bike panel repair, helicopter tape?

[chunkolini]

The previous owner of my Africa Twin was a bit of a berk.
he had fitted a nice new stainless exhaust system so that the mountings were pressing on the side panel, and it has split, split not cracked.
How would I repair this? if I line the sides up the spit is almost invisible.
Would clear helicopter tape on either side of the split do the job?
or do I need to mess about with glass fibre on the inside of the damage?

 

[mike os]

Not tried it for repair but what's the worst that can happen?

 

[dobbslc]

You can buy proper stuff to fix fairngs it's like a power that you put on the crack then drip on a liquid to set it off. It's pretty good I've used it to repair broken lugs before.
GRP will probably just peel off with a bit of flexing.

 

[reedx]

You can buy proper stuff to fix fairings it's like a power that you put on the crack then drip on a liquid to set it off. It's pretty good I've used it to repair broken lugs before.
GRP will probably just peel off with a bit of flexing.

It's called Plastex. I've had good results with it too.

Colin

 

[Pete.]

Visit your local double-glazing shop and get some of their Cyano glue they use for sticking on trims. It's a lot thicker than normal superglue, sets more slowly and is a lot stronger/resistant to flex. Lot cheaper too. Use that to glue the crack and it'll be close to invisible.
Now get some 60 grit paper and rough the inside. Find some 1mm aluminium sheet to make a patch, rough that up too and glue it to the inside with Gorilla glue (or any other PU adhesive) so that it spans the cracked area. Clamp it up gently whilst it cures

This'll give you a good firm repair probably second only to plastic welding.

My brother has that plastex stuff and I've used it. It's good I found that it produced a somewhat brittle joint.

 

[DanielW]

Is it plastic or fibreglass moulding? bike being 25 years old.

eitherway I'd use araldite and glue plastic strip along the split inside as a strengthing bond.

 

[chunkolini]

Cheers all, I will digest that this evening.
It is definitely plastic, that posh stuff they used to use, quite flexible and from what I remember a pain to glue.

 

[Rocketman]

Yeah I would put money on it that solvent weld wouldn't work, bet it's similar to the plastics they use for bumpers then. It would help if you could find out what plastic it is to be able to get the best option.

 

[DanielW]

Original araldite shouldn't be underestimated,I glued a penny to a piece of white wood to see its strength...couldn't shift it with a hammer and chisel unless I splintered the wood.

 

[DanielW]

Solvent weld is for polypropylene

 

[MattF]

Original araldite shouldn't be underestimated,I glued a penny to a piece of white wood to see its strength...couldn't shift it with a hammer and chisel unless I splintered the wood.

Araldite is quite fragile though, and not great at bonding to stuff like plastic unless you can key the surface.

 

[slim_boy_fat]

Baking powder + superglue (I've read)

 

[Rocketman]

Solvent weld works well on a few plastics not just polypropylene, acrylic for example is really good with solvent weld.

Araldite might work fine but it really depends on the plastic in question, some plastics it will be next to useless.

 

[brewdexta]

Is helicopter tape what you make sky hooks out of?

 

[Rocketman]

Araldite is quite fragile though, and not great at bonding to stuff like plastic unless you can key the surface.

Mattf you right. Gluing plastics is a mind field. It would be useful to look over the inside of the moulding to see if there is symbols for the actual plastic used. I would guess it's similar to something used on bumpers and body kits on cars so you can paint it and get some flex. It shouldn't be a problem fixing the crack with the right adhesive. I would tend to then put a flexible patch to add extra strength on the inside made from PE (only need to be 1-1.5mm thick) which would be simply attached by roughening both surfaces and using exterior grade silicon.

Going off topic a bit 10 minutes ago I sent off a remake tool design for a over moulded seal on a certain luxury SUV coming out next year. The first one didn't work, so they redesigned the part which I then did the mods to the tool design. Needed loads of inserts which needed laser welding on the surface so no witness line was left on the mouldings. Turns out that didn't work either, so the tool was scrapped and I have just sent off a new tool design to their latest product design. No wonder cars are so expensive.

 

[gordon stephenson]

X2 for the baking powder mixed with super glue, Not used it but seen demo's and it looked great,

 

[MattF]

I've tried baking powder in superglue, it didn't work..

Well, it worked for a bit but broke quite quickly. Maybe I overestimated the potential strength and flex resistance.

That mix is more a filler than a strengthened adhesive.

 

[Rocketman]

I think a appropriate epoxy type would be better than super glues even with the correct type of super glue for the plastic my gut feeling is a epoxy type would be better.

 

[CRB]

Check the panels' inside surface, there will be indentification of the composition.

PP and PE are both resistant to solvents, period, which is why they, solvents, are carried about in PP or PE, or glass, containers.

There are 'superglues' which bond PP and PE.

The fairings at that time were mainly ABS, which is solvent friendly.

Bumpers tended to be a mixture of ABS/PP, now though a lot of fairings and bumpers are ABS/PC/GF. Polycarbonate, the middle one, is also solvent friendly and by similar solvents which attack ABS and acrylic. GF is glass fibres, added to all manner of engineering plastics to enhance their heat resistance and strength.

I have some 2mm ABS if you want a little patch sending.

 

[MattF]

All the demos I saw used it for reattaching mount lugs and stuff, saying it strengthened the bond as well as being able to be built up around parts.

It's one of those things where it may possibly add a bit of adhesive strength, but it would be negligible if any. What it does is add structure, (which is what they're likely referring to as strength), hence allowing it to be used as a filler and for building up, as in the videos you've seen. Bicarb does also accelerate the cure slightly too, as I recall. It's like adding sand to cement. Cement is the binder, but the sand adds structure. Mortar would be worthless without sand.