Repairing cracks in Bondwood

[hitched]

We've noticed some cracks opening up in the bondwood on one side of our 1950s Roma and some bubbling on the roof. Photos 1-3 are of the cracks on the side and #4 is of the cracks with lifting on the roof.

A carpenter of many years has suggested sanding the bubbled areas so that the lifted laminate is removed and then levelling the surface with car bog and perhaps a similar treatment for the cracks on the wall. And then a serious repaint.

Does anyone have experience with successfully repairing this kind of damage or any ideas/opinions about the best way to go.

I wonder if these may have started whilst the caravan was a bit exposed whilst we built it's current shelter in which it's well protected from rain and sun.

Any thoughts appreciated.

[Don Ricardo]

Hi Hitched,

I'm afraid the cracking of the paint you have shown us is fairly typical of what can happen with a bondwood because of the movement in the ply. In my experience that is inevitable over time, but has probably been accelerated in this case by being a bit more exposed to the weather for a time.

I had the same problem when our Don was under a tarp roof for six months while we built it's new penthouse. The side most exposed to the elements deteriorated frighteningly quickly. It has only just been repainted, which involved sanding it back, using a filler to fill the cracks, painting the surface, sanding again, filling any residual cracks and sanding to get a smooth surface, and putting on another coat (or two) of paint.

I use high gloss oil based enamel, and usually count on getting five to seven years before having to repaint again. I think Cobber recommends using acrylic paint because of the technological advances in paint chemistry over the last few years means that acrylic paint expands and contracts without cracking better than oil-based paints. He may well be right (he usually is), but I've stuck with Dulux enamel, just because that's what our van was painted in originally.

There are some threads around that address the issue of the best paint to use and how to fill cracks, etc. I can't point you to any specifically, but if you do use the Search button or look in the Technical section you will probably find them...or ask Cobber - he always seems to be able to point to the right thread when you need it!

Keep asking questions on the forum and I'm sure others will tell you what they think.

Don Ricardo

[cobber]

G'day Megan,

I think we have had a chat previously about protecting this Roma ....aye?

Have you been able to put sides on the carport ? it would be the ideal thing to do because plywood caravans deteriorate quickly if exposed to sun or moisture continually.
If your van is exposed to those conditions and it is painted with an oil based enamel cracks in the paint, such as you are showing us, will develop more quickly than if it is painted with a water based acrylic. Moisture seeps in between the cracks and eventually softens the ply..... not good

OK............. your problem is the Roma is painted with oil based enamel and it's cracked...... what to do

It looks like it might have had numerous coats of paint applied over time and another coat now on top of all the other coats won't fix the problem.

As you say the problem is restricted to one side only, I expect you don't want to strip paint off the entire van... so I reckon you should just strip paint off the problem area back to the wood, give it a couple of coats of primer/sealer... sanding back to a smooth finish between coats, feather the edges where it meets the old painted areas and then get a good colour match and paint it with what is on the rest of the van....oil based enamel.

It won't be the perfect solution but it should stop further deterioration.
If you want the perfect solution strip all the pain off and have a look at this link to see what is recommended by the experts.

There was a suggestion on that other thread that the roof was covered with canvas, if that is the case I would just slit the bubble with a very sharp knife and squirt oil based enamel under it and over it and press it down when tacky

As has been mentioned by Don R if the van is exposed to the elements it will deteriorate..... no two ways about it, that is why ply wood vans need our love and protection if they are to survive as the true examples of …..”Australia's Touring Heritage”

Cobber.

[hitched]

Thanks for the advice - it is most appreciated.

Rest assured we took the advice re covering the sides in of the car port to ensure Roma is protected from the weather.

[millsy]

I have been repairing cracked bondwood areas in my two old vans with cotton bed sheet material. I just paint it on with water based paint. I used to mix up a slurry of aquadhere, watering it down a fair amount to thin it out. But now I just use slightly thinned water based paint. It seems to have all the bonding strength needed.

This follows the same principle as my plywood vintage glider I helped restore in the seventies. We had to 'rebag' the wings with dacron and dope. And If I remember correctly we did the fuselage too.

If you want the best finish on a side of a caravan you would first need to remove the old paint, which in itself is a big job of course. Then carefully prepare the surface to seal it with primer and filler, or full strength primer, into the cracks. Then to make sure the cracks don't just come back a couple of years later, cover the whole side with fabric as I explained. The fabric needs to be properly bonded with enough wet paint between the wood and the fabric, and a careful rubbing that smooths out the wrinkles and stretches it across the surface. But not so much rubbing that all the bonding paint gets forced out. But certainly enough to 'rub out' any lumps of excessive paint under the fabric though.

When this first 'painting'/bonding dries, then two or three more coats are needed to fill the grain of the fabric and produce a nice smooth finish. I have not actually covered the whole side of my van like this. Up to this stage I have only done 'quick fixes' with smaller strips and patches as required. Of course all of these little repair jobs are visible due to their edge lines. That's why I think the whole side would need to be covered. Might need to do it in three or four sections though, just to make it feasible.

A bit of practice on some scrap plywood would be the way to go I think.

I think this sort of treatment would last twenty years or more. A lot more if the van was under shelter. My two vans have never been under shelter and I am pretty sure the patches I did back in the eightys are still good today.

[scootman]

Another thing you can try is to use a very sharp stanley knife and draw your cutting line with that before using a saw.

[griffin]

It might be worth painting the area with Earl's Wood Hardener for rotted wood. That sounds a bit drastic but it claims: 'fully penetrates and revitalises rotted wood. Soft and rotted wood fibres are restored to near original strength." It is pre-mixed, water based and environmentally friendly.

I used it on in my Olympic on the edges of the chipboard cupboard doors which were flaking due to moisture absorption. After two applications it's was as tough as goats knees, and I painted the edge to make sure. The bottom of the chipboard table was the same and again two coats and its fine. I didn't paint it to see how it would go and there's no sign of flaking after two years.

Its even Aussie made it seems by Timbermate Products Pty Ltd, www.timbermate.com.au might give details. Ph 1800 354811.

Got mine from Bunnings, where else!

George

[groovygramps]

Hello Hitched,

How uncanny that I accessed the forum today, I am unable to do so as often as I would like.
Sorry to hear of your problem. I think it is about 9 years or more since restoration.

If you would like to have a look under the Members Photo Album page 22 Groovygramps 50's Roma Bondwood - reply 8 - 19th. April 2008 you will be able to read how Roma was restored.

Roma to my knowledge never had any canvas covering. Roma was always kept totally undercover with no exposure to moisture when not in use.

I still miss her but am happy that she has gone to a loving home.

kind regards groovygranny (Coral)

[hitched]

Hi Coral aka Groovygranny,

Nice to hear from you! We are taking Roma to the Nationals for a jaunt. Roma is well loved and enjoyed by us. Roma attracts her fair share of attention and admiration where ever she goes. She will certainly be amongst some beauties at the Nationals.

re problem - it is only small cracks in a relatively small area and we are keen to get on to this early.

Roma sends her love as we do too. How is Brian?

fond regards Megan and Patrick

[hitched]

A BIG thanks to everyone who posted their advice and experience - most helpful - thanks again