"New" diinghy, but damaged

[VicS]

I have been given this.

Unfortunately the outer skin is damaged in a couple of places.

Any suggestions on how to fudge some sort of repair

 

[BarryH]

Its plastic, so pass. Some sort of epoxy!?!

 

[dylanwinter]

roughen up the edges and slap some cheap polyester and chopped mat over it

total cost £15

bingo

D

 

[VicS]

I am using some epoxy at the moment
I may have some polyester resin.

I suppose it would be sensible to try both and see which, if either sticks better.

Id like to try to dry the foam core out a bit as well.

 

[charles_reed]

I am using some epoxy at the moment
I may have some polyester resin.

I suppose it would be sensible to try both and see which, if either sticks better.

Id like to try to dry the foam core out a bit as well.

Double-skin, foam-filled, vaccuum-formed. Make sure there is no water in the foam, before attempting any repair. Bag and hot-air dry with holes up.

Epoxy is superior to polyester for any repair but neither particularly successful, in my experience, as the skins delaminate.
The best you can do is make the interface watertight and fit rubbing protection strips.
The construction method had a brief nascence in the late 60's to early 80s - I had a Bonito with the same problem. If you want to stick any patches on use a hard-plastic adhesive, not nice stuff,
www.bostik.co.uk/sds/...sds/HardPlasticsClearAdhesive.../04415028.pdf‎

 

[jwilson]

From the photos of the two larger large holes it does not look like GRP - no signs of glass mat fibres - more a clean break, which is unusual for GRP. The edge damage does have some fibres showing though, so just maybe it is GRP. A number of double-skin dinghies have been made in various sorts of washing-up-bowl polyflexystuff that goes brittle when old and is almost unrepairable.

 

[greenalien]

For the best repair, split the hull and interior mouldings apart - this will then give the foam core a better chance to dry out - although, given its age, it may well disintegrate when removed. With interior as well as exterior access to the damage, a glass-epoxy patch applied from both sides has a much better chance of success, although the best option is to do a plastic welded repair using the same sort of plastic as the hull material - which could be ABS, or polystyrene - it's unlikely to be polypropylene. However, this is difficult, requiring a specialised hot-air gun, plus the correct plastic material for the repair. You may then need to replace the foam - make sure it's closed-cell type, either in slab form or as 2-pack.
If only applied from the outside, GRP and epoxy won't last - neither will stay attached to the plastic. For a quick bodge, try Sikaflex - it'll seal the holes and stick to the plastic, and you could then apply GRP on top - the Sikaflex will help hold it in place, at least for a while.
Depending on how wet the foam core is, the dinghy may sit lower in the water than originally designed - this means it will carry a reduced load and could be dangerous.

 

[chrisbitz]

What sort of foam do they use on boats?

Surely day 1 of the design meeting would specify closed cell foam that won't absorb water?

I'm assuming I'm missing a point here? Is it the same sort of foam that goes in the cavity of larger boats too?

 

[greenalien]

No doubt it was originally closed-cell foam - however, this may break down over time and become friable and porous, although this depends on the original chemical composition and isn't true for all closed-cell foam. I don't know what the implications are for larger boats with foam cores of similar material.

 

[srp]

I was given one of those some time ago, with very similar damage. Any repair will look like a bit of a bodge, so just slap a bit of epoxy /glass mat on it, or a plastic or thin stainless patch gobbed on with Sikaflex and self tappers. Or do what I did and ignore it - the closed cell foam won't soak up much water and it can drain out again when it's ashore. (Mine has been afloat on a garden pond for the last 8 years).
A stupid material to make a dinghy from, and the ugliest tenders known to man, but they are good load carriers and they row surprisingly well for their shape.

 

[oldharry]

Dont assume it is closed cell foam. I was given a similar 'project' dinghy with holes in the outer skin. I should have given it back.... the donor knew what he was getting rid of! The filler foam was saturated and the dinghy weighed a ton. Fortunately the outer skin was GRP, so cutting it off, removing the soaked foam, and replacing with closed cell was possible - but still vastly more effort than the dinghy was worth!

If its the same stuff as the old Tabur Yak was made of - basically the same stuff as those translucent plastic lunch boxes, then nothing, but nothing will stick to it for any length of time. The prescribed botch for a Tabur Yak is to 'weld' pieces of cut up lunch box over the damage using a hot air gun : too much heat, and suddenly without warning the hole gets a whole lot bigger.

 

[Giblets]

Any suggestions on how to fudge some sort of repair.

Good quality duck tape! (Well you did say "fudge"!)