Waterproofing... Help

[Divrdan007]

Last time I had me R/C boat out, I noticed it was taking on some water.
(Pro-Boat Nitro Fury)
I noticed a couple hair-line cracks in the hull (ABS Plastic).
There may be other cracks or leaks in the hull that I couldn't even see.
What is a good waterproofing product that I can spray or brush on the hull to
seal it?
As the hull is made of ABS plastic, I'm sure it flexes quite a bit as it hits
the chop in the water... so the waterproofing stuff should be plyable, durable,
yet assure a good water barrier.
Additionally, the stuff should have a good bond to ABS, and the end result
should be smooth.
Also... What should I do to the surface, (prior to waterproofing), to assure a
good bond?
Thanks in advance for any help.

[Fly Higher]

You want to get a couple of things before you start. Fiberglass cloth is
first. Depending on the size of the boat I'd go with 2 ounce cloth if it's
a small boat or 6 ounce for a bigger one. Next would be some liquid glue
made specifically for ABS. I'd be tempted to try a hardware store for the
right glue.

Then I'd clean the boat off real good. Probably even remove the engine,
radio etc just to have pleanty of room. Do a final wash with alcohol. In
the meantime, test the glue on a scrap piece of the plastic to make sure
it's not too strong.

The idea is to paint the glue on the plastic and lay the glass cloth on top
of it. Put the glue down first and then the glass. To try to paint it on
through the glass could cause you to apply too much and damage the plastic.
Especially if you use the 6 ounce cloth. Once the cloth is firmly on the
plastic, you can come back and paint epoxy on it to fill the weave. This
should give a good, tight seal and increase the strength. Depending on the
size of the boat I'd be tempted to do the outside of the hull too and simlpy
re-finish it.

F.H.


"Divrdan007" <divrdan007@aol.com> wrote in message
news:20030617080706.01247.00001005@mb-m18.aol.com...
> Last time I had me R/C boat out, I noticed it was taking on some water.
> (Pro-Boat Nitro Fury)
> I noticed a couple hair-line cracks in the hull (ABS Plastic).
> There may be other cracks or leaks in the hull that I couldn't even see.
> What is a good waterproofing product that I can spray or brush on the hull
to
> seal it?
> As the hull is made of ABS plastic, I'm sure it flexes quite a bit as it
hits
> the chop in the water... so the waterproofing stuff should be plyable,
durable,
> yet assure a good water barrier.
> Additionally, the stuff should have a good bond to ABS, and the end result
> should be smooth.
> Also... What should I do to the surface, (prior to waterproofing), to
assure a
> good bond?
> Thanks in advance for any help.

[Divrdan007]

>Subject: Re: Waterproofing... Help
>From: "Fly Higher"

>You want to get a couple of things before you start. Fiberglass cloth is
>first. Depending on the size of the boat I'd go with 2 ounce cloth if it's
>a small boat or 6 ounce for a bigger one. Next would be some liquid glue
>made specifically for ABS. I'd be tempted to try a hardware store for the
>right glue.
>
>Then I'd clean the boat off real good. Probably even remove the engine,
>radio etc just to have pleanty of room. Do a final wash with alcohol. In
>the meantime, test the glue on a scrap piece of the plastic to make sure
>it's not too strong.
>
>The idea is to paint the glue on the plastic and lay the glass cloth on top
>of it. Put the glue down first and then the glass. To try to paint it on
>through the glass could cause you to apply too much and damage the plastic.
>Especially if you use the 6 ounce cloth. Once the cloth is firmly on the
>plastic, you can come back and paint epoxy on it to fill the weave. This
>should give a good, tight seal and increase the strength. Depending on the
>size of the boat I'd be tempted to do the outside of the hull too and simlpy
>re-finish it.
>
>F.H.

Thanks for that suggestion, but I am afraid the fiberglass repair would add way
too much weight to the boat.
If I am unable to find a liquid product that would stick properly, and remain
flexible... I may just try your suggestion.
The Pro-Boat Nitro Fury is pretty small, (25"L x 10 1/2" beam) powered by a .12
nitro engine. She runs pretty fast now, but the added weight of all the
fiberglass and resin would really slow her down, (I think.)
I have seen a spray-on product that they advertise on TV, to be used to seal
leaks in garden hoses. I haven't seen the ad for a long time though. Would
anyone happen to remember what that stuff was called?
OR... know of a similar product that would ba available at the local
hardware/hobby shop?

[Umi_Ryuzuki]

If you can see the cracks, or flex the hull and open them up, I would suggest finding some low viscosity plastic cement and brush it onto, or into the crack.
Capilary action should suck the cement into the hairline, and weld the plastic closed.

"Plastruct" makes an general purpose Plastic solvent that would work on ABS called "Plastic Weld". Otherwise check in the yellow pages for a local plastic manufacturer. They work with acrylic/perspex, abs, and other plastics and they should have something that would weld the cracks.

The other option is pick up some sheet styrene, and glue it on the inside of the hull, behind the cracks.