, but atleast the fiberglass is protected and for him it doesnt look that bad.
12-19-2011, 11:16 PM #10
- Join Date
- Sep 2009
I don't know if you pulled up his photos or not, but I see a number of dings and holes that should be filled if he doesn't want delam down the road.
If I am going to take the time to fix the bottom, I tend to not want to do it half-assed.
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