Talk Composites - The Forum for Advanced Composites

VM100 Black Methacrylate Adhesive problem

http://www.talkcomposites.com/Topic36601.aspx

By Steve Broad - 5/12/2020 5:48:21 PM

Hi. I have had a bit of a disaster, that actually turned out to be a bit of a godsend.

Anyway, My passenger door is fibreglass but I have cut out most of it leaving just the edges to which I plan to stick carbon fibre panels. Did the cutting and made the panels, so far so good.

Sanded the carbon with 80 grit and cleaned with acetone and allowed to dry. Likewise the fibreglass.

Spread on the VM100 and clamped the panels on, one at a time, and left overnight to cure.

All looked Hunky Dory. Offered door up to the opening and discovered that is had twisted! Bugger, now how the hell do I get the carbon panels off? Turned out to be very easy as they just peeled off!

Question is, what dId I do wrong? Photos show edge of panel, I simply scraped off the glue residue with a Stanley blade. The glue is very securely adhered to the fibreglass.
By Steve Broad - 5/14/2020 2:08:10 PM

 
Warren (Staff) - 5/14/2020 1:46:11 PM
As above, if it is working fine now then contamination or poor surface prep are likely to be the only realistic causes.  Rougher the better with carbon bonding. 

Peel ply finish is generally a good finish to bond to so you can add peel ply into the part on all the bonding points.  If the peel ply areas are large, it might suck up enough resin to leave a few pinholes.  This can be avoided by using some XPREG XA120 150g Prepreg Adhesive Film in those peel ply'd areas to add a bit of extra resin.

Cheers Warren, pinholes aren't an issue as everything is painted to hide the carbon :-) Would you place the adhesive on the surface next to the peel ply?

My carbon supplier/sponsor agrees with you that it must be a contaminate issue:

If you lightly abrade the carbon surface to give a key it should bond fine with methacrylate. One way to do that would be with Scotchbrite type material which won’t damage a thin laminate. If you do that with soapy water to remove any grease or other residue then rinse with clean water and allow to thoroughly dry it should do the trick.