The Triumph Dolomite Club - Discussion Forum

The image above is the understand of the metal I cut out to repair three or four small paint blisters on the bonnet. The sort of holes that you might attempt to fix with filler. As you can see the metal is corroded over a large section and it shows why just fixing the visible hole doesn't always work.

Filler works perfectly well if used for its intended purpose of filling dents and divots , anyone attempting to fix holes with filler needs a slap

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Some people are like Slinky's, they serve no real purpose in life but bring a smile to your face when you push them down the stairs.

Alas it is often used to bridge holes. Even products that are meant for the job are likely to fail, like fiberglass, once you can see the paint blisters coming through, it is probably too late for an easy fix.

Unfotunatly, a lot of people dont realise filler is porous and that is why rust bubbles through. Fibreglass on the other hand is not.... and if a rust hole is cut out and fibreglassed both sides.... It will not rust as you have cut of it's oxygen supply and dampness Or you could weld a piece in.... But leave a pinhole in the weld and you will get a rust bubble

Tony.

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NOW A CLUB MEMBER 2017057

Allot of the time you can't get to both sides and even if you can you would need to remove all the rust, if you just stuck the fibreglass on rust, it will eventually blow off. You're also assuming you can get a perfect watertight seal, otherwise you glass fibre could easily hold moisture next to the metal of your repair.

You're right you need to seal welds but I have yet to have a welded repair blow through or show any signs of rusting. Attempts with other methods have always seen the rot return.

I was actually trying to point out the need to remove rust before doing anything And a lot of people dont have a welder, so fibreglass is the nearest thing to a half decent repair. I have done it in the past and not had a problem, so long as you think... If there is no oxygen or dampness it cant rust I must say do not ever use fibreglass or filler on structural items

Tony.

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NOW A CLUB MEMBER 2017057

Yeah but that is the problem, once rust has got into the metal, it is very difficult to seal it well enough to stop further moisture getting at it. All it has to do is continue rusting a little, it will expand and you will find a horror show underneath the fiberglass.

Welders aren't that expensive, £200 gets you a decent one. In the long run it is a false economy.

I have two bits of fibreglass on my 1850, one is around the petrol cap area, the other is in the inner rear arch on the same side. I cut all the rust out and made sure I put plenty of resin on the glass. That was 9 years ago.
When I can afford to have the NOS rear tonneau fitted to the car, that's when both pieces of fibreglass will be gone. For now it's waterproof and the rust was cut out. The petrol cap area looks like someone has repaired it - I'm no good at prep and paint.

Trying to get a paint repair to blend is a nightmare, I generally give up and do the whole panel and have never managed to get a decent finish. Reason why the pros charge so much.

One thing I noticed with my rear wings is there was sealant between the inner and outer wings. I assume this was put in at the factory, makes it a pain to weld, you have to clean out all the goo but when I cut away the old wheel arch from the offside the sealant had stopped the rot in its tracks.