I posted on this some time back, perhaps nearly a year, but can't seem to
find the original at the moment.

I have some moulded plastic fitting in my caravan which have proved flimsy.
I need to both repair and strengthen them.
As a first check, should a fibreglass repair kit - that is, two part epoxy
resin and some fibreglass matting - be suitable for this kind of repair?

I am about to investigate in more detail once I've emptied out the caravan
so I can get to the area in question.

Cheers



Dave R


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On 20/05/2021 12:04, David wrote:
I posted on this some time back, perhaps nearly a year, but can't seem to
find the original at the moment.

I have some moulded plastic fitting in my caravan which have proved flimsy.
I need to both repair and strengthen them.
As a first check, should a fibreglass repair kit - that is, two part epoxy
resin and some fibreglass matting - be suitable for this kind of repair?

I am about to investigate in more detail once I've emptied out the caravan
so I can get to the area in question.

Cheers



Dave R


What type of plastic? It's difficult to glue things to polyethylene and
polypropylene (for example), even though "sticky tape" of various sorts
will stick well.

Such a lot also depends on the loadings and requirements.

Traditional fibreglass kits use polyester resin rather than epoxy. It's
cheaper, more brittle, and does not stick quite so well to many things.
Epoxy plus fibre glass is good, provided it has the basic adhesion.
"Mechanical keying" is also a big help.

On Thu, 20 May 2021 12:12:55 +0100, newshound wrote:

On 20/05/2021 12:04, David wrote:
I posted on this some time back, perhaps nearly a year, but can't seem
to find the original at the moment.

I have some moulded plastic fitting in my caravan which have proved
flimsy.
I need to both repair and strengthen them.
As a first check, should a fibreglass repair kit - that is, two part
epoxy resin and some fibreglass matting - be suitable for this kind of
repair?

I am about to investigate in more detail once I've emptied out the
caravan so I can get to the area in question.

Cheers



Dave R


What type of plastic? It's difficult to glue things to polyethylene and
polypropylene (for example), even though "sticky tape" of various sorts
will stick well.

Such a lot also depends on the loadings and requirements.

Traditional fibreglass kits use polyester resin rather than epoxy. It's
cheaper, more brittle, and does not stick quite so well to many things.
Epoxy plus fibre glass is good, provided it has the basic adhesion.
"Mechanical keying" is also a big help.

I'm not sure how to tell what kind of plastic it is.

It is hard rather than soft+flexible.

Cheers



Dave R



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On 20/05/2021 13:46, David wrote:
On Thu, 20 May 2021 12:12:55 +0100, newshound wrote:

On 20/05/2021 12:04, David wrote:
I posted on this some time back, perhaps nearly a year, but can't seem
to find the original at the moment.

I have some moulded plastic fitting in my caravan which have proved
flimsy.
I need to both repair and strengthen them.
As a first check, should a fibreglass repair kit - that is, two part
epoxy resin and some fibreglass matting - be suitable for this kind of
repair?

I am about to investigate in more detail once I've emptied out the
caravan so I can get to the area in question.


What type of plastic? It's difficult to glue things to polyethylene and
polypropylene (for example), even though "sticky tape" of various sorts
will stick well.

Such a lot also depends on the loadings and requirements.

Traditional fibreglass kits use polyester resin rather than epoxy. It's
cheaper, more brittle, and does not stick quite so well to many things.
Epoxy plus fibre glass is good, provided it has the basic adhesion.
"Mechanical keying" is also a big help.

I'm not sure how to tell what kind of plastic it is.

It is hard rather than soft+flexible.

A crude guide is if it feels waxy then it is probably HDPE which almost
nothing will stick to reliably. If you can shave a piece off and try it
with various solvents and gentle heat that will distinguish cured resin
one time cure plastics from thermoplastics after that it is guesswork.

If you don't know what it is then slow epoxy is the least likely to
cause adverse solvent effects and be reasonably strong. Thermoplastic
glue sticks can be effective in the right circumstances too.

If you need a bit of flexibility and the load isn't too high I have had
some luck mending torn door seals with black Sugru (sp?).

--
Regards,
Martin Brown

On 20/05/2021 12:04, David wrote:
I have some moulded plastic fitting in my caravan which have proved flimsy.
I need to both repair and strengthen them.
As a first check, should a fibreglass repair kit - that is, two part epoxy
resin and some fibreglass matting - be suitable for this kind of repair?

Try to find out what the plastic is. There may be a symbol moulded into
it. If not, you could try Floplast SC250 solvent cement or similar, an
internet search will show you loads of suppliers.

A picture of the fitting might be helpful. If it's a plastic called ABS,
then the above will fix it "as new", and allow you to stick on more
similar plastic as reinforcement.

On Thu, 20 May 2021 14:35:07 +0100, Chris Bacon wrote:

On 20/05/2021 12:04, David wrote:
I have some moulded plastic fitting in my caravan which have proved
flimsy.
I need to both repair and strengthen them.
As a first check, should a fibreglass repair kit - that is, two part
epoxy resin and some fibreglass matting - be suitable for this kind of
repair?

Try to find out what the plastic is. There may be a symbol moulded into
it. If not, you could try Floplast SC250 solvent cement or similar, an
internet search will show you loads of suppliers.

A picture of the fitting might be helpful. If it's a plastic called ABS,
then the above will fix it "as new", and allow you to stick on more
similar plastic as reinforcement.

http://wiki.diyfaq.org.uk/index.php/
File:Broken_side_caravan_front_locker.jpg

and

http://wiki.diyfaq.org.uk/index.php/
File:Good_side_caravan_front_locker.jpg

Hopefully you will be able to see these.

I can't see any markings on the moulding but there could be some on the
inside. However taking it all apart could lead to more problems.

The edge of the plastic at the bottom of the door measures 3mm on my
digital callipers. I can't get the jaws in the hole but I assume that the
thickness is consistent.

Cheers



Dave R

--
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On 20/05/2021 17:52, David wrote:
http://wiki.diyfaq.org.uk/index.php/
File:Broken_side_caravan_front_locker.jpg

Eurgh. I'd *guess* it's some sort of foamed PVC. Floplast 250 sticks
that as well as ABS. You could experiment with some acetone, e.g. nail
varnish remover if you know anyone that uses such stuff, you could get
some on a clean rag and see if it dissolves any of the material when you
rub it on. If it does, solvent cement would be useful (the MEK in it is
rather more aggressive than acetone), but you still have the issue of
what to bond to it (maybe a ring doughnut shaped piece of stuff). More
of the same sort of material, or ABS.

However, is it either of those two plastics is the question!

On 20/05/2021 18:33, Chris Bacon wrote:
On 20/05/2021 17:52, David wrote:
http://wiki.diyfaq.org.uk/index.php/
File:Broken_side_caravan_front_locker.jpg

Eurgh. I'd *guess* it's some sort of foamed PVC. Floplast 250 sticks
that as well as ABS. You could experiment with some acetone, e.g. nail
varnish remover if you know anyone that uses such stuff, you could get
some on a clean rag and see if it dissolves any of the material when you
rub it on. If it does, solvent cement would be useful (the MEK in it is
rather more aggressive than acetone), but you still have the issue of
what to bond to it (maybe a ring doughnut shaped piece of stuff). More
of the same sort of material, or ABS.

However, is it either of those two plastics is the question!

Do you think it would be foamed at 3mm? I'd be more inclined to suspect
PE or PP, unfortunately.

But I agree with the rest. Given the geometry, after solvent testing it
would not be hard to do a little trial somewhere away from the damaged area.

I can't really figure out the problem from those images but, if there is
space behind, it might be possible to shape a piece of thin aluminium to
back up the whole damaged area. Then, if you attach that using pop
rivets from the front it's sometimes possible to make a fairly
inconspicuous repair even on polyethylene. (I have a heavy duty
wheelbarrow that I repaired that way). If you sandwich Sylglas tape
between the plate and the original that should give you quite a strong
repair.

"David" wrote in message
...
On Thu, 20 May 2021 12:12:55 +0100, newshound wrote:

On 20/05/2021 12:04, David wrote:
I posted on this some time back, perhaps nearly a year, but can't seem
to find the original at the moment.

I have some moulded plastic fitting in my caravan which have proved
flimsy.
I need to both repair and strengthen them.
As a first check, should a fibreglass repair kit - that is, two part
epoxy resin and some fibreglass matting - be suitable for this kind of
repair?

I am about to investigate in more detail once I've emptied out the
caravan so I can get to the area in question.

Cheers



Dave R


What type of plastic? It's difficult to glue things to polyethylene and
polypropylene (for example), even though "sticky tape" of various sorts
will stick well.

Such a lot also depends on the loadings and requirements.

Traditional fibreglass kits use polyester resin rather than epoxy. It's
cheaper, more brittle, and does not stick quite so well to many things.
Epoxy plus fibre glass is good, provided it has the basic adhesion.
"Mechanical keying" is also a big help.

I'm not sure how to tell what kind of plastic it is.

https://www.google.com/search?q=how+...+plastic+it+is

It is hard rather than soft+flexible.

Is it strong or brittle or bendy or what? What does it do?
Myself I'd have a bash at doing it and see what happens, if its naff now it
assumedly will be no naffer afterwards!
Brian

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This newsgroup posting comes to you directly from...
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Blind user, so no pictures please
Note this Signature is meaningless.!
"David" wrote in message
...
On Thu, 20 May 2021 12:12:55 +0100, newshound wrote:

On 20/05/2021 12:04, David wrote:
I posted on this some time back, perhaps nearly a year, but can't seem
to find the original at the moment.

I have some moulded plastic fitting in my caravan which have proved
flimsy.
I need to both repair and strengthen them.
As a first check, should a fibreglass repair kit - that is, two part
epoxy resin and some fibreglass matting - be suitable for this kind of
repair?

I am about to investigate in more detail once I've emptied out the
caravan so I can get to the area in question.

Cheers



Dave R


What type of plastic? It's difficult to glue things to polyethylene and
polypropylene (for example), even though "sticky tape" of various sorts
will stick well.

Such a lot also depends on the loadings and requirements.

Traditional fibreglass kits use polyester resin rather than epoxy. It's
cheaper, more brittle, and does not stick quite so well to many things.
Epoxy plus fibre glass is good, provided it has the basic adhesion.
"Mechanical keying" is also a big help.

I'm not sure how to tell what kind of plastic it is.

It is hard rather than soft+flexible.

Cheers



Dave R



--
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--
This email has been checked for viruses by Avast antivirus software.
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On Fri, 21 May 2021 09:11:18 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH the trolling senile asshole's latest troll**** unread

--
"Who or What is Rod Speed?
Rod Speed is an entirely modern phenomenon. Essentially, Rod Speed
is an insecure and worthless individual who has discovered he can
enhance his own self-esteem in his own eyes by playing "the big, hard
man" on the InterNet."
https://www.pcreview.co.uk/threads/r...d-faq.2973853/

On Thu, 20 May 2021 19:05:04 +0100, newshound wrote:

On 20/05/2021 18:33, Chris Bacon wrote:
On 20/05/2021 17:52, David wrote:
http://wiki.diyfaq.org.uk/index.php/
File:Broken_side_caravan_front_locker.jpg

Eurgh. I'd *guess* it's some sort of foamed PVC. Floplast 250 sticks
that as well as ABS. You could experiment with some acetone, e.g. nail
varnish remover if you know anyone that uses such stuff, you could get
some on a clean rag and see if it dissolves any of the material when
you rub it on. If it does, solvent cement would be useful (the MEK in
it is rather more aggressive than acetone), but you still have the
issue of what to bond to it (maybe a ring doughnut shaped piece of
stuff). More of the same sort of material, or ABS.

However, is it either of those two plastics is the question!

Do you think it would be foamed at 3mm? I'd be more inclined to suspect
PE or PP, unfortunately.

But I agree with the rest. Given the geometry, after solvent testing it
would not be hard to do a little trial somewhere away from the damaged
area.

I can't really figure out the problem from those images but, if there is
space behind, it might be possible to shape a piece of thin aluminium to
back up the whole damaged area. Then, if you attach that using pop
rivets from the front it's sometimes possible to make a fairly
inconspicuous repair even on polyethylene. (I have a heavy duty
wheelbarrow that I repaired that way). If you sandwich Sylglas tape
between the plate and the original that should give you quite a strong
repair.

The problem is that on one side the locking rod came out of the hole when
unlocking (design issue) and then went through the plastic when locking.

You should be able to see most of an off-round hole (to allow the fixing
to be adjusted) with shattered plastic below.

On the good side you can see a round metal guide clamped to the plastic by
two bolts so you can't see the hole.

The metal guide for the broken side isn't visible in the picture.

Looking at the whole thing - a very large sheet of black plastic with
various bends, lumps and bumps, I assume that this was probably made by
vacuum moulding a flat piece of plastic when warm and pliable but this is
just a guess.

My main concern with pop rivets and the like is not fouling anything, but
there does look to be some leeway, especially if the rivet heads are on
the inside. The main issue is access as I'm trying to work from within a
bulge so getting at the inside part may be tricky.

If I run out of time short term I plan to cut up a plastic container, cut
the hole, and duct tape it into place so that at least the end of the
locking rod is supported and pointing in roughly the right direction.

Thanks to all for the help so far.

Cheers


Dave R



--
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On 21/05/2021 13:05, David wrote:
On Thu, 20 May 2021 19:05:04 +0100, newshound wrote:

On 20/05/2021 18:33, Chris Bacon wrote:
On 20/05/2021 17:52, David wrote:
http://wiki.diyfaq.org.uk/index.php/
File:Broken_side_caravan_front_locker.jpg

Eurgh. I'd *guess* it's some sort of foamed PVC. Floplast 250 sticks
that as well as ABS. You could experiment with some acetone, e.g. nail
varnish remover if you know anyone that uses such stuff, you could get
some on a clean rag and see if it dissolves any of the material when
you rub it on. If it does, solvent cement would be useful (the MEK in
it is rather more aggressive than acetone), but you still have the
issue of what to bond to it (maybe a ring doughnut shaped piece of
stuff). More of the same sort of material, or ABS.

However, is it either of those two plastics is the question!

Do you think it would be foamed at 3mm? I'd be more inclined to suspect
PE or PP, unfortunately.

But I agree with the rest. Given the geometry, after solvent testing it
would not be hard to do a little trial somewhere away from the damaged
area.

I can't really figure out the problem from those images but, if there is
space behind, it might be possible to shape a piece of thin aluminium to
back up the whole damaged area. Then, if you attach that using pop
rivets from the front it's sometimes possible to make a fairly
inconspicuous repair even on polyethylene. (I have a heavy duty
wheelbarrow that I repaired that way). If you sandwich Sylglas tape
between the plate and the original that should give you quite a strong
repair.

The problem is that on one side the locking rod came out of the hole when
unlocking (design issue) and then went through the plastic when locking.

You should be able to see most of an off-round hole (to allow the fixing
to be adjusted) with shattered plastic below.

On the good side you can see a round metal guide clamped to the plastic by
two bolts so you can't see the hole.

The metal guide for the broken side isn't visible in the picture.

Looking at the whole thing - a very large sheet of black plastic with
various bends, lumps and bumps, I assume that this was probably made by
vacuum moulding a flat piece of plastic when warm and pliable but this is
just a guess.

It's a vacuum moulding for sure


My main concern with pop rivets and the like is not fouling anything, but
there does look to be some leeway, especially if the rivet heads are on
the inside. The main issue is access as I'm trying to work from within a
bulge so getting at the inside part may be tricky.

Another option if you want to fasten something to the *visible* side is
rivnuts (which are like pop-rivets but with a thread inside them). Much
used in kit-cars and the like, there are cunning tools that let you
position them without enough access on the visible side for a
conventional pliers or lazy tongs type tool.


If I run out of time short term I plan to cut up a plastic container, cut
the hole, and duct tape it into place so that at least the end of the
locking rod is supported and pointing in roughly the right direction.

Thanks to all for the help so far.

Cheers


Dave R

In article ,
David wrote:
I posted on this some time back, perhaps nearly a year, but can't seem
to find the original at the moment.

I have some moulded plastic fitting in my caravan which have proved
flimsy. I need to both repair and strengthen them. As a first check,
should a fibreglass repair kit - that is, two part epoxy resin and some
fibreglass matting - be suitable for this kind of repair?

I am about to investigate in more detail once I've emptied out the
caravan so I can get to the area in question.

The top hinge on my fridge broke the other day. May well have been my
fault - leaning on the top of the door.

It is made out of a semi rigid plastic. Being old, it may well have been
more flexible when new. But not very different from the sort of PVC
guttering etc is made of.

Luckily the break was in the top plate, rather than the hinge pin. So I
cut a piece of 1.5mm steel to cover the top plate and glued the whole lot
with Gorilla super glue. Left it a day to set fully, then painted the
steel to match the plastic. Seems to have worked OK.

--
*Happiness is seeing your mother-in-law on a milk carton

Dave Plowman London SW
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