Dinitrol stone chip problems after 2k priming

[nige73]

I applied Dinitrol stone chips 3 weeks ago to the sills and arch lips of a Vw t4 van using a gravity fed gun.The day after I applied several coats of Mipa high build 2 pack primer which was then flatted back when it was dry.I pulled the van out of the garage yesterday to find a crack had opened up on the profile above the sill.I pulled at it with my nail and it just peeled off and the underneath was just like hot chewing gun.On further inspection several other areas were lifting.The stone chip is still soft either because it did not cure fully or because the primer as softened it.Can anyone suggest why this as happened and how to avoid future problems with other projects.Would a infra red heat lamp assist in curing it or will I have to strip back and re prep?.

 

[norsa]

I don't know dinitrol but it sounds to me it hadn't fully flashed off before sealing with 2k

 

[nige73]

I don't know dinitrol but it sounds to me it hadn't fully flashed off before sealing with 2k

Thanks so what would be the best course of action now?,will it harden further if van is left out in the sun while still in primer?.

 

[series2]

Not sure about 2k paint, but if you apply stonechip over polyurethane sealer (which also contains isocyanates) before it has fully cured, it seriously slows down the cure time of the stonechip. The seam sealer I use mentions this in the TDS.

 

[norsa]

to be fair, i would scrape/wash it off. it should only go back as far as your original 2k primer. dont suppose dinitrol is a synthetic basec product is it? That would certainly screw things up under anything else. Just a thought. personally, i would use raptor. £20 per ltr but you have to buy 4 litres. (scope for selling it on ebay per 1ltr mind)
Nick

 

[nige73]

Thanks for your replys.I have spoke to Rejel who supply the Dinitrol and they can't give an explanation so I presume it is ok to use with 2k primer.Bare steel was primed with aerosol etch primer not 2k.Yes Raptor may be the way forward.

 

[barracuda816]

For What its worth if you end up redoing it i wouldn't use the etch primer, 2 pack epoxy is superior to etch. Then if you want to, just spray the raptor on top of the epoxy.

 

[nige73]

Thanks I'll look into that next time.

 

[steveo3002]

id imagine whats happened is that the stonechip skinned over and appeared dry when it wasnt , then the primer sealed it so the solvent couldnt escape

takes a fair while for thick coats to dry out fully

and just to be sure..the stuff you used is overpaintable and not a black underseal type of stuff?