Gel Spraying Techniques

What type of sprayer should I use to apply gel over a large area of the boat? I'll guess and say not an automotive sprayer.

How do I make sure it is the right thickness? Can I apply several thin coats or does it need to be all in one spray?

Worse yet, is this something that can only be done at a boat yard because of the extensive amount of equipment and experience required?

if you can find a shulz (im not sure of the spelling) its used for spraying thicker viscosity liquids, I use this type of gun for spraying undercoatings and bedliners and I'll even mix resin and spray it that way but you do have to clean the gun in a hurry

I know you guys are still using imperial in the states, but 22mm is some thick gel, you'll be lucky to get that on without a few runs!

Skibum, has the old gel been removed? If not then paint it, gel is a nightmare to work with if you are going about it backwards, ie gel last, it's a pain in dea$$ to sand if you don't get it right first time.

Tomski, I just noticed that you questioned a gel thickness of 22mm. Please note that I had posted the gel thickness of 22mil. which is .022 of a inch or in your case .5588mm , Pete

8122,

That expalins it! Transatlantic communication issues!

I think we'd call that 22thou here. Britain is a terrible place for measurement as we are part metric and part imperial. It's becoming more metric, but older people still work in imperial and people of my age (mid 30's) use both. I tend to just use what is most convenient for whatever i'm measuring.

Skibum, I say paint it if it star cracks and old repairs. Pretty much all coloured boats of any size are painted from the factory - sunseeker, princess etc. Awl Grip (american, i think) is the stuff, not easy to spray (but still a lot easier than gel) anf very tough and a fantastic shine, especially in dark colours.

Jumping in this thread late (and only read part of it, so sorry if I am repeating what others have already said). I personally recommend automotive type suction feed spray guns. Anything larger than the typical auto gun will be very problematic as you will have a hard time spraying more gel before it hardens in the gun. I tend to spray only a 1/2 pint at a time. The gelcoat MUST be thinned with Styrene (and ONLY Styrene) to a consistancy compatible with the auto spray gun. The gel is not harmed by thinning with Styrene and will harden just fine. If you have a large area, do NOT add wax to the gelcoat, so you can simply spray on the next coat. Add wax to the gelcoat on the final coat. A bit more catalyst is required when thinning gelcoat, so I suggest a test spray before the first time.

I also found that the small touchup spray guns worked the best, and I ended up using the small gun exclusively. I found the gun the held just the right amount of gel to not worry about the gel hardening in the gun before I could get it all sprayed.

I honestly forget what pressure I would spray at, but if memory serves it was about 35psi. Just make sure all the seals in the gun are good and tight (especially around the tip rod)and the gel will draw just fine.

A final thought: do NOT apply gelcoat in temperatures below 65 degrees. If you do, you will be wiping most of it off with Acetone as it will most likely not cure. If you catalyze the gel so it will harden below 65 degrees, then you will boil the gel and it will most likely harden in the gun within minutes.

A final final thought: When spraying gelcoat, it is best to apply the gelcoat in a overlapping circular motion...sort of like welding. This differs from spraying a car with a side to side overlapping motion. So, this means a more circular pattern out of the gun is preferable to a wide fan pattern. You are trying to build thickness without runs.

I only mix a quantity of gelcoat that I can spray in 30 minutes. After that, I start getting nervous. Then I have to have time to clean the gun Again, I think a quantity that can be held via a normal suction type automotive sprayer can be used, but larger quantities and man I would be a nervous wreck or try to work too fast and make more work for myself later.

The largest area I sprayed was the front half of the port side of my '93 SN...or just in front of the "S" to the tip of the bow.

David F wrote: I personally recommend automotive type suction feed spray guns...The gelcoat MUST be thinned with Styrene to a consistancy compatible with the auto spray gun...The gel is not harmed by thinning with Styrene and will harden just fine.

Where do you get your gel, wax, and styrene?

skibum, U S Composites are good for matching late model CC gel. You may have to buy a gal. if they need to mix a color. Mini-Craft of Florida has a standard line of hundreds of colors as well as matching gel pastes for patching both available in qts. If you are doing the whole boat, then a gal. is the way to go. Pete

Skibum, The entire boat is sprayed with the base color then the accent color is masked and sprayed just like you would do a car or truck. For bild, mutiple lite coats can be sprayed with time between them for the vehicle (solvent) to flash off.

I don't recall you ever posting what year and model boat are you doing?

Keep it original, Pete

Skibum, Am I correct that the boat has two colors of gel and then vinyl stripping between the two colors and then the "2001" is in vinyl too? If you can't find OEM vinyl grafics, a sign shop can duplicate it from a tracing of the old. I just picked up some on Friday that I had made for my 77 Tique. It's amazing what they can do by scanning the tracing and then with CAD clean it up and add any colors and borders etc. Pete

I have to quantify the clear gel with metal flakes spraying technique. By painting the base silver, it provides the base for the color. Then, I would cook up a batch of clear thick with metal flakes and apply a uniform coat. The remaining coats of gel would be only clear. That way the metal flakes would not be toward the surface. But the flakes would shine through.

Skibum, One thing to keep in mind about "customizing" is that I feel it may not look as good to other people that it does to you. It may even affect it's resale value and it's saleability. This is why I always suggest originality as close to as it was from the factory as posible. There are instances especially on older boats where the materials are no longer available but close matches can be made. I've see some real bad jobs out there that the first thing that comes to peoples minds is "why the @!# did he do that" The worst I think is a 1958 Atom that has been fibergla$$ed and painted. He probably didn't know what he was doing to a cla$$ic wood boat!

It sounds like you have made the decision that the gel is in bad enough shape that it's got to go. When fairing the hull be careful what you use for filling/fairing since gel may not stick to some epoxies. Pete

Skibum, David F is correct that masking tape will tear the gel line if it is removed after the gel cures BUT I always leave mine on the boat. Since you need to wet sand anyway, you can sand off what gel is on top of the tape untill the tape edge is exposed. This method keeps you from sanding beyond the area into where you don't want to sand plus if you need to give it another coat of gel, you won't need to remask. The tape will come off with a sharp clean gel line. Always use FINE LINE tape. If you are putting vinly over this line, the ridge from the gel can be knocked off with some wet dry. Pete

8122pbrainard where did you get the vinyl for your tique done? I have a 78 tique that I need vinyl for and there is not enough lettering left to make a trace.


Roger