Re-gelcoating my deck: Project thread

[jhulmer]

Originally Posted by UNCIVILIZED

Given the cracking, along with having that much room for reinforcements, how about a layer or two of an axial, along with some mat? Wouldn't that make things a good bit stronger than a joint maed mostly of CSM?

On the sanding, why a 16" or 18" board? The temptation for me is to build a custom "longboard", 21" long, & attach a piece of belt sander paper to it. Since said sandpaper seems to have a fairly impessive lifespan as compared to other varities.

UNCIVILIZED Speaking for myself I don't think I could handle anything longer then a 16". Damn thing will kill you on a hull!

[minaret]

Originally Posted by jhulmer

UNCIVILIZED Speaking for myself I don't think I could handle anything longer then a 16". Damn thing will kill you on a hull!

Sh*t, I've run a four man (about 12' x 2'), seen a six man in action. When you have to fair a 200' hull, you need a big board! Torture boards are fun, give you Popeye forearms!

[jhulmer]

Originally Posted by minaret

Sh*t, I've run a four man (about 12' x 2'), seen a six man in action. When you have to fair a 200' hull, you need a big board! Torture boards are fun, give you Popeye forearms!

That's a young man's game! I'll just eat me spinach!

You know, with all our technology the long board is still the best method to achieve a fair hull (or most compound curves). I guess if ain't broke don't fix it!

[minaret]

I really like these for some stuff. A bit heavier than a regular 3M torture board, but definitely earns it's place in the arsenal. The custom trowel too.



https://www.smsdistributors.com/coll...flexicat-tools

[minaret]

These are also the goods.



https://www.smsdistributors.com/coll...sanding-blocks

[jhulmer]

Originally Posted by minaret

These are also the goods.



https://www.smsdistributors.com/coll...sanding-blocks

I really like these. I haven't seen them before. I will order some of these for this deck project instead of shaping the Durablocks.
Thanks

[minaret]

Originally Posted by Suijin

Yeah but would you just grind down the whole thing, or as large an area as possible to cover all the cracks and do as many of them as possible in one go, or individually? If the former I'd take it down pretty uniformly past the CSM, then CSM/cloth/CSM. The gel is thick enough that I can fit three layers in and still get the original profile or close when I go back over with gel.

I'm thinking the former is faster but the latter is easier to fair to the original profile.

Yeah hate to say it but I'd probably do the former, ie grind and glass the whole thing. The gelcoat may not be shot, but it looks like the CSM is. I like your laminate schedule, if you add a peel ply that is.

[Suijin]

So I'm deep into finishing the "repair" part of the deck project, filling and fairing, filling and fairing. Thank GOD for Soft Sanders. These things are da bomb; I've had to make a few custom pads but the Soft Sander set has covered 90% of my needs.

The yard I'm at is itching to get work out of me. I'm paying for the shed and have had some metal work done, but their expectation is that they're going to be helping me with the spraying and reassembly, and I don't doubt that. At the very least I'm going to need more than two hands for stuff and I do want to get out of here sooner rather than later.

Their main coatings guy and I had a discussion on the deck of the boat and he was really dubious about spraying gelcoat. His concern was not the fairing afterwards but rather the potential for air bubbles in the gelcoat. As he pointed out, as you start fairing you're going to expose any bubbles and if they are all the way through you're pretty well hosed. That said, I don't believe he has a lot of experience spraying gel. He was advocating a regular gun for it over a dump gun or HVLP gun, which maybe is why he is concerned about bubbles?

That said, is there a foolproof way of spraying gel without bubbles? I have no experience spraying gel, so I don't have the benefit of experience with air temperature, catalyzing, thinning, various guns and tips, and general handling. I don't want to buy $500 of gel and screw it up.

Also, he insisted that if I did spray gel, I should prime with 545 first. I'm not sure if that is based on adhesion or fairing. Certainly it would be a lot easier to see what's fair and what's not with the 545, but then again the sprayed gel would fill/hide a bunch of stuff and it would be fairly straightforward to touch up downstream in the process. Should I prime the old gel (and now expanses of epoxy filler) with anything or just sand it and go right over it with the new gel?

I have to say, it's great to be at the "reconstruction" part of the project. It was really depressing, ripping the boat up, grinding out cracks etc. for weeks on end. There was no turning back, and it just felt like I was destroying the boat. It's a huge relief, and encouraging, to have it going the other way now.

[SV Siren]

Originally Posted by minaret

I really like these for some stuff. A bit heavier than a regular 3M torture board, but definitely earns it's place in the arsenal. The custom trowel too.



https://www.smsdistributors.com/coll...flexicat-tools

Minaret, I have visited this site a couple of times, and every time I look, they are always out of stock...have you or anyone ordered from them and received their order....??? I figure that once I am done, I could probably sell them and get at least some of my money back. They do look like the cats meow....

[minaret]

Originally Posted by SV Siren

Minaret, I have visited this site a couple of times, and every time I look, they are always out of stock...have you or anyone ordered from them and received their order....??? I figure that once I am done, I could probably sell them and get at least some of my money back. They do look like the cats meow....

Yes I've got mine but I do hear they moved their facility and retooled which resulted in a lack of availability. Love my board and trowel, but it is just one of my three standard boards. I usually only go to it for very compound surfaces like keels and rudders, where it really earns it's keep. Most people would be served just fine with a standard 3M stiff and a flexy.

[minaret]

Originally Posted by Suijin

So I'm deep into finishing the "repair" part of the deck project, filling and fairing, filling and fairing. Thank GOD for Soft Sanders. These things are da bomb; I've had to make a few custom pads but the Soft Sander set has covered 90% of my needs.

The yard I'm at is itching to get work out of me. I'm paying for the shed and have had some metal work done, but their expectation is that they're going to be helping me with the spraying and reassembly, and I don't doubt that. At the very least I'm going to need more than two hands for stuff and I do want to get out of here sooner rather than later.

Their main coatings guy and I had a discussion on the deck of the boat and he was really dubious about spraying gelcoat. His concern was not the fairing afterwards but rather the potential for air bubbles in the gelcoat. As he pointed out, as you start fairing you're going to expose any bubbles and if they are all the way through you're pretty well hosed. That said, I don't believe he has a lot of experience spraying gel. He was advocating a regular gun for it over a dump gun or HVLP gun, which maybe is why he is concerned about bubbles?

That said, is there a foolproof way of spraying gel without bubbles? I have no experience spraying gel, so I don't have the benefit of experience with air temperature, catalyzing, thinning, various guns and tips, and general handling. I don't want to buy $500 of gel and screw it up.

Also, he insisted that if I did spray gel, I should prime with 545 first. I'm not sure if that is based on adhesion or fairing. Certainly it would be a lot easier to see what's fair and what's not with the 545, but then again the sprayed gel would fill/hide a bunch of stuff and it would be fairly straightforward to touch up downstream in the process. Should I prime the old gel (and now expanses of epoxy filler) with anything or just sand it and go right over it with the new gel?

I have to say, it's great to be at the "reconstruction" part of the project. It was really depressing, ripping the boat up, grinding out cracks etc. for weeks on end. There was no turning back, and it just felt like I was destroying the boat. It's a huge relief, and encouraging, to have it going the other way now.

Sure are a lot of opinions out there! All I can say is I've never had a problem with bubbles. The key for me is don't over catalyze, and don't spray in direct sunlight on a hot day. A hot exotherm could cause microscopic bubbles in the gel to expand during the cure cycle, leading to the problem he is worried about. This is fairly common in early production hulls, leading to gelcoat porosity as a general problem. This is because production facilities often aren't temp controlled, and aren't worried about catalyzing hot as they are spraying in a mold. Just look at some of the many pics I've posted and you'll see that my gel shoots come out pinhole and porosity free. Gel technology has improved over time as well and so has application procedure, porosity is much less of an issue in newer production hulls as a result. The idea that there might be a bubble all the way through definitely shows a lack of experience in gel spraying; I generally apply at least three coats, as anyone who's done this would know. Even if you managed to boil your gel bad enough to have a severe problem with bubbles, how could they possibly be large enough to go through all the coats? It's just silly. As is the idea of spraying gel over 545. The whole point is to spray it directly onto your factory gel with no primer. 545 is much softer than gel, never apply a hard product over soft. The only time I ever do this is as a tie coat if I MUST apply gel over epoxy, which I don't normally ever do. Then I be certain to use the maximum possible amount of Cold Cure in my 545 to increase it's Barcol readings. Feel free to ask away for more tips on spraying gel if you like, but honestly it's not rocket science. Sounds like your painter is leary of what is for him the unknown...

[Suijin]

Thanks Minaret. To be clear, I was not trusting his advice (particularly since he does not have a lot of experience with spraying get), but it gave me pause in terms of what *I* might end up doing wrong since I have no practical experience with it at all.

A couple of questions:

My boat is in a insulated shed, so it's out of direct sunlight. That said, it is starting to get hot here in North Carolina and by the time I'm ready to spray, in a couple or a few weeks, it's going to be downright sweaty at times. Can it get too hot to spray gel, or can the humidity be too high? Are there any issues with spraying later in the afternoon when the temps are falling? I assume I'll start early morning for each shoot, and get three coats on for each section in a day.

Spraying gel over epoxy. It's my understanding that gel *will* adhere well to epoxy if a) the surface is properly prepped, i.e. sanding with 80/100, no blush, and well cleaned, and b) the epoxy is fully cured, which West advises as being two weeks. I've been filling with 406 and fairing with 410, because it sands like butter, but it is fairly soft, certainly softer than gel.

How would you prep the epoxy for the gel, and if you'd prime it, what would you use?

[jhulmer]

Suijin

I'm still behind you in my deck repairs and prep but still trying to educate myself for the gel shoot.

I asked Minaret the question about putting gel over my West epoxy repairs and he said to use a 545 tie coat. I'm sure he will elaborate more about this. like you, I was researching the subject and West doesn't have a problem with spraying gel over their product if you prep as you described. I have also seen a destructive peel test done by Boat Works Today on YouTube and the gel adhered very well to the West Systems epoxy. As a matter of fact it pulled the gel from the test substrate.

So, I too am curious as to what procedure to follow.

As to the question of what gun to use, I have only shot gel three times into a dinghy mold I made about ten years ago. Used a gel gun that spit it out like a kid blowing out his birthday cake candles. Worked okay for a mold and I was probably doing it wrong but the dinghy's turned out nice. I don't think it will work well for this application.

I plan to try this gun witch is available on Amazon:
The disposable components make cleanup easy. I have used it with polyurethane and worked great. Hopefully, it will shoot gel as well. I will be testing it on the bottom of my dinghy first to see how it works.

I'm with you, don't want to screw this up after all this prep work!

[minaret]

Originally Posted by jhulmer

Suijin

I'm still behind you in my deck repairs and prep but still trying to educate myself for the gel shoot.

I asked Minaret the question about putting gel over my West epoxy repairs and he said to use a 545 tie coat. I'm sure he will elaborate more about this. like you, I was researching the subject and West doesn't have a problem with spraying gel over their product if you prep as you described. I have also seen a destructive peel test done by Boat Works Today on YouTube and the gel adhered very well to the West Systems epoxy. As a matter of fact it pulled the gel from the test substrate.

So, I too am curious as to what procedure to follow.

As to the question of what gun to use, I have only shot gel three times into a dinghy mold I made about ten years ago. Used a gel gun that spit it out like a kid blowing out his birthday cake candles. Worked okay for a mold and I was probably doing it wrong but the dinghy's turned out nice. I don't think it will work well for this application.

I plan to try this gun witch is available on Amazon:
The disposable components make cleanup easy. I have used it with polyurethane and worked great. Hopefully, it will shoot gel as well. I will be testing it on the bottom of my dinghy first to see how it works.

I'm with you, don't want to screw this up after all this prep work!

If you do a forum search you will find this argument, like most, has been hashed out many times here. I'm well aware the manufacturer states it's ok to apply gel over epoxy, but that hasn't been my experience. And believe me I'm extremely fastidious about prep, far more so than most anyone.

IMHO the problem isn't with initial bond. Do the same tests after one year, then two, three, etc. and I might think it's worth something, particularly if exposure to the environment is involved as well. I' have on several occasions applied gel over epoxy and sent a great looking product out the door, with apparently excellent adhesion, only to have it fail after a few years. Never again!!

The problem I believe is that amine blush does not fully cease at initial cure. The cure cycle continues for at least a year, and very small amounts of amine leech out of the laminate over time. Poly laminate does this too, but with styrene and glycol (which is what causes blisters). Not such a problem for a compatible coating, but gel does not seem to like it at all IME. YMMV!



I picked up one of those guns not too long ago. Check out the reviews and you will note a number of people stating they leak at the trigger. I was hesitant to buy on this account. Went ahead and gave it a whirl, and sure enough it leaked at the trigger. There is usually a leather gasket with adjustable seal (like a packing gland) at the needle entry to the air cap, but this gun has no seal. Starts leaking about 5 minutes in and only gets worse. I returned mine. Not up to 3M's usual standards! Also didn't like the cheap plastic construction. Very flimsy. Just get the PPS adapter for the gun of your choice if you like the PPS system. For the record, I don't. The pots and liners are super expensive.



If you want to educate yourself on application methods and finish, please do a hatch or something first. You will probably be surprised how easy it is to get great results and it will help a lot to be a bit further down the learning curve before you try a big shoot. Good luck!

[minaret]

Originally Posted by Suijin

Thanks Minaret. To be clear, I was not trusting his advice (particularly since he does not have a lot of experience with spraying get), but it gave me pause in terms of what *I* might end up doing wrong since I have no practical experience with it at all.

A couple of questions:

My boat is in a insulated shed, so it's out of direct sunlight. That said, it is starting to get hot here in North Carolina and by the time I'm ready to spray, in a couple or a few weeks, it's going to be downright sweaty at times. Can it get too hot to spray gel, or can the humidity be too high? Are there any issues with spraying later in the afternoon when the temps are falling? I assume I'll start early morning for each shoot, and get three coats on for each section in a day.

Spraying gel over epoxy. It's my understanding that gel *will* adhere well to epoxy if a) the surface is properly prepped, i.e. sanding with 80/100, no blush, and well cleaned, and b) the epoxy is fully cured, which West advises as being two weeks. I've been filling with 406 and fairing with 410, because it sands like butter, but it is fairly soft, certainly softer than gel.

How would you prep the epoxy for the gel, and if you'd prime it, what would you use?

It was almost 120F in the shed when we shot most of this gel. Heat is not a problem if you follow some basic guidelines. That said, if you faired in epoxy, particularly 410 (which I never use), I would finish the job in primer and paint instead of gel.


Note in the first pic you can see the second chainplate over in the reflection. This means DOI is about two feet! Most marine LPU's brag about achieving a DOI of 9"-12".