Question from the UK. Overlaying.

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#1

Ah ha, i have been looking for a site like this for years!! The subtle language differences make these things tough to find!!

I have been overlaying for a number of years with different degrees of success and have tried most materials/resin systems.

I have read the forum from to to bottom and i have the same question alot of people have asked, sorry… I dont expect an answer, a link to the mentioned area will more than suffice.

HOW DO YOU GET THE OVERLAY TO STICK TO PLASTIC PERMANENTLY??

I know this question gets asked alot and the answers is always ‘read back’ whick i have done… all the way to the begining, but i think the info has been archived??

I have covered a few bits and pieces here in the UK for friends etc, everything from complete dashboards to tiny pieces of trim. I have tried every thing from polyester surfboard resins (silmar and iso7x) through to epoxy (sp115).

I find the polyester give a better short term finish but unless left to fully cure for 2 weeks plus, the resin sinks as soon as the sun hits it (we get a BIT of sun every now and again). The polester will also dettach from the plastic easily due to sinkage and shrinkage. I have tried to glue the carbon down with spray glue (reaction), PVA (doesnt have a huge sticking ability to non porous plastic, althou no reaction), PVC plastic adhesive (dries too quick to apply carbon properly and releases solvents when warmed buy sun that affect surface quality), epoxy resin (too brittle, fractures away from surface easily), polyester resin (similar to epoxy but with less adhesive qualities)

The epoxy, sp115, is a very clear system with uv stability but has a small overcoating window which is why i dont use it as much as i should. The benifit of the epoxy is you can adhere it down with a spray glue and get no reaction, but you still do not get a permenant bond, with a little abuse it will come off.

I spent ages covering the instument binicle of my 996 Porsche dash and got a beutiful finish with a polyester resin and PVC adhesive. I left it for a couple of weeks to fully cure. When the sun hit it the PVC adhesive began to create gluey marks between the resin and carbon, i assume solvents from the glue??. Even in a very stressed state the carbon was very difficult to remove!!! So PVC has the adhesive qualities but with drawbacks. I am wondering whether if i baked the glued carbon before resining will it cure the problem??

Also i have seen some reference to vacuum bagging the overlay. When i have tried this you end up with a little distortion in the weave, which in the light shows up badly. I assume this is lack of patience making sure all is straight??

Sorry for the huge first post and thanks in advance from the rainy UK!

Richard

#2

for the few bits ive done i simply sanded the parts with 40 grit aluoxide paper,sprayed spray adhesive on,layed the carbon on dry and brushed on 3 or 4 layers of epoxy resin,they aint never comin off!! you can also drill tiny holes in the part so the resin seeps thru and forms rivets.

#3

ahh lovely, i will give it a go!

Richard

#4

has anyone thought about spraing that krylon fusion plastic paint then overlaying over that? The paint is supposed to be the only paint that will fuse with plastic and not chip. So I would think the resin will fuse with the paint better then it would with plastic

#5

dunno? ive just spent a week removing an overlay that i messed up,i cant see it ever falling off in normal use!

#6

I have seen several dash overlays that have lifted a great deal

#7

so have i, usually mine!! I find that if you mess up part of the process and have to remove it you have no hope, if you get a lovely finish it drops off. The joys of overlaying.

Richard

#8

My thinking is the paint and the resin would react badly, so do a small test panel first…better to drill lots of small holes (acts as rivets) and / or lap over the edges.

#9

ggrop is right, the plastic is probably polypropylene and therefore nothing sticks. Drill holes and make it a mechancal bond