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Old 10-29-2013, 12:07 PM   #11
mugget
 
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Default Re: Composite Flooring: Waterproof, Rotproof, DIY

Cheers for the comments everyone.
Sorry for the delay in responding... I guess I forgot to subscribe to my own thread...

Quote:
Originally Posted by hein View Post
Terrific idea, beautiful work and awesome writeup. I can see from your flicker photos that this is not your first composite layup. Which core material did you use?
Cheers hein! The core is just a polyurethane foam, "structural" grade at 80kg/m3. Nothing fancy, looks like the same one that I use when making plugs etc. I asked about it when I picked it up, the guys that make it just pour the foam mixture into a giant rectangular tub, then they've got a big bandsaw that they cut it down with. Better them than me, the factory was covered in PU dust everywhere! The guy who was serving me had what seemed like a constant irritation that made him cough. Probably not a nice place to work...

As a side point, the same place sells refrigeration foam (for fitting out refrigerated trucks, cold rooms etc.), it's 40km/m3 but available in the same large size sheets. I'm using that (at 40mm thickness) to insulate the ceiling of the van. Much easier and less wastage than trying to use other insulation designed for buildings.

And nope, it's not my first composite project. It's really only my 2nd. (The first actually consists of a bunch of pieces, custom bodywork I'm doing for a KTM 380EXC supermoto build - but that's a whole other story!) But I'd say that a flat panel like this would be within most people's ability, just the size of the thing takes some time.

Quote:
Originally Posted by SullyVan View Post
Good god that's an expensive floor! :)
Yes... it's not for the fainthearted!
But it's the type of thing you only expect to do once, and composites are a big area of interest to me, so I want to try as many different things and take on as many projects as possible.

Quote:
Originally Posted by SullyVan View Post
First, a worry. Epoxy is known not to stick well to polyester. Really be sure that you have a good keyed surface to get it to stick.
Good point! For the top surface I put down peel ply after the final layer of glass. I completely forgot to mention that, and you can't see it in the photos because I had the panel upside down when I was trimming it. I just left the peel ply on while I was handling it and doing all the measuring & trimming, then took it off before doing the surface coat. It had been sitting for maybe 4-5 weeks before I did the surface coat, so hopefully no styrene or anything else hanging around to interfere with the epoxy.

Quote:
Originally Posted by SullyVan View Post
Second, the correction... Thicker core does not make a panel stronger. It makes it stiffer. The amount of glass you used is where the strength comes from. It takes the same force to break the panel you made no matter if you use 12mm or 25mm foam. The difference is the 25mm foam will not bend as much before breaking.
Thanks for that correction. These facts will stick in my brain, eventually I hope.
On the subject of glass and strength - what do you think about the amount of glass I used (1x 300gsm and 1x 450gsm for each side)? This was pretty much just a wild guess! It feels solid to walk on, across the largest span (about 20cm between the floor corrugations at one point) I can feel it flex a bit when walking over it. Mostly I will carry light loads, most it will likely see is when I load my bikes, heaviest being around 220kg (485lb) but I will make sure to position it so the corrugation "peak" is directly under the wheels.

And I would have loved to infuse this job - that's one thing I quickly came to appreciate about infusion, how it would make large jobs so much more manageable for a single person.

Another side point - the place I bought the foam also make pre-glassed panels and build caravans and custom trailers/transporters from them. They use a single layer of 600gsm CSM on the interior side which would be another option to save some money (their specs say 900gsm Biaxial/CSM on the gelcoat side - must be something like 300gsm Biaxial and 600gsm CSM?), the trade off being that the panel would be heavier because of more resin being used. I'm not sure of the strength, but CSM must be fine as that is their standard "RV Panel" (with a 20mm core).

On the subject of boats - on a composite forum I visit someone mentioned about an infusion job that went wrong, someone completely messed up the epoxy ratio. The job was an infusion on a 60' carbon fibre boat. OUCH!!
And yes, I believe that someone was in big, big trouble!
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Old 11-02-2013, 07:44 AM   #12
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Default Re: Composite Flooring: Waterproof, Rotproof, DIY

Doug M. - I didn't caulk around the edges, but here's how it looks now:


Composite floor by mugget, on Flickr

I used contact adhesive to stick that 5mm foam on. The idea here is that the corflute I'm using to line the interior walls will come down over the foam (which is closed cell, so it's waterproof), giving a bit of a barrier to stop any water going under the floor. The door edges are still open to water ingress, but maybe I can seal them up with a bit more foam as well.

My understanding is that there's really no need to seal the edges of the panel since it's a closed cell foam. But if the edge was exposed to wear or handling, etc. you might want to think about some protection to avoid delamination (i.e. if the edge is bumped and part of the glass starts to peel away from the foam). Not a problem for me because all those edges will be facing against the van interior and it will be bolted solid, so no risk of damage.

And interesting that you mention overhead cabinets hein. That is actually something else I've been seriously thinking about... many different ways you could do that as well. Perhaps something I will look into once this fitout gets further along.
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