Filler quantities for reinforcing (cabosil and microballoons)

[Ericfox]

Getting all my stuff from US Composites

1)How much of the aerosil/cabosil filler and Phenolic Microballoons should I buy? I am gonna do a 50/50 mix of it as a filler. They a few different quantities... I think the quantities go 1 qt, 2.5qt, 5 qt, 4 gallon. The weights for each are different as they are different materials. I am using as a filler for adhearing the footholds, filling the bondline, and filling under the pole.

2)They sell a lot of different rollers for smoothing out the glass and getting out the air bubbles... would anyone in particular work really good for what we do? I was gonna get the 1/2" dia. 3" wide roller, but US Composites sells many sizes and shapes available.... I see there are ones that are eggshaped and ones for corners too... recommendations?

3) do you guys recommend doing any reinforcement on the back wall that the cdi box mounts to?

 

[GDFL]

DO NOT GET CABOSIL. you will hate yourself for doing it. The stuff is basically sand popcorn so it is tough as hell to sand. I think they've got a guide on there for different fillers and they're sanding qualities. I got a 5 quart container and filled the bondline and some areas under the pole and some general filling and blending and still had about half of it left. I just looked at the site. I believe that I used the SM fairing compound and it turned out OK other than the purple color that it gets from having the phenolic spheres in there. Get the 5qt and have leftovers for later repairs. I see you want to do a 50/50 ratio of epoxy to filler. You can't really do it that way. You have to go for consistency rather than a magic number. Filling needs to be a bit thicker like peanut butter and bonding should be very slightly runny.

Any 4" fiberglass roller should help you. You don't need to get too fancy for basic work.

It might not hurt to throw a layer of biax on the black box mount area, especially if you are going to mount hood straps and a limiting strap. I didn't do it and most people dont, but it wouldn't hurt anything.

 

[Ericfox]

DO NOT GET CABOSIL. you will hate yourself for doing it. The stuff is basically sand popcorn so it is tough as hell to sand. I think they've got a guide on there for different fillers and they're sanding qualities. I got a 5 quart container and filled the bondline and some areas under the pole and some general filling and blending and still had about half of it left. I just looked at the site. I believe that I used the SM fairing compound and it turned out OK other than the purple color that it gets from having the phenolic spheres in there. Get the 5qt and have leftovers for later repairs. I see you want to do a 50/50 ratio of epoxy to filler. You can't really do it that way. You have to go for consistency rather than a magic number. Filling needs to be a bit thicker like peanut butter and bonding should be very slightly runny.

Any 4" fiberglass roller should help you. You don't need to get too fancy for basic work.

It might not hurt to throw a layer of biax on the black box mount area, especially if you are going to mount hood straps and a limiting strap. I didn't do it and most people dont, but it wouldn't hurt anything.

Thanks... I will look into getting another filler.

BTW- by 50/50 I meant the cabosil and microballoons as a 50/50. Then I would mix that 50/50 mix of fillers into the epoxy in whatever amount to make the peanut butter consistancy.

Thank you for the advice though about the filler and other stuff. -Eric

 

[WFO Speedracer]

Thanks... I will look into getting another filler.

BTW- by 50/50 I meant the cabosil and microballoons as a 50/50. Then I would mix that 50/50 mix of fillers into the epoxy in whatever amount to make the peanut butter consistancy.

Thank you for the advice though about the filler and other stuff. -Eric

You can intermix the fillers and a 50/50 mix of cabosil and sm fairing compound will work fine,the more cabosil you add the harder it will be to sand but it will be stronger,vice versa on the sm fairing filler,peanut butter consistancy is about right.Thsm filler has very little strength,its pretty much like bondo,just epoxy based,the cabosil is strong as death but like GDFL said it is a biotch to sand.

 

[Endo]

Just for my reference.... Cabosil as a filler if bonding and micro-balloons for a fairing compound?

 

[GDFL]

I'd avoid cabosil like the plague. For general use, you'll never tell a difference if you use microballoons to install footholds instead of using cabosil. The only difference you'd see is if you got sloppy and had to do a little sanding.

 

[yamaslut]

I always use cabosil.... I like it

I don't sand, I grind... he he he

 

[Crab]

What is the white/clear fluffy stuff Blowsion has in their kit, almost like snowflakes. I liked it as it uses way less epoxy than the SM filler to make a creamy paste, but don't inhale it....

 

[Endo]

I always use cabosil.... I like it

I don't sand, I grind... he he he

LOL

I like your style.

 

[yamaslut]

What is the white/clear fluffy stuff Blowsion has in their kit, almost like snowflakes. I liked it as it uses way less epoxy than the SM filler to make a creamy paste, but don't inhale it....

cabosil

 

[Crab]

cabosil

Then I likey.:djsmilie:

 

[Ericfox]

Just placed my order with US composites:

-3 yards 50" 1708 biaxial fiberglass (17oz)
-1 yard 50" red/black carbon/kevlar (5.5oz)
-4 yards 2" carbon tape
-some rollers, brushes, and other misc. items
-1 gallon fast cure epoxy/hardener
-2.5 quarts microballoons
-2.5 quarts aerosil/cabosil

Will put down 1708 for footholds and for sides and bottom of hull and all other reinforcing.... then will put carbon/kevlar over both sides for a little extra reinforcement. I think the carbon/kevlar looks cool too.

When you pour the filler/epoxy/harderer mix into the bondline how much is sitting in there after the pour? Doesn't epoxy get really really hot as it starts reacting with the hardener? I was just a little concerned of how hot it would get as it sits in there.... I plan on filling the bondline, putting the 1708 down, and the carbon/kevlar down on each side all in one step so I dont have to sand....

 

[Mark44]

I like to use two part foam in the bond line it is lighter and still keeps some flex in the hull. You can over reinforce. IMO

Mark44

 

[Ericfox]

Yeah... I was reading about that... it just seems like the majority of people used the filler to fill the bondline according to one of the polls someone had.... I imagine it works ok either way.... using the filler just made a little more sense to me personally... others may think the weight saving/flexibility by using the foam makes more sense...

What about the heat of filling as mentioned in my last post... anyone?

 

[Crab]

When I used that same stuff, I thought it was slow and not that hot at 70 degrees in the shop.

 

[Mark44]

Yea I may use filler if it was a surf ski but for flat I feel foam is fine but then again I think I would use foam anyway I like the hull to be able to flex.

Mark44

 

[Ericfox]

When I used that same stuff, I thought it was slow and not that hot at 70 degrees in the shop.

And you mixed the epoxy with the normal amount of hardener as recommended (4:1)and then added the filler to make it like peanut butter consistancy right?

 

[Ericfox]

I have heard that epoxy left in a container as its reacting can even catch fire... I assume it just does not have enough volume in the bondline to make this happen....

 

[GDFL]

If you spread it out, as in laying up glass or doing the bondline, it isn't going to get very hot. It will get very hot if left in the container. That's why you have the "pot life". How long it takes to get kicking in a "pot". You can increase your pot life time by using something more like a cake pan than a cup or doing that plus putting it on a bed of ice or ice water. Once it gets started, it really goes because the buildup of heat accelerates the reaction.

 

[Ericfox]

If you spread it out, as in laying up glass or doing the bondline, it isn't going to get very hot. It will get very hot if left in the container. That's why you have the "pot life". How long it takes to get kicking in a "pot". You can increase your pot life time by using something more like a cake pan than a cup or doing that plus putting it on a bed of ice or ice water. Once it gets started, it really goes because the buildup of heat accelerates the reaction.

Cool.

I was planning on trying a paint tray with the thin plastic liners you can buy in like packs of 10. Hopefully that will work good.

I have been thinking about the order I just placed....I have a black superjet... do you guys think (in your opinion) that the black/red carbon kevlar will look cool? or should I just get all black carbon 2x2 twill.... just looking for another opinion or two before I forget about it and wait for it to show up at my doorstep..

Thanks everyone!