daniel mason
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| posted on 17/1/15 at 04:57 PM |
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Repairing alloy honeycomb tub?
The small alloy section of my race car tub has around 10 x 6 mm holes in each side after the removal of the sidepods and associated brackets!
Is a blind rivet the best way to repair the affected areas or is there a neater option? Thanks
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FuryRebuild
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| posted on 17/1/15 at 05:25 PM |
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There are a few ways to look at this:
1) Rivets will work, but oddly, you can get a galvanic reaction with carbon (if your tubs CF), so I would stay away from that. Also, if you need to
get the rivet out, you may cause further damage to the tub
2) cut repair patches from carbon sheet and bond them over the holes. This gives you extra reinforcement and spreads the load should you need to drill
the hole again
3) The hole drilling may have displaced some of the honeycomb, thus slightly (but not significantly) weakening the tub in bend. One of the ways the
hobby-aircraft boys and girls work this (and make themselves hard points) is to mix some resin with
glass
microspheres and inject it into the holes. When mixed at 20% concentration, this stuff is very stiff and quite light. You will fill any void
made by the drilling and restore the integrity of the panel.
Belt and Braces - do 3 first, carefully sand back any areas where the filler bulges out, then do 2.
I hope this helps.
Mark
[Edited on 17/1/15 by FuryRebuild]
When all you have is a hammer, everything around you is a nail.
www.furyrebuild.co.uk
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gttztt
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 posted on 18/1/15 at 09:37 AM |
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Repairing alloy honeycomb tub?
As per what Mark said. Injecting resin into the void and covering the area with a riveted plate was the standard repair procedure on fast jets so
should be good on fast cars! Admittedly the epoxy mix was a bit special and if the mix went wrong you could have a bit of bother. Cue panicking rigger
running out of the hanger with a cup of smoking glue.
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daniel mason
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| posted on 18/1/15 at 09:53 AM |
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Thanks. They are only quite small holes as looking at the rivets they are around 4.8mm, but on drilling some have slightly widened! I don't
really want to stick a plate on the outside of the car as it's quite a nice bit of kit and would look awful.
It's not really a structural part as the majority of the tub is autoclaved carbon fibre
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FuryRebuild
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| posted on 18/1/15 at 10:07 AM |
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Gttztt - I've had a few pots of epoxy start to cure before I've managed to to infuse them. Yes they smoke, and I had a thermometer on mine
and stopped measuring at 80C. When a composites workshop burns down, it sometimes is because someone put a pot of curing resin in a bin. let's
face it, there's a lot of great, smelly, flamable chemicals in a composites bin, usually surrounded by lots of cloth, tissue, kitchen roll and
other tinder.
I bought a wheelie bin, and I keep it outside of the workshop for this stuff, and have a table outside as well for curing pots to sit on.
When all you have is a hammer, everything around you is a nail.
www.furyrebuild.co.uk
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FuryRebuild
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| posted on 18/1/15 at 10:18 AM |
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well, you could buy some black epoxy die, or buy some of the
structural adhesive and just shove it
in. I don't know if it's black or not. May be a little difficult to flatten off though afterwards.
In order to retain the integrity of your tub, you should fill the hole so there is something allowing the outside surface of the tub to pass its force
to the inside. you could use the glue/paste for filling the holes to also bond on a small carbon fibre disk (say the size of a 10p piece). If you key
the surfaces properly, the actual repair will be exceedingly strong.
When all you have is a hammer, everything around you is a nail.
www.furyrebuild.co.uk
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daniel mason
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| posted on 18/1/15 at 11:47 AM |
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Thanks,the car is yellow and I don't want to stick anything to the outside. It just needs to look tidy and then I'll wrap it or sticker it
over to hide!
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