So with the block back from the machine shop it was time to get on with painting it. I decided to paint the block chevy orange.
After doing a bit of reading on the web, por-15 seemed to get good reviews so I decided to go with that. I found a company called Frost who supplied the paint in the UK (http://www.frost.co.uk/).
After reading up on Por-15 it became apparent that as with most things, preparation is key. Por-15 recommend that you degrease the parts first and then prep them before painting. They provide the following two products - Marine clean to degrease, and Metal prep.
I made up a solution of 1 part Marine clean to 4 parts hot water and sprayed the entire block a couple of times. I then got the jet wash on it and rinsed off all the degreaser. I then used my compressor to air dry the entire block.
For good measure I decided to degrease the block a second time, followed by a rinse with the jet wash and dry with the air compressor.
Once I was happy that the block was degreased I moved on to the next stage which was to use the Por-15 Metal prep. This can be painted on and according to Por-15 it removes rust and provides a base for the paint to bind. You don't dilute this down - just paint it straight on to the block - it should only go on the parts you are painting and you have to keep the block wet with the product. So I gave the block a good painting with the metal prep and then every 10 minutes went over it again. After 30 minutes I rinsed the block again with the jet wash and dried it with the compressor. Once the block was prepped and dried, I decided to leave it to dry overnight just to be sure. I noticed when the block was dry a white residue where the metal prep had been - this is normal and can be painted over.
The next stage was to mask all the parts I did not want to paint. I used blue automotive masking tape which I got from Cromwell Tools. This was a really tricky job and took a couple of hours. I used a sharp craft knife to carefully trim the masking tape away.
I also discovered a video on youtube which showed a guy gently tapping on the masking tape with a hammer on the edges. I was a bit dubious about this as hitting a cast iron block with a metal hammer didn't seem like a good idea but I gave it a try on the bits that were difficult to cut and it worked really well. The trick is to use your finger to fold the masking tape over the edge, then very very gently tap lightly with the hammer on the edge and the tape will fall away.
The block was now ready to paint. As the Por-15 dries very quickly I decanted out what I needed into a plastic container and then resealed the tin. By the way, you need to mix the paint thoroughly before using.
The first cost seemed to go on well. I noticed that some of the raised bits like the casting number did not seem to cover well, the paint seemed to run off, but I thought I'd get this on the second coat.
Overall I was happy with the paint so far, but I could see that it would need a second coat. I left it a couple of hours and then applied a second coat. This went on okay but again the raised bits did not seem to take the paint.
In the end, I gave the block 4 coats of paint. To be honest, I was a bit disappointed with the Por-15 and wouldn't use it again. There are still some parts of the block where the paint hasn't covered well - all raised parts. But I'm probably just being too critical and once it's in the car with all the shiny bits on it will look fine.
A couple of other things to mention - mask off anything you don't want to get paint on. I didn't and the paint ran onto parts of the block where I didn't want it. I cleaned it up with paint stripper.
I also decided to paint the block with out the freeze plugs in. I then had to spend ages with a cotton bud and paint stripper cleaning the freeze plug holes to remove excess paint. I'd recommend masking these over.
Finally, as I mentioned, I'm not too impressed with Por-15 - next time I'd probably use a spray engine paint.
