Tips for Restoring Crumbling Emergency Hatches???

[kadoat]

I was up on my bus today resealing my emergency hatches when I noticed a problem. The exterior surface of my hatches were all crumbly. It was handy fro removing the old silicon that had been slathered on by the previous owner but I imagine it's going to cause trouble creating a good seal when I put on the new proflex. Does anybody have any tips??

I found a solution to a similar problem back when I was working on my Geo Metro. These cars are notorious for getting 'dash cancer'. Basically, the dash gets all discolored and crumbly from UV radiation. The folks online showed that a heat gun (after removing the crumbles with some abrasive) does a fantastic job of restoring the surface. I may end up trying that but I figured I'd pick your brains here first.

 

[Tango-SKO]

Can't imagine plastic ever "coming back" once it's that far gone (crumbly) (?) But let us know if you stumbled on to a miracle cure.

 

[kadoat]

Ok, well I went ahead and tried the Geo Metro dash cancer trick. Here's how it went:

This picture does a better job of showing the state of the hatch when I started. I began with a metal bristle brush but soon found out that it wasn't going to remove that tape. You can see, though, that it did remove some of the loose surface plastic (the crumbly bit).

After futzing around, I found a scrap piece of acrylic that did a wonderful job.

I wound up simply scraping off the top of the damaged plastic, revealing a cleaner and much smother surface.

Below is a close-up showing the fresh surface and is where I decided to stop. You can see that it's much smoother than when I started. I think this alone would be sufficient to get a good seal with Proflex.

Anyhow, I went ahead and used the heat gun to see what would happen. You can kinda see from the photo below that it did, indeed, produce a smoother surface. It's a bit more apparent when you run your fingers over it. Most notably, all those tiny grey cracks got smoothed over. That being said, I'm not sure it's totally necessary.

I also tried the heat gun on a section of the original surface. It did seal all the tiny cracks and didn't scrape off with my thumbnail (before I started, stuff would come off with a brush of my fingers) but I have a feeling it's better to go ahead and scrape the surface clean beforehand.

 

[Ryank327]

I bet if you hit it with some 300-400 grit sandpaper to smooth it out a little before the heat gun that would make it come out really nice. Usually when plastic looks like this it is just some surface erosion and the core is still good clean plastic. Don't sand too much of course you don't want to sand so much you weaken the plastic.

 

[Hvbuzz]

Here's my suggestion...

20150417_125603 by Hvbuzz, on Flickr

I spent four years trying to seal them up, granted mine were more cracked. But they get old and brittle and crack. Then leak water. Seal and repeat, then still leak. Not worth my time.

My fix, no more leaks!

20150417_165717 by Hvbuzz, on Flickr

When this one gets old and brittle in 10 years, I'll go get an easy and cheap replacement.

 

[milkmania]

Here's my suggestion...

20150417_125603 by Hvbuzz, on Flickr

I spent four years trying to seal them up, granted mine were more cracked. But they get old and brittle and crack. Then leak water. Seal and repeat, then still leak. Not worth my time.

My fix, no more leaks!

20150417_165717 by Hvbuzz, on Flickr

When this one gets old and brittle in 10 years, I'll go get an easy and cheap replacement.

gonna take a lotta grease to get my big ass through that hole!

 

[kadoat]

I bet if you hit it with some 300-400 grit sandpaper to smooth it out a little before the heat gun that would make it come out really nice. Usually when plastic looks like this it is just some surface erosion and the core is still good clean plastic. Don't sand too much of course you don't want to sand so much you weaken the plastic.

Yeah, sandpaper probably would have been helpful.



To HvBuzz,

One day I plan on replacing the hatches entirely but today is not that day. I'm debating on whether or not to put a deck up top, which will affect the design on the hatch. Anyhow, that's further down the line.