Pace frame

[johndeverill]

This is just the type of thing stickers are for

Some minor bump on the down tube next to the bb, so you buy it, build it and whats the worst that can happen ?

Certainly its not going to disintegrate and pitch you towards a fractured skull, at worst the area might crack.
So the occasional outing, but dont ride it like its a DH monster, no need to wobble, straining at the pedals.

Were it mine I could wrap that area in epoxy soaked carbon fiber cloth and use my vacuum laminating kit to clamp it tighter than a ducks bum, which is waterproof incidentally. 8 tons square meter is going to bind it to that tube and it aint coming off.

You'd need to fully prep the aluminium and also put a layer of fibreglass in between the carbon and aluminium or you could cause the aluminium tube to corrode away!!

 

[longun]

Re:

It be rite

 

[dyna-ti]

You'd need to fully prep the aluminium and also put a layer of fibreglass in between the carbon and aluminium or you could cause the aluminium tube to corrode away!!

Why fiberglass :?
Wouldnt the epoxy resin bond tight enough to the frame, given thats likely going to be roughened to provide a sealed bond ?.
I think you're mistaken, as epoxy would just be like a paint layer. I wasn't meaning that you create a sleeve.

 

[johndeverill]

Re:

Nope, not mistaken as it's my day job!

If carbon comes into contact with aluminium moisture can cause the aluminium to oxidise and literally turn to dust! :shock: Either putting a layer of very fine glass veil as the first layer of the layup or applying a tie-coat of epoxy, letting it cure, and then laying up on that should prevent any fibre to aluminium contact. Bascially its galvanic corrosion that causes the issue so if the two materials cannot come into contact it should alleviate the issue.

We could get into phosporic acid anodising, chromate conversion coatings, etc. but that's probably taking things a little too far for a bike frame!!

If you ever want any composite tips just shout!

 

[Magpiegifts]

no, but if it stays low enough i may be tempted.

Did you end up buying it,seeing how it went for peanuts in the end?

 

[dyna-ti]

Re: Re:

Nope, not mistaken as it's my day job!

If carbon comes into contact with aluminium moisture can cause the aluminium to oxidise and literally turn to dust! :shock: Either putting a layer of very fine glass veil as the first layer of the layup or applying a tie-coat of epoxy, letting it cure, and then laying up on that should prevent any fibre to aluminium contact. Bascially its galvanic corrosion that causes the issue so if the two materials cannot come into contact it should alleviate the issue.

We could get into phosporic acid anodising, chromate conversion coatings, etc. but that's probably taking things a little too far for a bike frame!!

If you ever want any composite tips just shout!

That is interesting :?

So if i paint an alloy frame in an epoxy based paint, the frame is going to disintegrate under the coating ?.
I find that somewhat surprising.

Wouldnt then just a coat of etch primer solve the issue ? :?

 

[mk one]

no, but if it stays low enough i may be tempted.

Did you end up buying it,seeing how it went for peanuts in the end?

I didn't, i actually forgot about it tbh.

Hopefully someone on here bought it though and we shall see it restored to glory.

 

[johndeverill]

Re: Re:

Nope, not mistaken as it's my day job!

If carbon comes into contact with aluminium moisture can cause the aluminium to oxidise and literally turn to dust! :shock: Either putting a layer of very fine glass veil as the first layer of the layup or applying a tie-coat of epoxy, letting it cure, and then laying up on that should prevent any fibre to aluminium contact. Bascially its galvanic corrosion that causes the issue so if the two materials cannot come into contact it should alleviate the issue.

We could get into phosporic acid anodising, chromate conversion coatings, etc. but that's probably taking things a little too far for a bike frame!!

If you ever want any composite tips just shout!

That is interesting :?

So if i paint an alloy frame in an epoxy based paint, the frame is going to disintegrate under the coating ?.
I find that somewhat surprising.

Wouldnt then just a coat of etch primer solve the issue ? :?

No, a layer of epoxy only will protect it. It's if the carbon fibres are in direct contact with the aluminium. Wet layup and vacuum bagging directly can press the fibres up against the aluminium hence a cured layer of pure epoxy or, better still, a thin layer of fibreglass/epoxy will isolate the aluminium from the carbon fibres.

 

[dyna-ti]

Have to say one of the best things about forums is the amount of knowledge in a range of subjects you get.
I've used epoxy in furniture(the syringe stuff is a householders dream of a glue that Actually Works) but i didnt think it could actually be the cause of problems. I was looking to use carbon matting at some point, but it appears ill need to actually do a fair bit of research before embarking on it.

Cheers