I have an issue that some ACM panels that we fitted at a school last week have all fallen off. We used this product Novaweld Signfix 33 to fix the studs to the rear and then chemfixed to the wall. This product claims to be suitable for use on ACM. The ACM has now fallen off and the studs are still in the wall with no adhesive on them at all, they look brand new. The ACM is only 3mm thick and 700 x 600 in size so not even heavy. The adhesive was applied as per the instructions and left over the weekend to cure. What product do you guys use?
I need to get something for tommorow as the school opens on Monday!!
after cleaning the surface with Isopropynol or similar, did you cross-score the surface with the likes of a Stanley blade or similar?
around 18 years ago, We didn’t do this once and got the exact same result as you have!
it is definitely better to check if you have the correct compatible adhesive too. we tried arldite once and as much as it worked, we found the adhesive to brittle and rigid. so if your board is expanding and contracting in sun and cold days, it will move where your adhesive will be rigid and both will separate.
you also have to be careful about the quality of the ACM -Vs- adhesive. some two-part adhesives mix and cure at a high temperature. this can cause dimpling on the face of cheap or thin aluminium skinned ACM. not noticeable in the workshop, but once on a building front and the sun shines on it, it looks like the surface of a golfball.
The nova weld 33 is sold for ACM materials for that exact reason. It doesn’t leave the horrible marks on the front. As for the scoring we used wire wool scoured /keyed the area and then cleaned with IPA.
Do you think we need to make the key marks deeper then?
we don’t scour it as such, we clean, then using a Stanley knife, just quickly cross-hatch score, not deep, but you can feel it. you have a combination of smooth and scores. a bit like what builders do when rendering a wall prior to rough-casting etc
I always used this for putting studs on & several other types of bonding, if you use the primer 1st it works really well because its a polymer it allows for expansion & contraction. A sign I fitted 7 years ago is still hanging on this stuff.