RE: Lead Coatings

["Caines, Gary (GA44)" <Gary.Caines@IAC.honeywell.com>]

Scott,

I will post this to Radsafe because it may be useful to others.  I had this 
same question come up about 15 years ago and found a very good solution. 
 There are products on the market that are designed to coat tool handles 
with a plastic coating.  These products are in liquid form supplied in paint 
cans and you simply dip the object into the can.  I cannot remember the 
brand name of the product I used, but there are several brands available.  I 
purchased mine at an Ace hardware store and the can size was one quart or 
gallon.  If I remember correctly, it was even available in different colors. 
 The color I used was a red-orange.

To coat the lead bricks, I drilled a small hole (2.0 mm) in one end of the 
brick, and inserted a small cup hook.  I held the brick by the cup hook and 
then immersed it into the coating material.  Afterwards I suspended the 
brick by the cup hook on a piece of wire to allow the material to cure. 
 Once the material cured, I removed the cup hook and patched the small hole 
with more of the plastic coating.  The coating was approximatley 2-3 mm 
thick.  To get a thicker coating, simply repeat the process.  There are two 
caveats with using this process.  Number one is the fact that when the lead 
bricks are stacked to make a radiation shield one layer thick, the thick 
coating on two adjacent bricks separates the lead in the two bricks, 
allowing leakage of radiation.  When I used them in this fashion I always 
used a minimum of a double row of coated bricks and staggered them so that 
the seams did not line up.  The other caveat is that with the lead bricks 
being so heavy and the edges somewhat sharp, it was easy to cut slices in 
the coating if handling of the bricks was rough.  This material proved to be 
extremely durable.  With the brand I used it was also possible to cut and 
peel off the material later, if desired.

 I also coated some graphic bricks that were being used as neutron 
reflectors, using the same technique, with satisfactory results.

Regards,
Gary Caines,
Radiological Operations Manager
Honeywell Inc.  IAC
gary.caines@iac.honeywell.com
Tel:  404-248-2350
Fax: 404-248-2593
 ----------
From: schwahn@CEBAF.GOV
To: radsafe@romulus.ehs.uiuc.edu
Subject: Lead Coatings
Date: Thursday, October 30, 1997 8:15AM

I did a search on the entire RADSAFE database for the answer to this 
question,
so even though the subject sounds familiar to me, I will ask.  Please 
forgive
me if this is a repeat topic.

Do any of you have _recommendations_ for vendors/products to coat lead 
bricks?
 I recall that there was this off-white paint-on stuff that "gooped up" and
peeled off too easily (Latex, I believe).  Then there was this thin orange
paint that scraped off with not much effort.  By recommendations, I am
requesting not so much products that you use, but products you use and are
_happy_ with.

I am sure this is not of general interest, so please reply to my personal
e-mail address.  I will gather the answers to distribute to anyone who wants
them.

Thanks.

Scott O. Schwahn, CHP
Thomas Jefferson National Accelerator Facility
Newport News, VA
schwahn@jlab.org