composite repair joke
Firstly, lets deal with Lt.Fubar's question. The 787 is a predominantly fibre composite laminated construction, with much of the fuselage, wings, floor beams, empenage and control surfaces fabricated in that material. The Airbus A380 uses some of that same technology but also uses a large amount of GLARE a Glass Laminated Aluminium REinforcement material which is made by bonding thin foils of aluminium alloy (about 0.1 mm thick) interspersed with layers of fibre glass. This is used extensively in the crown of the fuselage.
Now to the repair outlined in that web page. Where do I start? The colour is not so good, but that looks like Flashbreaker 1 tape in the "coating removed" picture. That particular tape and a number of variants use a silicone adhesive which I have found transfers as a release contaminant onto surfaces to which you are about to bond. Bad karma.
Wot, not even a solvent clean? No abrasion to generate an active surface?
Next to the "Heat Pad". Let me assure you that of there is any substructure in the area a single heat blanket will not produce an adequate adhesive cure. Depending on where the control thermocouple is located (didn't mention thermocouples did they?) one of two things will result, either the thin skin will risk overheat damage of the repair adhesive over the thicker structure will not cure. You need to analyse the structure and use separate heater blankets for each structural region, one over thin sections and another over the thicker section. The issue of where to locate thermocouples is also of importance. They can not just be applied anywhere. It is important to find the hottest point under each heated zone to prevent overheat damage. However you also need to find the coldest point around the repair to provide assurance that the adhesive has been fully cured.
Just had a horrible thought; maybe they didn't mention thermocouples because they plan to use those dreaded heater blankets with the thermocouples built in!!!! These are useless. Let me demonstrate this. Place the heater blanket on a bench away from the repair site and turn it on. When it reaches temperature, measure the temperature of the skin in the repair site. Has the heater blanket made any difference? No, because the temperatures measured are those in the blanket, not at the repair. It is the temperature of the repair which will determine if the adhesive is cured or if the structure suffers heat damage. Therefore the temperature must be measured there, not in the blanket. This is even more important if these is any substructure.
With regard to vacuum, just hope that the damage is not through the panel and that there are no leaking fasteners in the area.
Next the 35 minute cure cycle. Unless the adhesive is a thermoplastic, I fail to see how this is achievable. If the adhesive is an epoxy then there is a required heat up rate and a soak period at cure temperature. Excessive heat up results in microvoiding, and most epoxy adhesives require a soak period of about one hour.
As for the overall time of 59 minutes, this is stuff that would make Tinkerbell blush. If everything was at hand and ready, and everything went perfectly, you would still need a whole bucket of "speed" to do this repair in anything like 59 minutes.
And that doesn't address the issue of envirnomental controls to reduce contamination.
You are right Muduckace, it would be humorous if they weren't serious.
Regards
blakmax