Day 334 Flo Blasting hull
The fun and frolic of sandblasting is upon us once again! We had to rent a compressor again as the parts for ours still haven't arrived yet. I'm one notch away from designing my own ignition system believe me! ( I already have a working prototype involving a hall effect IC and a couple of amps, but I accidentally fried the coil....ooops! One more thing to buy.) By the time we get the thing running again, it will be time to sell it!
The whole sandblasting thing is rather boring to write about, but there are a few pointers I can share.

We have been reusing sand as it would take 100 bags instead of 20 if we didn't. Laying out large tarps around the area greatly eases this task. As Gena does all of the blasting, my job is to run around scooping and sifting sand to recycle. I can just keep up with the rate she uses it at.

Gena mentioned that the reused sand actually cuts better than the new stuff. Go figure. The pattern may be somewhat important but it differs very little from new to used sand.

 

 

  
Using a smaller blasting tip is better because the sand still has good speed when it comes out. With a much higher throughput, the big tips would be good and fast, but our pot is only good to 160 psi and only so much air can come down the feed hose at that pressure. If you want a faster blast experience, use a higher psi pot. The compressor of course will need to be much larger as well.

The finish should be a near white according to the coating manufacturer. Looks Like Gena got that down!

 

 
 

Enhanced image of blow through
Different colors result from areas where the steel was heated or welded and any imperfections in the steel show up nicely.

Lucky this is the case as 2 small punctures under the hull cooling plate showed up. The image above is enhanced for better clarity. This was from the plasma cutter when the hull cooling system was being installed. Some of it had to be cut out and re-welded inside. Above these holes is a solid weld ( indicated by the "shadow" ) but it's a potential corrosion hazard so must be filled in.

A careful weld will fix it.

Me siftin'. Just keeping up with Gena!		  All of that "grout" was removed (as shown in video )as it would have taken days to remove it. We have a different filler that's bit easier to remove with sandpaper.
 After the sandblasting is complete we will "wash" the steel as before on the deck, then give the bottom a coat.

 

 		  The paint we have was intended for the sides but with masking time and what remains to be sandblasted, there won't be enough time this weekend to do that.

Rather than let moisture cause rust and require a sweep blast ( about half the time of actual mill scale removal ) we have decided to just get a coat on there for protection.

Some of the welds along under the water line will still need smoothing.
 

 

 

Day 334:
14 hours : Sandblasted hull


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