a couple fiberglass questions

[Woodonglass]

If you're rolling it's still the same. You want to do wet on wet coats. As soon as the first one is tacky enuf to allow another coat to be applied...put another coat on!!! You'll get much better cohesion between coats that way. You want to use Ultra Fine Foam rollers to prohibit orange peel. Rolling Gelcoat is NOT the optimum method of application but it can be done. If you want a bit of a texture on the deck, using a nylon roller with a medium texture can sometime yield some good textured results especially if you roll it just as it's tacking up.

 

[Georgesalmon]

Just saw the "why not wipe with acetone". As Wog said the factory boys don't do it and that's what I was from 1975 till I retired. If you just get a rag wet with acetone and rub it all over your not wiping up anything, just spreading stuff around. You should wipe, fold the rag, wipe, fold the rag, etc. Reasons we didn't do that are that while your wiping its easy to rub over an adjacent area that might have contaminants on it and you'll spread them around on your surface. Another is that unless your buying laboratory grade acetone its likely that the acetone is recycled and already has contaminants in it and once again you can mess up your newly abraded surface. We had a lot of people laying up fiberglass and not taking any chances contaminating a surface was important. A newly abraded surface is about as clean as you can get. If you vacuum up the dust the little bit that's left is just resin and glass and will combine quite nicely with the new resin.

I know of a company to remain unnamed, that had a bunch of gel coat just fall off of several hulls. All of their hulls were over 25' so not many restoring that size on here. After much research and huge cost it was found out that those hull molds were sprayed with gel coat on Friday. Then Monday morning they were wiped with acetone to get a little sticky back and layup was started. Now, was the fault because they sat to long after spraying (Friday to Monday)? Or was wiping with acetone the problem? This was more than 20 years ago and to this day that company does not spray gel coat on Friday without a layup nor wipe anything with acetone. They do still abrade surfaces that have sat longer than overnight and vacuum up the dust. My experience is with new construction though, not so much with restoration work except my own personal hulls. My son does own a boat manufacturing company so I get to keep up with new technology now and then. Again, JMHO.

 

[Mikeopsycho]

Thanks guys.

Oh-oh, a difference of opinion on wiping with acetone. Hmmmm, now I'm going to have to decide what school of thought to follow. Geaogesalmon, your post makes a lot of sense to me, thanks for your input. What do you think about wiping down new wood with acetone after sanding? Same thing I'm guessing.

I'll check out Boatworkstoday, thanks Rickmerrill. And thanks to you too WOG, I'm always happy to hear your suggestions. I'm planning to gelcoat the entire sole of my boat with the idea that if I like the finish I'll just stop there, and If I don't really like how it comes out I can cover it with marine grade vinyl flooring. I'm thinking of adding crushed walnut shells (the consistency of sand) to the top coat for a non-skid surface. This is my tentative plan until someone tells me I'm nuts. :crazy:

 

[Georgesalmon]

I wouldn't wipe down wood after sanding either but,,,,,,,,,,,,,,,,,,,,,,,,,,in point of fact its probably 6 of one, half dozen of the other. I'm sure your going to have fiberglass on the wood before the gel coat? Gel coat will be good to have on the sole, most gel coat has UV inhibiters in it and most resin does not. Make sure its got surfacing agent (wax) in the final layer. I think you will find its pretty slippery if you don't throw some type of grit in or on it. I'm a big fan of vinyl on floors. I'm mostly fishing and its nice to use my wash down pump after every a few salmon and get the slime off. But I still use carpet on the verticle surfaces for looks.

 

[Rickmerrill]

Good point on cleaning technique George. From my DIY car painting days it was wash with soap and water, wipe down with solvent (in one direction and flip rag each pass to a fresh side), sand, final wipe down. The idea was water and solvent dissolve different things and sanding can push contaminants further into the paint so you start with an un contaminated surface and keep it that way - if you touched the surface with your finger you had to wipe it down again. If you didn't you usually get fish eyes. A lot of people think solvents magically make it go away not knowing it's the transfer to the rag that's going on. Mike, I don't think it's so much a debate as it's different techniques for different conditions. For example, I walk around my hull in street shoes and sweat drops hit areas I'm going to glass. I have to clean first but I'd also feel comfortable glassing to freshly sanded and vacuumed area. I guess you can take this all too far and never get anything finished but judging by the results we see with projects here you can get away with a little grinding contaminants into the hull here surface and poor cleaning techniques there.

 

[Mikeopsycho]

Yes, there'll be at least 2 layers of CSM, maybe more if the folks here think there should be more, on the deck before the gelcoat.

I hear you Rickm. Today I did some glassing and did not use acetone, just vacuumed thoroughly after scuffing the surface of old glass, and sanding new wood. Seemed OK, who knows.

As far as flipping a rag each pass to a fresh side, I can't quite picture how to do this. Same with the wipe, fold the rag, wipe, fold the rag method. Aren't there just 2 sides on a rag? Maybe there's a video somewhere out there demonstrating proper wipe down techniques?

Thanks for all the great info guys, I appreciate it.

 

[Woodonglass]

GS makes all good points. Vacuuming and brushing is fine but I'll always do a wipedown with Acetone prior to my layup. After Grinding I actually pour it on and wipe it down to flush the "Pores" out not just a damp cloth. If it's a fresh layup that's cure for over 2 or 3 days then a damp wipe down is all that I think is necessary and very little danger of contamination unless of course something has occured to cause this and if that's the case I would recommend sanding and a more thorough flushing with solvent of the area in question. But like Georges says, either way will prolly work. As long as the working area is fairly clean and free of contamination and the layup is done well with no Bubbles, it'll adhere well. But again, GS WAS/IS a PRO and I'm just an

 

[Mikeopsycho]

Thanks WOG. I think I'll do what seems right at the time, depending on my mood, the alignment of the stars and other proven decision making methods. Most of my work will be under the floor so I'll never know how well it holds up.

 

[Rickmerrill]

Mike, There are only two sides to a rag unless you fold it first! Paper towels work too.

 

[Georgesalmon]

I usually fold the rag twice into a square then I actually have 8 sides about the size of your hand. Pretty common technique for wiping or polishing wax. Like in a mold or on a car.

 

[Mikeopsycho]

OK, I think I got it now (slow learner) :loco: Till now I've been slopping acetone around with a rag, wiping every which way, probably spreading any contaminants around fairly evenly instead of removing them. Where I do clean with acetone I'll do a much better job from now on. :eagerness:

 

[Daniel1947]

How about using "Tack" clothes for the final wipe down after scuffing/sanding? I know in the old days, there wasn't an auto painter that was worth his weight that didn't use a Tack cloth just prior to spraying the paint. It didn't leave a residue and would remove every piece of dust, lint or sanding trash that was left. Speaking of scuffing....what grit would be recommended for the sanding? 80? 100? 120?

 

[Woodonglass]

Tack Cloths work, 60 grit is good for scuffing Glass prior to laying the next layer of glass.

 

[Daniel1947]

Once again Wood to the rescue. Thanks for the info....anyone want to buy 5 gallons of Acetone? :laugh:

 

[greenbush future]

Good stuff shared in this thread guys, I learned a bunch about layups, cleaning, and general glass layup procedures. Thanks,.