I Need To Know About Fillers From the 'Pros'

[dozer91250]

I'm new here and have read a ton of stuff, some I wish I would read sooner (I now have tons of Jiff in both creamy and extra crunchy, not what PB meant. I know that now), but I can't seem to get consistent answers on epoxy based and poly based compatibility.

Correct me if I am wrong, but polyester resins (ie gelcoat) will not adhere properly to epoxy resins. Assuming that statement is correct:

(1) I am perplexed that many of the fillers and fairings are epoxy based. If you use any epoxy based products on the substrate are you then prevented from using any polyester based topcoats?
(I have asked my Orca Guard Gelcoat vendor, Fiberlay (sea, wa) and have received conflicting answers about compatibility, the product tech sheets are woefully inadequate, and the product mfr will not respond to inquiries so the question remains).

(2) If so, is there some sort of a surface sealer or tie coat that you would seal over the epoxy based products to allow the polyester based topcoats to adhere properly?

Thanks,

 

[Bondo]

Re: I Need To Know About Fillers From the 'Pros'

I'm new here and have read a ton of stuff, some I wish I would read sooner (I now have tons of Jiff in both creamy and extra crunchy, not what PB meant. I know that now), but I can't seem to get consistent answers on epoxy based and poly based compatibility.

Correct me if I am wrong, but polyester resins (ie gelcoat) will not adhere properly to epoxy resins. Assuming that statement is correct:

(1) I am perplexed that many of the fillers and fairings are epoxy based. If you use any epoxy based products on the substrate are you then prevented from using any polyester based topcoats?
(I have asked my Orca Guard Gelcoat vendor, Fiberlay (sea, wa) and have received conflicting answers about compatibility, the product tech sheets are woefully inadequate, and the product mfr will not respond to inquiries so the question remains).

(2) If so, is there some sort of a surface sealer or tie coat that you would seal over the epoxy based products to allow the polyester based topcoats to adhere properly?

Thanks,

Ayuh,... Welcome Aboard,... Please read the forum postin' rules, 'n guidlelines,...

Also, please don't post in the antique threads,...

You'll get more, 'n much Better answers startin' a New thread of yer own....

 

[Woodonglass]

Re: I Need To Know About Fillers From the 'Pros'

What Epoxy based fillers and fairings are you referring to?

 

[dozer91250]

Re: I Need To Know About Fillers From the 'Pros'

I'm not asking about any specific products (I edited this first sentence). In my research I have seen reference to epoxy fairings, fillers, and primers
(like Awlgrip Products by type and post # 15 in this thread:
http://forums.iboats.com/boat-resto...ir/all-you-need-know-about-fillers-pros-cons-
536004.html).
that are using epoxies. There had been discussion about West System's claim that you can gelcoat over one of their epoxy systems, but after investigation one of their representatives said it was not a good idea.

My general question is it an absolute bad idea to every use a polyester based product directly over the top of an epoxy based product whether it be a laminated resin, filler, fairings, or primer?

I am currently working on a project and have opted to just stick with polyester based products from start to finish, only because I am pretty certain that they are compatible. I may be wrong, but it is my understanding that epoxies can have certain application and performance qualities that are just not attainable with polyester based products, like wet curing epoxies (for example: PC-11? White Paste Epoxy Cures: Wet, Dry & UNDERWATER).

Thanks for the help.

 

[Woodonglass]

Re: I Need To Know About Fillers From the 'Pros'

Not sure what you are trying to do. If you are doing normal layups on a regular boat restoration on a normal mfg boat, then there is no reason not to use poly on everything. Epoxy has some nice characteristics above and beyond Poly but in most cases they are not needed in a normal boat restoration/repair scenario. If Gelcoat is involved epoxy is for sure not desirable. For specialty cases then epoxy might be the way to go. You would need to be more specific on exactly what you are wanting to accomplish for any of the members to make a qualified response as to which product would be the right one to use. That's my way of thinkin.

 

[dozer91250]

Re: I Need To Know About Fillers From the 'Pros'

I was just looking for a general answer as to the compatibility between polyester based gelcoats and any epoxy based products.

The specific project I am working on is a restoration of a 1972 16' Fiberform w/ a Johnson 100 outboard. The boat had some significant damage along the keel that soaked the foam and damage to the top deck in multiple places. My grandfather bought it new and all the grandchildren pretty much grew up in it. I am sticking with the original combat green color after realizing he picked it because it matched the color of his flight jacket from his time as a pilot with Strategic Air Command. I couldn't change that and I know I can't change the name.


I am using Orca Guard gelcoat from Fiberlay out of Seattle, WA for no other reason then they had the ability to optically match the original color of the top deck. I am using their Air Dry Clear Hi-Gloss Coating gelcoat additive for a deeper gloss in 30% 1st, 30% 2nd, and 50% 3rd and final coat mixes with 2% MEKP catalyst and 5% styrene monomer for thinning. I'm using Engineered Solutions pressure pot HVLP spray gun w/ 2.5mm nozzle for application in a downdraft spray booth.

For the repairs I stuck with poly laminating resin (I'll edit to add specific brand later I forget at the moment), Evercoat Kitty Hair to smooth out the glass repairs and for small damage, no fairing, Half-Time automotive glazing putty for pin holes and chips in the gelcoat, and Evercoat's Finish Sand 4:1 primer for covering the repairs. I realize now that the automotive product is not ideal, but in my automotive glass repair experience it has not posed any problems. I am hoping to be able to shoot it this weekend.

 

[dozer91250]

Re: I Need To Know About Fillers From the 'Pros'

I remember at least one application now that I was thinking would be a good application for epoxy.

The transom wood is not rotten, but it is wet where the hardware holes went through the transom. I was going to bore those holes out approximately 25% larger then required for the hardware. Then, I was going to completely fill the hole with an epoxy plug, come back and re-drill the required size hole for the hardware, and essentially seal off the transom wood from the hardware altogether. This would leave a small area of exposed epoxy near the hardware holes that would have to have topcoat applied. If gelcoat would lift from epoxy, I would think it would be particularly problematic at a hard edge like that.

 

[Woodonglass]

Re: I Need To Know About Fillers From the 'Pros'

Oversize drilling the transom holes is a good idea IF that is the only area of softness. Have you core sampled the transom on the inside down low in the bilge area to ensure it's integrity? Does the Deck have any soft spots at all? I'd hate to put a new Dress on her only to have to get her dirty. To answer your specific transom question. I would use Thickened Poly resin to fill the oversized holes. (Resin, Cabosil and cut up pieces of CSM to make what we call Structural Peanut Butter) to fill the holes) then redrill them. That way the GelCoat will have no problems adhering. She's a beutiful boat. Very similar to my Blue Flamingo. Auto Filler is not ideal due to the components used. They don't have to worry about being immersed in water for long periods of time and absorbing moisture. I make my own fairing materials when working on boats.

Have you Gelcoated before?

 

[dozer91250]

Re: I Need To Know About Fillers From the 'Pros'

Nope, this is my first venture into it. As for the automotive filler, I made the assumption that having 24mil (8mil x 3coats) of gelcoat sealing the automotive filler would keep it protected from moisture. There are only two spots below the waterline where I have used enough to be concerned about. I may just go back and cut those off and fill them back up with Evercoat Short Strand before priming. I have no idea where I could get cabosil around here, we have zero fiberglass suppliers around here. All we have are the minimal offerings through boat supply outfits and auto parts stores. Is cabosil something a non-professional supply house would have?

I have not core drilled the transom, but I know the boat pretty well and last year was the first year in a decade that it lived in the water. Previously, it was used on the occasional weekend and parked in the dry desert sun on a trailer the rest of the time. The transom is actually mostly exposed on the inside of the boat above the waterline so it has the opportunity to dry out.

In addition to that, I've had a few inadvertent ad-hoc transom structural tests in the past couple of years. The first of which involved the steering cable bolt falling out at 35 knots (very exciting and Loctite'd now), the second was hitting a submerged bridge piling in the Snake River with the lower unit at 10-15mph, and the final test was when a friend dropped it off the trailer on a boat ramp. After compiling the data from those structural tests my team concluded that the transom is still alright.

 

[SigSaurP229]

Re: I Need To Know About Fillers From the 'Pros'

Just as long as you are aware that the only way to properly check a transom is to take core samples. After that many incidents I would be inclined to change it anyway, if you are doing major structural repairs now why not spend the extra $100 to do the transom as well?

You have as good of reason as any to do a resoration do it right.

 

[Yacht Dr.]

Re: I Need To Know About Fillers From the 'Pros'

I was just looking for a general answer as to the compatibility between polyester based gelcoats and any epoxy based products.

The general rule of thumb is that poly is not very good over Epoxy.

There have been cases of which epoxy does not cure correctly over another poly or VE resin base. I dont know why but it has happend.

Thats why I go for what was on there in the first place rather than what is Thought to be better.

YD.

 

[Woodonglass]

Re: I Need To Know About Fillers From the 'Pros'

Ok, first off I am NOT a Gelcoat guy. But I've learned a LOT from the PRO's here on the forum. Still got a lot to learn. Here's what I've learned which ain't much. The equipment you have is what your need. You will need to be very ON TOP of it when you start spraying. If it sets up in the pot and the hoses and gun...You're TOAST. You need GALLONS of Acetone for Clean up. Your Spraying window will be somewhere around 15-25 minutes depending on how HOT your mix is and your temps. You'll need enuf for 2-3 coats maybe more. You want to try to get the thickness of 20-30 mils cuz you'll be sanding off a LOT of it. Corners are critical. Orange peel WILL occur. Lots of sanding will be needed afterwards. This will be a good read for you...Re-Gelcoating your boat Ondarvr is a good guy to PM for advice on Gelcoat. YD is another one.

 

[dozer91250]

Re: I Need To Know About Fillers From the 'Pros'

Thanks for all the info guys. I don't want to get off topic here, ie fillers, so what I was going to make a more complete project thread w/specific materials, product specs, etc. with all your wise criticisms of my process that someone else could follow. For anybody not located near a good fiberglass supply house accurate technical information is tough to find. Auto body supply outfits that know there auto body stuff are a lot easier to find and unfortunately they are frequently all toooo happy to give you POOR advice when it comes to marine fiberglass work. I know I've already had bad information, even from my products' vendor.

 

[ondarvr]

Re: I Need To Know About Fillers From the 'Pros'

You said you don't have any place to buy fiberglass supplies, "around here", we don't know where "around here" is. You did mention the Snake river though, so that sort of narrows it down, but it's still a large area.

There are normally places to buy stuff locally or online.

 

[dozer91250]

Re: I Need To Know About Fillers From the 'Pros'

Spokane, WA, there are 5 outfits that actually do anything significant as far as marine fiberglass repairs. The name that kept coming up as the go to guy for the boat shops was Rod at Custom Fiberglass. I called him up and he told me there was no one in Spokane/Couer d'Alene area that knew there stuff so he deals with Fiberlay in Seattle, WA for everything. With as many lakes as we have around here it surprised the heck out of me that there isn't a supplier. I also talked to the owner of one of the pro auto body suppliers and he said that once the manufacturers left town no one could stay in business with a fiberglass line.

 

[ondarvr]

Re: I Need To Know About Fillers From the 'Pros'

I know Rod, did you ask him if you could buy some supplies from him?

Lifetime Pools also does some glass work and may have some stuff you could buy. There are several other larger fabricators, but they probably wouldn't sell stuff. Double L in Coeur D Alene may sell you supplies.

If you buy fillers from Fiberlay the shipping cost shouldn't be too bad, Dave should be able to fix you up.

 

[dozer91250]

Re: I Need To Know About Fillers From the 'Pros'

Small world, Dave is whom I ended up working with. I think I am set at this point. I've decided to keep the wavy 'character' of the original Fiberform anyway and only restore her to 'like new' condition. I'd just hate to take that away from the ol' girl. Maybe, after a few years when I get the opportunity to discover what I messed up this go round I'll pull it back in and make her better than new condition.

 

[ondarvr]

Re: I Need To Know About Fillers From the 'Pros'

I worked with Dave for about 5 or 6 years, that was about 20 years ago. Rod used to go with me to Alaska on fishing trips.

 

[Yacht Dr.]

Re: I Need To Know About Fillers From the 'Pros'

I hope your compatibility questions have been answered here ..

There is one thing about poly over epoxy in small areas .. POST CURE. Meaning that if you must use epoxy for a repair ( or think its needed ) .. then post cure it.

Post Cure is heating it up for 24 hrs + with a heat lamp. From my understanding Epoxy after cure will still flash off for a bit. But post (after) curing is needed for it to become Inert quicker.

Basically the polyester resin can not attack the epoxy chemically. So its bonding is more Mechanical than Chemical.

So understand that it is Possible to go over small amounts of epoxy with Poly .. as long as the Epoxy is prepped/cured correctly.

I would not try to repair or coat poly over epoxy in larger areas .. but small chips or dings I think could be OK.

YD.