MapisM
Well-known member
Yes I was, but I see your point!
Hard Top for Blue Angel (Canados 70s)
- Thread starter BartW
- Start date
P4Paul
Active member
The headlines are England managed to win, London Irish managed to lose!
On the boat and working from bits of paper, the camera on the phone and a laptop about to run out of charge so I hope this works.
A quick scribble of my thoughts behind the complete moulding.
Moulding #1 on its own with metal incorporated in the sandwich to bolt the roof runners to.
Moulding #2 on its own with a secondary scribble to try and show that the ribs are integral. After uploading the photo I realised there are a couple of lines around the rib area that shouldn't be there but I am sure you can see beyond the drawing and get the concept.
I would keep bulk out of certain parts of #2 to allow it to be pulled around to help lock into #1.
The more I think about it I would ditch the foam and use coremat to bulk out and then assemble the two mouldings with a two part structural epoxy to end up with a double sided moulding. You just need to make sure there are small vents added into the ribs to allow any air to expand in the heat, I would line the cable runs with pipe stuffed with foam to help with chafe avoidance on the cables.
Apologies if anything isn't clear.
I just realised that I missed off the sail track for the sides, but you can see the area in the assembled moulding to allow that to be attached. I would probably stick a strip of aluminium in the sandwich along the edge to take the sail track fixings - in hindsight I think with a bit more playing around you could hide most of the sail track behind the trim panel.
As always, even now I can see little tweaks to help improve the cleanness of the end product.
Cheers
Paul.
On the boat and working from bits of paper, the camera on the phone and a laptop about to run out of charge so I hope this works.
A quick scribble of my thoughts behind the complete moulding.
Moulding #1 on its own with metal incorporated in the sandwich to bolt the roof runners to.
Moulding #2 on its own with a secondary scribble to try and show that the ribs are integral. After uploading the photo I realised there are a couple of lines around the rib area that shouldn't be there but I am sure you can see beyond the drawing and get the concept.
I would keep bulk out of certain parts of #2 to allow it to be pulled around to help lock into #1.
The more I think about it I would ditch the foam and use coremat to bulk out and then assemble the two mouldings with a two part structural epoxy to end up with a double sided moulding. You just need to make sure there are small vents added into the ribs to allow any air to expand in the heat, I would line the cable runs with pipe stuffed with foam to help with chafe avoidance on the cables.
Apologies if anything isn't clear.
I just realised that I missed off the sail track for the sides, but you can see the area in the assembled moulding to allow that to be attached. I would probably stick a strip of aluminium in the sandwich along the edge to take the sail track fixings - in hindsight I think with a bit more playing around you could hide most of the sail track behind the trim panel.
As always, even now I can see little tweaks to help improve the cleanness of the end product.
Cheers
Paul.
BartW
Well-known member
Thank yo so much Paul,
For your contribution to my project !
Good tip !
I’ll consider to do the same for the mounting pillars
The concept is very clear Paul,
Just one thing I don’t understand;
The moulding 2 goes also in the section above the trim panel,
So in that zone (right side of the drawing / assembly) imo we don’t need a moulding 2, moulding 2 can be half the size as in my drawing ?
The epoxy with mat- outside skin + core + epoxy with mat - inside skin can all be done in moulding 1, as the rough area is covered behind the trim panel.
I’ll make a new drawing
Don’t hesitate to give comments
Much apreaciated, thanks again…
For your contribution to my project !
Good tip !
I’ll consider to do the same for the mounting pillars
Exactly my thought, also for the trim panel, if that is Epoxy-ed in position it makes the assembly A LOT more stiff and strong
After uploading the photo I realised there are a couple of lines around the rib area that shouldn't be there but I am sure you can see beyond the drawing and get the concept.
….
Apologies if anything isn't clear.
The concept is very clear Paul,
Just one thing I don’t understand;
The moulding 2 goes also in the section above the trim panel,
So in that zone (right side of the drawing / assembly) imo we don’t need a moulding 2, moulding 2 can be half the size as in my drawing ?
The epoxy with mat- outside skin + core + epoxy with mat - inside skin can all be done in moulding 1, as the rough area is covered behind the trim panel.
I’ll make a new drawing
Don’t hesitate to give comments
Much apreaciated, thanks again…
BartW
Well-known member
interesting Idea Paul,
or 3D printing ?
I'm not sure if the size I need is available, but going to investigate this method
answering Vas and Mapism Q,
for smoothing the surface: decent 'filler' primer, and then spray painting ?
P4Paul
Active member
You are correct but taking moulding #2 above the trim panel means you can incorporate the ribs in moulding 2 and use the shape and structural epoxy to build up the strength and rigidity of moulding #1. You will also need some shape to help prevent the roof panting (sagging) between the forehead stainless legs and the aft shark fins.
rafiki_
Well-known member
The largest 3-D table I know of is 1mx0.8mx0.5m. These are used for making moulds for carbon parts. For BA hardtop, you would make a series of moulds, then stitch them together to make the complete mould. I think this route more expensive than the 5-axis cutter.
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BartW
Well-known member
I shurely will investigate the 5axis cutter P ! thanks !
do you have experience ? why not in wood, MDF or ... ?
BartW
Well-known member
ha, ha,
your idea brought me to a company at 10km from my office,
http://www.polyester-mineralcomposite.be/artwork
it seems that they are able to make this (they don't know yet ;-) )
would be good to discuss the mouldings and sequence of assembling etc.. with them,
thank you P, great stuff
rafiki_
Well-known member
I think it much cheaper and easier in polystyrene Bart. You can get blocks of this, and glue together to make the full mould.
I am on hols this week, so away from the office, back next Monday, so can ask the experts then, if you can wait that long? Sounds like you have a potential solution close to home though?
BartW
Well-known member
yes OK you're right about the Polysterene,
If we can involve the GRP manufacturer they will shurely give advice, or do the mould themselves, etc..
project is completely in between the regular job, so no hurry,
this weekend I'm on the boat, will try to take some detailed dimensions.
rafiki_
Well-known member
Great, I'm sure between the forum and your local guy, we can make this work��
BartW
Well-known member
BartW
Well-known member
a rough calculation (brother in law) tells me that a allum tube profile (as above) on 2 mounting points separated 4meter, with a weight in the middle of 100kg,
will bend 1cm, (chordal height)
but same size in GRP will bend double of that !
hmm, the bending / elasticity needs attention !
BartW
Well-known member
Paul I still don't understand this,
is it not more easy to:
place mould for moulding part nr 1 (upside down) on the work bench,
put in gelcoat and all that,
then firs layers of epoxy and glass mat
then coring material
then more layers of epoxy and glass,
then Ribs (coring material)
then layers of epoxy and glass over the ribs
then
bring the premade moulding part nr2 over the gutter (for smooth finish of gutter on underside)
and when all is dry,
glue the trim panel in position with epoxy glue
so that all becomes one piece
perhaps I'm wrong on this,
so don't hesitate to shoot
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P4Paul
Active member
I don't think you are wrong, I think we are both thinking the same things but actioning them in different ways. :encouragement:
Where you are using your trim panel as a structural part of the shape, in my sketch the trim panel was removable to allow cable access etc.
My old mentor drummed it into me that a customer never gets to see the raw (non gelcoat) side of a fibreglass moulding. It is what you don't see that makes all the difference between good and great!
BartW
Well-known member
I don't think you are wrong, I think we are both thinking the same things but actioning them in different ways. :encouragement:
Where you are using your trim panel as a structural part of the shape, in my sketch the trim panel was removable to allow cable access etc.
My old mentor drummed it into me that a customer never gets to see the raw (non gelcoat) side of a fibreglass moulding. It is what you don't see that makes all the difference between good and great!
all clear now,
I think if we sat together on a table all would be much more easy
I'll leave this so far, until we are talking with the Guy's who will do the grp work, and go on from there
thanks !
jfm
Well-known member
For a one off hand made item, I think two separate mouldings is a challenge, and unnecessary. Sure you can do it if you make plugs/moulds with a 5 axis cutter, but then you are into thousands of pounds because the equipment owner has got to amortise the £1m+ that the machine cost.
The luxury you have here Bart is that this is a one-time only mould, so you can have returns on the mould tool that you remove to get the finished product out - you can even smash the mould off because it is going in the trash anyway. This will help you keep only gelcoated surfaces visible. I would make the thing in a single one-piece mould, made in MDF, spray painted, with faceted compound curves, and then add a simple second trim moulding to hide the raw finish. Heavy brushed gelcoat would let you fix imperfections afterwards. Would cost just time, not big fees for getting the drawing CAD-ed and then renting time on a 5 axis cutter etc etc. Like this for the side sections:
The luxury you have here Bart is that this is a one-time only mould, so you can have returns on the mould tool that you remove to get the finished product out - you can even smash the mould off because it is going in the trash anyway. This will help you keep only gelcoated surfaces visible. I would make the thing in a single one-piece mould, made in MDF, spray painted, with faceted compound curves, and then add a simple second trim moulding to hide the raw finish. Heavy brushed gelcoat would let you fix imperfections afterwards. Would cost just time, not big fees for getting the drawing CAD-ed and then renting time on a 5 axis cutter etc etc. Like this for the side sections:
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BartW
Well-known member
Thanks John for the drawing,
Seems perfect as could be expected ;-)
A few remarks /questions,
1. I didn’t and still don’t understand the procedure of making and fitting that moulding nr 2, (neither in my own drawing)
I mean, you wouldn’t expect that the “bad side’ of two mouldings would nicely and predictably fit together,
Can’t we just sand and polish and spray paint the ‘bad side of moulding nr 1 , and do without moulding nr 2
No worry’s I’ll discuss this detail with the grp man, they will have that kind of experience
2. Initially I had my doubts about the dimensions, but after comparing with different examples here on my quay in Porto Montenegro, I think this looks really slim and relatively small, so all good on that.
My design was aimed at continuing the shape / corner of the radar arch, But I think that the shape in your drawing looks ok near the RA, and very nice on its own
on some models Azimut fe, this looks not coherent or out of proportion, (imo)
3. Initially everybody on here had concerns about stiffness etc.. in that respect, wouldn’t it be better to make the trimpanel part of the assembly (epoxy glue-ing …) ? and / or replace the core material along the gutter by a 120 x 60 alum tube ?
If this could help avoiding more then one pillar on each side, I would prefer this.
4. Are you sure about that hight of the gutter, 175 mm? the cross section of my drawing is taken from the drawing from Makefast, this seems lower,
does the underside fabric of the roof stay between the gutter side wals so to speak ?
5. Where would you position the pillar / flange under this section ?
6. When you’re at the boat, can you check the cordal hight of your gliding system ?
Many thanks !
Seems perfect as could be expected ;-)
A few remarks /questions,
1. I didn’t and still don’t understand the procedure of making and fitting that moulding nr 2, (neither in my own drawing)
I mean, you wouldn’t expect that the “bad side’ of two mouldings would nicely and predictably fit together,
Can’t we just sand and polish and spray paint the ‘bad side of moulding nr 1 , and do without moulding nr 2
No worry’s I’ll discuss this detail with the grp man, they will have that kind of experience
2. Initially I had my doubts about the dimensions, but after comparing with different examples here on my quay in Porto Montenegro, I think this looks really slim and relatively small, so all good on that.
My design was aimed at continuing the shape / corner of the radar arch, But I think that the shape in your drawing looks ok near the RA, and very nice on its own
on some models Azimut fe, this looks not coherent or out of proportion, (imo)
3. Initially everybody on here had concerns about stiffness etc.. in that respect, wouldn’t it be better to make the trimpanel part of the assembly (epoxy glue-ing …) ? and / or replace the core material along the gutter by a 120 x 60 alum tube ?
If this could help avoiding more then one pillar on each side, I would prefer this.
4. Are you sure about that hight of the gutter, 175 mm? the cross section of my drawing is taken from the drawing from Makefast, this seems lower,
does the underside fabric of the roof stay between the gutter side wals so to speak ?
5. Where would you position the pillar / flange under this section ?
6. When you’re at the boat, can you check the cordal hight of your gliding system ?
Many thanks !
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BartW
Well-known member
oops, hight under the radar arch is only 190cm,
I knew this was low but didn't expect that low
so have to adapt Jfm drawing, and make the outside rib, less lower than the trim panel, maybe just 2cm ...
and keep everything from the hardtop as high as possible, above 1,9m......
or
get rid op the radar arch, or the top part of it...
that is a tough one,
needs some more considerations and thinking
I knew this was low but didn't expect that low
so have to adapt Jfm drawing, and make the outside rib, less lower than the trim panel, maybe just 2cm ...
and keep everything from the hardtop as high as possible, above 1,9m......
or
get rid op the radar arch, or the top part of it...
that is a tough one,
needs some more considerations and thinking
P4Paul
Active member
For a one off hand made item, I think two separate mouldings is a challenge, and unnecessary. Sure you can do it if you make plugs/moulds with a 5 axis cutter, but then you are into thousands of pounds because the equipment owner has got to amortise the £1m+ that the machine cost.
or use a gauged wax film from the backside of the initial moulding to generate the secondary skin, gauged wax is c.£10per/msq
The luxury you have here Bart is that this is a one-time only mould, so you can have returns on the mould tool that you remove to get the finished product out - you can even smash the mould off because it is going in the trash anyway. This will help you keep only gelcoated surfaces visible. I would make the thing in a single one-piece mould, made in MDF, spray painted, with faceted compound curves, and then add a simple second trim moulding to hide the raw finish. Heavy brushed gelcoat would let you fix imperfections afterwards. Would cost just time, not big fees for getting the drawing CAD-ed and then renting time on a 5 axis cutter etc etc. Like this for the side sections:
Yep, i agree, if skills are available to make a sacrificial mouldings, go for it! As the old motor sport term suggested; splash moulds are cash moulds!
Should have said, make sure you check out the costs of converting a five axis machined block of polystyrene into a mouldable buck.
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