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Getting ready to spray gelcoat
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| CaptSpike |
Posted on 09/27/11 - 4:06 AM
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What is board sanding?
What is the best way to sand the keels and lip under the gunnel edge?
Spike
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| ritzyrags |
Posted on 09/27/11 - 6:18 AM
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A board sander will be a tool that will allow you to sand a material with a rectangular hard surface under the attached sand paper.
Gunnel details will be done by hand with or without a cloth backing.
I have had good results by simply folding the sp sheet in quarters and using each side in turn until discard.
The DA sander by Porter Cable has proven to be the most useful tool when resurfacing glass.
http://www.whalercentral.com/showuser...to_id=1382
Hope that will help a bit.
Edited by ritzyrags on 09/27/11 - 12:34 PM
Dont lie
Dont Cheat
And dont give up.. |
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| modenacart |
Posted on 09/27/11 - 4:02 PM
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http://www.youtube.com/watch?v=_9MhXv...9MhXvC-rE8
Do a search for block sanding. I used a flexible board instead of a solid one. If you don't block, you won't get flat surfaces. I would challenge that my sides are flatter than they were when it left the factory.
They that give up essential liberty to obtain a little temporary safety deserve neither liberty or safety.
--Benjamin Franklin |
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| CaptSpike |
Posted on 10/04/11 - 4:21 PM
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OK I swore I was going to take the weekend off from the project and I almost did. Sat. evening I went out and tried some wet sanding by the bow just to see what I was up against. I couldn't believe how easy it sanded and how nice it started to look. Then Sunday around 11am I decided to hit the really bad areas with the DA sander and see what else I could get done. Well it went pretty good. I realized after close look that the reason the ground out stress crack are showing is cause the gel coat was very thin over the areas. I had a few spots on one side that never fully cured???? I was able to sand most of one side and the stern when it began to rain. That ended my dry sanding of the tougher spots. So I continued to wet sand some of the other not so rough areas. All in all it definitely needs another coat or two. I am thinking of buying another gallon of waxed and one without wax just so I can get a couple coats without sanding in between. This first coat I have applied is really thin and you can see that well in the sunlight. I ended up buying a HVLP gun with a larger tip from Northern tool, $50 so it was cheap enough to try anyway. just in case the 3m hvlp gun struggles with the next gallon, lol.
Still not entirely sure I could spray well enough with the 3m gun so for $50 another gun with larger tip is worth a shot. Especially with all the time and $$ already invested. I spent over $100 on sand paper to find out it wasn't wet paper, just dry. Hope I can send it back to McMaster......
So hopefully I can get out of work early enough to get some more sanding in before the weekend and maybe spray on Sunday or Monday since it is supposed to warm up.
Quick question. Since I sprayed with the wax coat what exactly do I need to do before the next coats? Obviously sand the imperfections out but what about getting the wax off? Some areas are fine and don't really need to be sanded before the next coat for cosmetic reasons. Would just an acetone wipe get the wax off for the next coat or do I need to do more than that?
Thanks,
Spike
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| ritzyrags |
Posted on 10/04/11 - 8:30 PM
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Dish washing soap has been used to remove the waxy film.
Build up enough thickness to be able to do some sanding.
You may have to sand many times to make it smooth and right.
Many factors will come into play.
I would use gel with wax for the last coat s only
Dont lie
Dont Cheat
And dont give up.. |
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| Karlow |
Posted on 10/05/11 - 12:54 PM
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I shot GC on a console that I built a month ago or so.
I used two gal. because it was not properly flared prior.
The fiberglass was printing through the GC.
If the console was properly prepared, it would take about a gal. maybe a little more.
I used a 3/4 hp compressor and a LVHP gun with a small tip.
The GC was shot w/o wax except for the top coat.
Prior to shooting, I would thin it down to the consistency of milk with acetone.
Each batch was about 8-10 Oz. It takes a while.
To sand it, I started with 80 gt and a DA sander.
You can use the heavy sander until the orange peal is gone.
Then you can drop down to 240gt and go over it again.
Now you are ready to wet sand starting with 400gt.
You best bet is to shoot more GC. When sanding, avoid the edges.
They are easy to burn through.
How did it turn out?
It could use another coat of GC.
When you go for a polish finish, you will find that you need to do more wet sanding.
The problem is your top concerned is burning though the GC.
Then you would need to buy another gal, wait another week for it to show up, spend another week of spare time.
Spray, Spray, Spray...sand, sand, sand, sand...wet sand, wet sand, wet sand.....polish polish...
Go back to wet sand, of ever worse go back to Spray!
It looks good, but not great. When it gets dirty you are more likely to see the areas the needed more sanding.
On the port side there is a dark spot, the GC is likely a litter too thin there and the filler is showing through.
This time next year, I will be on to my next project and no longer concerned.
Take a look on my page.
KP
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| CaptSpike |
Posted on 10/05/11 - 3:49 PM
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Well I picked up two more gallons of gel coat, one with wax and one without. I will make sure I get good coverage with the unwaxed and then shoot a final coat of waxed. Hopefully I can get my buddy to help me so he can clean the spray tip while I keep spraying with the other one (3m primer gun).
Anyway I'll report how it comes out. hoping to shoot sometime this weekend (fingers crossed).
Spike
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| ritzyrags |
Posted on 10/05/11 - 4:38 PM
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Karlow,
Use Styrene as a thinner and not Acetone.
You will see better results.
Dont lie
Dont Cheat
And dont give up.. |
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| Karlow |
Posted on 10/05/11 - 10:29 PM
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Serge
I call the manufacture Fiberglass site.com
They said Acetone, not styrene. You know I was able to reach them in the middle of the day on a Sat. During the summer no less. I had styrene for thinning some epoxy paint, but they said Acetone. It seemed to work OK. I was shooting GC over epoxy and glass. The only problems I had was when I shot the bottom of the console. It did not want to setup. It could have been a mixing error (counting drops of activator), Maybe I did not wash the epoxy well enough on then bottom. Or maybe i switched the mixing sequence thin then activate vs activate and then thin.
Who knows?
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| ritzyrags |
Posted on 10/06/11 - 9:20 AM
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Seems like this advise from your rep is contrary to my experience
In any event try your best to always use FRESH materials
The MEKP is an important part of components and should always be reasonably fresh.
For covering epoxy with a Polyester gel you will need to severely sand and scuff the epoxy surfaces in order to get an applicable bond.
Dont lie
Dont Cheat
And dont give up.. |
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| JohnnyCW |
Posted on 10/06/11 - 10:01 AM
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I've been told that acetone can play a role in inhibiting the MEK to some measure which can cause unexpected issues with curing.
I've used acetone a lot throughout the years and don't recall any specific problems though I've had the occasional instance where it did take the application longer to harden than I expected. I chalked it up to differing ambient conditions when it did happened but maybe it was the acetone.
I've only used styrene for small repairs and had good experiences with it but not enough experience to compare the two very well.
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| CaptSpike |
Posted on 10/10/11 - 3:08 PM
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Well round two went much better. The inline water separators before the gun helped a lot. Problem was I only had two, should have gotten more. Anyway a big key was lighting up the shelter I sprayed in. I could see the gel coat laying down better with the light. I used the same gun as before, a 3m accuspray gun with a 1.8 tip. To start it would spray nice but then start to spatter. I soon realized stopping and cleaning the tip, which is super easy with this style gun, was well worth it and helped lay the gel coat down nicely. I used up almost the entire gallon of no wax first. Then I noted I wasn't going to have enough styrene to make the entire final coat. I called around a couple places but no luck. It was Sunday after all. I had two options at this point. Let it sit with the no wax coat kicked and finish it up Monday after picking up more styrene or trudge on. I opted for the later figuring if it screwed up I could always just coat it again later. So I started laying down the waxed coat. I ended up thinning with acetone and found 1/2 and oz to the spray cup was the perfect ratio. I sprayed from a pretty good distance away so the acetone could separate before the gel coat hit the boat (I had read that as a suggestion somewhere). I figured with all the post I read in the past where 50% said never use acetone and another 50% had without any problems I gave it a shot. Seems to have worked out from what I see so far. The temp did drop fast last evening and we had a lot of dew this morning, including the spray job, so I brought the boat outside to soak up the sun and help cure it to the final stages. This afternoon I put it back in the garage (house not shelter) and will let it sit till the weekend before I do any sanding.
I haven't taken any shot # 2 pictures yet but will before I start to wet sand.
Thanks for any help I got here and other sites where people can access great information that wouldn't be readily available locally.
Spike
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| jasttn |
Posted on 10/10/11 - 4:34 PM
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Board sanding is an old trick that bodyshop guys do to get a nice straight surface. My uncle taught me a trick of using a paint stirring stick and wrap the paper around the stick and use the stick as your sanding block. This gives you a much straighter and true surface when done right.
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| CaptSpike |
Posted on 10/15/11 - 2:31 PM
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Added the latest pictures today. I think leaving the boat in the shelter was a bad move. Looking closely today I have a bunch of fish eyes and other imperfections. I started to sand them out and in one spot by the time I got the imperfections out I could see a repair of the stress crack as the gel coat was very thin there. Guess I will continue on and just add gel coat where it needs it after I am done. I can say one thing this is a ton of work. Wishing now I had just painted it. Looking back at all the time and $$ I spent it probably would have been cheaper to do that (even thought the paint is very expensive). Anyway it was a good day for sanding. Using 320 grit so it isn't exactly flying off, lol. Not much else to do today (at least nothing I wanted to do, chores).
Chipping away a little at a time. Hopefully I don't end up with too many spots needing more coverage.
Spike
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| modenacart |
Posted on 10/15/11 - 7:08 PM
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It takes a lot of gelcoat to properly do a boat. It took me about 8 gallons for my 17 montauk. You quickly learn who had actually done the work and who is repeating garbage when you start to do work yourself. I had morons tell me that you could regel a montauk with 2-3 gallons. What a joke.
They that give up essential liberty to obtain a little temporary safety deserve neither liberty or safety.
--Benjamin Franklin |
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| Gamalot |
Posted on 10/16/11 - 6:08 AM
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CaptSpike wrote:
Added the latest pictures today. I think leaving the boat in the shelter was a bad move. Looking closely today I have a bunch of fish eyes and other imperfections. I started to sand them out and in one spot by the time I got the imperfections out I could see a repair of the stress crack as the gel coat was very thin there. Guess I will continue on and just add gel coat where it needs it after I am done. I can say one thing this is a ton of work. Wishing now I had just painted it. Looking back at all the time and $$ I spent it probably would have been cheaper to do that (even thought the paint is very expensive). Anyway it was a good day for sanding. Using 320 grit so it isn't exactly flying off, lol. Not much else to do today (at least nothing I wanted to do, chores).
Chipping away a little at a time. Hopefully I don't end up with too many spots needing more coverage.
Spike
When I used the Spectrum GC Patch kit on my CC and was just covering over the holes I had filled in I ran in to much the same issue. No matter how hard I tried and how I prepared each old hole, as soon as I began the final sanding I ended up going through the existing GC all around the patch.
As Modenacart can attest, there is a science to getting this done right and the job will go much better after you learn the technique of mixing and spraying. High humidity and moisture either in the air lines or even in the outside air can cause all sorts of issues. What is most aggravating for me is in the process where we spray a gallon of GC on and then end up sanding a half gallon back off to remove orange peel and other blemishes to get it to look good.
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| kamie |
Posted on 10/16/11 - 9:14 AM
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Spike,
how thick was the gelcoat before you started to sand?
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| CaptSpike |
Posted on 10/22/11 - 3:32 PM
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How thick was the gel coat is the question. My answer is a two part answer. The original gel coat layer was pretty thick and for the most part still on the boat. After repair the gel coat I applied is ???? thick. Honestly I have no idea. I know when applying it covered what was there. 1st attempt I was left with some sagging and rough spots so it had to be pretty thick to do that, though I don't believe I got even coverage everywhere. Those rough areas were sanded down and I then applied two coats of non waxed and one coat of waxed. I do not know how much was applied with those coats only that looking at an angle I could see the wet coat area vs what was already there in previous coats. I would have thought there was more than enough there, and in most areas there is. Not being to experienced at spraying anything, getting even coverage seems to be my downfall.
This morning I finished the initial sanding of side one and moved to the stern and finished that up. As I proceeded up side two (the worst side repair wise) I started to see the "veins" I had ground out beneath the sanded area. Add to that the fact that my sanders swivel joint started to leak and I was pissing out so much air the compressors couldn't keep up for squat. I blew a gasket. I put the boat back into the garage with a feeling that I just wasted the last two months of my life.............and got no where. Tomorrow I will try to return the sander, and then finish this initial sanding. At that point I am done for this year. I am not going to touch it again until spring. At that point I will decide if I should continue with more gel coat or just paint it and be done with it. There is new gel coat over the repair areas so I am not so concerned with the seems leaking and painting will finish it off without any risk of sanding back down to the gel coat again.
Pretty frustrated,
Spike
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| ritzyrags |
Posted on 10/22/11 - 4:59 PM
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Yes,
It is always a bit frustrating to see things not going exactly the way you had planned.
You are right,
Take a break from it and regroup.
Look at what is the obvious problem
Take note and correct it.
Seems like you may have to spray more coats on your repair areas.
Clean up all oil before the spray.
Above all be patient and steady
After all you are learning as you go right?
Dont lie
Dont Cheat
And dont give up.. |
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| CaptSpike |
Posted on 06/23/13 - 2:24 PM
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Update: Well it has been a while and I figure I would update everyone and anyone else that may be in the same situation I am/was. After trying to find a professional to finish the job last yr (OK so I didn't look hard enuf) the boat wasn't touched. This spring I said I'd finish it with a nice easy paint job. I chose EZ-poxy2 paint. I applied the EZPrime and when I finished I could see my overlapped joints along with some spot sagging. I was pretty disappointed to say the least. So I sanded down the bad spots and applied a second coat of primer. Yup you guessed it same results......... So yesterday I sanded down the areas again and decided to apply the topcoat since there really was no other reason for a third prime coat at this point. The EZ-poxy2 went on nicely and aside from a few bugs looked like it was going to be a nice job. I went down this morning to find a bunch of small lumps. like debris was in the paint, but it wasn't there when I laid the paint down or when I checked it before closing up the night before.I could also see my overlap areas on this coat as well. So much for the self leveling properties. So I remembered what the guy at West marine said and with coat #2 going on today I thinned the paint. After sanding out the unknown lumps and a few runs I started to apply the paint. Initially I started to get the same results on application with something looking like it was in the paint????? I brushed them out and continued on, keeping a nice wet edge with overlap of each section. It was looking great and going on great. When I finished and went upstairs it looked very good. I was certain the thinning had done the job. Well I just went down to check on it and it is dry to the touch. However I can once again see the overlap again and I am seeing more of this debris appear in the paint. I am totally discouraged at this point. At least if it was going to look this bad I would rather have had it be gelcoat than paint........
Any ideas as to what is going wrong here? This paint isn't cheap and investing yet another qt into the job may not be a solution.....
I just want to flip the boat and finish the inside so I can use it. My wife says I'm being to picky and maybe I am, if I only had minimal time in the restore, but with the amount of time I have invested I certainly don't want to end up with a sub par job.
Spike
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