Monday, May 13, 2024

PMF (Poor Man's Fibreglass) Time

It was time to attach the roof to the walls, and then start the laminating. 

I removed the cabin from the chassis. Checked it all over and filled any gaps or holes. I used a foaming polyurethane glue. Using a plastic spatula to spread it into and over any holes, then tape over with masking tape. Without the tape, it was sometimes too bubbled to give a smooth look when sanded. As it was setting, pressed with the spatula to pop the bubbles and force into the gap/hole. After it set, removed the tape and sanded it smooth. 

After all the gaps had been filled, it was flipped it on its roof. I wanted to start from the base and work towards the roof, so any seams would overlap downwards when it is upright. I cut the fabric to fit the base. It overlaps 90mm on all sides. I marked the edges to help line up the fabric when replacing it over the paint. 

Was happy and a bit miffed to find the fabric is 1140mm wide. I had in my head that it was 1000mm wide. That's great as less seams needed.    The side laminate is one piece of fabric wrapped from the back, down the side, across the front, down the second side to the back. Over five metres.  I'll have to cut 10mm off all of it.  Miffed, as when I lowered the roof, the height from the bottom of the floor to the top of roof is 1130mm.  I'd have made the roof 10mm higher if I'd known.

I had decided to just use paint to attach the fabric.  Applied paint on the foam, press the fabric into the paint.  I put a plastic bag over one hand to smooth the fabric. The plastic slides. The other hand, I could grab and stretch the fabric to help pull out any wrinkles. Another coat of paint was immediately applied over the top to wet the fabric fully.  It was important to get the fabric saturated, else it didn't stick well to the foam. 

I had a few bubbles appear after it had dried. To fix them, I used a pin and punctured the bubbles. Keep pricking the bubbles to make a lot of holes. Can't have to many holes. Some of the bubbles deflated with this. But if they didn't, I smoothed them flat and apply more paint over the top. They stayed down after that.  

Everything went pretty good. Only worry for me was that the fabric was soaking up the paint. 

Finally I flipped the cabin on the base and to laminate the roof. And this is where I stuffed up. For reasons that escape me now, I decided to use Titebond 2 rather than paint. Big mistake. It was harder to apply. It was tacky and the plastic bag trick didn't work. I had to pull the fabric tight. At the end, it looked good wet, but as it started to dry a lot of bubbles started to show. Then the weather turned to rain, and humidity was high for two weeks. The glue didn't want to dry fully. It was staying tacky. I read about using an electric iron, but lacking this, I boiled a saucepan of water and used that. I put baking paper down first and sat the saucepan of boiling water on top. The good news was that the tacky glue hardened after it cooled. Bad news was the the flat looking bubbles actually bubbled upwards. So many bubbles. Some returned to flat when cool, some didn't.  What would happen in the sun? I didn't want to find out. And it looked terrible.

I peeled the fabric and glue off. Need to pull it in a peeling motion. Filled in any patches that needed it and sanded the roof again. Now I'm waiting for more fine weather to redo the roof fabric layer with paint. 
Gluing the roof on 
Used straps and weights

Fabric ready on the base
Applying the paint
Smooth it with hand in a plastic bag
Base all attached
Fabric and paint on the side 
Side all attached
Marking the roof fabric 
Flat bubbles on the roof

Bubbles getting worse

Removing the roof fabric