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Author: Subject: Deformed GRP correction
PeterV

posted on 27/1/11 at 10:54 PM Reply With Quote
Deformed GRP correction

Any ideas of reshaping a deformed GRP wheel arch. The wheel arch seems to have tightened up so I have lost around 10mm clearance at the back of the rear wheel. Still have around 12mm clearance but it just looks odd when compared to the other side.

Think it probably happened when the bodywork was still green and I was doing prep work on it before fitting. I had the body sitting on the workshop floor during that time

Will heating and blocking in position work with GRP?

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RazMan

posted on 27/1/11 at 11:44 PM Reply With Quote
If you can apply some pressure in the right position while heating up the arch, over a few hours (sometimes days) the distortion will go. I had a heavy toolbox on my front clip for a month to correct a shut line - it eventually corrected it. When my car is in direct sunlight for a few hours, everything seems to move





Cheers,
Raz

When thinking outside the box doesn't work any more, it's time to build a new box

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gottabedone

posted on 28/1/11 at 06:35 AM Reply With Quote
hmmmmm, I'm sure I parked my car here!!!.................oh wait it's over there, it must have been sunny

Steve

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PeterV

posted on 28/1/11 at 08:26 AM Reply With Quote
quote:
Originally posted by gottabedone
hmmmmm, I'm sure I parked my car here!!!.................oh wait it's over there, it must have been sunny

Steve

Scary these solar powered cars, think I'll stick with oil

Cheers Raz will give it a go, sounds like a mild heat is all thats needed.

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Daddylonglegs

posted on 28/1/11 at 09:03 AM Reply With Quote
quote:
Originally posted by RazMan
When my car is in direct sunlight for a few hours, everything seems to move


I guess it holds it's shape for 360 days a year over here then?





It looks like the Midget is winning at the moment......

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Triton

posted on 28/1/11 at 09:55 AM Reply With Quote
Yep the stuff moves and yep if you can hold it in place and you happen to know a paint shop who would let you chuck it in their oven overnight while oven is cooling you might be lucky. Worked for me in the past.

Bonnets are the kiddies that move all over the joint and should really be made with high temp resin but nobody does..





My Daughter has taken over production of the damn fine Triton race seats and her contact email is emmatrs@live.co.uk.

www.tritonraceseats.com

www.hairyhedgehog.com

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PeterV

posted on 28/1/11 at 10:24 AM Reply With Quote
Everything has been positioned with blocks and string. Workshop temp has been rasied to 32 with thundering great gas space heaters. Body temp is around 40-45 with 2 heat-shrink guns and a paint stripper heat gun all targeted on the offending curves. Never nailed heat guns to planks of wood before, tiz a surreal experience. Snowmen everywhere be affraid

I'm going for 4 hours of this treatment then cooling.

Things will be allowed to cool over the rest of the weekend. Forcast is for +4 overnight this weekend so that should set it. I'll open the workshop windows tomorrow night and let it cool right down.

Keeping everything crossed!!!

All this just for 10mm....................

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RazMan

posted on 28/1/11 at 12:43 PM Reply With Quote
I swear that Essex just warmed up a degree!

I hope the plan works





Cheers,
Raz

When thinking outside the box doesn't work any more, it's time to build a new box

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PeterV

posted on 28/1/11 at 01:51 PM Reply With Quote
quote:
Originally posted by RazMan
I swear that Essex just warmed up a degree!



Global warming eat your heart out

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PeterV

posted on 30/1/11 at 06:47 PM Reply With Quote
The result is good...... ish

Sunday morning the blocks were removed and the gap is 22mm which is just over size
Sunday afternoon the gap had closed up to 18mm which is acceptable but worrying
Sunday evening the gap remained 18mm so I am a little more relaxed

Bad news The rear of the wheel arch now has a couple of small ripples. They are very small and will sand out as they are far less than the thickness of gel coat. I will add some gel coat before sanding just to make sure I kill them off with one hit. This is not a problem for me as I am painting the car. But for those using a gel coat finish be aware of this problem

It seems the GRP will flex / expand / contract at different rate to the gel coat. The GRP in this case moved as expected but the gel coat did not want to, hence ripple.

End result (providing the gap does not change by Monday evening) will be a lot of work to gain 8mm. But the look of the rear end of the car will be much much better as 2mm is difficult to spot but a 10mm error show up big time.

IMHO 10mm movement is the absolute max that should be attempted using this idea when the part has a gel coat.

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PeterV

posted on 1/2/11 at 09:17 PM Reply With Quote
Final Update to this bit of work is that the new gap has remained constant even after a couple of days of heating and cooling the workshop. So I'm going to buff out the ripples and all should be well
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