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PostPosted: Tue Dec 04, 2012 11:28 pm 
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Those who had read that I have been fighting with depression for the past 18 months might be interested to know that I have found that carving new body parts from PVC foam blocks with a rasp to be quite an enjoyable process even some what therapeutic. I now have two problems though one I have a work space full of flammable shavings that is in every nook and cranny of the shop and two it's not done the Arthur in my elbows any good at all. Who knows if I can find a cheaper brand of body filler you might be seeing a few designs coming from me......well funding and interest of future purchase permitting of course.

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PostPosted: Wed Dec 05, 2012 7:30 am 
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Those who had read that I have been fighting with depression for the past 18 months might be interested to know that I have found that carving new body parts from PVC foam blocks with a rasp to be quite an enjoyable process even some what therapeutic. I now have two problems though one I have a work space full of flammable shavings that is in every nook and cranny of the shop and two it's not done the Arthur in my elbows any good at all. Who knows if I can find a cheaper brand of body filler you might be seeing a few designs coming from me......well funding and interest of future purchase permitting of course.
What? prosthetics or kidneys and stuff like that :shock: :twisted:

Bob :)


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PostPosted: Wed Dec 05, 2012 7:37 am 
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Those who had read that I have been fighting with depression for the past 18 months might be interested to know that I have found that carving new body parts from PVC foam blocks with a rasp to be quite an enjoyable process even some what therapeutic. I now have two problems though one I have a work space full of flammable shavings that is in every nook and cranny of the shop and two it's not done the Arthur in my elbows any good at all. Who knows if I can find a cheaper brand of body filler you might be seeing a few designs coming from me......well funding and interest of future purchase permitting of course.
What? prosthetics or kidneys and stuff like that :shock: :twisted:

Bob :)

Kidneys please phil :-)

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PostPosted: Wed Dec 05, 2012 8:20 am 
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Eveyone should have a nickname so your new one will be frankestien phil :twisted: :twisted:

Bob :D


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PostPosted: Wed Dec 05, 2012 9:02 am 
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I have found that carving new body parts from PVC foam blocks with a rasp to be quite an enjoyable process..... Who knows if I can find a cheaper brand of body filler you might be seeing a few designs coming from me......
PVC I assume you mean polystyrene? Those are horrible to use since its "beads" crumbles off when shaped and messing up the whole place.

Im working with GRP almost daily (boats etc) and found the easiest and simplest way to build plugs are to use two part close cell rigid expansion PU (polyurethane foam) to work from. The density foam I use is 38kg/m3.
For smaller plugs I build a cheap wood box to approx size slightly larger than the part needed. Line box with old news paper, mix foam and pour into box. After a few minutes the foam is cured and removed and then start shaping the foam to what ever size or form you need - just need a rasp to get throught the paper and then use a piece of foam to shape it with.
When to have a large part - foam expensive to waste - build the box as mentioned above and have enough empty sealed plastic bottles at hand. Mix and pour some/little foam into box and let it expand till started to firm up, add the bottles and mix and pour enough foam to cover bottles and fills box. Proceed as described above. Usually these types of foams expands 20 - 25 times their volume and easy to calculate how much to use and scale whats needed.

When the part is formed out of the foam, spread with laminating resin and laminate a 450g/csm over the whole area to give a firm base to apply fairing compound. The filler I use I make myself by using "grp Micro balloons" mixed with resin until a paste with the viscosity of tooth paste. This is very light and easy to sand down - I use "AbraMat aluminum oxide strips #80 grit to rough down the filler. Mix enough filler with hardener and apply with scarper and need some pressure for the filler to stick to the glassed plug for initial layer and thereafter it goes on like a feather.
When you are basically done with the shape, final smaller dents and marks can be fixed with normal body filler. When the plug is finished and you happy with result after smoothing with wet/dry sand paper, spray with a two pack primer (filler) and the type I use in South Africa is called MS primer and yellow cream in colour. After that cured, sand down with #1500 - #2000 grit wet until perfect. Polish to high sheen using ram wax (avoid silicon based polishes and waxes like the plaque because the mold will then stick to the plug)
Take off the mold.

If you are aware of what I tried to explained, sorry old chap, but perhaps this ramble can be useful to someone else not in the know. :)


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PostPosted: Wed Dec 05, 2012 10:02 am 
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So far I have only made a bonnet power/bulge for my currently featureless body work it looks a bit like a Dax Rush vent so nice and meaty. What I'm currently using is sheets of pink high density Styrofoam I did a test piece and the resin melted the surface of it so I sealed it with with PVA, then fine surface filler and sand to finish. The two part expanding foam, can you laminate straight over it or do you need to use the right foam with the correct resin, is it polyurethane expanding foam and polyester resin? When I did this stuff at collage every thing was provided I did'nt take much notice of what it said on the tins, so after a 12 year break I'm trying to remember how it's done.

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Last edited by Talon-Phil on Wed Dec 05, 2012 10:15 am, edited 1 time in total.

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PostPosted: Wed Dec 05, 2012 10:10 am 
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The two part PU foam I used goes by the local name of RX121 and 44V20 fwiw. It is more commonly used as buoyancy in boats.

As said Talon, I just spread some normal GP laminating resin directly on the foam and whilst wet, lay down the CSM directly on the foam. GP resin does not attack polyurethane foam. You should be able to buy PU foam in sheets of any thickness as we do here and that simplifies things a bit getting bigger as it can be "build" in a form held together with string.


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PostPosted: Wed Dec 05, 2012 10:21 am 
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Ah that's the problem then I've used the wrong foam as a base.

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PostPosted: Wed Dec 05, 2012 10:34 am 
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Hi Phil

This is the type of foam that Wynand uses.

http://www.cfsnet.co.uk/acatalog/CFS_Ca ... d_415.html


If you only need to do a small part, expanding builders foam should do the trick ( The stuff used for filling gaps around window & door frames )
My local el cheapo hardware store sells tins of that at a reasonable price.

There is some great info on the CFS web site :)

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PostPosted: Wed Dec 05, 2012 11:50 am 
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Talon, I take this liberty to post some pics showing how I used PU foam to made the nosecone. The flange on the nosecone is because it is a split mold and the smaller part is actually the bonnet recess lip and need to split to get molding out of the mold. Just ask if you want more info or pics showing different issues.
Hope this helps :)

Shaped foam plug - needs to be faired hence the need fo glassing to firm it up
Image

CSM applied to foam plug - wet foam first before laying on the mat.
Image

Plug completed and faired with filler described and ready for spray filler paint for final finishing
Image

Plug sprayed and finished, polished and pva mold release getting applied over the polished ram wax just to be sure of a release...
Image

Gelcoat of the mold getting applied to the plug
Image

Finished mold and flange just released with water from plug, hence the dirt on it.
Image


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