Van's Air Force
Don't miss anything! Register now for full access to the definitive RV support community.
Cab-O-Sil vs Flox
- Thread starter Dorfie
- Start date
I used flox on my doors. Flox was used exclusively for structural joints building the Cozy MKIV so it was what I had on hand. After prepping the joint with 36 grit Zircon paper, clean up the dust and make sure everything is sanded,,,,no shinny spots. Paint both mating surfaces with a very light coat of pure mixed epoxy before applying the flox.
Michael Burbidge
Well Known Member
Zircon paper...
What is zircon paper? Is it special for sanding fiberglass?
Michael
What is zircon paper? Is it special for sanding fiberglass?
Michael
tfarrell839
Active Member
Cab-o-sil is a thickener only
Cab o sil is silica. It's a thixotrphic agent. It's like the cornstarch of the epoxy world. You can add it up to 20% by volume. It adds no stregnth to the resin, but it also doesn't weaken it. Bonding the doors with Flox, with not too much flox in the mix, will cause the resin to thicken as well, and it is a stronger bond than just pure resin. I don't see a problem. You could also use a structural adhesive, such as some of the hysol products. Squeeze it well so you get a nice tight joint.
Cab o sil is silica. It's a thixotrphic agent. It's like the cornstarch of the epoxy world. You can add it up to 20% by volume. It adds no stregnth to the resin, but it also doesn't weaken it. Bonding the doors with Flox, with not too much flox in the mix, will cause the resin to thicken as well, and it is a stronger bond than just pure resin. I don't see a problem. You could also use a structural adhesive, such as some of the hysol products. Squeeze it well so you get a nice tight joint.
Zircon only refers to a brand or type of grit paper.
It is basically 36 grit abrasive.
When doing the glass, I would always recommend a variety of coarse grit abrasives - mostly on long blocks.
Tip Time:
Make up the following -
18" x 3 x 3/4 MDF or good ply. Go to Home Despot or similar and look at belt sanding abrasive - it comes on a stout fabric backer.
Seal the MDF/ply with rattle can paint - nothing fancy, then use a branded contact adhesive to stick the fabric to the block.
I use 36/60 (double sided) on one block and 60/80 on the other block - never finer.......
If you are doing profiles, such as the canopy, use a piece of 4 x 2 around a foot long, profile one side using a plane to what you want the fillet to be and use 60 grit paper this time, again contact adhesive on.
Why so coarse ?
Because you are using it in a slow forward motion much like a file - the purpose is to remove material in an even manner, or to prep the surface as a good key to take adhesive, or epoxy.
If you are working towards a final surface, once you are close - then go in with finer grit paper to proceed towards a finish.
It is basically 36 grit abrasive.
When doing the glass, I would always recommend a variety of coarse grit abrasives - mostly on long blocks.
Tip Time:
Make up the following -
18" x 3 x 3/4 MDF or good ply. Go to Home Despot or similar and look at belt sanding abrasive - it comes on a stout fabric backer.
Seal the MDF/ply with rattle can paint - nothing fancy, then use a branded contact adhesive to stick the fabric to the block.
I use 36/60 (double sided) on one block and 60/80 on the other block - never finer.......
If you are doing profiles, such as the canopy, use a piece of 4 x 2 around a foot long, profile one side using a plane to what you want the fillet to be and use 60 grit paper this time, again contact adhesive on.
Why so coarse ?
Because you are using it in a slow forward motion much like a file - the purpose is to remove material in an even manner, or to prep the surface as a good key to take adhesive, or epoxy.
If you are working towards a final surface, once you are close - then go in with finer grit paper to proceed towards a finish.
Michael Burbidge
Well Known Member
Perfect timing...
The timing of this advice is perfect. I finished laying up my canopy fairing yesterday and am fretting how to remove enough fiberglass to get it to the appropriate shape. There is more fiberglass than I would like to remove, especially along the side of the fairing.
If I was to do the layup over again I would not wrap the first layers all the way around. (1/2 and 3/4 inch width pieces) This is because the curvature is flatter on the sides than on the front. So I have a bit of fiberglass to remove along the sides.
Michael-
The timing of this advice is perfect. I finished laying up my canopy fairing yesterday and am fretting how to remove enough fiberglass to get it to the appropriate shape. There is more fiberglass than I would like to remove, especially along the side of the fairing.
If I was to do the layup over again I would not wrap the first layers all the way around. (1/2 and 3/4 inch width pieces) This is because the curvature is flatter on the sides than on the front. So I have a bit of fiberglass to remove along the sides.
Michael-
Michael,
If you need any further assistance, PM or email - we are all here to help
M
If you need any further assistance, PM or email - we are all here to help
M
Thanks
Thanks for the responses. Flox it will be! If I mix flox to a thickness that it "does not pour" from the cup, is that thickness still OK? (Thats what the plans states for cab-o-sil use)
I got some ParaBeam (described as 3D FG) FG with the kit. It is much thicker, like two outer layers of FG with interconnecting fibers. It goes between the outer and inner door shells at two places each door. How do you wet these thicker pieces with resin? Will brush-on work? Submerge and squeeze access resin out?
Cheers.
Johan
Thanks for the responses. Flox it will be! If I mix flox to a thickness that it "does not pour" from the cup, is that thickness still OK? (Thats what the plans states for cab-o-sil use)
I got some ParaBeam (described as 3D FG) FG with the kit. It is much thicker, like two outer layers of FG with interconnecting fibers. It goes between the outer and inner door shells at two places each door. How do you wet these thicker pieces with resin? Will brush-on work? Submerge and squeeze access resin out?
Cheers.
Johan
Gary 40274
Well Known Member
Wet vs Dry
One of the problems I have seen, is that folks get the resin cabosil mix either too wet of too dry. You want it wet enough so that it wets out on both surfaces of the door, but not so wet that it runs away from the bonding site. I suspect that most of the door flexibility problems stem from not getting a good bond between the two halves.
As far as wetting out the multi layer fiberglass, put it on a piece of poly sheet and wet it out with a stippling brush to get the correct resin/glass ratio. Then pick it up and place it in the desired location and stipple in place.
Gary Specketer Tech Counselor
Fiberglass guy
One of the problems I have seen, is that folks get the resin cabosil mix either too wet of too dry. You want it wet enough so that it wets out on both surfaces of the door, but not so wet that it runs away from the bonding site. I suspect that most of the door flexibility problems stem from not getting a good bond between the two halves.
As far as wetting out the multi layer fiberglass, put it on a piece of poly sheet and wet it out with a stippling brush to get the correct resin/glass ratio. Then pick it up and place it in the desired location and stipple in place.
Gary Specketer Tech Counselor
Fiberglass guy
