Polishing SP SPG plastic face?

[HenrikBP]

Finally got around to trying a few things to buff out the worst scratches. It ended up being surprisingly easy once I got started:

- hand sanded the face using progressively finer wet sand paper; 320 grit to 600 grit. This left the face with a slightly hazed finish - which got me thinking ...

- in the garage I found 3M Perfect-It Swirl Mark Remover for Dark colors. Using a soft, lint-free rag (old t-shirt) I buffed the SPG face, and except for some very shallow swirl marks (invisible unless you catch the light just right), the face is now as good as new.

- In retrospect I could have spent a bit more time with the 600 grit paper and possibly gotten rid of those last swirl marks. But in reality it doesn't matter one bit

Thanks again for all your suggestions. Now I just need to find new gaskets to seal the face in the case.

Henrik

 

[gypsyjim]

Always more than one way to skin the cat. (rumor has it cats don't like any of them though)

Glad things worked out.

 

[HenrikBP]

AWAP; do you by chance remember what size oring you used as replacement for these SP SPGs?

From measuring and guesstimating, it looks like size dash 031 ought to work, but I'd appreciate recommendations.

Thanks

Henrik

 

[redacted]

AWAP; do you by chance remember what size oring you used as replacement for these SP SPGs?

From measuring and guesstimating, it looks like size dash 031 ought to work, but I'd appreciate recommendations.

Thanks

Henrik

Questions like that are going to make me organize my notes some day. I used an 032 in my 2" SP SPG and it is working fine.

 

[HenrikBP]

Questions like that are going to make me organize my notes some day.

I know the feeling ...

Thanks

Henrik

 

[spoolin01]

Finally got around to trying a few things to buff out the worst scratches. It ended up being surprisingly easy once I got started:

I'm too lazy and the shoulders too old for hand polishing, but I've done this many times with a bench grinder fitted with a soft buffing wheel. It's not hard to keep from melting the plastic - use a soft wheel, only the white or red rouge, not the coarser stuff, and don't press hard or long. Takes about 10 seconds and it's glassy polished. Deeper scratches can be worked out with a little longer effort. It's a periodic ritual with gauges and flashlight lenses. A wheel on a Dremel works for tight spaces. I'd think 320 was too coarse for light scratches, and too 'broad swath' for single deep ones. You can focus the effort pretty well with a firmer buffing wheel. I cleaned up a pencil-smudged plastic dive slate a couple weeks back - the softer plastic was harder to work with but manageable. This is one of the cases where the cat can almost skin itself...

 

[HenrikBP]

Spoolin; thanks for the ideas. The hand sanding was really *much* easier than I thought. 320 was a tad coarse, but the 3M compound did a good job on it. One step finer would have been better though.

You're right about it cutting a wide swath. The lens was pretty bad to begin with so most of it benefitted from the work. But it'd be tricky to just buff out a single scratch.

Henrik