Hi Row, Claudio’s brilliant work with the distribution of hull volumes on these different three plans has me intrigued too & could not choose between them hence reason for building all three.
Took pic today after trimming off laminating FBG to give better understanding of the different hull profiles
Reckon we have your rain here today as snow our washed away.
Sorry to hear about the finance directors woe’s especailly this time of the year & wish you & your family the very best for Christmas, with accumlating brownie points, you will be happy camper getting some time on your wonderful project in the new year.
“Density” :scared: sensitive subject right now, Claudio & anyone following the IACC 120 rules subject knows what I’m talking about, but I guess you’re meaning the construction process so far.
On two hulls I’ve used 3 x 5 mm balsa for planking took approx 15 hrs per hull, I ran out of balsa at one stage and steamed formed 3 x 50 mm sheets on the Le Defi mould, only took 4-5 hours.
Next, applied 2 libel coats of epoxy inside the moulds to prevent the balsa deflecting between 98.5 mm spaced shadows, when sanding later.
Then applied light weight model filler used on the hulls with many hours sanding and checking the hull form under shadow lights (to see any deformations or hollows) and checking hull dimensions using the cradle shadows that I’d cut earlier.
Warmed the moulds up so they were hot to touch and then hand laid-up one layer of 80 gsm twill FBG on each hull, as balsa cools down the epoxy gets sucked in the balsa to the point that it looks like the FBG is becoming starved of epoxy. If you have close look at the photo posted above you can see there is no flooding (glossy effect from epoxy) on the lamination surface, in my humble opinion this is wasted sanding time later.
Next steps, will fair the laminated moulds again with light weight model filler (exposed FBG weave acts like grip for the filler) and the do the final sanding and using tracer paint to check for hollows again until the mould is perfectly smooth. (1-2 hours work)
I will be following Claudio’s making a female mould closely (I have never done it before) as I’m thinking I may try this option because of the large area of graphics on the NZL-20 hull that will possibly disturb laminar flow. Thinking to have NZL-20 graphics made in reverse, apply them onto the male mould so they impregnate the graphics into female mould, then I would have perfectly flat hull surface after applying final graphics on the finished hull.
For the other two hulls, I will simply wrap the moulds in very thin packing tape (mould release) then laminate the hulls using latex for final product.
I don’t visualize you reverse graphic thing though. Applying the graphics onto the male mould will make bumps that will carve in the female mould… and bumps on the final hull. Applying the graphics then will double the urbulance!? Unless I am not following you correctly, which is probably the case since there is no need to reverse the graphics with my description.
Thanks for asking about my project. I have unfortunately not much to report as you could have tell from my none growing thread. I did reorganized my workshop, partly because it was an uninspiring mess, partly because I had to fit out a proper (wider) work surface. I have also supplied it with all the basic material for the hull. Oh, and also… I am not doing the ETNZ NZL-92 anymore. The weekend I was about to glue my paper template on the hardwood, Claudio came out with yet another of his effervescent idea, the NZL-20. I was seduced at first sight by its line. Somehow it looks more like my conceptualization of a sailboat. Later narrow and square AC 1:1 designs may have proven to be faster, they seem to deviate from the imagery of my youth. I was again about to glue my paper template on the hardwood when “THE” mythical Black Magic came out. Darn!!!
My “life” is not so complicated in though. Either of the three will suit my needs and my aspiration. This starting line stop/stuck is due to the fact that we had a rough time in the past three months at home and I didn’t had the chance to really tackle the project. Nothing serious thankfully, just a never ending series of cold/flue/gastro/sinusitis for the four of us. So playing with the drawings in the silence of some baby watch nights kinda compensates my appetite for this hobby. Well, I am trying to convince myself here since I can’t wait to begin :mad:
You may hold my final choice in your hands if I cannot begin the construction before you conduct your tests between the three designs. As a mechanical engineer, I am excited about the results. But if things settle down sooner, I’ll be a good boy and choose my NLZ by myself.
You are 100% right Sylvian my left brain short-circuit my right brain, but I do need to reverse the graphics on female mould, Claudio must have been laughing like hell when he read it, …it is the 2nd time I got this ass about face :lol:
Thanks Alan …time-out for a holiday !
P.S BM 1995 has some very magical elements in it’s design that Claudio spent very long time reading actual boats tank tests done in Holland …but then Le Defi has lower wetted surface & NZL-20 well what can I say, I’m a Kiwi so have to build all three and absolutely intrigued to how these compare with later the V 5.0 yacht designs.
Very many thanks for all of your advice and direction in the last year. Who knows ? I may even have something complete & sailing in 2012… - Am actually aiming for June at the latest, as that’s when the real ‘J’s’, old and new will be racing just down the road from me.
Once again, Christmas greetings & wishing you the very best for the coming new year.
The transparent gelcoat arrived and test made by adding the cadmimium powder .
The mix was left for 12h rest.
Added hardener and brushed on piece og glass put in vertical position to check the thixotropic performance.
Small dropping effect, probably a small quantity of silica will help but really not necessary !
2 hours later started the lamination with 2x50g/m² + 2x 80g/m².
24hours at 22°C + 4hours at 55°C.
The weight is 235mm x 103mm is 24.70g close to 10g/dm² but also too strong !!
Next trial with 2x50g/m² + 1x80g/m² with the CD65 female mold !
Average gelcoat thickness 0.30mm. Next will be with two layers of gelcoat at 1.5 hour interval.
Ok I’m back from holidays and with few days left before back to work have taken the laminated moulds & faired them again then sanded to final finish using the cradle frames as double check for hull shape.
Next sprayed the moulds with primer and 600 grit sanding ready for wrapping them with thin packing tape that will be the release surface for hull laminations. Just one point using packing tape I found that you can re-lift the tape once applied to the hull however, after 1 hour or so if want to lift the tape the film will de-laminate from the adhesive and you need light solvent to get the adhesive off the hull surface.:scared:
Takes approx 1 hour to tape each hull carefully while avoiding trapping air underneath the tape. Ordered the latex and when arrives will start with hull laminations.
Yesterday I wandered into building supply shop to snoop around and came across furnace mortar used for patching up fire places hmmm only 5 Euro for 5 Kg bag and states that it is good to use up to 1400 degree’s C … perfect !
Back home made up split mould box using old bulb as shape, the idea is to mould two halves and bolt them together to pour one piece lead bulbs.
After making up a moulding box waxed inside of the mould (stop moisture absorption into wooden box) cut out small piece of chicken fencing wire to use as reinforcement in the mortar then mixed up the mortar with water and poured it into the mould, goes off pretty quickly and then left over night to start drying.
This morning popped the mould and perfectly smooth and very hard surface finish, tech sheet says it needs few days to completely dry and then slowly pre-heat mould before finally using it at temperature. (Lead only needs 350 C to melt)
Given the smooth and hard finish of furnace mortar I’m thinking of possibly making a mould off a carbon keel & rudder fin to see how it turns out, beats having CNC mould made, quick, easy & cheap…hmmm maybe idea to use it for female hull mould also :rolleyes:?
Hi Alan
I just tried refractory cement for a bulb mould. The lead glued the two halves of the mold together so well that I had to smash the mould to get it apart. Mine had dried for a month or more and it still bubbled and popped. I have a small bald spot to show for it. Now, my mould may have been different material than yours because mine didn’t turn out that smooth. The cement had lots of grog in it. Anyway, maybe some kind of release agent(I’ve heard of useing lamp black or graphite. Never tried it.) may be prudent and make sure it’s dry.The mould I’m curing right now is made of 66% plaster of paris and 34% portland cement. I’m drying it in front of the stove and after 4 or 5 days its still losing 100-120 grams of moisture a day. I’ll keep drying until the weight levels out. It’s hard to beleive that these things are losing that much moisture when they feel bone dry.
I’m wondering if this mixture of POP and Portland cement is what was refered to as “white cement” in a previous thread. The fin making thread I think. I mixed some 6mm chopped glass in with it. It is quite hard.
Anyway, good luck
Don
I’m not sure how this refractory cement will work, (mainly used for furnace facing) the mixture was rather fluffy that become gooey when mixed with water to working texture similar to stiff dough. The mould generated quite a bit of heat when drying, not sure of the composition but after 24 hours when I popped the mould it is stone hard with smooth surface.
After your comment about lead gluing to the surface of your refractory mix I can only think of using something like black carbon soot as a release anyway will not pouring until early summer anyway.
I’ve looked around for greensand but pretty hard to come by in these parts, it packs well into a mould and allows steam to easily escape out of the pores and pouring low-melting alloys into greensand is very safe!
Read somewhere that Portland/Sand (masonry mix) works well too, but please let us know how you go with Portland/Paris mix.
Hey Alan try using USED foundry sand for making lead bulbs. Locate a specialty (small) nearby and ask to by their used sand. Stuff should be cheap as they have to dispose of it after using it. good luck Barry
I have made two molds for fibre parts, the same way you have done with the bulb. I made a mould for the front piece, and some internal structure. The last one was to complex for my skills, I tried with 3 layers of carbon and peelply on both sides. (On the picture I have not finished removing the peelply, cut my finger on a carbon piece, so decided it was enough for the day:)). I might try to do it again, but with strips of carbon instead of one piece covering the whole part, it was to difficult for my skill, even with the vacuum bag.
For the moulds I used hobby plaster, i think it is normally used for sculptures etc. This leaves a very smooth surface. And if you wet sand it, using only very little water it becomes even better.
Hi Barry, sorry have been on bus travel but your idea of used foundry sand is a good one, my company has a foundry and tried to get some bulbs made there a while back but having “homers” done is a no no, so resorted to making them myself … If this mould does not work out I’ll need to slip 2-3 kgs of used sand in my breif case next time I’m at the foundry
Gidday, Anders glad to see you are back into it mate like your moulding of parts especially for silicon bumpers but wondering which other parts your moulding …bulkheads ? was the peel-ply necessary ?
A little update. My mold(s) has been drying now for about two weeks and the moisture drop is down to 5-10 grams per day. I have them sitting right in front of the fan of our natural gas stove where the temperature is
185f. The stove has been running about 33% of the time. I think this is about as fast as they would dry. I’ll wait for a week or so before I try casting.
Don
Decided to test the bulb moulds (made 3 weeks ago) in closed fire place slightly just above the fire base temperatures slightly below 900°C.
After two hours hair-line cracks appeared in moulds which was perfect as only need to heat them to around 350°C for lead pouring (in summer outside:rolleyes:)
Assuming that you’ll be casting one piece bulbs (clamping the 2 halves together?), you’ll need to be extremely careful pouring the molten lead because of the risk of air bubbles forming. It may pay you to create a pour hole at one end with a vent placed centrally (at point of max depth) with the molds horizontal. Although the resultant casting will have a little more finishing, better be safe than sorry…
If you’re planning to cast each half separately then ignore the above!
You are 100% right Sylvian my left brain short-circuit my right brain, but I do need to reverse the graphics on female mould, Claudio must have been laughing like hell when he read it, …it is the 2nd time I got this ass about face :lol:
anyway will not pouring until early summer anyway.