There is a special polish for fiberglass boats and caravans, try that. Also have found in my own case, wash first with a good car wash ( I've used ct20 befour ) and a good pressure wash, allow to dry off and then use the polish of your choice. Apply thinly as some are a bugger to get off. I have also used a power buff that has helped a great deal.
Can't think of the name of it but its in a blue & white screw top plastic container from BCF. It's a restoration polish for fibreglass boats that's designed to bring up a dull surface. I used it on "Roadworx" 18 months ago because the body was very dull and it came up a treat. Since then, I've just used a simple wash & wax detergent from Repco and I'll do another buff up with the BCF product (of which I've still got half a container left) before our next migration north in a few months.
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Steve, Di & Ziggy We named our Motorhome "Roadworx" because on the road works "On The Road Again" Ford Transit with 302 Windsor V8 conversion, C4 Auto, 9 Inch Ford Diff All Lighting L.E.D., 260 Amp/h AGM, 530 Watt Solar + Kipor Backup Gen.
Oxalic acid does a good job on oxidised GRP Apply it with a cloth, leave it for a few minutes and hose it off (a pressure cleaner would be good). All shiney again and so easy. You can dilute it if desired, but as acids go it is pretty friendly.Of course you still need to wax it to keep it in that nice state.
Oxalic acid is also good for erasing metal rust stains on GRP and stainless steel (not sure about other metals).
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BJC
"A year from now you'll wish you had started today."
I have tried many specialised FB polishes over the last 4 years, some are good but a bugger to put on, some go powdery pretty quick due to UV breakdown, the best I have found for ease of use and lasting finish is Nufinish, comes in an orange bottle or tin.
Simply the easiest to apply and gets a great shine which lasts for months and beads water well over 6 months still.
I wash regularly with CT18 truckwash but only half strength.
