Fillet putty increasing viscosity after applying.

A couple of things.......

Went to the boatyard early this morning to work on the fly bridge. I'm actually doing fillets. Pretty hot, it was in the low 70's (F) at 6:30AM. I only mix about 6oz at a time in these conditions. First batch was with fast hardener, no problem. Tried the "ball" technique. Like everything else it seemed a little awkward at first. I was working inside a locker so if it wasn't too pretty I'm the only one who would know. I'm going to keep trying the "ball" technique but I'm not good enough to use it where it will show. Maybe I'll get better.

Second batch of "fast" kicked in the pot. Only 4oz.! Approaching 90 degrees. Too hot so switched to medium hardener. I mixed 6oz. with silica and deliberately left it a little thin. Sure enough as it heated up it became too thin. Scraped it off and mixed a new batch. This time more like mortar, pretty stiff. I had no problems with this stuff and it did thin out a bit as it heated up. That thinning was actually good though as the fillet smoothed out nicely. Had to work quickly though, ambient temp mid 90's by now..

So, I'm thinking that maybe jetboy is mixing too thin or leaving it in the pot too long. I mix fast and add the silica quickly. My goal is to get the mix out of the pot and onto the joint as fast as I can.

Thanks for the tips guys!

MIA

 

In difficult places I take the biax strip ready when filleting. Spread the putty over the joint and press the gf over. Easy to fair with finger or what ever and helps to keep the filleting putty in place. Brush over with some more epoxy and done..

The heat and faster hardening, me thinks, with silica is due the changed isolation properties of the putty.

 

Today I finished up the two hulls and put the first layer of outer glass on them. I put a sheet of plastic down and mixed the epoxy with slow hardener about 12 ounces, then would mix about 6 ounces on the board with silica. Worked great. No heat issues, and didn't flow on me.

It's a bit slower to mix a little at a time with a knife on a sheet rather than in a pot with a mechanical mixer, but it saves a LOT more time not having to re-do the fillets 2 or 3 times. In a few hours I'll flip em over and start the interior fillets. The shape looks great. I'm getting super excited about this boat!

 

Once you work enough epoxy, you learn the tricks and procedures that are effective. Stick with the procedures you've established and don't vary them or you'll "discover" more issues.

 

Kinda bringing up an old post but I have a question and comment. After working on a number of fillets on my new flybridge I'm starting to really like PAR's "ball" idea. I'm using a ping pong ball (see a photo in a previous post here) and once I got the masking at the correct distance from the joint it worked really well. I also tried the soup spoon technique on a joint and that worked too.

A couple of questions.

Inside corners. I'm struggling with them. I can use a small detail brush to feather out the faring but I'm still going to be sanding. You know how much a pain it is to sand an inside corner. I've been starting from the inside corner and working out. As soon as I'm out an inch or two the joint looks great. Any tips for working that very inside part?

I'm using about 40% q-cells and 60% cabo-sil by volume to make up my paste. I notice if I get to much q-cells in the mix the paste doesn't seem to flow out as nicely. I know somebody's going to say "then don't use so much q-cells" but I'm just wondering if some of you guys that do a lot of this work have any rules of thumb.

On the lighter side my wife and son stopped down today (they hadn't seen the project for months) and my 14 year old son said "gee dad, it actually looks like a boat now." Probably the nicest compliment a kid could have given me.

MIA

 

Mix in a little talc with your fillet materials. Yep, get some Johnson & Johnson baby powder and have at it. You'll smell better too, but it's real benefit is how is smooths out the mixture.

Inside corners are always troublesome. The very beginning and last little bit are the tough points, especially with the ball method. To "clean" them up, just wait and let the goo get right about to the gel stage. It'll be firm, probably warm too. using a practiced gloved finger, dipped in alcohol, smear the edges smooth and very lightly smooth the surface. You can carefully work the corners with a rounded over stick and again the alcohol finger. Saves a bit of sanding, but does take some practice.

 

If you do end up having to sand, these are really effective for corners:

 

A drum sander of the appropriate diameter is the easiest and fastest method. I have several different diameter drums and they make quick work of inside corners.

 

Handy to know - I have a full range of drums. Thanks PAR.

 

Well I just got home from doing some fillet work.

PAR, thank you!

The talc helped make the paste a little smoother.

The "finger" idea really worked out great. The inside joints are almost perfect. The outside joints look good too. I found that as I smoothed out the outside joints I could push the gelled paste back towards the corner and into a nice shape with a mixing stick wet down with alcohol. Even the straight sections benefited from a bit of smoothing. I'd say that that one tip saved me about 5 or 6 hours of detail sanding on my flybridge.

Time now to wet myself down with a little alcohol.

Regards,

MIA

 

Send a 6 pack my way . . .