Finally ready for Filon!

[Atomic77]

Ok my fellow Filon people... the time is here. My walls are finally prepped and ready to apply Filon this weekend! I can't tell you how excited i am to be at this stage...Finally!!! I am planning to bond the Filon to my Lauan walls with West Systems Epoxy and doing a vacuum bag. I'm wondering... has anyone else used this method? I know the vacuum clamp method has been used by a couple people here with good success. But has anyone used epoxy to bond with? So... now is your chance to help me out with any tips, suggestions or just general encouragement because Saturday is the big day! (I know...overly excited here but it seems like this milestone has been a very, very long time coming with many, many hours of labor leading up to this moment!)

[mikeschn]

Are you applying Filon before you assemble the walls to the floor and cabinet structure? If so, how will you put your screws in?

Mike...

[Atomic77]

Copied and pasted from my build journal where I was asked the same question...

There is no hardware going through the walls or outer skin. The Filon is not penetrated in any way other than the cutouts for the necessary doors, windows, etc. The walls have 2x2" cleats mounted at the bottom that make a "ledge" for the wall to sit on the flooring. 4" bolts go through the cleats into the floor and through the frame. In my original trial run, there was a substantial space between skirt and the frame, (intentionally built in) so yes, there is adequate allowance for the layer of fiberglass and epoxy. So... whether there is Filon on the outer wall or not, it makes no difference regarding how the walls mount to the frame. All the mounting bolts go through the internal cleats and are hidden by the bed, kitchen cabinets, dinette seating, bathroom cabinets and the closet.

One of my friends was looking at the design and asked if the bolts through the cleats are the only things holding the walls onto the trailer. Technically, the answer is yes. But realistically the answer is not entirely... because the walls are bolted and bonded to the internal walls, the dinette seating, the cabinets, the bed, spars, etc.

The strength is in the sum of the parts...

[mikeschn]

Just making sure you thought it through.

Looks like the perfect T@B clone!

Mike...

[Atomic77]

Thanks Mike... I really wanted the T@B L400 but they only make those in Europe. So I said what the heck... let's build one. It's considerably larger than the ones here in the states. Both wider and longer.

[aggie79]

I hate to ask a dumb question since, by the evident demonstration of your incredible skills you more than know what you're doing, but have you tried a sample bond of filon to plywood with epoxy? I have very little epoxy experience and no vacuum bonding experience so please take this into consideration. Potential concerns are: epoxy compatibility with filon, having enough "tooth" for the epoxy to adhere to the filon, and "starving" the bond join. (I guess the latter could be overcome by adding "flour" or cabosil to the epoxy.)

Anyway, please don't dwell on my musings. You have a fantastic beautiful build in progress.

[Atomic77]

Well, to answer your question regarding if I have done a sample piece yet the answer in a word is, no. I don't pick the Filon up until Saturday morning so I don't have any of the material. But... I have done a considerable amount of work with epoxy, fiberglass, carbon fiber, etc. And I have done quite a bit of research regarding Filon and RV repairs. I've seen many instances of the repairs being made with epoxy to bond Filon to Lauan. I also have studied West systems documentation which specifically states it can be used with Filon. Therefore, I feel pretty good about what I'm getting ready to do but again, I've yet to have someone specifically tell me they have done it. But thank you for your kind words.

[aggie79]

That is great news! I appreciate the info and your research, and look forward to the installation of the filon. Thank you!

[Atomic77]

Thank you! After I get the Filon home Saturday I will bag a test piece and do some shear strength testing. Everything looks good on paper but I'll put it to the test. I was reading last night about West Systems epoxy having the same expansion and contraction rates as Filon, how it is about the same as Filon regarding flexibility and how it's used almost exclusively in the industry to seam-in and repair Filon. So I think I'm good. But I would sure like to hear from someone who has actually done it first hand. If not, I guess I will be the one who has done it first hand. Lol!

[Atomic77]

I hate to ask a dumb question since, by the evident demonstration of your incredible skills you more than know what you're doing, but have you tried a sample bond of filon to plywood with epoxy? I have very little epoxy experience and no vacuum bonding experience so please take this into consideration. Potential concerns are: epoxy compatibility with filon, having enough "tooth" for the epoxy to adhere to the filon, and "starving" the bond join. (I guess the latter could be overcome by adding "flour" or cabosil to the epoxy.)

Anyway, please don't dwell on my musings. You have a fantastic beautiful build in progress.

I did some research on your concerns...and here's what I have discovered.
-It appears that Filon has very different sides. (At least the Filon that I am getting on Saturday.) The outside is coated with a layer of gelcoat. This gives the exterior a nice finish that doesn't need to be painted. The other side is not gelcoated and unfinished. It has a rougher, more porous texture. There's the tooth we're looking for.
-Regarding the starvation of the bond joint...There's a bit of a trick to getting the right amount of epoxy on the surface...the Lauan tends to want to soak it up a bit. The trick is to get plenty on without going overboard. When I make my vacuum bag, I will have a layer of cotton covering the piece that will soak up any excess that is squeezed out by the vacuum clamp. Viscosity is important and the epoxy needs to be able to flow evenly so thickner is not recommended. But when I do thicken it I always use Aerosil, which is a fumed silica... or on occasion I will also used finely ground cotton.
-As far as compatibility is concerned, I stopped by our local RV dealer and they took me back to the repair shop and showed me a large Filon repair. They patched in a large piece using epoxy, then taped the seams and used epoxy on that side as well.
Thanks for your concerns... they have helped me to further my knowledge of the product!

[dales133]

If the luan soaks up the epoxy to fast maybe look at coating the luan with a sealer and letting it dry before you fit the filon

[Atomic77]

Did you see that I posted pix of the 30A outlet?

[aggie79]

I hate to ask a dumb question since, by the evident demonstration of your incredible skills you more than know what you're doing, but have you tried a sample bond of filon to plywood with epoxy? I have very little epoxy experience and no vacuum bonding experience so please take this into consideration. Potential concerns are: epoxy compatibility with filon, having enough "tooth" for the epoxy to adhere to the filon, and "starving" the bond join. (I guess the latter could be overcome by adding "flour" or cabosil to the epoxy.)

Anyway, please don't dwell on my musings. You have a fantastic beautiful build in progress.

I did some research on your concerns...and here's what I have discovered.
-It appears that Filon has very different sides. (At least the Filon that I am getting on Saturday.) The outside is coated with a layer of gelcoat. This gives the exterior a nice finish that doesn't need to be painted. The other side is not gelcoated and unfinished. It has a rougher, more porous texture. There's the tooth we're looking for.
-Regarding the starvation of the bond joint...There's a bit of a trick to getting the right amount of epoxy on the surface...the Lauan tends to want to soak it up a bit. The trick is to get plenty on without going overboard. When I make my vacuum bag, I will have a layer of cotton covering the piece that will soak up any excess that is squeezed out by the vacuum clamp. Viscosity is important and the epoxy needs to be able to flow evenly so thickner is not recommended. But when I do thicken it I always use Aerosil, which is a fumed silica... or on occasion I will also used finely ground cotton.
-As far as compatibility is concerned, I stopped by our local RV dealer and they took me back to the repair shop and showed me a large Filon repair. They patched in a large piece using epoxy, then taped the seams and used epoxy on that side as well.
Thanks for your concerns... they have helped me to further my knowledge of the product!

Great information! Thank you.

I went back and read your entire thread. Please accept my apologies for not seeing your extensive composite experience before posting my questions. In reality, I have been thinking about a similar process for a future second build. I guess I was voicing concerns that I would encounter if I tried such a process.

I know you are going to be quite busy during the layup so pictures are probably going to be difficult/impossible. Perhaps after your finished you can describe how things went for us epoxy/composite newbies.

[Atomic77]

Please...apologies are unnecessary! It's like Carrie says... You can't think of everything! And that's what I love about the forum... Getting to bounce questions and ideas off each other! I will definitely have pictures of the Filon lay up in our build journal. And although I work with epoxy, carbon fiber, fiberglass, etc. regularly, I have never worked with Filon so this is new territory! And from the apparent lack of response around here regarding Filon, I'm guessing it's new territory for the majority of us. Anyway, thanks for your input. It's always appreciated when someone provokes thought!

[dales133]

No I missed it I'll have to rewind!