Sunday, June 24, 2007

Sanding and more sanding, inside and out!

aChris and Tyler have gotten the hull sanded down to the final two layers of old bottom paint. They are taking care and are going down through the layers slowly. They alone have done the boat from the waterline down and have been staying with the project and are doing a great job. THANKS GUYS!! They have kept me motivated and on task on the interior while they sanded the hull. I used a Dewalt 60 grit Zirconia Flap Disc in a 4" electric grinder and sanded down the old tabbing on the interior. The flap sander made it a simple task although it did make for a lot of fiberglass dust. I'm starting from the bow and working my way aft.
I used an air DA with 180 grit disks to sand the gelcoat in the chain locker. It made a lot of fine and heavy dust that drifted down the hull and gathered in the V of the bow. I stopped often to vacuum it up. The dust clogged the filter of the shop vac very quickly. I had to stop and clean the filter more frequently than I would have liked. The gelcoat dust on the filter was so evenly dispersed it resembled frosting on a cake and formed a layer 1/4" thick rendering the vacuum useless after only a couple minutes use. I wanted to reinforce the hull-deck joint from the inside with West system epoxy and biaxial cloth. To do this it required the removal of the gelcoat and a good scuffing-up of the glass that was not gelcoated. The area is hard to get up into with power tools. I tried a variety of tools without success, they were too big or chucked at the wrong angle to allow the bit to get into the small space. I purchased a 120 degree die grinder and tried a variety of accessories (pictured above) to get into the space. The large wheels (upper left) where too much for the die grinder and immediately stalled it out. The die grinder would operate with light pressure with the medium sized flap wheel (lower left) but the pressure was not sufficient to get the desired results. The wire wheels (lower right) worked very well but tended to cut groves along the edges of their diameter. I finally settled on a one inch diameter flap wheel (pictures in the die grinder); it worked very well, was easy to control, and wore itself into the shape of the area I was sanding which made it easier to control.

We have been using 3M respirators with particulate cartridges when we sand (pictured above) and change the cartridge type when we use resins etc. We wear Tyvek overalls with hoods and buy the XXXXL size. Even the skinniest guys on our crew prefer the largest size. Yes, they are baggy when worn in the warm season (without coats on). But they allow for a lot of air movement inside the suit to help keep you cool and we rarely tear the crotch out of them when bending or stretching into awkward places (an all to often occurrence with the smaller sizes). Head socks and rubber gloves complete the ensemble.


Anonymous said...

Dear Diary... errr... cousin Don,

congrats on the purchase of another fine project... i remember the fishing boat project years ago.

Good luck, happy sanding, etc.


Your cuz, Bruce.

Don said...

Thanks Bruce, Its gonna be a while before this on gets splashed!

Ariel, CD 36 said...

You can buy dust bags for shop vacs that filter the fine grinding dust pretty well. They sure save the cylindrical filters and the headache of repeatedly cleaning them.

Don said...

Thanks David, I'll look into them.