Thought i would share my new project, I’ve been hand shaping a few spoons lately and want to mold them to save the effort, so i’m putting the effort into making a new plug and mold for a velo type flex spoon for myself.
Experience in molding large pieces is very little to none, i’ve molded lots of small parts and fins as well as fin bases, but nothing like this.
My goal within this is to not spend a lot of money along the way until it comes to building the actual spoon out of it, so here’s where i’m at so far, more to come as I go along…first is the plug build, then i’ll be sharing the mold build, then through the finished first spoon…so bear with me
picked up 3 2’x4’ sheets of EPS foam from the shipping store next door and traced my rocker template on it 12 times to get a 24" wide blank:
2) then added the last 1’ of the board on once those were glued together and shaped it out. 4" of nose rocker, last 3’ of the curve is dead flat, and a straight rail line linking it all together:
3) then I ate pizza:
4) Then 2 layers of 6oz glass and hotcoated:
5) Sanded out and applied 1 metric crap ton of bondo:
Then sanded off .9 metric tons of bondo, first with the grinder and 120 grit to knock off the bulk of the material, then moved to a block with 60 grit to even out everything and make sure its 100% flat and flowing. the blue paint is to mark out the finished rail line for level mounting to the flange.
This is a pretty cool project, the plug is looking good.When shaping the foam, what did you find you were using most: sanding pad, surform, planer, or what?
A comment... long time ago a neighbor had a '57 Chevy and tried to make a mold for a hood. I didn't see it, but he told me that although he made the mold, when he took the finished part off, it warped. I expect he used poly resin, which since it is not 100 percent reactive (contains a lot of solvent, which evaporates) and there were stresses induced from drying/shrinkage/evaporation. I think (now, thirty years later) that he might have been able to avoid warpage by using epoxy resin which is 100% reactive. Perhaps you will discover this.
There have been threads related to mold making on this forum, the search function will turn them up.
Interested to follow your progress. I made a spoon once, many moons ago, but only put on a little fin. One day out at Velzyland, I learned that fin was far too small as I drifted down the face... couldn't recover, proned out at the bottom, probably didn't make the wave. It could sideslip pretty good, though,and that was cool then. The wide tail and drift factor suggest why GG put large fins on his.
I think it's "Kensurf" who had much commercial experience with molds. He noted that one of the problems is joining the two halves structurally/effectively.
Very cool - have a big EPS blank sitting in the cellar now for a similar project, though I'm thinking about details and such. Thinking an oversized male mold ( not necessarily spoon-nosed) , bandsaw the laminate to outline shape, vac on urethane or other foam sheet stuff ( or even balsa-core sheet material) and vac on deck/top laminations.
If you were to do it all over again, would you think about using a different foam and poly resin rather than EPS/epoxy?? Maybe a colored/dyed glue so you'd have ...well, indicator lines to help keep the shape symmetrical?
Keep up the good work, looking forward to seeing more... all suggestions you might have for my little project ( next winter probably) are very welcome.
if i did it over again and wasn’t so intent on building it NOW, i’d use Poly everything just to speed things up and use UV resin; i used epoxy for the first lam layer then UV poly for the second layer of 6oz to speed it up, i dont have lots of epoxy around…
the shape i wasn’t so worried about, ive shaped a few of them and shape lots and lots of hulls pretty much daily so it’s a shape that I know and am confident in.
Next i have to put up the flange build photos, which was easy…then i’m gonna hotcoat the whole thing all nice like and mold off of that; i’m not gonna do the whole primer paint thing, just use a really good layer of mold release, i don’t really care if i destroy the plug in the process as long as the mold come out nicely
used lots of planer, then 39 grit block and not much screening because it woulnd’t cut the gorilla glue lines…flattest result came from the block sanding but i did 90% of it with the planer!
I think it's "Kensurf" who had much commercial experience with molds. He noted that one of the problems is joining the two halves structurally/effectively.
mounted 'er to the flange-thingy, then filled the edge up with bondo and sanded it back into a nice wee radius because there is little i get more frustrated with than pulling plugs out of molds:
Plug mounted to plywood, reinforced and straightened with 2x4’s and the gloss and polished slightly.
will be using partall as the release between the plug and mold later this week!
the only major problem so far was that the plug was glassed lightly, and grew a little sink hole around the tail area where it flattens off, so i had to route out the
back of the plug’s plywood brace and push it back out with super thin EPS foam scraps…worked like a charm!
the plug was hotcoated and polished out from 320, i don’t care too much about gloss finishes on this project because i used Partall film for the release agent (painted on) and that stuff doesn’t lay down 100% perfectly anyways.
I layed the mold up after 2 layers of Partall, my schedule went:
1 black hotcoat
1 clear hotcoat
3 layers of 3/4oz mat
1 layer of 24oz roving
The back was braced with some wood bits…
after she cured I drilled 3 holes in the bottom of the mold to relieve some air suction problems with spoon shapes. they came apart like butter once I started prying…
This tuned out great, it’s been a long time since I’ve seen someone do this. This is going to start a regular 'ol prayer session and bring out the kneelers.
I didn’t take any photos of the first half of the layup, but I shot 6 layers of 6oz pretty quickly; then destroyed the old plug and built a dam for within the board to contain rails…then, the best part…the (black pigmented) Pour Foam:
I’m so excited to have this project underway/done and fully useable at any time for the future…i’ll be doing another in the next week or so and I’ve definitely learned a lot from
