How would you skin this?

[drshoe]

Hi all,

I am in the scheming phase for my second tiny trailer, similar shape and construction to my previous one (see link in signature) but a little wider and without the angled panel at the front. Essentially, a rectangle with a highly sloped hatch section on the back. Anyways, with my current plans I can see an opportunity to assemble each exterior wall and the ceiling (1/4 ply, 1x2 studs between 3/4 foam, 1/8 beadboard) on the ground first before putting them together without having to pierce the exterior with any fasteners. I am all about keeping things simple, and I don't need this trailer to last forever maybe 10 years or so, but the exterior ply on my first trailer checked really quickly.

Fiberglass seems like an obvious choice, but how would you apply it? One possibility is to fiberglass each wall as it is constructed on the ground then tape and glass the seams after construction. Another options is to wrap each wall with the fabric as it is constructed and glass after construction which could eliminate the need treat the seams specially. However, I've heard it is best to saturate the wood with epoxy prior to applying the fabric - does it even matter with 1/4 ply?

What other materials would work to wrap the walls similar to glass fabric?

What other options should I consider given my needs? I like the idea of Monstaliner but will it hold the plywood together the way fiberglass does?

[tony.latham]

One possibility is to fiberglass each wall as it is constructed...

It's a lot easier to glass the walls on the bench.





And the roof when it's ready:



Gravity can be your friend.

Tony

[friz]

I'm with Tony on this. Do anything you can flat.

Sent from my SM-S906U using Tapatalk

[Tom&Shelly]

I like the idea of Monstaliner but will it hold the plywood together the way fiberglass does?

Tony, and then we, used Monstaliner over the fiberglass. Can't remember the name of the primer we used off-hand, but we followed Tony's lead, and it's in his (and our) build journals.

Tom

[twisted lines]

I have used the monstraliner and am just starting another without the ply skin

[KCStudly]

It is not strictly necessary to pre-wet base surface prior to placing glass weave, but it is advisable. Wood (any thickness) and foam (... any surface with porosity or crevices) has the ability to wick the epoxy out of the glass as you apply it.

Wetting the surface before laying the glass hedges your bet against starving the glass.

Presealing the surface with epoxy and allowing it to cure before laying the glass really ensures that you won't starve the glass, but then you have to re-prep the surface again (wash amine, scuff and clean) before layup, and if you don't catch it while it's still "green" you only get a mechanical bond, not the preferred chemical "monolithic pour".

If you don't pre-wet or pre-seal, you can still push enough epoxy through the weave, but you have to stick with it during the whole wet phase to make sure you don't get any dry spots developing, and you might tend to use more resin (which costs more money, adds weight and reduces strength).

I have run into issues with large blisters forming immediately and still years after laying glass directly onto foam without pre-sealing. Not sure if this is due to poor prep (scuffed, but didn't wipe with alcohol as is often recommended, used light weight spackle in areas and may not have sealed fully, or just some weird out gassing or thermal expansion yet to be proven... my blisters are puffy, "pressurized").

If I had it to do over I would pre-seal. My habit was to take layups in reasonable time frames, because it wasn't practical for me to do all day and night marathon wet sessions, so I always had to wash amine and do mechanical prep for the next session anyway.

[tony.latham]

I fall into the fiberglassing camp, applying the cloth over dry wood and wetting it from the top.

Here's how I explain it in my book:

As you wet out the cloth, keep in mind that some of the epoxy will absorb into the wood, which can lead to resin-starved fiberglass. The squeegee is your stethoscope. It will vibrate over starved cloth and glide over areas of excess epoxy. Look at the layup from a low angle for dull or shiny spots. If a spot seems whitish, it needs more resin. Properly saturated cloth is transparent. Adding resin to saturated cloth doesn’t increase the strength.

Pay attention to the edges of the wall and ensure good saturation. If you have a raised spot in the fiberglass, work it flat with the squeegee.

When you think you’re done, take a twenty-minute break and then check to make sure that some of the cloth hasn’t lifted. You can push those spots down with the squeegee. Additional epoxy can be added as long as it’s still tacky.



It works well for me.



Tony

[Pmullen503]

......

I have run into issues with large blisters forming immediately and still years after laying glass directly onto foam without pre-sealing. Not sure if this is due to poor prep (scuffed, but didn't wipe with alcohol as is often recommended, used light weight spackle in areas and may not have sealed fully, or just some weird out gassing or thermal expansion yet to be proven... my blisters are puffy, "pressurized").
.........

What happened is the spackle separated. If you cut into the blister you'd find the split happened through the spackle itself. Been there, done that.

If you have low spots in foam, like the lettering on the foam, steam it first with a wet towel and a hot iron to raise the lettering. To fill dents in foam use epoxy with microballoons and get it really smooth and level while it's wet. You really can't sand it flush to the foam because it's harder than the surrounding foam.

If you really need a flat surface, it's better to cover the foam with thin plywood first then epoxy over that.