Not sure about using hot glue but where I work, we have a plastic welder
that can weld PE,PP,or ABS. We use it to fabricate mainly PP. The way it
works is that it is pneumatically fed melted .125 dia. plastic through the
gun and out a heated tip. The heated tip premelts the parent plastic and
simultaneously lays down a bead of new material. The trick is that the new
material does not have a chance to oxidize before it is in contact with the
parent material and it is at the correct temp. of course. The problem with
the welds is that the physical properties will be different then the molded
(?) parent part; i.e. different flex, elongation, etc.

All that said, it is an expensive tool; about $2400.00. Obviously not worth
it in your case. But I have seen a welder that Harbor Freight sells if I
recall. I'm not sure how it works, but knowing their tools, it may sorta
kinda work once or twice which may be good enough and cheap. Another option
might be to find someone who fabricates plastic chemical tanks. In my past
life I worked with platers who used fabricated plastic tanks, and those guys
used welders.


Good luck - it may be wise to stick close to shore in your polyboat.

Rob H


"Ignoramus32317" wrote in message
...
In addition to my 21 ft boat, I recently found a 4x8 plastic boat that
someone put out as garbage. It is kind of doublehulled and seems to be
made of high density polyethylene (HDPE), like plastic buckets. I am
delighted because I can use this boat on some little lakes nearby.

It seems super safe (double hull) and super stable.

It does have however a few small cracks in the hull that need
repair. What is the right way to repair HDPE? Can I use glue guns with
hot melt glue?

i

Poly can be repaired with epoxy but only if you are very careful and follow
the WEST directions carefully.
"Ignoramus32317" wrote in message
...
In addition to my 21 ft boat, I recently found a 4x8 plastic boat that
someone put out as garbage. It is kind of doublehulled and seems to be
made of high density polyethylene (HDPE), like plastic buckets. I am
delighted because I can use this boat on some little lakes nearby.

It seems super safe (double hull) and super stable.

It does have however a few small cracks in the hull that need
repair. What is the right way to repair HDPE? Can I use glue guns with
hot melt glue?

i

Virtually NOTHING will stick to HDPE except HDPE. If you're located
near a ski area or in the northern part of the US where skiing is done,
take the boat to a ski repair shop. HDPE requires an 'artist' to weld
the cracks, etc. with similar HDPE 'welding rod'. A local 'plastics
welder' can also do the same. Most other 'repairs' will soon fail.

Ignoramus32317 wrote:
In addition to my 21 ft boat, I recently found a 4x8 plastic boat that
someone put out as garbage. It is kind of doublehulled and seems to be
made of high density polyethylene (HDPE), like plastic buckets. I am
delighted because I can use this boat on some little lakes nearby.

It seems super safe (double hull) and super stable.

It does have however a few small cracks in the hull that need
repair. What is the right way to repair HDPE? Can I use glue guns with
hot melt glue?

i

take the boat to a ski repair shop. HDPE requires an 'artist' to weld
the cracks, etc. with similar HDPE 'welding rod'. A local 'plastics
welder' can also do the same. Most other 'repairs' will soon fail.

You can buy an inexpensive repair kit and"welding gun" kinda like a
soldering gun at any tool outlet like Northern Tools and do it yourself.Make
sure you use the correct welding rod(polypropolene).
I have the same boat you found and they are great boats! Put an electric
trolling motor or up to a 5hp gas outboard. On the electric use 2 batteries...1
to go and 1 to come back.Hard wire the batteries to a 1-2 or both perko
switch.Do NOT use the alligator clips.

HAVE FUN!
Larry Hill

Thanks Larry. I will experiment a little, I bought a glue gun from Home
Depot and I will try to just put a bead of glue on some inconspicuous
place, and see how it will hold up. If it does not, I will try some
plastic weldong. The boat is supersafe because it is full of styrofoam
inside, I think, and I need it to boat on several small lakes
nearby.

A glue gun will not work. You have to melt the polypropolene.
Larry Hill

A glue gun will not work. You have to melt the polypropolene.
Larry Hill

A local vendor showed me a technique for installing fittings into plastic
holding tanks.
It's called "spin welding", and it sounds really complex until you see that it
simply involves cutting a hole and then,literally, spinning the new fitting at
a high speed until the plastic melts and bonds together.

hiya
Im a plastics engineer by trade and yes you are correct almost no glue will
adhere to HDPE or PP (polypropolene) do you know which one it is ? I once
saw topper dingies being moulded on 6000 ton machines and i think they were
PP.
Anyway, welding is the way to go, epoxy is just silly. Most good auto
bodyshops have plastic welding gear for the repair of car bumpers (
fenders ) most car bumpers are ABS though so they may have to order in some
filler rod to do your job , Just ask

fragged

"Ignoramus32317" wrote in message
...
In addition to my 21 ft boat, I recently found a 4x8 plastic boat that
someone put out as garbage. It is kind of doublehulled and seems to be
made of high density polyethylene (HDPE), like plastic buckets. I am
delighted because I can use this boat on some little lakes nearby.

It seems super safe (double hull) and super stable.

It does have however a few small cracks in the hull that need
repair. What is the right way to repair HDPE? Can I use glue guns with
hot melt glue?

i