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Post by Koala on Dec 29, 2007 16:50:34 GMT 10
I am looking for a bit of advice on what may be causing a problem I have with a couple of patches on the teardrop. The problem is that when the teardrop gets wet the ply seems to swell in a couple of places around the door openings. I have used sealer and undercoat before painting using oil based paints and have done this exercise twice but the problem remains. And yes I have painted the ends of the ply. It looks like what happens to untreated ply when left out in the weather, how it splits around the edges but it doesn't break the paint on mine.
When it dries out you wouldn't know there had been a problem. I guess no one else would notice unless looking for it but it annoys me.
Any suggestions??
Ken
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Post by Deleted on Dec 29, 2007 20:52:09 GMT 10
Hi Ken Sand the end grain of the timber and treat / paint with bondcrete. Then repaint top coat. Once water gets into the laminates of ply it works like a capillary action and is drawn up through the grain. swelling in wet/steamy conditions and recoverying in warm/dry climate Take a look at the "Skirts " of most ply vans. At some stage they have been either trimmed shorter as the rot works its way up from the bottom edge or... has had a skirting board nailed, screwed/ glued around the bottom edge to hide any uneveness, I have just been through this exercise on "Mildred.D. splinterwood" If vans are left under carports etc Condensation dripping down the sides of the van on damp nights and getting behind the j mould where it wraps around and heads along to the bottom of the door is a common cause of rot in this area. But hey... what would i know.about preserving firewood  . i am a new member of the fibreglass trust  . Reddo |
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Post by Franklin1 on Dec 29, 2007 20:55:08 GMT 10
Hi Ken, I'm guessing you've already spent a fair bit of time sussing out the cause, so my opinion has probably already been considered... From your description, it would appear the bond in the layers of ply has broken down. The website for the Engineered Wood Products Association of Australasia gives a brief mention of plywood swelling... paa.asn.au/TechInfo/FinishesExterior.html , and scroll down to the second heading "Edge Sealing" (but also read the top heading on painting...they don't advocate enamel paints.) Elsewhere within the website is information on the different bonding classifications used in ply manufacture... paa.asn.au/TechInfo/InfoGlueLines.htmlMaybe the ply you've used wasn't the most suitable, or maybe it was faulty to begin with?? Depending on how big the area is that swells, you might be able to inject some resin/hardener glue back into the glueline to re-bond the layer(s), or gently prise the layers apart (along the cut edge) with a chisel and butter some glue back into the joint with a knife. Why only around the door?? Why not around a window (assuming you have one), or along the bottom edge of the cabin, or anywhere else there is a cut edge "exposed"?? Sorry I can't help more... cheers, Al. |
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