Thread subject: Whaler Central - Boston Whaler Boat Information and Photos :: Finally sprayed the gelcoat
Posted by kamie on 10/01/12 - 6:02 PM
#1
This past weekend marked a milestone in my project 13's life. The outside was finally sprayed with a new coating of gelcoat and while I had reservations and I still haven't started the sanding part, i think it came out OK. I finally decided to purchase a compressor, and found a 20 gallon oil bath compressor for $200 locally on craigs list. Here is a list of the rest of the items
HVLP spray gun with a 2.5mm tip from tcpglobal
www.tcpglobal.com
Gelcoat and styrene from Eastern Burlap
www.easternburlap.com
Acetone, gloves, mask and other assorted supplies from Home Depot.
In theory i could have sprayed the gelcoat unthinned through the 2.5mm tip but i couldn't get it to flow out easily so I opted to thin 10%. I setup a system where I measured out gelcoat and thinner then dumped the gelcoat into a paper cup, added catalyst and mixed. Once that was mixed for about a minute, i added the thinner, mixed and then loaded the gun. My first stop was to hook up the air and do a short pattern check on brown paper before proceeding to spray the hull. I added the pattern check because one batch i had issues with the gun, an adjustment for the trigger came loose and it was impossible to spray. I didn't realize until after I emptied that cup so after that I checked. Once I finished spraying a batch, the gun was rinsed with acetone, and then taken apart and cleaned in an acetone bath and reassembled and tested before mixing the next batch.
The cup on the gun holds 32 oz but with thinner I was only spraying 16 oz of gelcoat at a time so it took me awhile to spray all the gelcoat. In total I sprayed 1 gallon of unwaxed and 1 quart of waxed gelcoat. If you believe the coverage numbers that means there is a total of 22 mils of gelcoat on the boat prior to sanding. There didn't seem to be as much orange peel as I was predicting but that will be determined when i get back down and start sanding. All said it wasn't as bad as i was expecting and while i'm sure there are places where I may sand through the gelcoat and have to respray it was a lot easier than I expected it would be.
Posted shots in my project album of the supplies and the compressor as well as shots of the sprayed hull. It took me a total of 5 hours to spray all the coats. I had to wait until the temp was above 60 as well as wait until the sun moved to a point where the boat wasn't in direct sun. The front yard faces east so I didn't really get started until lunch and it was starting to get dark when i finished. Next step is to sand the hull and respray any thin spots. Then get the hull off the trailer, the trailer fitted with new stoltz rollers so they won't mark up the newly sprayed hull. After that get a new weight for the hull and get her back on the trailer for the next phase of the project wet foam removal and interior fixing.
Edited by kamie on 10/01/12 - 6:05 PM
Posted by Barryg on 10/02/12 - 6:21 AM
#2
Looks very nice Kamie. So nice to see all the patches and discolorations disappear with spraying of the gel-coat. I am doing the 1968 Nauset also so looks very familiar just on a slightly shorter scale. I have about a gallon and a half applied at the moment. It seems that I lose a good bit of gelcoat through spraying. I just finished rolling some for the purpose of building up the thickness. I used a foam roller and it came out fine with no loss of product. More sanding and then a final spray before the sanding and polishing comes.Good Luck, BG
Posted by jfortson on 10/02/12 - 7:22 AM
#3
Were you able to cover the entire outside with only 1 gal and 10% reduction?
Also, the same question for the 1 qt containing wax - did 1 qt cover the entire outside? Was the waxed reduced only 10% to get that much coverage?
Posted by kamie on 10/02/12 - 2:28 PM
#4
Barry,
If your spraying, make sure you have the gun setup correctly. I did a lot of practice with water and gelcoat with no catalyst, if you don't you will spray more product into the air, than on the boat. If you have a pressure regulator use it to set the air pressure at the gun and open the air control on the gun all the way open. Open your product flow knob all the way open and then play with the fan control until you get a good solid oval of product. Measure how wide the product oval is, hold the gun that far away from the surface and overlap by 1/2 the width. It seemed to work will for me although I know the grass directly under the boat has a slight white tint.
Jfortson
The gelcoat I was using covers 76 sqft to a depth of 15-18 mills, the 13 foot is 72 sqft of surface area. I thinned both the waxed and unwaxed so they were easier to spray. The gallon of unwaxed covered the boat to a good depth and none of the repairs were visible. The quart of waxed was sprayed to add additional thickness to account for sanding and to allow all the gelcoat to cure. The coverage of any gelcoat your using or plan to use may be different so you should check with the manufacture.
Posted by kamie on 10/06/12 - 1:00 PM
#5
Today was the first time I had seen the boat since spraying gelcoat. A couple observations,
I will need to add a couple layers to the stern. When I sprayed I started at the bow and covered the port and the starboard side. I did spray the stern but when i started to sand it was clearly not thick enough to get a smooth finish. I will order another quart of un-waxed gelcoat and respray the stern and a couple spots along the smirk that seem thin.
If you think your repairs are smooth, they probably aren't. I knew I had some places that could use additional sanding or fairing and I was right. Gloss white gelcoat, like gloss paint shows all the shadows and inperfections.
I sanded with 120 to smooth down the sections where the gun wasn't working correctly. I used 320 to smooth that those sanding marks but there are still someplaces that could be sanded farther to make them perfectly smooth. I then sanded the entire hull with 400 wet/dry to see how it would look.. With the exception of noted issues the hull is looking smooth. I will take more photo's once I finish 800,1000 and 1500 grits of wet/dry sanding.
Posted by kamie on 10/21/12 - 7:12 AM
#6
I resprayed the stern and and some other parts that were thin. I only thinned about 5% and while it seemed harder to spray, the finish was smoother. I probably would have been well served to respray the entire hull with a coat of unwaxed and then waxed, as clearly the first batch the catalyst was off. She had cured but was chalky, the second spray was hard and well cured. I will update my project when i finish wet sanding and polishing.
Next task, figure out how to get her off the trailer and flipped without dinging the new gelcoat.
Posted by kamie on 10/21/12 - 11:41 AM
#7
Clearly I should respray the outside but since it is getting too cold to spray, i punted and got her off the trailer. She is now flipped on a tarp in the yard while I put the new stoltz rollers on the trailer, get a weight for the rig empty so I know how much the boat weights. I couldn't resist digging out a bit of foam and while the top couple inched is dry there is still water soaked foam below.
Posted by sraab928 on 10/21/12 - 3:58 PM
#8
I just went through your album and its looking great! Keep us posted.
Posted by kamie on 10/22/12 - 5:30 AM
#9
I will, some how I thought the inside looked better. Now that I have her flipped, there will be a flurry of activity before I close her up for the winter.
Posted by sraab928 on 10/22/12 - 5:39 AM
#10
I am so thankful that winter has become a foreign word for me...
Posted by Barryg on 10/22/12 - 9:36 AM
#11
Looks very nice Kamie. I always hate not to do the inside after the bottom turns out so nice. THe 1968 Nauset has been in a dock house most of its life so the interior is in great shape . Still able to spray so the project must go on.BG
Posted by kamie on 10/22/12 - 4:01 PM
#12
In my case, I will work on the inside as we typically have warm days during the fall and winter. My hope is to get the interior designed and cut out of MDF and then pull the inside apart in the spring. Once that is finished, i will pull her off the trailer, flip, sand and respray the outside one more time and she should be ready. Hoping by early next summer to have her in the water for snakehead fishing.
Posted by kamie on 10/23/12 - 10:38 AM
#13
I got a weight on her and she still weights between 360 and 400 pounds. The before and after weights were not taken close enough to be 100% sure.
That is the good news, the bad news, the trailer was a lot rustier than I thought and it fell apart on the way from the ramp. Time to rehab a trailer.
Photo's on my project page.
Posted by kamie on 10/23/12 - 7:00 PM
#16
I saw PVG8's float test, and sent him a couple questions, mainly where is his lower through hull in relation to the water line. On my 13, the through hull is just below the water level. I believe his is just above the water line.
I already know that the water is concentrated in the stern so the fact it sits low in the stern doesn't surprise me at all.
Edited by kamie on 10/23/12 - 7:02 PM