Gelcoat screw up??

[MattyL13]

So, while I'm waiting for some parts to come in I decided to start sanding the hull of a free boat I picked up. 2 years ago some idiot (who shall remain nameless so I don't embarrass myself) was cleaning this free boat he got. It had been sitting unused, uncovered in a cornfield for the past 20 years or so and was covered in all kinds of things. After a good cleaning, this idiots dad came out and started to apply polyurethane to the boat. after a small area was tested, the idiot decided it looked pretty good for a 20 year old boat and it was actually shiny. So the rest of the hull was painted with the poly. 2 years later, the idiot decides he's finally going to finish this boat project he started and noticed that the polyurethane had yellowed pretty badly he then decides to sand this away and buff and polish the hull. So the idiot starts sanding with 1200 grit wet paper and thinks "wow, this really sucks, maybe I'll try 220 since this is the next lowest grit I have on hand". the 220 seemed to be working well until the idiots arms got tired. This guy again starts thinking and decides to use a random orbital sander with a 220 pad. since 220 worked well by hand, it outta work even better when plugged in, right? worked great and didn't tire the arms so badly. so after sanding an entire side of the boat,this guy starts wondering if he just successfully sanded away the gel coat by using this lazy method and starts to look very closely at the hull. Turns out the hull is extremely smooth and when wiped with a wet rag, shines very nicely. When it dries, its a bit dull and somewhat chalky. The idiot then tries to convince himself he only sanded until the yellowish, somewhat still shiny polyurethane was gone but then can't decide if he's sure or not. Especially since he doesn't know anything about fiberglass restoration.

SOOOO did I just ruin the gelcoat on my boat? I've read that gel coat is about 20 thousandths thick, give or take. If I did screw up, how can I fix this? The good news is that I only sanded the solid blue color right around the waterline of the boat. I didn't sand anywhere that has the speckles in it just in case I screwed up.

Thoughts?

Thanks in advance

 

[Woodonglass]

Re: Gelcoat screw up??

Pics would help! I would stop Sanding though and just wipe her down with ACETONE. IT will EAT the POLY right off the Gel Coat AND Help remove the Chalking GelCoat layer too. It will NOT harm the Gelcoat as Long as you don't leave it on TOO long. Wet a rag and rub it down.

My Signature line has a link on how to post your pics.

 

[MattyL13]

Re: Gelcoat screw up??

http://s1177.photobucket.com/albums/x356/mattyl131/

try this photobucket link. My computer won't let me upload to iBoats for some reason. My settings are correct.....

 

[Woodonglass]

Re: Gelcoat screw up??

Not sure what you did but pics are NOT working... Might be to big. Try resizing to 640 x480

 

[MattyL13]

Re: Gelcoat screw up??


Unsanded, yellowed Polyurethane

Unsanded poly





Sanded and dusty, not wiped off yet

Here we go.....


Pics added to Photobucket. Link is posted above. Sorry

 

[MattyL13]

Re: Gelcoat screw up??

View attachment 87906
Sanded and wiped down, still wet from damp rag. nice and shiny

View attachment 87907
Sanded, left side damp and shiny, right side dry and kinda dull

 

[Woodonglass]

Re: Gelcoat screw up??

Well first 5 pics working but last two not. what ever you did on them try it again. Have your tried wiping the poly with the Acetone??

 

[MattyL13]

Re: Gelcoat screw up??

No, didn't try to use acetone yet. I started puking last night and still feel pretty bad. Gonna take today off I think. Besides, the wife sent me to my room to "think about what I did". She said it looked better before I touched it. But what does she know anyway, she can't even drive a boat.

 

[MattyL13]

Re: Gelcoat screw up??

well, I just tried the acetone. This is bugging me to no end. Turns out the acetone didn't even touch the poly. Didn't strip it, disolve it or even soften it. I just looked at the hull again and I'm trying to talk myself in to believing I didn't screw it up. .020" is little less than 1/32" give or take. Comparing what I sanded to what I didn't sand, I can't see that I went nearly that deep. Somebody tell me I didn't wreck it please.

 

[Yacht Dr.]

Re: Gelcoat screw up??

Hello Matty and welcome to Iboats..

I dont think you screwed it up..but its hard to tell.

This is what I would do.

1. Get a resporator ! Use it
2. Get a black marker and scribble about 1 sq foot.
3. With a damp acetone rag smear the markings around so you get a good purple haze. ( it will show your sanding scratches )
4. wetsand with 400 untill most of the scratches are gone.
5. wetsand with 600 grit until all of the scratches are gone.
6. repeat steps 2 and 3.
7. sand final with 1000 or 1200 grit.
8. buff area.

This will give you an indication if you have allready sanded too much with 220.

YD.

 

[oops!]

Re: Gelcoat screw up??

yd has ya covered....

220 is usually ok if you dont stand there sanding for hours.......if you can see fiberglass.....you went thru.....and thats another thing......but you would know if you did.

i uasually start at a 280 ish...then the 400 and up to a 1000 or 1500 if i really want to go over board.

 

[Yacht Dr.]

Re: Gelcoat screw up??

yd has ya covered....

220 is usually ok if you dont stand there sanding for hours.......if you can see fiberglass.....you went thru.....and thats another thing......but you would know if you did.

i uasually start at a 280 ish...then the 400 and up to a 1000 or 1500 if i really want to go over board.

I was more concerned about having more agressive grit paper after the 220.. you Dont want to risk oversanding with course grit paper that you cant buff out..

You start with 220..then sand with 280..then 320..then 400..then 600...then up and up..

Seems Too Many grits .. YOU might go through !..

YD.