Stress crack removal

[chris52]

Well its been over 25 years since I did Fibreglass laminating as a job. Anyway this is how we used to get stress crack out then I don't know if things have changed or if people have better procedures. If you have please let me know.

First I marked out the stress crack area with a pencil.


This is made much easier with a light shinned behind


Grind out all the crack so they don't show


Cut out layers of tissue and mat depending of depth you have to grind. Soak the area with resin lay the mat/tissue one piece at a time soaking with resin and making sure all the air is out.


Finally sand the new fibreglass to get a key and finish with a good flexible Filler. The rest is up to the body shop to finish off.


This is how it looked when I got it

Edited by chris52 on Saturday 5th April 21:46

[prideaux]

Thank you Chris keep the lessons coming I am sure there are lots of us that will be interested
A

[alphaone]

+1

I am finding it very interesting, I have never worked with fibreglass before so am on a steep learning curve so thanks for posting the subject and pics.

[phillpot]

Useful article, for those of us who haven't had a life time of experience working on TVR's so need to learn by reading things...... Repairing Fibreglass.

[ATE399J]

This is the bible on fibreglass repairs:-

http://www.amazon.co.uk/Restore-Fibreglass-Bodywor...

I had a copy, leant it to someone and never got it back.

I think the extract in the link in the post above is from it.

Edited by ATE399J on Sunday 6th April 13:45

[madsvlund]

And remember to use a dust mask when grinding and cutting, and a proper A1 breath mask when playing with styrene/polyester. It's really nasty stuff.

From my experience, is packing tape a real good mold release. In case you need to fill a hole, or have to grind all the way throu the fiber to remove a crak. After grinding the broken fiber away, cover a piece of wood, cardboard or similar with a layer of packing tape, and tape that piece over the hole (on the visible side) and fill the holde from the backside with fiber and polyester. This make a really smooth and level finish on the front side.


Another thing, an air grinder and a carbide tool is really great for the rough work

[Hansoplast]

Hi Chris,

Just some remarks / extra info.

I do not bring the filler on and leave that to the painter.
Sometimes he does not like the material you use.
Or when there are problems after painting he relates that to your work.

The fun in this work is in the learning proces.
Sometimes I used to much resin so had to sand it all down and that is not the fun part.

Next week the painter will come to have a look at the car (and my work) for the pricing.
Hope that all my hours spend on the body will help to keep the price down.

Hans.

[cantus]

hee Chris,
yes , that is the way to do it. I did a lot of Fiberglass work and till today I repair cracks like you showed it.
This works for small repairs. When the whole car is full of cracks it is better to sand off the whole car till the glassfibre .
so make sure all paint is gone . than put a complete thin woven layer all over the car.
I did this 25 years ago on a Grantura Mk3 and till today not one crack came back.

[chris52]

Thanks guys

Did a little more today. The roof had at some point been damaged. Don't know how this happened here as the rest of the body is original with no major repairs. Having said that I didn't get a bonnet so maybe that tells the tale.
Anyway it had been bodge repaired with loads of filler and no stress crack repair. I dug out all the filler and did it properly.
From this


To this


Chris

[Old Git]

Years ago I had a Vixen S1 and once I'd stripped the paint I can honestly say the entire body shell was covered with stress cracks. I doubt there was more than 10% which could have been left untouched if repairs were to be done 'properly'. In the end I took all the paint off, repaired the areas where the fibreglass was actually fractured and frayed edges of cloth were showing, then covered the entire car in two layers of tissue. Once skimmed with filler and painted I never had any problems with cracks reappearing (I owned the car for 28 years). I don't think 'proper' repairs are possible on some cars unless you purchase a new body shell and bodgery has to be resorted to. The way some of the glass was originally laid up, the bad design (how do you stop short Vixen S1 doors cracking at the top rear corner just below the window frame?) and poor execution means that cars used hard are going to craze.

[AceOfHearts]

What are you guys using to grind this damaged glass back?

[phillpot]

Angle grinder with a flap disc and also found a power file useful.

[TVR Beaver]

The roof looks great from what it was!!... great job!
interesting comments about doing the full car with a layer or two

[chris52]

AceOfHearts said:

What are you guys using to grind this damaged glass back?

As Philpot said an angle grinder with a flap disc but be very careful as it cuts through the glass very quickly and in no time at all you can have gone all the way through.
Chris

[AceOfHearts]

chris52 said:

AceOfHearts said:

What are you guys using to grind this damaged glass back?

As Philpot said an angle grinder with a flap disc but be very careful as it cuts through the glass very quickly and in no time at all you can have gone all the way through.
Chris

Thanks very much, I have a load of flap discs already and I will be very careful when I make a start.

Plenty of mechanical stuff still to sort, but i hope to be able to do the bodywork myself as well

[oliverb205]

Hi Chris,

It's hard to remember from the only time I saw the car when Philip bought it 14 years ago, but I am 99% sure that the bonnet was misshapen having been damaged and poorly repaired. I can't remember the roof, but must assume it was all down to the same accident damage. I'll see if Philip can remember how bad it was.

But I have to say you are doing a fantastic job on it.

Oliver.

[chris52]

Thanks Oliver I would be interested if you find anything out.
Chris