Bad bog, Bogging, Bogging Port hulls

Bad Bog Off But Still Need Sanding

Posted by Paul

Ok, do you want the good news or the bad news? I have removed all the suspect bog from the hull using a chisel. And in all it only took 15 hours. That’s the good news. I am 5 hours ahead of forecast for the job. Now the bad news. I sanded a 1 meter section of hull at the bow and it took nearly half an hour to fully remove the remnants of bog. And I have another 15 meters of hull to do. (4 meters of hull has good bog, leaving 8 meters each side = 16 meters) so at this rate instead of 3-4 hours sanding I am looking at 7-8 hours of sanding. The stuff doesn’t sand off the way hard bog does, it kind of rolls up into tiny balls before the sander is able to remove them. Maybe it will be like the chiseling (and most other jobs) in that I get faster at it as I go. It is difficult to rush or push harder as it is very important not to damage the glass so care and accuracy is much more important than speed on this.

Anyway, however long it takes in hours, I will have the hull sanded back by Sunday (I could do it all by Friday night hopefully) and we plan to resin coat the hull Monday morning and bog Monday afternoon while the resin is still green. Even if I do manage to finish sanding on Friday we are unlikely to bring the resin and bogging forward in our planning as we have a family bbq Sunday afternoon before we all head off to “monster trucks” at Gosford show grounds. If this weekend all goes to plan then I will have lost exactly 2 weeks by this little interlude. Not so bad.

box of boghull showing bog removed

And there may be a silver lining. I removed 7kgs of bog by chisel! You can see it all in the picture of it in the box. Jacob, Jo’s youngest son helped by sweeping it all up and putting it in this box for me. And with the sanding to get the rest off, the tape lines are much fairer than they were so the new layer of bog should be thinner to get the same smooth result and therefore less sanding will be needed and will use less bog second time around.

Here is a before and after of what the hull needs to look like before I can be confident that the bond between the new layer of resin has bonded well to the now keyed (sanded rough) resin of the original glassing. If I leave too much bad bog on it can weaken this bond because it has no strength to hold the 2 layers together. If it is almost all gone then the 2 layers of resin will bond to each other and completely surround and even soak through the miniscule amounts of soft bog left.

bog remnants still onbog sanded off

I am still waiting on the rest of the parts needed to get the super sucker working and as a result I am banned from sanding the good bog back until it is going. The sanding of the bad bog does not create much dust so I can get away with that. It kind of balls up and drops off. The resin being sanded creates a little dust but manageable.

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