Teardrops n Tiny Travel Trailers

Looking for a little bit of guidance from those who know more and better than I...

Looking for a good, spreadable adhesive to attach filon to XPS for the exterior of my build. Leaning towards contact cement, but not sure if there's a good spreadable option. Three things I need the product to do:
1. Be strong and long lasting (obviously)
2. No two part epoxy! I have a severe allergy to resin, which is why I'm doing Filon ($$$)
3. Must be spreadable, not sprayable. I don't have access to a gun.

Thank you very much!

I'd use 3M 30 NF contact adhesive with a roller but not many here would.

In my experience the 30 NF didn't work as well as expected, and that was with wood to foam.

I brushed it on roughed up foam and it seemed to take a lot of (expensive) product to coat.

In my humid climate it took way longer than the instruction time to flash off.

IIRC, the instructions call for 300 lbs from a roller, so a pretty high point load, and I just wasn't able to get that with random gravity clamps (I feared a laminate roller would mar up my okume panels).

Not sure it will stick to frp or other plastics well. Do your homework.

A number of other RV sites/bulletin boards conclude Staybond E-183 for filon. It is a solvent based contact cement, whereas the 3M 30NF is water based. Unclear if the foam is affected by the Staybond.

As far as pressure, I've just used a mallet and cloth padded piece of 2x4.

I installed a cork floor last fall and used Wakol D 3540, a water based contact cement. Id be tempted to experiment.

I'd also like to experiment with Loctite Power Grab Express All-Purpose Interior Construction Adhesive, a trowel on goop. Some descriptions say good on foam. I do not know how it does in sunlight.

Thank you all so much for your guidance! Definitely means the world to me and my build.

I am leaning towards the Loctite Power Grab - as its readily available locally for a good price (box store), it's low odor/no VOC/water-based, and it seems pretty resilient to weather. Also, it looks like I won't have to press the crap out of it to get a good seal to the foam.

I like the Staybond product, but it is really expensive (not a completely deal-breaker). However, it dries red, which I fear will bleed through my Arctic White Filon roll.

Going to do a couple tests of composite panels this weekend before I start the build. Here's what I'm planning for my structure: 1/8" birch plywood on the interior, 1-1'2" XPS foam core, and filon on the exterior. I will try a couple different adhesives to see how they work.

Dang, this allergy sucks! Wish I could just glass and epoxy this job and call it good. Unfortunately, that would land me in the ER, and that's no bueno for me or anybody.

Thank you all so much for your help! Excited to get this trailer on the road. Will be sharing pics and progress on here throughout the build.

i used loctite pl 300 to bond shower surround to foam on a foamie about 5 or 6 years ago. It sits in the woods as a hunting blind and is still going strong