Cosworth YB Turbo Into Elan

[stevebroad]

Yeah, they aren't, so mine are also generic. I also make my own aluminium ones on the lathe.

[stevebroad]

Ten layers of carbon later (apologies for out of focus image). Tomorrow I will vacuum bag and cure.

[stevebroad]

Bagged up door window frame and slung it into my new oven. First use of oven with carbon and with full use of the programmable controller. I had to program it to raise the temp to 80 deg C at 3 deg/minute then hold for 30 minutes before continuing up to 120 and holding there for two hours.

Worked pretty will although temps were around 5 deg higher than set. Not an issue but I need to work out what I did wrong.

What I was impressed with the performance of the oven. Worked perfectly with very little heat loss. With 120 deg C inside the door was 19.6 with the surrounding workshop walls 16. Happy with that.

Tomorrow I will tidy up and post result of many hours of fabrication. If it works then I will make the passenger side frame. However, I must get on with the roof mould.

[stevebroad]

Update on door window frame. Tidied it up, but will leave final detailed shaping until carbon roof is made and I can match it up to the opening.

With regard to the roof, first half of the mul dhas been laid up. Luckily it has to cure for 24 hours before I can remove the central devider as I have run out of firbeglass. I will order a roll in a minute, should be here on Tuesday.

[nmauduit]

nice! will you rigidify the mould (wood beams or tubes with extra lamination...) before curing the final part ?

[stevebroad]

nice! will you rigidify the mould (wood beams or tubes with extra lamination...) before curing the final part ?

Thanks.

Not usually required as I make the moulds pretty strong. Plus post curing the mould (at a 0.3 deg C ramp) prior to use sets the mould pretty well. If I had any flappy bits I would secure them, like I did on the bottom of the wings on the flip front. The strip around the bottom of the rear screen will, however, be secured to the top with FG reinforcement as additional insurance.

Update - Or, some scrap carbon fabric

[stevebroad]

A days work (which includes waiting for gelcoat to tack up) and the second half of the mould is done. It has to be left for at least 24 hours to properly cure then I can begin the task of releasing it, which can go one of two ways

[nmauduit]

you're to make a separate piece for the screen ? to avoid lock in or to make sure that the shape is accurately aligned?

[stevebroad]

you're to make a separate piece for the screen ? to avoid lock in or to make sure that the shape is accurately aligned?

The screen lip is built into the patrern and hence the mould. Hopefully I have done a good enough job lining opposing faces so the scrren will sit snuggly on to the lip.

[nmauduit]

you're to make a separate piece for the screen ? to avoid lock in or to make sure that the shape is accurately aligned?

The screen lip is built into the patrern and hence the mould. Hopefully I have done a good enough job lining opposing faces so the scrren will sit snuggly on to the lip.

ok, I was wondering about the blue modelling clay, I guess you've smoothed the step then...

[stevebroad]

you're to make a separate piece for the screen ? to avoid lock in or to make sure that the shape is accurately aligned?

The screen lip is built into the patrern and hence the mould. Hopefully I have done a good enough job lining opposing faces so the scrren will sit snuggly on to the lip.

ok, I was wondering about the blue modelling clay, I guess you've smoothed the step then...

Ah, the blue modelling clay is acutally mould paste. It is used to make moulds or smooth out sharp internal corners that the fibreglass won't stay in. The paste is reinforced with fibres and is very strong. This insures that the internal corners and edges of the mould are not full of voids, meaning that the glass lip should be good.

Lay on gel coat, the mould paste then fibreglass.

[stevebroad]

You are never too old to learn new techniques. I have been making car parts out of fibreglass for nigh on 50 years with a lot of success.

Started off simply attaching arches to Anglias and progressed over the years to culminate in producing moulds for prepreg carbon parts including the complete front clip for the Elan.

Over the years I have used the same method - cut the FG piece to the required size, lay on a board, soak with resin, pick up and position in place. Works well if a little (OK, very) messy but I knew no better.

When making the mould for the roof I used this method for the first section, angain no problems apart from the frist layer of lightweight woven cloth being awkward with a mnd of its own. The subsequent heavier layers weren't a problem.

However, I was watching a video of an Australian guy making a mould for his race car and noticed that he brushed resin on to the pattern first then added DRY FG and brushed on resin afterwards. This was a lightbulb moment! SO much easier. I made the second part of the roof mould using this method - cleaner AND quicker

One downside of this method is that it traps more air bubbles than the wet lay method.

It has since transpired that this is the normal way to do it and even my son does it this way! Oh well, better late than never

[nmauduit]

ah ok, the blue paste hardens like a filler then ? I noted it was applied just after the gelcoat, which raised my attention... as for resin application, I've been doing the tack first then soak through with a brush in most cases as I'm not usually doing huges quantities at a time (I'm also systematically using "tear cloth" - edit: peel ply that is -, which I find almost as effective as pulling vacuum to remove excess, and leaves a surface ready to build up extra layers with minimal work). But I'm still toying around the prepeg carbon step...

[stevebroad]

ah ok, the blue paste hardens like a filler then ? I noted it was applied just after the gelcoat, which raised my attention... as for resin application, I've been doing the tack first the soak through with a brush in most cases as I'm not usually doing huges quantities at a time (I'm also systematiccaly using "tear cloth", which I find almost as effective as pulling vacuum to remove excess, and leaves a surface ready to build up extra layers with minimal work). But I'm still toying around the prepeg carbon step...

Yes, but more like P40, the one with the fibreglass strands in it. You can make stndalone moulds with it,

By tear cloth, do you mean peel ply?

If you can progress to prepreg you won't regret it I have rolls of CF cloth that will probably not be used.

[661]

However, I was watching a video of an Australian guy making a mould for his race car and noticed that he brushed resin on to the pattern first then added DRY FG and brushed on resin afterwards. This was a lightbulb moment! SO much easier. I made the second part of the roof mould using this method - cleaner AND quicker

It has since transpired that this is the normal way to do it and even my son does it this way! Oh well, better late than never

I must say I do the dry cloth method onto a soaked base, however, watching 'Bitchin' rides' ,as you do in lockdown, they do it your old way 'because it's more effective at getting rid of the air bubbles'.
I guess it doesn't matter for a mould.