Putties, fillers and fairing compounds

[heartofgold]

Let's see if we can drum up some interest in this one. Everyone uses filling and fairing compounds such as 3M Marine Filler, 3M High Strength Marine Filler, Dura Glass, Quickfair, AwlFair, Interfill, West System with Fairing Filler or Microballoons, and many others. Each of these has it's place and use.

Which of these products does everyone like to use, and for what applications? Are there any particular products which you avoid using, and why?

[Tim]

My basic compound is epoxy mixed with phenolic microballoons and cabosil to the desired consistency. This is good stuff because it is strong, easy to sand, and completely customizable to the given job; some fill jobs require something extremely stiff, and others something more forgiving and easier to spread. It's nice to be able to make exactly what you need, tailored to the application.

I have recently been using System Three Quik-Fair for fairing on the Daysailor deck. It's OK, just. As of this writing, I have two coats of the stuff on, and I'm actually going to switch back to a self-mixed fairing compound for remaining filling. I find the Quik-Fair to be exceedingly sticky and difficult to spread well--more difficult than a typical epoxy/microballoon mixture. It sands pretty well, but I'm simply not finding the product to be a boon to my productivity, nor is it particularly time-saving--and perhaps the opposite. It's not cheap, though I haven't (nor will I ever) do any sort of cost analysis versus epoxy and fillers; and on top of it all, I hate mixing the stuff. (Not that mixing dry powders, especially cabosil [aka the white powder of death], is fun either.) Overall, I guess you might say I'm underwhelmed by it. I really wanted to like it, but I just don't very much. Sorry, System Three!

I like Interlux Interfill for final filling, mostly to fill the fine pinholes and such left behind in the standard epoxy/microballoon mixture. Interfill is very smooth and creamy, and works wonders for this final application.

I will also try some of the Awlgrip surfacing products later on. To date, I have not yet used them.

3M regular marine filler is a polyester product--it's fine as far as that goes, but we don't like polyester putties. The high-strength and premium 3M fillers are vinylester-based. They are decent fillers, but I don't use them for the stuff I do. Since I always have epoxy around, it's just easier to be able to mix fairing compounds as needed, rather than having a specific product around. These sorts of fillers are good if you do a lot of small filling repairs, but aren't much use for new construction or major boat overhauls.

[Dan]

I don't mean to derail this topic but what exactly is the difference between phenolic microballons and glass bubbles like Qcell that I am using for fairing compound?
Is there a specific purpose for each or is it more personel preference?
Why is Cabosil the power of death?

[Tim]

The main difference is really just the construction of the hollow spheres (which is what a microballoon is). Glass spheres are, of course, glass, while phenolic are a plastic type. I think weights of the two products are similar, but phenolic microballoons might be easier to sand. Phenolic microballoons can run into problems if used in polyester resin, as a reaction with the styrene can cause the bubbles to collapse. Glass spheres are OK in this regard. Both types make good fairing compounds. The dark color of phenolic can be good when working with wood, if you are looking to blend the color at all.

I have dubbed cabosil "the white powder of death" because it is just so light and fluffy, and expands to fill all available air space whenever given the chance. The fine particles are easily inhaled, and cannot be good for the lungs. I hate the stuff because the mere process of mixing it into a pot of resin causes the cabosil to fly through the air and go everywhere. I wear a dust mask or respirator most of the time when mixing, but sometimes I don't for a small batch, and that's when I notice how bad the stuff really is.

[Bill A]

FYI:
I use Quickfair whenever I need to fair in a small ding. I use kithchen measuring spoons and measure it out like shortening. If I need a real small amount I might use a 1/2 teaspoon, scoop it full, then scrape it level with a mixing stick. The mixing stick removes the Quickfair pretty cleanly from the spoon onto a mixing board. I have used this technique probably 10 times with no mixing/ratio problems.
It seems the Quickfair is more tolerant of ratios then the usual liquid epoxy method. Plus, like you said, I don't have to add in the Cab-O-Sil and microballons. These are especially a pain in small batches.
Also:
If you put a Halogen shop light about a 2 feet away from a Quickfair repair to heat it up to about 100 deg F, it will be sandable in about an hour.
-Bill

[Tim]

I've softened my opinions on Quik-Fair a bit since I posted that. While mixing larger batches is messy, the product is actually quite good ad skim coats and the like. What it's not as good at, and what I didn't like before, was for coarse fairing.

Just today, I used some more of the product on the cockpit sole in the Daysailor. I mixed the amounts by eye this time on a flat board using a wide putty knife. Assuming this attempt is successful (and I have no reason to believe otherwise), I expect that I'll continue to find uses for the product in the shop.

I'm soon going to be trying a new product for the coarse hull fairing. Details later.

[heartofgold]

Tim,

I recently used Awl Fair for the first time. It mixed easily and applied very smoothly. It took several hours to kick, but it sanded very well, with no problems. A bit on the pricy side, but certainly worthy of the Awl Grip name. I would not apply this too thick, but so far it is an excellent fairing surfacer.

I have to pick on you about your recent experience (on the daysailor) with Interlux Interfill. Last year I asked you about this product (via email?), and you provided me with a glowing review of this smooth filling putty. I didn't really appreciate your admiration of this product, but I now see (as you discovered this past week) that the "new" interfill is not what is used to be.

Based upon what you have said on the forum and on the daysailor pages, I think you will find Awl Fair to be what you are looking for. Maybe not for the earlier stages of fairing, but certainly for the final layer or two.

I would like to hear your opinions on the vinylester products (such as 3M Marine Premium Filler). What is "vinylester" and how is it different from epoxy. Though I don't intend to use any products this way, I recently read in the West System manual that certain fillers (405?) could not be mixed with vinylester products; later I read that other fillers (407, 410?) could be applied on top of vinylester. Anyway, it peaked my curiosity.

[Tim]

I have to pick on you about your recent experience (on the daysailor) with Interlux Interfill. Last year I asked you about this product (via email?), and you provided me with a glowing review of this smooth filling putty. I didn't really appreciate your admiration of this product, but I now see (as you discovered this past week) that the "new" interfill is not what is used to be.

Right you are! Silly me...I naively thought that Interfill was simply a renamed version of the older product (417/418) that it ostensibly replaces. No one was more surprised than I when I opened the cans last week to find a gritty, pumice-hand-cleaner texture catalyst and a black base component. I was sorely disappointed. Why they made this change is beyond my comprehension, particularly when it's not for the better.

Lesson learned (again): never assume! I guess I'd better be careful what I say, or it might come back to haunt me! :<)

I recently used Awl Fair for the first time. It mixed easily and applied very smoothly.

I plan on using a comparable product for hull fairing on the Daysailor. For this project, I'm giving a new family of products a try. These products, called AlexSeal, represent a possible advance in the LPU market.

AlexSeal was engineered and designed by the same person who, 30 years ago, created the product that became Awlgrip. As the story is told to me, this man's noncompete agreement with US Paint has now expired, following his leaving the company some time ago, and he has untaken the task of creating this new LPU system that enhances all that is good about Awlgrip, and improves upon its weaknesses (namely application and repairability).

Awlgrip is a great product, but admittedly it is now old technology. Whether or not AlexSeal is a better product remains to be seen. However, I feel it is worth trying out on this project, and I look forward to using something new. All I know about is my tiny little corner of the world here, but Hinckley, Morris, and a number of small-volume, high-end local boatyards have all begun trying out this product on a variety of their projects--some for customer boats, some (Hinckley) for workboats and company-owned show boats.

In any event, I figure little ol' me could do worse than follow in these footsteps. Pricing for AlexSeal is virtually identical to Awlgrip, so there is no benefit there one way or another. But if indeed the product exceeds Awlgrip as designed, then it may well be the wave of the future.

AlexSeal

[heartofgold]

There's a product we have been using in the yard which I would like to offer to everyone here. It is a roll on epoxy primer/filler which we often use to prep surfaces prior to initial priming. It is a PPG product, released under the "Specialty Products" name. The product is SX 1060 (the hardner is SX 1061).

One of the guys with whom I work is retired from PPG (several of those years were in R&D), and he brought with him a wealth of information about a whole spectrum of products. Though many of PPG's products are sold to the automotive industry, some of them are usable in a marine environment.

This particular product is a grey primer (not unlike Awlgrip 545 in appearance). After mixing with the hardner, we roll the product on the surface, back and forth twice, and then leave it. Though as thin as 545, it leaves behind a thick coating, which fills pinholes, small scratches and other imperfections. It may be recoated in 15 minutes or sanded within about 2 hours (depending upon weather conditions and UV exposure). It sands easily for a day or two before completely curing. The beauty of this product is that it, as a true epoxy, it is compatible with other products, including Awlgrip or even gel coat. Because it goes on thick and even, it is easy to use a longboard to find low spots (remember it's an epoxy, so it can be covered by any filler/surfacing material), but it also fills.

Some of you may have read a previous post in which I was looking to repaint my mast. My concern was finding a surfacer to fill the dings and scratches. As this product is Awlgrip compatible, I may try it after I complete the Alumiprep and Alodine. I'll keep everyone posted on that process, which I hope to begin in about 3 or 4 weeks.

[Rachel]

That PPG product sounds like it would work well as a first coat to repair that overall spider crazing I've seen on a few Tritons and A-30s.

That crazing scared me away from the first good Triton I looked at because I thought it would be like repairing plaster - where you have to gouge out each crack to make it a little bigger, then fill, etc.

I couldn't imagine gouging out 350,000 individual spider cracks; there would have been no gelcoat left between them!

Then, a yardworker next door to the cruising boat I was cleaning up and winterizing began repairing the spider cracks on his own, personal A-30. He started with a filler product without doing anything special to the crazing. When I complimented him on his boat, and asked him what he was using to repair the cracks, he just said "it's an epoxy filler product made for the automotive industry; you wouldn't know it."

So helpful :-) I doubt it was the same one you're talking about because it was a reddish color. But it must have been the same concept.

I was never clear about what product or technique to use on those cracks.

Thanks for mentioning it.

--- Rachel

[Tim]

I don't think any primer, high-build or otherwise, is ultimately thick enough to permanently hide the sort of crazing seen on many older boats. The surest-fire way to eliminate these cracks is to remove all the cracked material down to stable laminate...and even that is not necessarily a guarantee of perfect success. Plus, this is a huge amount of work.

Enlarging existing cracks is only a stopgap measure, and should be reserved only for isolated areas. Cracks addressed in this manner tend to eventually print through the paint surface anyway.

Soon, we're going to be trying a different fix on Triton 668 here at the shop: laminating a thin layer of fiberglass cloth over the entire badly cracked, crazed, and pitted deck. The thought is that hopefully this new material will stabilize the gelcoat and such beneath and provide a long-lasting smooth surface. Only time will tell, but drastic problems sometimes call for a new approach to the issue, especially when the other options are ineffective or unsavory.

I love people who like to be secretive about their methodology or products used, as if they're somehow threatened that someone else (gasp) might find out. It's unhelpful, and my experience is that generally these sorts of folks aren't worth listening to anyway.

[dasein668]

Soon, we're going to be trying a different fix on Triton 668 here at the shop: laminating a thin layer of fiberglass cloth over the entire badly cracked, crazed, and pitted deck. The thought is that hopefully this new material will stabilize the gelcoat and such beneath and provide a long-lasting smooth surface.

Here is a representative picture of my decks. In fact, this may be "better-than-representative!"


The smooth areas on the cabin trunk are also uniformly crazed. As part of the prep for laying down new glass we ground down the old nonskid and filled all the cracks and missing chips of gelcoat, using epoxy thickened with cabosil and microballoons, as best as we could. See below for another "representative" shot. We shall see how this technique holds up, but I've got to believe that it won't be worse than any other option...