PMF over Kilz Exterior

[teardropty]

Recently I inherited a partially built tiny camper that a friend had started. He used plywood for the exterior, sealed all the edge with metal drywall edging/PL glue and painted it with Kilz Exterior Oil-based primer. I am not sure what his next step was but I come to the group seeking ideas/opinions for how to finish it. In an ideal world I would cover with aluminum sheeting but frankly that isn't in the budget. I am thinking PMF - poor man's fiberglass to finish it up but will it adhere properly to the Kilz? I have done some PMF on small projects but it always was prepped with a mix of polyurethane and paint thinner (25%) prior to the paint and sheeting/canvasing. Would the Kilz properly seal the wood and allow proper bonding with the canvas? Any other ideas for finishing the exterior? Thanks.

[John61CT]

Well "PMF" does not itself specify the adhesive / paint type especially since Glidden Gripper is gone

so really the question is, what are / were your intentions there?

Might be worth just experimenting with different choices, use pull tests after curing.

One should be just using that primer as an adhesive for the canvas, never know might be great, and certainly should stick to itself.

If that works then a compatible outer paint should be easy to identify, a tough "porch paint" or for concrete, decks etc

Make sure very UV resistant

[RJ Howell]

I sampled Kilz on foam and it sort-of worked to attach the PMF. As just primer not seeing an issue except that it's oil based and need to prep accordingly. Some 'bonding' primers are meant to do just and personally I had good luck using a quality bonding primer with the cloth.

I'll refer to others if the TBII system can work over oil or what prep may need to be done.

Could you take a picture of this metal D/W trim that was used please. Curious if it's what I'm thinking it is.

[teardropty]

To be clear the Kilz is already painted unto the trailer. It was that way when I got it 2 months ago. I am just wondering if the Kilz is "waterproof" enough to be used in place of the mix of polyurethane before I proceed with the PMF? Foamies don't require a waterproofing "MIX" but from my understanding wood substrate does. Thoughts?

[RJ Howell]

No Kilz is not waterproof, it's a primer. Good one yet I found not all that good for adhering the Foam/PMF. I have no experience bonding cloth to plywood.
With PMF the 'waterproofing' is in the finish coats of paint.

[rjgimp]

Yeah... I don't understand the need for the surface to be waterproof before applying a covering of PMF. If the surface IS waterproof why bother with PMF, and if you are going to entirely cover the thing with PMF anyway why would it matter?

[teardropty]

Thanks for the replies guys. Yeah, I was thinking Kilz wouldn't be waterproof. I did go ahead and do a test area and TBII held up great to a pull test over the Kilz. The test area where I used an exterior porch paint as the adhesive didn't fair so well. My conclusion is that TBII will work the best over the plywood/kilz. As for RJ comment, yeah, I never used the step of coating with polyurethane and then doing the PMF process. I agree logic is that the whole PMF is the waterproofing. Thanks for the inputs and I will get some pictures posted soon.

[ulrikesembler]

Hope you found the best solutions for finishing your camper's design. Also, with such great work, I recommend using a cover for your camper to keep all the work intact. A camper is a wonderful thing to have. Still, even the best-maintained one will experience wear and tear over time—making it necessary to preserve what you've already done. A cover also comes in handy if you're away and there's a storm coming or if you're in an RV park where it rains regularly. I recently got a new one from a car cover storethat fits perfectly, made from waterproof materials.