foam durability as it ages?

[KCStudly]

This is not the first mention of gesso.

Link to big Thrifty Thread March 25, 2012

[GPW]

Been here so long , we’re starting to repeat ourselves ...

[KCStudly]

Me, too, am we.

[GPW]

As far as durability is concerned , we can babble on endlessly (as apparently we already have ) about how foam lasts , but the real test is "the test of time" .... No way to accurately predict the results without waiting years ... But we can say with a small assurance of accuracy , that anything Plastic will eventually deteriorate in the light radiation of our local star (Sun) ... We’ve seen that with beaded foam left out for a long time , but then again only the immediate surface is affected ... Thinner Blue and pink foams seem to get more brittle under the same conditions ... (1/4” as we’ve tested for 10+ years with planes ) Note: the Green foam (Amaco) seemed to be the quickest to be affected , then pink (OC) , then the Blu (Dow) ... (observed)
But (and here’s the kicker), once covered, protected , the foam remains largely unaffected ...for a yet undetermined length of time ... So basically , anything that provides a protective skin will much lengthen the effective lifespan of the foam materials ... Fiberglass, Al, canvas, bedsheets ,cardboard, newspaper , pasta ... whatever...

But then again , I think we already said that before too eh ?

[Lonewolf42301]

But then again , I think we already said that before too eh ?

Maybe so, but I've been readin a week now and still haven't found details I look for.... Everything is buried in off topic chatter.... but im trying....

[GPW]

Off topic chatter ??? What exactly are you looking for LW ???

[Lonewolf42301]

Off topic chatter ??? What exactly are you looking for LW ???

Still reading but found some info I wanted on Krusty's thread... number and weight of fiberglass used.... From what few searches in have done, fiberglass cloth isn't any more expensive then a lot of canoe grade canvas but is a lot more expensive. Seriously think I will use the epoxy and glass as mine will see a few thousand miles each year over all terrain types from bare ground to gravel to super highways. Heck, when we got home this year from our annual big trip, we had loged 5400 miles on the bike, and that was just 1 trip. That didn't count the weekender trips we do....... I'm thinking on the sides and inside that 1 layer of 10oz glass will be ok with 2+ on roof and floor? The website showing the Goldbrand pop-up trailer really has my interest and strongly considering building that with a few differences of my own such as electric brakes, a drop down foam core table hinged and built into side for cooking, outside access to storage compartments under the bed ( doors would be hidden when top half is lowered down in transport mode), detachable awning made with tent material, a/c and a 12 gal water storage tank just in front of axle with batteries just behind in the floor. Just building it over and over in my mind trying to anticipate problems and plan it all out....

[KCStudly]

The biggest hurdle I see you having is weight. Water tanks, batteries, awnings, storage, 10oz cloth (as apposed to 6 oz), lifting roof, etc. are all things that add weight.

My advice, scale back not up, and start doing some serious weight analysis. Add it all up, don't assume anything, count every stick, screw and gallon of epoxy. I think you will quickly find the limit of your bike's towing capacity.

12 gal of water weighs 100 lbs w/o the tank.

[GPW]

I don’t know if youse’ guys remember a while back (long time ago ) ... Glassice building a fiberglass/Foamie ... You may want to read though that thread ... it was quite long and there was a LOT of glas’ that went on ... and then we never heard from him again ...

[Lonewolf42301]

The biggest hurdle I see you having is weight. Water tanks, batteries, awnings, storage, 10oz cloth (as apposed to 6 oz), lifting roof, etc. are all things that add weight.

My advice, scale back not up, and start doing some serious weight analysis. Add it all up, don't assume anything, count every stick, screw and gallon of epoxy. I think you will quickly find the limit of your bike's towing capacity.

12 gal of water weighs 100 lbs w/o the tank.

Really wont be hauling any more then what I do now. I will be adding a hacked a/c, small generator, lite battery bank, water tank( which will be filler after arrival) But will be losing 2 aluminum tables, a heavy 3 1/2 season tent, canopy, and an air mattress. And reading the Goldbrand site on what he did, the trailer won't be much heavier then what I am towing now, as mine has an 0.120 aluminum tubed floor pan in it and steel frame rails and bracing ....Battery reserve only needs to be big enuf for some lighting at night, 2-3 hrs of stereo time, and if its cold, a heated mattress pad.

[Jst83]

So basically , anything that provides a protective skin will much lengthen the effective lifespan of the foam materials ... Fiberglass, Al, canvas, bedsheets ,cardboard, newspaper , pasta ... whatever...

But then again , I think we already said that before too eh ?

Pasta

[KCStudly]

My first thought when he included "pasta" was the macaroni crafts we did in grade school; a Styrofoam cone covered with white glue, rolled in elbow macaroni and spray painted gold.

Google images: Macaroni crafts

[GPW]

OK, maybe not Pasta ... Just trying to make the point the foam needs something over it , if only paint ...

[Mary C]

GPW would gesso work over gripper, is gripper sandable? I have decided that mine is in need of some finishing details about 20 hours ....................

Mary C.

[Westcliffe01]

Something I have not heard mentioned (and which is a huge labor saving) is bonding filon siding on both sides of a foam core. One would have to scuff the side that one is going to bond, but looking at http://www.rvpartsnation.com/product/1217/arctic-white-fiberglass-filon 10' x 101" is $210. One could make a straight and level oversize work surface and use vacuum bagging to apply clamp pressure and produce huge panels that are perfectly finished inside and outside and also very flat. That way there would be very little actual wet layups needed except for bonding the panels together at the edges and also very little needed in the way of painting/finishing.

One can use such panels (with proportionate thickness core foam) to make just about everything in the camper that is flat, including the table, drawers, furniture etc. One needs to identify sources for architectural extrusions to help with making joins at 90 degrees and for edge closures. Where I live there is a company that makes nothing else, but they don't generally market to the public.

I have done the math, and at least for the composite facings (ignoring finish for the moment) it is not financially viable to use wet layup when one can bond Filon to a core. One could also use contact adhesive, but that is relatively tricky to apply, particularly when working alone.

As far as durability is concerned, my main concern would be the ability of the structure to withstand the racking induced by the feeble trailer frames that are used. With the boxy structures that are commonly used, the stress is concentrated in the 90 degree joints between floor and wall, wall to roof, front to side walls etc. The lighter the structure, the less racking, unless one comes up with a 3 point mount and allows the trailer frame to move independently of the trailer structure. Rob Gray, builder of http://www.robgray.com/graynomad/wothahellizat/wot2/index.php Mk1 and 2 has a page that goes into detail about designing and building the isolation mount for wothahellizat so that the structure could survive the twisting of the chassis without damage. http://www.robgray.com/graynomad/wothahellizat/wot2/diaries/diary_06/index.php
Picture of chassis vs structure articulation here


The whole thing is a fascinating read btw, this guy has done extremely well for a software writer...

Filon certainly has a track record and in commercial RV applications, the bonding process is the weak link.