I am experimenting with some aerial designs and wondered if anyone
had used / knows whether
hot melt glue is good to seal and waterproof connections and its
electrical characteristics ?

(I will just go and stick some in the microwave with a glass of
water and see if it melts ! )

Thanks,

Nick

It won't melt easy in the microwave.

It is relatively good performance for shortwave. But be aware there are several different substances in sell as hot melt glue.
You cannot easely extrapolate to other frequencies other than 2.45GHz !

regards -
Henry

--
www.ehydra.dyndns.info


"Nick" schrieb im Newsbeitrag ...
| I am experimenting with some aerial designs and wondered if anyone
| had used / knows whether
| hot melt glue is good to seal and waterproof connections and its
| electrical characteristics ?
|
| (I will just go and stick some in the microwave with a glass of
| water and see if it melts ! )
|
| Thanks,
|
| Nick
|
|

Hi Henry,

Thanks for that - I will see if it affects the signal / SWR if I
place it next to the aerial as well then.

Cheers

Nick

One other posibility , tho never tried it, is the
repair kit (fiberglass), for boat hulls, kind of
an epoxy resin, might also work, tho obviously
more expensive. Just a suggestion-- Jim NN7k

Nick wrote:
Hi Henry,

Thanks for that - I will see if it affects the signal / SWR if I
place it next to the aerial as well then.

Cheers

One problem, maybe....

The hardener for fiberglass resin is methyl ethyl keytone peroxide it
reacts with the cobalt in the resin.
I have no idea of what that would do on a circuit board. I do know however,
that fiberglass panels work well as insulators.
, Having built boats for 18 years , I have some large panels (cutouts from
building boats) that I use at the feed point, for (multi wire) parallel
dipoles.
FRP- fiberglass reinforced plastic ..makes a good insulator and it
extremely strong.



"Jim - NN7K" wrote in message
. net...
One other posibility , tho never tried it, is the
repair kit (fiberglass), for boat hulls, kind of
an epoxy resin, might also work, tho obviously
more expensive. Just a suggestion-- Jim NN7k

Nick wrote:
Hi Henry,

Thanks for that - I will see if it affects the signal / SWR if I
place it next to the aerial as well then.

Cheers

On Sun, 10 Jun 2007 17:23:40 -0400, "merlin-7"
wrote:

One problem, maybe....

The hardener for fiberglass resin is methyl ethyl keytone peroxide it
reacts with the cobalt in the resin.

I use a lot of MEKP and Cobalt with Vinyl Ester Resin (Dow Derakane)
in building an airplane,
http://www.rogerhalstead.com/G3_files/GIII_Diary.htm but I've not seem
"or smelled" it in epoxies. Once mixed it has a very sharp smell. The
Cobalt is a "promoter" and the MEKP is a catalyst. Nasty stuff on bare
skin. MEKP and Cobalt have a bad disposition if they get together.
Keep well apart. Derakane has a much lower viscosity than most
epoxies.

OTOH the West System Epoxy sure does get hot when it decides its time
to cure and you don't need to wear a mask for organic fumes.

I have no idea of what that would do on a circuit board. I do know however,

Both work just fine, but while you can change your mind with the hot
melt glue it's difficult to do with the resin and epoxy.

Sand and fill, sand and fill...fill and sand, fill and sand...

that fiberglass panels work well as insulators.
, Having built boats for 18 years , I have some large panels (cutouts from
building boats) that I use at the feed point, for (multi wire) parallel
dipoles.
FRP- fiberglass reinforced plastic ..makes a good insulator and it
extremely strong.

And very sensitive to UV light unless protected.

Nick wrote:
I am experimenting with some aerial designs and wondered if anyone
had used / knows whether
hot melt glue is good to seal and waterproof connections and its
electrical characteristics ?

Ordinary semi-translucent HMG is excellent for electrical sealing, both
indoors and outdoors, and has very good insulating and RF properties.

(I will just go and stick some in the microwave with a glass of
water and see if it melts ! )

HMG is chemically very similar to polyethylene, so it has very low
losses at 2.45GHz and all lower frequencies. That means you can use it
in almost any RF application where moulded polyethylene would be OK.

The only significant differences are mechanical. HMG is softer and more
flexible, and has a lower softening temperature, but those properties
also make it a better adhesive and sealant.


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

"Ian White GM3SEK" wrote in message
...
Nick wrote:
I am experimenting with some aerial designs and wondered if
anyone
had used / knows whether
hot melt glue is good to seal and waterproof connections and its
electrical characteristics ?

Ordinary semi-translucent HMG is excellent for electrical
sealing, both indoors and outdoors, and has very good insulating
and RF properties.

(I will just go and stick some in the microwave with a glass of
water and see if it melts ! )

HMG is chemically very similar to polyethylene, so it has very
low losses at 2.45GHz and all lower frequencies. That means you
can use it in almost any RF application where moulded
polyethylene would be OK.

The only significant differences are mechanical. HMG is softer
and more flexible, and has a lower softening temperature, but
those properties also make it a better adhesive and sealant.


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom
(RSGB)
http://www.ifwtech.co.uk/g3sek

Hi Ian,

Thanks for that input - I did put some in the microwave and it was
fine as you said, and I have wrapped / smeared
some around some 14 gauge Cu wire and bent it around and it adheres
remarkably well ! Any idea how it suffers UV ?

It only really needs to last a year or so as by then I am re-doing
aerials and things...

Thanks again,

Nick

"Nick" schrieb im Newsbeitrag ...
| Thanks for that input - I did put some in the microwave and it was
| fine as you said, and I have wrapped / smeared
| some around some 14 gauge Cu wire and bent it around and it adheres
| remarkably well ! Any idea how it suffers UV ?
|
| It only really needs to last a year or so as by then I am re-doing
| aerials and things...

All plastics suffer from UV if they do not mixed with chemical stabilizers. Often that is ordinary carbon.
For a year lasting that should be of no problem.
Be aware, that the material will considerable soften above 80°C celsius.

I use it often. Cheap and of good value for money.

regards -
Henry

Nick wrote:

Thanks for that input - I did put some in the microwave and it was fine
as you said, and I have wrapped / smeared some around some 14 gauge Cu
wire and bent it around and it adheres remarkably well ! Any idea how
it suffers UV ?

Not bad at all - much better than epoxy, for example. It turns slightly
more opaque, but doesn't crack or peel.

It only really needs to last a year or so as by then I am re-doing
aerials and things...

You don't say where you are in the world, but in these latitudes ( low
and mid-50s) I've used it for several years without problems. For a year
or two, I'd guess it would be fine almost anywhere.


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek