Monthly Archives: May 2015

Half the tub glassed. 

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4 layers of 450gsm, and whatever tooling resin Nord produce. I’ve almost finished now, but calculate I need about 3kg more resin than I have, so have stopped. It was a bummer because I had enough time to get totally done. Better order another 25kg   

It has a much lower styrene content than laminating resin as well, which is nice. I catalysed it at 1% and that was enough. For mixing 1kg the brush was just starting to drag as the pot was finishing. 

I expected a harsher exotherm though. But puzzled at that. I will post cure the mould though. 

  

First panel of the mould done

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 Not a lot to see really. 4 layers of 450 down. Rollered in with a bristle roller, and a heater in there on low to be sure the exotherm kicks in at these temps and 1% catalyst. 

This is the first time I’ve used mould making resin and it’s odd stuff. Very gloopy. It also dissolves the binder brilliantly. 

 

Dry stack weight

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This is a sample stock of the cloth I’m going to use in the final tub.i’ve waited now and I’m going to wait again after I have infused and peeled it out so that I can understand just how much redding it up salt. This stack is 200 mm X 200 mm Square. 

I will feed the approximate dye mentions of the top into my CAD package to get the square service area and then do some addy ups and divides which will tell me how much the stack ought to weigh. 

 

When PVA goes wrong

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When trying to overspray the PVA with a very dilute solution, we find it fish-eyes and no amount of brush-work puts it right. 

Peel it off, wash it off, and start again

 I could have gone for leaving the matte finish from the original PVA I laid down but then that would have negated all the benefits of using the really nice shiny plastic. Only option is to clean it all off and start again. If I was to go with a matte finish, it would mean lots of time spent polishing parts rather than letting the part material do the work for me.

   

PVA Partially applied, and a mistake, I think

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IMG_1647.JPGSo, here’s the tub, with a dust cover over the top. Great, thinks I – all is now ready for spraying. To be sure it’s ready, I have vacuumed it and cleaned it with a micro-pore cloth and panel-wipe.

 

 

 

 

 

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Now, I’ve started spraying the PVA. There’s still lots to do though – I want a nice thick heavy coat on. It’s a shiny finish PVA, but it’s not coming up as shiny as the original back on the poly board.

So, my potential problem is that I have left it a little tacky when I put the dust cover back on. It will, or it won’t stick. It is release film so I stand a chance. worst case is I get a sponge brush from East Coast Fibreglass, and they reckon you can get a good finish from that.

Needless to say, I can resurrect some of the finish imperfections here in the final part. The final part will have an outer layer of clear gel-coat which will take a bit of flatting and polishing if I need it to.