white undercoat spray, before and after slight wet sanding !
Packing tape covering
ClaudioD
Today was time for AZUR HULL lamination directly over the packing tape surface!!
3 layers of glass/epoxy of 105g/m² twill type.
ClaudioD
Hi Claudio
Why did you use peel ply? Does it help fill the weave?
Don
Hi Don,
since de rugosity of the glass is there, it is sure that I will use some paint undercoat, as did it yesterday, or polyester filler.
Decision for tomorrow !
The peelply is used just to remove the excess of resin, if any.
Cheers
ClaudioD
The HULL is ready out of the mould.
Started the 3 of August and demoulded th 11 of August
Weight 278g - was expected 245g, probably to much resin during lamination . Hull surface 38.01 dm²
therefore the excess of weight is less then 1g/dm².
Decision taken : to use white paint under coat as sanding tracer.
Non problems , since the sanding will arrange all that !
Next step will concentrate on the negative shadows drawing to be used as support during various assembly operations.
ClaudioD
Hi Claudio, well and good ! wen will be come the deck and fittings ? thanks, GINO ITA95
Hi Gino,
Actually the main part of my tread was dedicated to demonstrate, step by step, the use of a cheap material as the polystyrene foam.
The AZUR hull is ready in spite of some unexpected dimensional problems with the polystyrene bloc’s preparation.
The forthcoming activity will be rather normal.
The deck, I hope, will be wood strips within two glass layers , weight permitting.
Fitting are the classic ones used on M class.
Actually I’m in standby before starting sanding again, since I’m preparing the negative shadows necessary for the assembly support
.
Cheers
ClaudioD
the negative shadows are printed and glued, ready to start cutting !
Support ready with aligment.
Hull , 3 hours to make it smooth ! btw a lot of gramms came out, I believe some additional inner layers of 50g/m² or 1 layer of hybrid carbon/kevlar of 60g/m² will be considered !!!
Several spot checks show that the lamination tickness is actually of 0.30/0.33mm.
ClaudioD
Beam clamp bonding .
ClaudioD
preparing the Transom template, not easy to make it with a flexxible lamination !
ClaudioD
Before starting any bonding, I put back in the hull the shadows forms left from the negative cutting. It happen that the band saw thickness is very close to the hull skin thickness therefore all the shadows can be positioned almost at the original place.
I done that in order to check the hull form and alignment. It is much easier to check these aspects when the female mould is available.
The use of the “negative” support will help to ensure that the hull is not twisted from bow to transom during bondings.
ClaudioD
PS :
Some shortages made by my son while I was laminating :
http://youtu.be/i1_FmCgx2Ok
In this one the tissue weight was 49.32g therefore the resin was supposed to be of similar weight.
Preparing the mix, I put 36.89g of resin and added 55% of hardener , as specified by the manufacturer. Finally the total weight came up to 58.55g instead of 57.17g according to balance measurement.
Continuing lamination of the third layer :
http://youtu.be/nc0gYixGuBo
and finishing :
Supposing that there was an excess of resin I decided to use the remedy ! The peel- ply is an absorbing tissue very effective ! The one I use is a roll strip 5cm wide
After lamination I have applied several strips of peel-ply as visibles in this picture : http://www.rcsailing.net/forum1/attachment.php?attachmentid=8784&d=1312974162 already presented earlier n°45
ClaudioD
ClaudioD,
A suggestion: Try using a 3" wide foam paint roller, for applying the epoxy. It goes on much quicker, and evenly.
Just mix up your epoxy as normal. Then pour it out on plastic picnic plate (paper plates will work, but it absorbs the epoxy, don’t use waxed paper plates though, the wax messes with the epoxy), then load up the foam roller (just like painting a house). The first coat load the roller “heavy” so it will saturate the cloth quickly. You will quickly realize how to roll it on so you don’t disturb the cloth.
The beauty of this is that you get nice thin even coats of epoxy with no runs or drips. Depending on the brand of epoxy you apply the subsequent coats before the previous coat fully cures (most epoxies say when it is tacky like tape you can apply the next coat). You quit applying epoxy when you can no longer see the fabric weave. Thinner but more coats of epoxy are better then one or two thick coats.
Hi Guzz,
I’m use to my method and I 'm very satisfied with. One day may happen to use a roller, but I’m afraid to loose control of ratio 50/50 .
To much resin could be wasted including the one left in the bin.
When you wait too long for the subsequent layers, the previous resin will not impregnate the second layer.
Instead if you apply in the row the second and third layers, the fresh resin already present in the first layer will start wetting the other layers and only few additional resin will be nessarry to impregnate the full assembly without wasting resin or put too much on it.
The peelply will do the rest, to note that it will stay on the lamination only for about one hour when it become visible that the peelply has saturated.
Thank you anyhow for the advice.
Cheers
ClaudioD
I’m thinking to include and bond polystyrene ribbons inside the hull and cover them with glass - epoxy to obtain a strong sandwich.
The actual weight of the hull with deck-line strips and transom reinforcement is of 248g, raising from the 209g after sanding operation.
The polystyrene ribbons are about 32g .
Filling up the hull with water, the measured displacement is 4120g against the 3980g as design. The hull is therefore a little larger, probably because I did 'nt sand the master sufficietly. According to my calculations there is 0.37mm in excess. bof !!
This encourage me to go for the sandwich, probably covering partially the hull with polystyrene where there are more efforts !!
ClaudioD
PS : decision taken ! polystyrene ribbons are under epoxy bonding process.
The central part is doubled with 105g/m² glass before polystirene bonding, similarly the foward part where the jib attachment will be.
The game so far is costing 94g.
Is time for me to pull some conclusions :
The measured inner Displacement is 140g larger then designed , and this is due to the direct lamination onto the the master mould.
The final displacement will be 3979 g + 140 g = 4545 g ready to sail .
The calculated budget is 4455 g including the Bulb of 3150 g, giving thus a margin of 90 g.
According to the Water Plan any mm of variation close to the water line, corresponds to 137g.
For the future I will choose a female mould to avoid long sanding of the master.
For the lamination I will choose 2 layers of 105g/m² with a layer of plystyrene of 1.5mm thick in bewteen. This sandwich assembly will provide a very rigid and strong hull.
In the drawing above I set the rudder stock and the fin box positions including the mast steps composed of 3 carbon tubes, the fairlead position and the jib attachments and the servos positions with the sheeting circuit as well.
I will stop here for a while, in order to recover the polystyrene master in view of a female mould fabrication.
This tread remains a very valid solution for economic aspects in spite of more sanding.
Based upon the actual experience, I would suggest for a new direct lamination : 3 layers of 80 g/m² + 1 layer of 50/60 g/m², knowing that the last layer will be removed by the sanding operation. Polystirene ribbons not considered here.
Cheers
ClaudioD
Hallo everyone, does anybody knows if I can find the AZUR-V full size drawings? Thank you.
Hi Sotiris
Scale 1:1 drawing I never made it, unless you want Corel draw original and then scale it with a printer, but I can offer now the attachment in PDF
ClaudioD
sotiris
IF you are state side. I can print the pdf to full size on a plotter. and ship them to you. but generally if you go to any office supply/printing store, they can also print the PDF full size.
since the drawing has a scale and measurement points, you can ensure it is full size before you pay for the printing…
Marc
Dear Claudio,
Thank you very much for your immediate reply and the drawings.
I will try to scale it and print it so as to start and building it. Will be back with some pictures hopefully, as soon as possible.