Hairline cracks at front of van (2) Robert and Dave

[g1]

Thanks Robert and Dave for your your earlier advice. Is there any way to tell by looking if it's GRP or acrylic capped ABS ? (Incidentally, the cracks are where the front meets the awning rail just below level of bottom of window and the van about 9 yrs old).

Whatever material it is, are they likely to spread? I was thinking of making a mark at the end of each crack and leaving for a month or so or do you think they're best repaired asap ?

Thanks,

Wes

 

[rob_jax]

Wes,

The easy way to tell between GRP and Acrylic capped ABS is to look at the back of the sheet - GRP is rough on the back, the other is smooth on both sides. But GRP can now be made in the same way as Acrylic capped ABS - and have a smooth top and bottom......

GRP and Acrylic capped ABS do feel different to the touch and they look different, the GRP Gel-coat has a visible depth.

But given the age, I'd guess GRP

Will the crack spread - must certainly but not too fast. And only when you tow the caravan - as the framework moves, the panel will flex and the crack will spread. Not completely true - if you let water get underneath, the crack will expand during freezing weather.

If you plan to fix this yourself, or have it repaired professionally, the sooner the better.

If you can get access to the back of the panel, then you can lay on a section of glass matting, soak and stipple with GRP, and that will cure the fatigue and strength issues with the panel.

Then gouge out the crack and fill with white (or body coloured) polyester resin (that's the P in GRP)

Robert

As an aside - the first thing I built with GRP was sea canoe, then when I was flying gliders a lot - I made mouldings to improve aerodynamics in GRP - a set of wing extensions (winglets) for the end of the wings (and look like a curled hand) would otherwise cost

 

[Robert_374242026]

Today i looked again at the hairline cracks on the front of our Coachman.When the gas locker is opened you can see right up to the area where the cracks are but in my case they are not right through the ABS.So by removing the protecting cover fixed by two srews i will coat the inside with the matting/resin stuff and fill the outside with white gel coat as suggested.

 

[Robert_374242026]

I mentioned that i was going to apply resin/matting to the underside of the ABS which has got these cracks in but cannot get definate advise as to whether this method would "stick" to the ABS. Is there anybody out there who does know?, would be much obliged for an answer.

 

[rob_jax]

Robert,

If you are sure the material is ABS, then you must use an ABS compatible repair kit - you may be able to buy this as a bumper repair kit.

If it is GRP - then it's an easy repair - the polyester resin easily and permanently bonds to the old resin.

Robert