Headlamp Cowl Crack Repair

[DVD3500]

I admit I did what I call a "social media search" which is I did a single search and when the answer didn`t appear on the first page I decided to ask the question. 😄

Seriously I did a search and didn`t find anything...

The headlamp cowls on my MKIV/1500 hood/bonnet have smallish cracks and a small chunk broken out.

Finding better replacements has been tough. They are usually no better than what I already have or someone has managed to strip the bolts/threads making for fun with a helicoil which on pot metal is nigh on impossible.

I used to build model cars so I am familiar with fine filler but have never worked on pot metal.

I have heard of people using solder to fill cracks.

Not sure what I will do for the chunk missing.

I don`t have pictures handy as the car is 60 miles away but I can get them if necessary.

Thankful for any ideas!

 

[Colin Lindsay]

Not structural, so any good filler will work so long as vibrations don't shake it out again. Maybe some of the current 'chemical metal' type of filler? 

[DVD3500]

Someone here in Germany mentioned 2K metal filler..?

Not sure what that is..

[dannyb]

51 minutes ago, DVD3500 said:

Someone here in Germany mentioned 2K metal filler..?

Not sure what that is..

It's a resin and hardener you mix. Such as J B weld.

Danny

[chrishawley]

It's a very good question as to what exactly the cowls are made of. Not steel, obviously. But not Mazak either since they never rot in the 'spotty' mazak-like way.

If a cowl had a chip in a non-stressed area then an metallic expoxy filler/bonder would make a good reapair. Common products of this sort in England are JB Weld and QuickSteel. Milliput (much loved buy aquarium owners) is similar.  Pretty tough and can (within limits) be drilled and tapped. These are not the same as metallised body fillers (e.g. Alusoft) which are ordinary body fillers but with a aluminium powder added to make them tougher and less water-permeable than ordinary talc-based fillers: But a body filler nonetheless.

If it's a stress fracture (typically the inner corner) then situation is more difficult. There's nothing that can be applied which will prevent the fracture from reappearing some time later. The cowls can  be welded (I have had it done) but requires a skillful welder with the right grade of filler rods.

If replacement is the best option I wouldn't be that much put off by damaged thread or studs. Helicoil might not be feasible but there's plenty of other threading solutions such as Time-Sert or, where the outer stud is concerned, simply aralditing a stud into the remants of the previous hole. Perhaps the bigger problem with second hand cowls is that they don't fit, having developed a 'set' in their previous life. I've leant (the hard way!) to always try and conserve the vehicle's existing fittings whever possible.

 

Hope that's some ideas.

 

[DVD3500]

Cheers Chris... lots of interesting ideas.

To be honest, even if the fix does come back after a few years it's not the end of the world.

Heck, I am as old as the car I already have things that will NEVER be fixed... 😄

 

[Unkel Kunkel]

A suggestion :For the bit that’s missing, I would go for an epoxy filler - I find the best one  is made by Plastic Padding  -called  ‘ Super Steel’  - available at Halfords.

The usual method to prevent a crack spreading  in most materials is to drill a tiny hole - to reduce the stresses  at the end of the crack - so this should be considered  - and the crack and hole filled with the epoxy after cleaning with acetone.