How To Repair Peeling Plywood With Epoxy
- #ane
Deleted member 36384
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Hi,
Water has entered ply from the edge which has caused deterioration ranging from complete crumbling of the ply edge to but dampness.
The source of the water (rain) has been identified and corrected and all is now drying out. To pull the whole panel out and supersede it would be a large job and before undertaking information technology I am investigating alternative methods.
The damaged edge of the panel is accessible and I can cut dorsum to good ply where it crumbles away, which is just a very brusque length. The small impairment, which is the majority (some ply separation as well as the dampness), I would like to stabilise and then preserve, if suitable.
The panel is the interior lining of the saloon, running along the double-decker roof sides, surrounding the windows. A previous owner filled the gap betwixt the frames and panel with brown sealant, meanwhile the h2o had still been entering from underneath the frame, behind the sealant.
Any ideas, or products to effect repair and preservation. The stop will exist painted. A wooden motor boat I delivered was held together with Git Rot. I am not and then sure this is a good idea but would like your opinions.
Regards,
BlowingOldBoots
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- #2
Tranona
Well-known fellow member
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- 10 Nov 2007
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- 35,286
Epoxy with a filler such as microballoons. Can likewise use veneers or drinking glass tape to build upwards thickness. Sounds like it is not-structural and so yous need to concentrate on stabilising by drying out and soaking in epoxy then building upward the surface to be level and smooth to take your last finish. Bodily textile will depend on extent of damage and rigidity of what is left.
- #3
The problem with end grain rot in ply is the altitude information technology travels within the laminations. Rain ingress tends to rot from the inside out, and then that the centre laminations have rotted farther down the exterior veneers which have remained dry. Fifty-fifty with BS1088 the interior sheets may be of inferior grade material which rots faster making water ingress impairment worse than it appears from outside. Still information technology is possible to make an 'invisible repair' to a ply sheet, although it requires a caste of skill.
I have seen terminate grain rot go right downwards one unmarried internal lamination, effectively splitting the front end from the back, although from exterior the ply looked fine. It is not unusual where the outer veneers only evidence damage an inch or 2 back from the border, to find the water has penetrated upward to a foot down the inside laminations, even on BS1088. If the interior sheets are thicker than the external veneers then this is invariably softer woods, and although the skin veneers may look perfectly OK, the inside laminations will near certainly be extensively damaged.
The 'invisible repair' is acheived past finer creating a long scarph along the border of the sheet where the new ply is going in. The scarph needs to be at least iv:1 to give a potent joint, glued with epoxy. In a structural component, 6:one or more than will be needed. On non structural trim, a narrower scarph volition exist suffice depending on the thickness of the ply.
Substituting with another material tin be done, simply it can be a lot more hard to achieve a properly matching finish. The problem with substitutes similar Git Rot is firstly information technology is extremely difficult to dry the damaged internal laminate sheets, because the glue is waterproof and traps the wet, allowing information technology to continue to destroy the ply. Git Rot type compounds volition not displace whatsoever moisture remaining, and then just seal it in with disasterous results. secondly, it is extremely hard to get any such materials to penetrate and fully impregnate the damaged timber right back to where information technology is sound. This is why sheathing an old gunkhole and so rarely works. New ply should have less than 15% moisture content, so volition allows epoxies etc to take up. Epoxy suppliers frequently recommend even lower wet content than that as a maximum permissible level for ply. Older ply which has been immersed or has been damp will have months of forced drying to get dorsum to such a low moisture level, and this is rarely practical.
I take tried almost of the 'patent repairs' over many years of owning elderly plywood boats, and establish the hard fashion that the only cloth that really works on plywood is more plywood.
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- #four
Might exist easier to supervene upon? See this blog, from here onwards for a few pages.
- #5
Get it really dry out and glaze with epoxy, thin equally you similar, a few coats. It will soak well in and build up the adhesion between plies whilst actually adding structural integrity to the veneers.
I did it on some compound curved sections at the bow when restoring my Heron. It worked an absolute care for. Also stabilised the transom on some other boat the same way.
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- #half dozen
As others take indicated the get-go and most important signal is to ensure it is a dry every bit possible, no amount of work or coin will fix your problem if moistuire is nevertheless inside.
I utilize oestrus lamps and a moisture meter befor even contemplating this blazon of repair.
Once dry, expose the edge and use thinned epoxy resin, yous tin sparse it by adding up to 35% Methylated Spirits by weight to a mixed batch or epoxy resin.
Make pocket-sized batches and add together slowly allowing the resin to become wall inside the laminated layers.
When information technology volition take no more mix in some Micro-fibres, this will add strength but clean up as you go considering it's hard piece of work sanding any excess off.
You could Micro-balloons (Closed cell only) if structural strength is non disquisitional, it's very easy to sand.
Expert luck and fair winds. 
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- #7
I successful method of repairing plywood if not fitting a complete new console is firstly equally others have said, eradicate the existing decay & cut the area out into the parent console with directly edges.
Scarfing plywood in situ is extremely hard & non like shooting fish in a barrel to fit. Improve to scribe a direct line virtually 2" dorsum from each straight edge & cut one-half thickness abroad to leave a clean step. The new panel is cut precisely to fit with similar step. This can then exist offered up & finally fabricated a perfect fit with no gaps, quite easy generally.
Now gum & spiral the console into position. You can use a permanent batten on the reverse side for extra strength overlapping the whole joint, or only a temporary 1 to spiral into to agree the glue join together whilst setting.
There are one or two photos of this type of repair on my website http://www.turbolink.co.united kingdom of great britain and northern ireland/seasurveys2011/example2.html
John Lilley
- #8
Although you say that replacement is a big job, y'all'll have noticed that the repair is not exactly a minor affair either! I've spent hours or even days taking rotten pieces out of a ply deck and trying to attain a good border to fit new panels in. Even and then, the new metric ply was slightly thinner than the original imperial size so had to be faired upwardly to the old level. When the boat was sold on, the new owner took the whole deck off and replaced it in total, in less time than it took us to patch it. This had the added advantage that he could seal the whole panel, edges included with epoxy before it was fitted.
Total replacement may seem similar a brave decision, but may well relieve an atrocious lot of time and reach a far better result.
Rob.
- #nine
Agree with Johnlilley, a stepped scarph faired along one of the internal veneers will do just as well, and is probably easier.
- #10
This is a production which is known every bit CPES (articulate penetrating epoxy sealer) in the States and is epoxy based but very sparse.
http://www.mbfg.co.uk/epoxy-resins/eposeal-300-epoxy-primer.html
Information technology volition soak into the ply and seal information technology from any future h2o ingress. you will however need to replace the rotted ply first by cutting back to good forest and and then coat with this. It wont do anything for the rotted ply simply is much improve at getting into the wood than normal epoxy. Three or four coats will completly seal the woods.
Tom
- #11
Deleted member 36384
Invitee
Thanks everyone for the very useful replies. I now have some tips and guidance which volition help me to make the conclusion to repair or supercede. I am now of the opinion that the panel volition have to come off. At the bottom of the console is a shelf, which runs from the lower edge of the panel and under the side deck; below the shelf are lockers. Hence, its worth knowing if this shelf is suffering h2o impairment.
You know what its like, the panel will come off and then its headlining, trim, hidden wire etc etc. But i must do the right job on a boat!
Hopefully the console can be salvaged, if not, it should at least make a skilful plenty template.
I appreciate your communication and insights.
Thank you,
BlowingOldBoots
- #12
I meet this repair as existence a 2-stage process: stabilise what you already have, and then effect a repair.
Stabilising isn't every bit easy every bit it might first appear. Cutting-back to good, dry out woods is the theoretical answer, only as someone has already said, moisture creep forth the inner laminations may continue further-in than you lot might appreciate.
Estrus lamps and a dehumidifier is 1 approach - just you'll need to completely 'mask off' an area with polyethylene sheeting and tape so that you don't dehumidify the whole gunkhole plus a fair few cubic metres of temper every time yous open up the hatch to see how things are progressing ...
If you tin can get the wood thoroughly dry by such means, then a lick of general purpose epoxy resin diluted with c. ten% acetone or thinners applied to the end grain should do the play a joke on.
Another approach would be to have that some moisture will remain after cutting-dorsum, so use that wet to cure polyurethane sealant brushed onto the end-grain. That sealant can then be used as a base of operations for an epoxy-based repair. The only existent disadvantage to this approach is that you'll take a helluva lot of polyurethane sealant left over subsequently.
Thousand.P. epoxy resin and G4 sealant tin both exist obtained from:
http://www.resin-supplies.co.uk (no connection, simply a very satisfied customer over many years).
I won't comment of the bodily repair process - there's been some practiced suggestions so far - a stepped repair sounds good to me.
Ok - ignore all of the in a higher place - I've just seen the above post which arrived whilst I was typing mine ...
- #thirteen
SHUG
Active member
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- eighteen Dec 2022
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Many resin based glues rely on water to cure so it would seem reasonable to work this kind of adhesive into slightly dam ply and then clamp up to cure.
- #xiv
Yes but they don't displace water in the timber - once more they just seal it in.
- #15
I'd 2d the 'replace' option every bit it volition final longer and you go the satisfaction of knowing it'southward done well and will ultimately be a improve job. I'd certainly resin-glaze the new plywood however - unless it will be a varnished/caulked finish etc or otherwise sealed.
I'g facing a like dilemma with the Fletcher Arrowbolt I'grand restoring. The ply flooring was rotted away, just the stringers, whilst sopping wet have only rotted at the exposed ends - the majority yet existence solid. However I have decided that although more piece of work & toll, the all-time method is probably to supersede completely - it's the just manner to exist sure it won't come back to bite you lot afterward! Thus that's what I'm doing even though it will almost certainly push the project well into next twelvemonth. Never having done whatsoever gunkhole restoration earlier it'southward proving an interesting and enlightening experience rolleyes, but as all hardwood and plywood will exist resin coated earlier plumbing fixtures, I will at least have faith in the finished commodity non rotting again for a very long time.
Thread over on the Mobo forum if you want a skilful laugh at the calibration of the job in hand! http://www.ybw.com/forums/showthread.php?t=285958
Source: https://forums.ybw.com/index.php?threads%2Frepairing-ply-decay-due-to-water-ingress-other-solutions.302736%2F
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