PMF paint problems

[Kajsama]

Hi Everyone! First time builder/PMF-er here. I have some concerns about how my PMF is going. For context, I have done these steps so far:

- Surface prep of XPS foam (made tiny holes with pet brush, and yes this took forever!)
- Placement of fabric (old bedsheets) over exterior using Titebond II. I didn't do this perfectly (ie there are small wrinkles in some places) but I was overall satisfied cosmetically and fabric adhered well (without being saturated in glue).
- Painting over fabric with diluted exterior acrylic paint (50:50, then 75:25 paint:water), followed by 2 layers of non-diluted paint. I have not sanded in between, as the texture was looking pretty good/acceptable to a type B person such as myself.

At this time, I feel that the surface of the PMF should be hardened. However, I am still able to press into the foam quite easily with my finger. My leading hypothesis is that the paint has not dried properly due to low temperatures--I am in upstate NY, working in a garage with temps typically around 30 degrees.

Alternatively, I could just need to do more coats of paint. Or perhaps something about my technique or materials up until this point has been wrong (i.e, wrong fabric, wrong paint, etc)--although from what I can tell, people have success with almost any type of fabric and exterior paint, and 2 coats is generally sufficient.

I have been combing the threads and unable to figure out what the issue is! I am wondering:

1. What is the issue?
2. What steps can I take to correct this? (I.e. more coats, sanding down existing coats and then repainting when warmer, or...please don't say it...stripping off the fabric and completely starting over?)

Thank you so much fam!

- Kajsa

[Pmullen503]

Latex paint shouldn't be applied below 50F.

Leave it alone. It should set up when it gets warmer. Don't expect to have a very durable surface with just a bed sheet covering. Latex paint will stay somewhat flexible so it will never get super hard.

That's OK because small dents and dings will self heal in the sun. It's a feature of PMF not a bug.

[Kajsama]

Hi—thanks for your reply!

I do want the trailer to be durable. How much would you say the paint will improve when the temp warms up? A few dents are acceptable, but it seems that currently there would be much more than that if I took it out on the road.

Would it be worth it to completely redo with thicker fabric (or, canvas drop cloths) or an alternative paint?

Thanks again!

[Pmullen503]

I'd wait to see the result after the paint fully cures.

[philpom]

I agree to wait and see but bed sheets won't hold much paint so it probably won't stiffen up much but maybe it will. While I did my PMF over wood so it's a bit of a different beast, I used 7.5 pound cotton duck canvas. My method was:

-Moisten the fabric
-Roll TB II on the wood
-Apply the fabric and used a plastic knife to work it in (slightly watered down glue)
-Rolled slightly watered down TB II over the outside of the fabric working it in more with the tape knife and allowed it to dry well
-Applied 3 coats of Sherwin Williams exterior acrylic Duration paint allowing 3 hours between coats (4 coats on the roof)[/list][/list][/list]

It took nearly 2 months before I considered it fully cured but provided a durable finish. I did not sand so before I applied paint it was a rough surface kinda like sand paper but that particular paint is thick and it adhered very well and filled it out well.

I did this in September and it was pretty warm so the water in the TB II was required to provide enough working time to apply it.

[pchast]

I did my canvas covering in warmer weather. The latex still took a couple of
weeks to cure. I should have waited more in between coats. it may have made
a difference.