Yes.. that my thoughts also.. That is why I was looking for a better controller with PID controll. but that is for diffrent projects..

This morning I mixed up some gelcoat from the unimold system and tested it on a pice of scrap i have treated the same way as the roof plug. The roof and the test pice is painted with Standox 2k auto paint so to night i will see the result. I am so exited to finaly start getting the roof done.

But.. I need to know this before I can continue:

When doing the post cure of the mold made with the unimold system.. My impression is that it cures in room temp for about 24h and then demold from the plug and after that I put it in the oven for the post cure process.. Is that correct? 

I made the mold now.. 2 layers of gel coat a coupling coat and 5 layers of 450g fiberglass useing Easy composits unimold kit. I skiped the wood reinforcement. Everything stated to cure so fast I didn´t have time for it.. So I added a fifth layer instead.. It got very heavy and rigid enough and it would have been enough with 4 layers. I got it cured for about 35 hours and it released perfectly from the plug. I will wet send the surface and polish it and see if I can get it a 100% since I wasen´t 100% happy with my painters job with the roof plug. I use a orbital sander and was going to start with 1000 grit and work my way up to 2 or 3000.
I trimmed the edges and put it in the post cure oven.. And since it didn´t have a over temp protection I am not comfortable with leaving it alone so I have to guard it for like 16 hours.. And that sucks big time. 

Wet sanded



Polished and treated with easy lease and wax. You can see the "cludlyness" due to using the same rug with easy lease for each coats.. Later it transfered to the mold so always use new clean dust free rug or cloths.. Dry old release agents were dissolved and transfered to the surface with the different coats.  



Gel coat applyed..



All layup done.. It gelled pretty fast and I learned that it is better to use less hardener to get a longer pot life. About 1,5kg was what I hade time to apply each time.. It was a bit stress ful and later after post cure I did have a few imperfections due to air bubbles trapped although I used a rollers etc to squeeze all air out


When I am satisfied with the mold I will add easy lease again and start with the layup.

Since this is my first infusion project I rely appreciate some help from you guys setting up the mesh, spiral and the in and outlet. Maybe I need a "flow brake" near the vacuum port etc. I will confirm here before I do the vacuum test and infuse..

Ok.. After post cure knight..

Everything worked alright accept when I got to the last 2h 90 deg stage.. The fan stoped after 45min to1 hour.. I pulled the fan and when I took it apart there was an temp protection circuit inside the motor. I bypassed it and put everything together again and it worked.  I am glad I caught it right away since the heat element was still functioning. If I hadn´t been there it would have caught fire at some point.  Temperature had dived to 60 deg.and I re set the oven to 75 deg for about 1,5 hours and then 90 deg for another 2 hours. It took all knight and I was going to bed 06:30.

Today I was exited to take the mold out and start wet sending etc.. I first discovered 3 defects that looks like air between the gel coat and the reinforcement.. O no big deal.. that can be grinded out and fixed..   I think..
 

Then I got the roof mold on stands and can look more at the whole shape of it.. I then discovered it has warped.. I did not support the whole mold around the edges during the post cure due to I wanted air to circulate all around it..


Here you can see that the edge is not a nice curve of the roof..
I got so gut damn depressed.. I fell like getting real drunk..

Am I over complicating things with the post cure stuff?   I figured I need it to get a roof  that can stand the sun?


This was how it was positioned in the oven.. You can see I guess how it will sag over the supports..

The only thing I can think of to try and fix this is by putting it back in the oven and support it the other way and hopes it takes it shape back..I will try ramping it from 60 to 90 in 10deg stages for 2 hours each. that is at least another 8 hours.

In my opinion a simple "torsion" warp won't bean issue here. As a more or less flat sheet your roof will not have much resistance against torsion. So yor warped roof will fit quite nicely. You will always face tolerances to a certain degree, but luckily for you so did the engineers, who build the original car.
As long as the warping isn't too bad, I would say, you should just continue. More difficult would be a second degree deformation (a sphere has a different radius), or a "hanging edge" with a high deformation over a small distance.

Yes.. I might get a decent result from just glue a finished part in to place.. I need to figure out if it is worth taking a chance or if I am going to make another mold.
In the mean time I have put the mold back in the oven on 4 supports. One in every corner and hoping it will go back a bit.. Maybe even add some wight to it to force it back some.. I doubt it be successful though. I so want a perfect roof and enjoy the satisfaction of have done it myself..  At this stage I rely regret taking  the stock roof off to begin with..

About the air bubbles in the mold.. During post cure they expanded and when the roof mold cooled to room temps it leaves viable defects..   

How do I repair these.. I ground them out and fill them with tooling gel coat and then it is a matter of sanding and buffing or is it anything else I need to know?
I have something about adding wax in the back of my head about repairs.. Anyone?

Best way of doing a thing like this must be to skip the post cure of the mold and find a infusion resin that can handle the sun when dried in room temps.. I don´t know if that exists though.

Don't stress about the warp, as oekmont said a bit of torsional warp isn't going to make a difference. You'll notice how much torsional flex your finished part has when you demoulded that, it will be far more flexible than your mould and will be easy enough to bond in place. 

With regards to the blisters, just chip them out, use a blade of some sort to key up the fibreglass underneath a bit and clean with acetone. Then you will need a wax-in-styrene additive to put in the gelcoat to get it to cure hard, or you can just put a piece of tape or plastic over the gelcoat so that it is covered from the air, this will do the same thing. You'll then need to flat it back and polish it up.

Looking at your pictures, it seems like the mold isn't only twisted, but also has a wrong curve along the length. Because of the double folded edge, this might make it more difficult, to get an even unwarped look during the final fit process.
To me, your temper setup seems far from ideal, with the heater directly under the mold. this way, you will get an very uneven temperature gradient over the mold, likely causing the warping. A simple solution might be to use more than one heater, ideally less powerful. Or to build a circulation channel, in wich the heater is placed.

You might be right..  But i think the main cause is the weight of the mold and how I supported it..  Maybe I should have done the post cure with the roof plug and the roof mold together.. I was afraid of release issues if I did that or how the filler and paint on the plug would react.  

Another thing that would have helped is my original  ide of wood reinforcements. I skipped those because of the short put life I experienced and not knowing how those would interact with the mold during post cure.

I put the roof plug back in the oven supported on each corner and hopeing it will go back by its own weight.. It is pretty heavy and I didn´t dare weigh it down.  By a quick look at it in the oven this morning before going to work it looks alot better.   I did:

60 deg for 2,5 hours
70 deg for 2 hours
80 deg for 2  hours
90 deg for 2,5 hours

I just let it cool of slowly in the oven by just pulling the plug to the heater.   I will inspekt it more when I get home and give you the verdict.

About the oven design..  I messured the temps in several places in the oven and ones it´s heated up the temps all around it was pretty good. I don´t remember exactly but it was something like within 5 or a few deg..
 The heater is on for maybe 10 sec and then it is off for about 20 sec and then it repeats itself oven and over with the help of the thermostat.  From when the heater starts and to it shuts off it is about 4-7deg at the top of the oven.

In front of the mold and in the rear there is 20cm of gap to the oven walls so the fan can circulate the air and the fan is on 100% of the time.. But I agree it could be made better.. Idon´t think it is the issue for this though.

Well.. I had a propeller and got a banana..

God news is that i can´t see any traces of the warping.
Bad news is that it sagd to much and are shaped more like a banana.. 

But by just bending it a bit in the oposit direction it got a bit better instantly.. So I think I can work with that at least.. 

Later today I will lay the mold over the plug again and see if i can clamp it down and let it sit for a few days and see how it goes.