Responses: Resins

Responses: Resins

My original post,

We are having a hard time finding resin that is easily sanded and will set up
well (like sometime this month) when using a thin coat. In the old days I
slushed many a hard socket with polyester resin to tighten the fit. Maybe
I'm rusty but even the polyester we get today doesn't seem to set up well
when used in a coating or thin layer type of application. Siegelharz is too
hard to sand. Any Ideas would be appreciated.

The responses;
*************
Eddie, I use a Selley's product, Plastibond. This is a automotive body
filler that can be put in the socket soft, then the patient dons the leg
with a gladwrap (cling film) film over the liner to keep it clean. This
stuff sands well and sets quickly.
*************
Eddie, in my opinion you really only have one choice and that is the 4110
resin you are using now. Here is an idea though try using powder mixed in
with the resin and use more naugutuck. I am talking regular baby powder or
even amputalc. This makes it easier to sand out, trust me.

***********
I've found that preparation is the most important part of a 4110 finish in
the socket. Using a fine soft-end cone(tripled up is good so the very end
will give slightly as you sand) with either a flexible shaft grinder or a
Trautman(I prefer the shaft grinder) lightly sand the entire surface of the
socket.

If you are applying 4110 over a previously treated area care should be
taken to remove as much of the old finish as possible. Using a med. grit
sandpaper (120-150) hand sand the entire surface of the socket. Then hand
sand the entire surface again with 360 grit sand paper. You can use wet/dry
paper to wet sand the socket but if you do this, make sure to dry the
socket completly before proceding. When you are satisfied with your finish
blow out the dust with an air hose after you make sure any residual
moisture in the air line has been released. Never touch the socket with
your hands once you are finished sanding. If you have ever experienced
fish eyes in your finish this is caused by the oil in your hands or
silicone in the air that someone has recently used nearby.

Place the socket securely in a leg vice. I like to put the posterior seat
down. This lets me get a good smooth surface over the seat. Now begin
mixing your resin. Never mix ANY 4134 with your 4110 as this will cause a
tacky finish. Pour out approximately 150 grams of 4110, add to this 10
grams of paste-mix thoroughly.

Prepare a 1 wide paint brush by cleaning it in MEK or denatured alcohol. I
like to tape a couple of depressors on the sides of the brush so I don't
have any problems reaching the distal end. You are now ready to promote
your 4110 mixture with 1 - 1 1/2 cc of promoter. Mix thoroughly. Begin your
painting at the distal end of the socket, working your way up and around
the socket- finishing over the posterior seat. You must continue to paint
the surface of the socket until the resin begins to gel. Always be
careful to brush out the runs as you go. The resin will try to puddle in
the posterior distal portion of the socket- you must try to keep this resin
brushed out.

Your ultimate goal is to have your resin set up as you are taking your last
brush stroke across the seat. This takes alot of practice. Before applying
your second coat repeat the prep process. If your first coat is very rough
then use a machine sander again. If pretty smooth you can get away with
just hand sanding on the second coat.

Hope this helps you out some and its nice to see someone using something
from the old days!

*************
Segalhearts..... is a good one if you have good vents. Very toxic smelling.
You can use AME but look at the brand specs. Some require 2% and some
require 3% using the values suggested by the manufacturer you have about 20
to 25 min. working time. Increasing this slightly will reduce the reaction
time.
***********
Add microballoons (microspheres) to your Siegelharz resin, to thicken it
to a heavy cream consistency before slushing your socket. It will set
up well and is easier to sand.
************
i have found that a majority of the new resins won't set up unless it
is under vacuum, hence the tackiness. you still may be able to get some
polyester resin from a few suppliers such as Pell or SPS. i used some up
north a couple of years ago that was from Pell. it wasnt the red polyester
that i used to cut my teeth on but a brown polyester resin. you could
always get some marine grade polyester resin at a boat store if our vendors
have quit stocking 4110.
************
Try Methylmethacralate, it's a two part (one powder, one liquid) resin that
can be pigmented. While it's setting it can be formed with your hand, and
once it begins to get hard you can continue to form it by wetting it with
acetone. It's easy to sand once hard, and smoothes up well. Most suppliers
should have it, I get mine from PEL here in the Midwest. Just make sure to
rough up the socket before hand so that you get good adhesion.

**************
Thanks to all who responded. A friend, not on the LISTSERV, also suggested we
try Cascades' AME. We tried it and I think it is going to work
satisfactorily. The fillers; powder, microballoons, etc., work well too if
you aren't looking for that glass like finished surface we were needing in
this application. Our biggest problem was likely the age of the polyester
resin we were using.

Eddie White, CP

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